Theory and pragmatics of the `tz` code and data

Time

-# @(#)Makefile	8.9
+# Make and install tzdb code and data.
+
 # This file is in the public domain, so clarified as of
 # 2009-05-17 by Arthur David Olson.
 
-# Change the line below for your time zone (after finding the zone you want in
-# the time zone files, or adding it to a time zone file).
-# Alternately, if you discover you've got the wrong time zone, you can just
-#	zic -l rightzone
-# to correct things.
+# Package name for the code distribution.
+PACKAGE=	tzcode
+
+# Version number for the distribution, overridden in the 'tarballs' rule below.
+VERSION=	unknown
+
+# Email address for bug reports.
+BUGEMAIL=	tz@iana.org
+
+# DATAFORM selects the data format.
+# Available formats represent essentially the same data, albeit
+# possibly with minor discrepancies that users are not likely to notice.
+# To get new features and the best data right away, use:
+#	DATAFORM=	vanguard
+# To wait a while before using new features, to give downstream users
+# time to upgrade zic (the default), use:
+#	DATAFORM=	main
+# To wait even longer for new features, use:
+#	DATAFORM=	rearguard
+# Rearguard users might also want "ZFLAGS = -b fat"; see below.
+DATAFORM=		main
+
+# Change the line below for your timezone (after finding the one you want in
+# one of the $(TDATA) source files, or adding it to a source file).
+# Alternatively, if you discover you've got the wrong timezone, you can just
+# 'zic -l -' to remove it, or 'zic -l rightzone' to change it.
 # Use the command
 #	make zonenames
 # to get a list of the values you can use for LOCALTIME.
 
-LOCALTIME=	GMT
-
-# If you want something other than Eastern United States time as a template
-# for handling POSIX-style time zone environment variables,
-# change the line below (after finding the zone you want in the
-# time zone files, or adding it to a time zone file).
-# (When a POSIX-style environment variable is handled, the rules in the
-# template file are used to determine "spring forward" and "fall back" days and
-# times; the environment variable itself specifies UTC offsets of standard and
-# summer time.)
-# Alternately, if you discover you've got the wrong time zone, you can just
-#	zic -p rightzone
-# to correct things.
+LOCALTIME=	Factory
+
+# The POSIXRULES macro controls interpretation of nonstandard and obsolete
+# POSIX-like TZ settings like TZ='EET-2EEST' that lack DST transition rules.
+# Such a setting uses the rules in a template file to determine
+# "spring forward" and "fall back" days and times; the environment
+# variable itself specifies UT offsets of standard and daylight saving time.
+#
+# If POSIXRULES is '-', no template is installed; this is the default.
+#
+# Any other value for POSIXRULES is obsolete and should not be relied on, as:
+# * It does not work correctly in popular implementations such as GNU/Linux.
+# * It does not work even in tzcode, except for historical timestamps
+#   that precede the last explicit transition in the POSIXRULES file.
+#   Hence it typically does not work for current and future timestamps.
+# In short, software should avoid ruleless settings like TZ='EET-2EEST'
+# and so should not depend on the value of POSIXRULES.
+#
+# If, despite the above, you want a template for handling these settings,
+# you can change the line below (after finding the timezone you want in the
+# one of the $(TDATA) source files, or adding it to a source file).
+# Alternatively, if you discover you've got the wrong timezone, you can just
+# 'zic -p -' to remove it, or 'zic -p rightzone' to change it.
 # Use the command
 #	make zonenames
 # to get a list of the values you can use for POSIXRULES.
-# If you want POSIX compatibility, use "America/New_York".
 
-POSIXRULES=	America/New_York
+POSIXRULES=	-
 
 # Also see TZDEFRULESTRING below, which takes effect only
 # if the time zone files cannot be accessed.
 
-# Everything gets put in subdirectories of. . .
 
-TOPDIR=		/usr/local
+# Installation locations.
+#
+# The defaults are suitable for Debian, except that if REDO is
+# posix_right or right_posix then files that Debian puts under
+# /usr/share/zoneinfo/posix and /usr/share/zoneinfo/right are instead
+# put under /usr/share/zoneinfo-posix and /usr/share/zoneinfo-leaps,
+# respectively.  Problems with the Debian approach are discussed in
+# the commentary for the right_posix rule (below).
 
-# "Compiled" time zone information is placed in the "TZDIR" directory
-# (and subdirectories).
-# Use an absolute path name for TZDIR unless you're just testing the software.
+# Destination directory, which can be used for staging.
+# 'make DESTDIR=/stage install' installs under /stage (e.g., to
+# /stage/etc/localtime instead of to /etc/localtime).  Files under
+# /stage are not intended to work as-is, but can be copied by hand to
+# the root directory later.  If DESTDIR is empty, 'make install' does
+# not stage, but installs directly into production locations.
+DESTDIR =
 
-TZDIR=		$(TOPDIR)/etc/zoneinfo
+# Everything is installed into subdirectories of TOPDIR, and used there.
+# TOPDIR should be empty (meaning the root directory),
+# or a directory name that does not end in "/".
+# TOPDIR should be empty or an absolute name unless you're just testing.
+TOPDIR =
 
-# The "tzselect", "zic", and "zdump" commands get installed in. . .
+# The default local timezone is taken from the file TZDEFAULT.
+TZDEFAULT = $(TOPDIR)/etc/localtime
 
-ETCDIR=		$(TOPDIR)/etc
+# The subdirectory containing installed program and data files, and
+# likewise for installed files that can be shared among architectures.
+# These should be relative file names.
+USRDIR = usr
+USRSHAREDIR = $(USRDIR)/share
 
-# If you "make INSTALL", the "date" command gets installed in. . .
+# "Compiled" timezone information is placed in the "TZDIR" directory
+# (and subdirectories).
+# TZDIR_BASENAME should not contain "/" and should not be ".", ".." or empty.
+TZDIR_BASENAME=	zoneinfo
+TZDIR = $(TOPDIR)/$(USRSHAREDIR)/$(TZDIR_BASENAME)
 
-BINDIR=		$(TOPDIR)/bin
+# The "tzselect" and (if you do "make INSTALL") "date" commands go in:
+BINDIR = $(TOPDIR)/$(USRDIR)/bin
 
-# Manual pages go in subdirectories of. . .
+# The "zdump" command goes in:
+ZDUMPDIR = $(BINDIR)
 
-MANDIR=		$(TOPDIR)/man
+# The "zic" command goes in:
+ZICDIR = $(TOPDIR)/$(USRDIR)/sbin
+
+# Manual pages go in subdirectories of. . .
+MANDIR = $(TOPDIR)/$(USRSHAREDIR)/man
 
 # Library functions are put in an archive in LIBDIR.
+LIBDIR = $(TOPDIR)/$(USRDIR)/lib
 
-LIBDIR=		$(TOPDIR)/lib
-TZLIB=		$(LIBDIR)/libtz.a
 
-# If you always want time values interpreted as "seconds since the epoch
-# (not counting leap seconds)", use
+# Types to try, as an alternative to time_t.
+TIME_T_ALTERNATIVES = $(TIME_T_ALTERNATIVES_HEAD) $(TIME_T_ALTERNATIVES_TAIL)
+TIME_T_ALTERNATIVES_HEAD = int_least64_t
+TIME_T_ALTERNATIVES_TAIL = int_least32_t uint_least32_t uint_least64_t
+
+# What kind of TZif data files to generate.  (TZif is the binary time
+# zone data format that zic generates; see Internet RFC 8536.)
+# If you want only POSIX time, with time values interpreted as
+# seconds since the epoch (not counting leap seconds), use
 #	REDO=		posix_only
-# below.  If you always want right time values interpreted as "seconds since
-# the epoch" (counting leap seconds)", use
+# below.  If you want only "right" time, with values interpreted
+# as seconds since the epoch (counting leap seconds), use
 #	REDO=		right_only
 # below.  If you want both sets of data available, with leap seconds not
 # counted normally, use
 #	REDO=		posix_right
 # below.  If you want both sets of data available, with leap seconds counted
 # normally, use
 #	REDO=		right_posix
-# below.
-# POSIX mandates that leap seconds not be counted; for compatibility with it,
-# use either "posix_only" or "posix_right".
+# below.  POSIX mandates that leap seconds not be counted; for compatibility
+# with it, use "posix_only" or "posix_right".  Use POSIX time on systems with
+# leap smearing; this can work better than unsmeared "right" time with
+# applications that are not leap second aware, and is closer to unsmeared
+# "right" time than unsmeared POSIX time is (e.g., 0.5 vs 1.0 s max error).
 
 REDO=		posix_right
 
-# Since "." may not be in PATH...
+# Whether to put an "Expires" line in the leapseconds file.
+# Use EXPIRES_LINE=1 to put the line in, 0 to omit it.
+# The EXPIRES_LINE value matters only if REDO's value contains "right".
+# If you change EXPIRES_LINE, remove the leapseconds file before running "make".
+# zic's support for the Expires line was introduced in tzdb 2020a,
+# and was modified in tzdb 2021b to generate version 4 TZif files.
+# EXPIRES_LINE defaults to 0 for now so that the leapseconds file
+# can be given to pre-2020a zic implementations and so that TZif files
+# built by newer zic implementations can be read by pre-2021b libraries.
+EXPIRES_LINE=	0
+
+# To install data in text form that has all the information of the TZif data,
+# (optionally incorporating leap second information), use
+#	TZDATA_TEXT=	tzdata.zi leapseconds
+# To install text data without leap second information (e.g., because
+# REDO='posix_only'), use
+#	TZDATA_TEXT=	tzdata.zi
+# To avoid installing text data, use
+#	TZDATA_TEXT=
+
+TZDATA_TEXT=	leapseconds tzdata.zi
+
+# For backward-compatibility links for old zone names, use
+#	BACKWARD=	backward
+# To omit these links, use
+#	BACKWARD=
+
+BACKWARD=	backward
 
-YEARISTYPE=	./yearistype
+# If you want out-of-scope and often-wrong data from the file 'backzone',
+# but only for entries listed in the backward-compatibility file zone.tab, use
+#	PACKRATDATA=	backzone
+#	PACKRATLIST=	zone.tab
+# If you want all the 'backzone' data, use
+#	PACKRATDATA=	backzone
+#	PACKRATLIST=
+# To omit this data, use
+#	PACKRATDATA=
+#	PACKRATLIST=
+
+PACKRATDATA=
+PACKRATLIST=
+
+# The name of a locale using the UTF-8 encoding, used during self-tests.
+# The tests are skipped if the name does not appear to work on this system.
+
+UTF8_LOCALE=	en_US.utf8
 
 # Non-default libraries needed to link.
-# Add -lintl if you want to use `gettext' on Solaris.
 LDLIBS=
 
-# Add the following to the end of the "CFLAGS=" line as needed.
-#  -DHAVE_ADJTIME=0 if `adjtime' does not exist (SVR0?)
-#  -DHAVE_GETTEXT=1 if `gettext' works (GNU, Linux, Solaris); also see LDLIBS
-#  -DHAVE_INCOMPATIBLE_CTIME_R=1 if your system's time.h declares
-#	ctime_r and asctime_r incompatibly with the POSIX standard (Solaris 8).
-#  -DHAVE_SETTIMEOFDAY=0 if settimeofday does not exist (SVR0?)
-#  -DHAVE_SETTIMEOFDAY=1 if settimeofday has just 1 arg (SVR4)
-#  -DHAVE_SETTIMEOFDAY=2 if settimeofday uses 2nd arg (4.3BSD)
-#  -DHAVE_SETTIMEOFDAY=3 if settimeofday ignores 2nd arg (4.4BSD)
-#  -DHAVE_STDINT_H=1 if you have a pre-C99 compiler with "stdint.h"
+# Add the following to the end of the "CFLAGS=" line as needed to override
+# defaults specified in the source code.  "-DFOO" is equivalent to "-DFOO=1".
+#  -DDEPRECATE_TWO_DIGIT_YEARS for optional runtime warnings about strftime
+#	formats that generate only the last two digits of year numbers
+#  -DEPOCH_LOCAL if the 'time' function returns local time not UT
+#  -DEPOCH_OFFSET=N if the 'time' function returns a value N greater
+#	than what POSIX specifies, assuming local time is UT.
+#	For example, N is 252460800 on AmigaOS.
+#  -DHAVE_DECL_ASCTIME_R=0 if  does not declare asctime_r
+#  -DHAVE_DECL_ENVIRON if  declares 'environ'
+#  -DHAVE_DIRECT_H if mkdir needs  (MS-Windows)
+#  -DHAVE_GENERIC=0 if _Generic does not work
+#  -DHAVE_GETTEXT if 'gettext' works (e.g., GNU/Linux, FreeBSD, Solaris)
+#  -DHAVE_INCOMPATIBLE_CTIME_R if your system's time.h declares
+#	ctime_r and asctime_r incompatibly with the POSIX standard
+#	(Solaris when _POSIX_PTHREAD_SEMANTICS is not defined).
+#  -DHAVE_INTTYPES_H if you have a non-C99 compiler with 
+#  -DHAVE_LINK=0 if your system lacks a link function
+#  -DHAVE_LOCALTIME_R=0 if your system lacks a localtime_r function
+#  -DHAVE_LOCALTIME_RZ=0 if you do not want zdump to use localtime_rz
+#	localtime_rz can make zdump significantly faster, but is nonstandard.
+#  -DHAVE_MALLOC_ERRNO=0 if malloc etc. do not set errno on failure.
+#  -DHAVE_POSIX_DECLS=0 if your system's include files do not declare
+#	functions like 'link' or variables like 'tzname' required by POSIX
+#  -DHAVE_SNPRINTF=0 if your system lacks the snprintf function
+#  -DHAVE_STDBOOL_H if you have a non-C99 compiler with 
+#  -DHAVE_STDINT_H if you have a non-C99 compiler with 
+#  -DHAVE_STRFTIME_L if  declares locale_t and strftime_l
+#  -DHAVE_STRDUP=0 if your system lacks the strdup function
+#  -DHAVE_STRTOLL=0 if your system lacks the strtoll function
 #  -DHAVE_SYMLINK=0 if your system lacks the symlink function
-#  -DHAVE_SYS_STAT_H=0 if your compiler lacks a "sys/stat.h"
-#  -DHAVE_SYS_WAIT_H=0 if your compiler lacks a "sys/wait.h"
-#  -DLOCALE_HOME=\"path\" if locales are in "path", not "/usr/lib/locale"
-#  -DHAVE_UNISTD_H=0 if your compiler lacks a "unistd.h" (Microsoft C++ 7?)
-#  -DHAVE_UTMPX_H=1 if your compiler has a "utmpx.h"
-#  -DTZDEFRULESTRING=\",date/time,date/time\" to default to the specified
-#	DST transitions if the time zone files cannot be accessed
+#  -DHAVE_SYS_STAT_H=0 if your compiler lacks a 
+#  -DHAVE_TZSET=0 if your system lacks a tzset function
+#  -DHAVE_UNISTD_H=0 if your compiler lacks a 
+#  -Dlocale_t=XXX if your system uses XXX instead of locale_t
+#  -DRESERVE_STD_EXT_IDS if your platform reserves standard identifiers
+#	with external linkage, e.g., applications cannot define 'localtime'.
+#  -Dssize_t=long on hosts like MS-Windows that lack ssize_t
+#  -DSUPPRESS_TZDIR to not prepend TZDIR to file names; this has
+#	security implications and is not recommended for general use
+#  -DTHREAD_SAFE to make localtime.c thread-safe, as POSIX requires;
+#	not needed by the main-program tz code, which is single-threaded.
+#	Append other compiler flags as needed, e.g., -pthread on GNU/Linux.
+#  -Dtime_tz=\"T\" to use T as the time_t type, rather than the system time_t
+#	This is intended for internal use only; it mangles external names.
 #  -DTZ_DOMAIN=\"foo\" to use "foo" for gettext domain name; default is "tz"
-#  -TTZ_DOMAINDIR=\"/path\" to use "/path" for gettext directory;
+#  -DTZ_DOMAINDIR=\"/path\" to use "/path" for gettext directory;
 #	the default is system-supplied, typically "/usr/lib/locale"
-#  $(GCC_DEBUG_FLAGS) if you are using GCC and want lots of checking
-#  -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU=1
-#	if you do not want run time warnings about formats that may cause
-#	year 2000 grief
+#  -DTZDEFRULESTRING=\",date/time,date/time\" to default to the specified
+#	DST transitions if the time zone files cannot be accessed
+#  -DUNINIT_TRAP if reading uninitialized storage can cause problems
+#	other than simply getting garbage data
+#  -DUSE_LTZ=0 to build zdump with the system time zone library
+#	Also set TZDOBJS=zdump.o and CHECK_TIME_T_ALTERNATIVES= below.
+#  -DZIC_BLOAT_DEFAULT=\"fat\" to default zic's -b option to "fat", and
+#	similarly for "slim".  Fat TZif files work around incompatibilities
+#	and bugs in some TZif readers, notably readers that mishandle 64-bit
+#	data in TZif files.  Slim TZif files are more efficient and do not
+#	work around these incompatibilities and bugs.  If not given, the
+#	default is "slim".
 #  -DZIC_MAX_ABBR_LEN_WO_WARN=3
 #	(or some other number) to set the maximum time zone abbreviation length
 #	that zic will accept without a warning (the default is 6)
-GCC_DEBUG_FLAGS = -Dlint -g -O -fno-common \
-	-Wall -Wcast-qual -Wconversion -Wmissing-prototypes \
-	-Wnested-externs -Wpointer-arith -Wshadow \
-	-Wtraditional # -Wstrict-prototypes -Wwrite-strings
-#
-# If you want to use System V compatibility code, add
-#	-DUSG_COMPAT
-# to the end of the "CFLAGS=" line.  This arrange for "timezone" and "daylight"
-# variables to be kept up-to-date by the time conversion functions.  Neither
-# "timezone" nor "daylight" is described in X3J11's work.
+#  $(GCC_DEBUG_FLAGS) if you are using recent GCC and want lots of checking
+# Select instrumentation via "make GCC_INSTRUMENT='whatever'".
+GCC_INSTRUMENT = \
+  -fsanitize=undefined -fsanitize-address-use-after-scope \
+  -fsanitize-undefined-trap-on-error -fstack-protector
+# Omit -fanalyzer from GCC_DEBUG_FLAGS, as it makes GCC too slow.
+GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \
+  $(GCC_INSTRUMENT) \
+  -Wall -Wextra \
+  -Walloc-size-larger-than=100000 -Warray-bounds=2 \
+  -Wbad-function-cast -Wbidi-chars=any,ucn -Wcast-align=strict -Wdate-time \
+  -Wdeclaration-after-statement -Wdouble-promotion \
+  -Wduplicated-branches -Wduplicated-cond \
+  -Wformat=2 -Wformat-overflow=2 -Wformat-signedness -Wformat-truncation \
+  -Winit-self -Wlogical-op \
+  -Wmissing-declarations -Wmissing-prototypes -Wnested-externs \
+  -Wnull-dereference \
+  -Wold-style-definition -Woverlength-strings -Wpointer-arith \
+  -Wshadow -Wshift-overflow=2 -Wstrict-overflow \
+  -Wstrict-prototypes -Wstringop-overflow=4 \
+  -Wstringop-truncation -Wsuggest-attribute=cold \
+  -Wsuggest-attribute=const -Wsuggest-attribute=format \
+  -Wsuggest-attribute=malloc \
+  -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure \
+  -Wtrampolines -Wundef -Wuninitialized -Wunused-macros -Wuse-after-free=3 \
+  -Wvariadic-macros -Wvla -Wwrite-strings \
+  -Wno-address -Wno-format-nonliteral -Wno-sign-compare \
+  -Wno-type-limits -Wno-unused-parameter
 #
 # If your system has a "GMT offset" field in its "struct tm"s
 # (or if you decide to add such a field in your system's "time.h" file),
 # add the name to a define such as
 #	-DTM_GMTOFF=tm_gmtoff
-# or
-#	-DTM_GMTOFF=_tm_gmtoff
-# to the end of the "CFLAGS=" line.
-# Neither tm_gmtoff nor _tm_gmtoff is described in X3J11's work;
-# in its work, use of "tm_gmtoff" is described as non-conforming.
-# Both Linux and BSD have done the equivalent of defining TM_GMTOFF in
-# their recent releases.
-#
-# If your system has a "zone abbreviation" field in its "struct tm"s
-# (or if you decide to add such a field in your system's "time.h" file),
-# add the name to a define such as
+# to the end of the "CFLAGS=" line.  If not defined, the code attempts to
+# guess TM_GMTOFF from other macros; define NO_TM_GMTOFF to suppress this.
+# Similarly, if your system has a "zone abbreviation" field, define
 #	-DTM_ZONE=tm_zone
-# or
-#	-DTM_ZONE=_tm_zone
-# to the end of the "CFLAGS=" line.
-# Neither tm_zone nor _tm_zone is described in X3J11's work;
-# in its work, use of "tm_zone" is described as non-conforming.
-# Both UCB and Sun have done the equivalent of defining TM_ZONE in
-# their recent releases.
+# and define NO_TM_ZONE to suppress any guessing.  Although these two fields
+# not required by POSIX, a future version of POSIX is planned to require them
+# and they are widely available on GNU/Linux and BSD systems.
+#
+# The next batch of options control support for external variables
+# exported by tzcode.  In practice these variables are less useful
+# than TM_GMTOFF and TM_ZONE.  However, most of them are standardized.
+# #
+# # To omit or support the external variable "tzname", add one of:
+# #	-DHAVE_TZNAME=0 # do not support "tzname"
+# #	-DHAVE_TZNAME=1 # support "tzname", which is defined by system library
+# #	-DHAVE_TZNAME=2 # support and define "tzname"
+# # to the "CFLAGS=" line.  "tzname" is required by POSIX 1988 and later.
+# # If not defined, the code attempts to guess HAVE_TZNAME from other macros.
+# # Warning: unless time_tz is also defined, HAVE_TZNAME=1 can cause
+# # crashes when combined with some platforms' standard libraries,
+# # presumably due to memory allocation issues.
+# #
+# # To omit or support the external variables "timezone" and "daylight", add
+# #	-DUSG_COMPAT=0 # do not support
+# #	-DUSG_COMPAT=1 # support, and variables are defined by system library
+# #	-DUSG_COMPAT=2 # support and define variables
+# # to the "CFLAGS=" line; "timezone" and "daylight" are inspired by
+# # Unix Systems Group code and are required by POSIX 2008 (with XSI) and later.
+# # If not defined, the code attempts to guess USG_COMPAT from other macros.
+# #
+# # To support the external variable "altzone", add
+# #	-DALTZONE=0 # do not support
+# #	-DALTZONE=1 # support "altzone", which is defined by system library
+# #	-DALTZONE=2 # support and define "altzone"
+# # to the end of the "CFLAGS=" line; although "altzone" appeared in
+# # System V Release 3.1 it has not been standardized.
+# # If not defined, the code attempts to guess ALTZONE from other macros.
 #
 # If you want functions that were inspired by early versions of X3J11's work,
 # add
 #	-DSTD_INSPIRED
 # to the end of the "CFLAGS=" line.  This arranges for the functions
-# "tzsetwall", "offtime", "timelocal", "timegm", "timeoff",
+# "offtime", "timelocal", "timegm", "timeoff",
 # "posix2time", and "time2posix" to be added to the time conversion library.
-# "tzsetwall" is like "tzset" except that it arranges for local wall clock
-# time (rather than the time specified in the TZ environment variable)
-# to be used.
 # "offtime" is like "gmtime" except that it accepts a second (long) argument
 # that gives an offset to add to the time_t when converting it.
 # "timelocal" is equivalent to "mktime".
 # "timegm" is like "timelocal" except that it turns a struct tm into
-# a time_t using UTC (rather than local time as "timelocal" does).
+# a time_t using UT (rather than local time as "timelocal" does).
 # "timeoff" is like "timegm" except that it accepts a second (long) argument
 # that gives an offset to use when converting to a time_t.
 # "posix2time" and "time2posix" are described in an included manual page.
 # X3J11's work does not describe any of these functions.
-# Sun has provided "tzsetwall", "timelocal", and "timegm" in SunOS 4.0.
 # These functions may well disappear in future releases of the time
 # conversion package.
 #
-# If you want Source Code Control System ID's left out of object modules, add
-#	-DNOID
-# to the end of the "CFLAGS=" line.
-#
-# If you'll never want to handle solar-time-based time zones, add
-#	-DNOSOLAR
-# to the end of the "CFLAGS=" line
-# (and comment out the "SDATA=" line below).
-# This reduces (slightly) the run-time data-space requirements of
-# the time conversion functions; it may reduce the acceptability of your system
-# to folks in oil- and cash-rich places.
+# If you don't want functions that were inspired by NetBSD, add
+#	-DNETBSD_INSPIRED=0
+# to the end of the "CFLAGS=" line.  Otherwise, the functions
+# "localtime_rz", "mktime_z", "tzalloc", and "tzfree" are added to the
+# time library, and if STD_INSPIRED is also defined the functions
+# "posix2time_z" and "time2posix_z" are added as well.
+# The functions ending in "_z" (or "_rz") are like their unsuffixed
+# (or suffixed-by-"_r") counterparts, except with an extra first
+# argument of opaque type timezone_t that specifies the timezone.
+# "tzalloc" allocates a timezone_t value, and "tzfree" frees it.
 #
 # If you want to allocate state structures in localtime, add
 #	-DALL_STATE
 # to the end of the "CFLAGS=" line.  Storage is obtained by calling malloc.
 #
-# If you want an "altzone" variable (a la System V Release 3.1), add
-#	-DALTZONE
-# to the end of the "CFLAGS=" line.
-# This variable is not described in X3J11's work.
-#
-# If you want a "gtime" function (a la MACH), add
-#	-DCMUCS
-# to the end of the "CFLAGS=" line
-# This function is not described in X3J11's work.
-#
 # NIST-PCTS:151-2, Version 1.4, (1993-12-03) is a test suite put
 # out by the National Institute of Standards and Technology
 # which claims to test C and Posix conformance.  If you want to pass PCTS, add
 #	-DPCTS
 # to the end of the "CFLAGS=" line.
 #
 # If you want strict compliance with XPG4 as of 1994-04-09, add
 #	-DXPG4_1994_04_09
 # to the end of the "CFLAGS=" line.  This causes "strftime" to always return
-# 53 as a week number (rather than 52 or 53) for those days in January that
-# before the first Monday in January when a "%V" format is used and January 1
+# 53 as a week number (rather than 52 or 53) for January days before
+# January's first Monday when a "%V" format is used and January 1
 # falls on a Friday, Saturday, or Sunday.
 
 CFLAGS=
 
-# If you want zic's -s option used when installing, uncomment the next line
-# ZFLAGS=	-s
+# Linker flags.  Default to $(LFLAGS) for backwards compatibility
+# to release 2012h and earlier.
+
+LDFLAGS=	$(LFLAGS)
+
+# For leap seconds, this Makefile uses LEAPSECONDS='-L leapseconds' in
+# submake command lines.  The default is no leap seconds.
+
+LEAPSECONDS=
+
+# The zic command and its arguments.
 
 zic=		./zic
 ZIC=		$(zic) $(ZFLAGS)
 
-# The name of a Posix-compliant `awk' on your system.
-AWK=		nawk
+# To shrink the size of installed TZif files,
+# append "-r @N" to omit data before N-seconds-after-the-Epoch.
+# To grow the files and work around older application bugs, append "-b fat";
+# see ZIC_BLOAT_DEFAULT above.
+# See the zic man page for more about -b and -r.
+ZFLAGS=
+
+# How to use zic to install TZif files.
+
+ZIC_INSTALL=	$(ZIC) -d '$(DESTDIR)$(TZDIR)' $(LEAPSECONDS)
+
+# The name of a Posix-compliant 'awk' on your system.
+# mawk 1.3.3 and Solaris 10 /usr/bin/awk do not work.
+# Also, it is better (though not essential) if 'awk' supports UTF-8,
+# and unfortunately mawk and busybox awk do not support UTF-8.
+# Try AWK=gawk or AWK=nawk if your awk has the abovementioned problems.
+AWK=		awk
+
+# The full path name of a Posix-compliant shell, preferably one that supports
+# the Korn shell's 'select' statement as an extension.
+# These days, Bash is the most popular.
+# It should be OK to set this to /bin/sh, on platforms where /bin/sh
+# lacks 'select' or doesn't completely conform to Posix, but /bin/bash
+# is typically nicer if it works.
+KSHELL=		/bin/bash
+
+# Name of curl , used for HTML validation.
+CURL=		curl
+
+# Name of GNU Privacy Guard , used to sign distributions.
+GPG=		gpg
+
+# This expensive test requires USE_LTZ.
+# To suppress it, define this macro to be empty.
+CHECK_TIME_T_ALTERNATIVES = check_time_t_alternatives
+
+# SAFE_CHAR is a regular expression that matches a safe character.
+# Some parts of this distribution are limited to safe characters;
+# others can use any UTF-8 character.
+# For now, the safe characters are a safe subset of ASCII.
+# The caller must set the shell variable 'sharp' to the character '#',
+# since Makefile macros cannot contain '#'.
+# TAB_CHAR is a single tab character, in single quotes.
+TAB_CHAR=	'	'
+SAFE_CHARSET1=	$(TAB_CHAR)' !\"'$$sharp'$$%&'\''()*+,./0123456789:;<=>?@'
+SAFE_CHARSET2=	'ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\^_`'
+SAFE_CHARSET3=	'abcdefghijklmnopqrstuvwxyz{|}~'
+SAFE_CHARSET=	$(SAFE_CHARSET1)$(SAFE_CHARSET2)$(SAFE_CHARSET3)
+SAFE_CHAR=	'[]'$(SAFE_CHARSET)'-]'
+
+# These characters are Latin-1, and so are likely to be displayable
+# even in editors with limited character sets.
+UNUSUAL_OK_LATIN_1 = «°±»½¾×
+# This IPA symbol is represented in Unicode as the composition of
+# U+0075 and U+032F, and U+032F is not considered alphabetic by some
+# grep implementations that do not grok composition.
+UNUSUAL_OK_IPA = u̯
+# Non-ASCII non-letters that OK_CHAR allows, as these characters are
+# useful in commentary.
+UNUSUAL_OK_CHARSET= $(UNUSUAL_OK_LATIN_1)$(UNUSUAL_OK_IPA)
 
-# The path where SGML DTDs are kept.
-SGML_SEARCH_PATH= $(TOPDIR)/share/doc/sgml-lib/REC-html401-19991224/
+# Put this in a bracket expression to match spaces.
+s = [:space:]
 
-# The catalog file(s) to use when validating.
-SGML_CATALOG_FILES= HTML4.cat
+# OK_CHAR matches any character allowed in the distributed files.
+# This is the same as SAFE_CHAR, except that UNUSUAL_OK_CHARSET and
+# multibyte letters are also allowed so that commentary can contain a
+# few safe symbols and people's names and can quote non-English sources.
+# Other non-letters are limited to ASCII renderings for the
+# convenience of maintainers using XEmacs 21.5.34, which by default
+# mishandles Unicode characters U+0100 and greater.
+OK_CHAR=	'[][:alpha:]$(UNUSUAL_OK_CHARSET)'$(SAFE_CHARSET)'-]'
 
-# The name, arguments and environment of a program to validate your web pages.
-# See  for a validator, and
-#  for a validation library.
-VALIDATE = nsgmls
-VALIDATE_FLAGS = -s -B -wall -wno-unused-param
-VALIDATE_ENV = \
-  SGML_CATALOG_FILES=$(SGML_CATALOG_FILES) \
-  SGML_SEARCH_PATH=$(SGML_SEARCH_PATH) \
-  SP_CHARSET_FIXED=YES \
-  SP_ENCODING=UTF-8
+# SAFE_LINE matches a line of safe characters.
+# SAFE_SHARP_LINE is similar, except any OK character can follow '#';
+# this is so that comments can contain non-ASCII characters.
+# OK_LINE matches a line of OK characters.
+SAFE_LINE=	'^'$(SAFE_CHAR)'*$$'
+SAFE_SHARP_LINE='^'$(SAFE_CHAR)'*('$$sharp$(OK_CHAR)'*)?$$'
+OK_LINE=	'^'$(OK_CHAR)'*$$'
+
+# Flags to give 'tar' when making a distribution.
+# Try to use flags appropriate for GNU tar.
+GNUTARFLAGS= --format=pax --pax-option='delete=atime,delete=ctime' \
+  --numeric-owner --owner=0 --group=0 \
+  --mode=go+u,go-w --sort=name
+TARFLAGS=	`if tar $(GNUTARFLAGS) --version >/dev/null 2>&1; \
+		 then echo $(GNUTARFLAGS); \
+		 else :; \
+		 fi`
+
+# Flags to give 'gzip' when making a distribution.
+GZIPFLAGS=	-9n
 
 ###############################################################################
 
+#MAKE=		make
+
 cc=		cc
-CC=		$(cc) -DTZDIR=\"$(TZDIR)\"
+CC=		$(cc) -DTZDIR='"$(TZDIR)"'
+
+AR=		ar
 
-TZCSRCS=	zic.c localtime.c asctime.c scheck.c ialloc.c
-TZCOBJS=	zic.o localtime.o asctime.o scheck.o ialloc.o
-TZDSRCS=	zdump.c localtime.c ialloc.c
-TZDOBJS=	zdump.o localtime.o ialloc.o
-DATESRCS=	date.c localtime.c strftime.c asctime.c
+# ':' on typical hosts; 'ranlib' on the ancient hosts that still need ranlib.
+RANLIB=		:
+
+TZCOBJS=	zic.o
+TZDOBJS=	zdump.o localtime.o asctime.o strftime.o
 DATEOBJS=	date.o localtime.o strftime.o asctime.o
-LIBSRCS=	localtime.c asctime.c difftime.c
-LIBOBJS=	localtime.o asctime.o difftime.o
+LIBSRCS=	localtime.c asctime.c difftime.c strftime.c
+LIBOBJS=	localtime.o asctime.o difftime.o strftime.o
 HEADERS=	tzfile.h private.h
-NONLIBSRCS=	zic.c zdump.c scheck.c ialloc.c
-NEWUCBSRCS=	date.c strftime.c
-SOURCES=	$(HEADERS) $(LIBSRCS) $(NONLIBSRCS) $(NEWUCBSRCS) tzselect.ksh
+NONLIBSRCS=	zic.c zdump.c
+NEWUCBSRCS=	date.c
+SOURCES=	$(HEADERS) $(LIBSRCS) $(NONLIBSRCS) $(NEWUCBSRCS) \
+			tzselect.ksh workman.sh
 MANS=		newctime.3 newstrftime.3 newtzset.3 time2posix.3 \
 			tzfile.5 tzselect.8 zic.8 zdump.8
-DOCS=		README Theory $(MANS) date.1 Makefile
+MANTXTS=	newctime.3.txt newstrftime.3.txt newtzset.3.txt \
+			time2posix.3.txt \
+			tzfile.5.txt tzselect.8.txt zic.8.txt zdump.8.txt \
+			date.1.txt
+COMMON=		calendars CONTRIBUTING LICENSE Makefile \
+			NEWS README SECURITY theory.html version
+WEB_PAGES=	tz-art.html tz-how-to.html tz-link.html
+CHECK_WEB_PAGES=check_theory.html check_tz-art.html \
+			check_tz-how-to.html check_tz-link.html
+DOCS=		$(MANS) date.1 $(MANTXTS) $(WEB_PAGES)
 PRIMARY_YDATA=	africa antarctica asia australasia \
 		europe northamerica southamerica
-YDATA=		$(PRIMARY_YDATA) pacificnew etcetera backward
-NDATA=		systemv factory
-SDATA=		solar87 solar88 solar89
-TDATA=		$(YDATA) $(NDATA) $(SDATA)
-TABDATA=	iso3166.tab zone.tab
-DATA=		$(YDATA) $(NDATA) $(SDATA) $(TABDATA) leapseconds yearistype.sh
-WEB_PAGES=	tz-art.htm tz-link.htm
-MISC=		usno1988 usno1989 usno1989a usno1995 usno1997 usno1998 \
-			itca.jpg $(WEB_PAGES) checktab.awk workman.sh \
-			zoneinfo2tdf.pl
-ENCHILADA=	$(DOCS) $(SOURCES) $(DATA) $(MISC)
+YDATA=		$(PRIMARY_YDATA) etcetera
+NDATA=		factory
+TDATA_TO_CHECK=	$(YDATA) $(NDATA) backward
+TDATA=		$(YDATA) $(NDATA) $(BACKWARD)
+ZONETABLES=	zone1970.tab zone.tab
+TABDATA=	iso3166.tab $(TZDATA_TEXT) $(ZONETABLES)
+LEAP_DEPS=	leapseconds.awk leap-seconds.list
+TZDATA_ZI_DEPS=	ziguard.awk zishrink.awk version $(TDATA) \
+		  $(PACKRATDATA) $(PACKRATLIST)
+DSTDATA_ZI_DEPS= ziguard.awk $(TDATA) $(PACKRATDATA) $(PACKRATLIST)
+DATA=		$(TDATA_TO_CHECK) backzone iso3166.tab leap-seconds.list \
+			leapseconds $(ZONETABLES)
+AWK_SCRIPTS=	checklinks.awk checktab.awk leapseconds.awk \
+			ziguard.awk zishrink.awk
+MISC=		$(AWK_SCRIPTS)
+TZS_YEAR=	2050
+TZS_CUTOFF_FLAG=	-c $(TZS_YEAR)
+TZS=		to$(TZS_YEAR).tzs
+TZS_NEW=	to$(TZS_YEAR)new.tzs
+TZS_DEPS=	$(YDATA) asctime.c localtime.c \
+			private.h tzfile.h zdump.c zic.c
+TZDATA_DIST = $(COMMON) $(DATA) $(MISC)
+# EIGHT_YARDS is just a yard short of the whole ENCHILADA.
+EIGHT_YARDS = $(TZDATA_DIST) $(DOCS) $(SOURCES) tzdata.zi
+ENCHILADA = $(EIGHT_YARDS) $(TZS)
+
+# Consult these files when deciding whether to rebuild the 'version' file.
+# This list is not the same as the output of 'git ls-files', since
+# .gitignore is not distributed.
+VERSION_DEPS= \
+		calendars CONTRIBUTING LICENSE Makefile NEWS README SECURITY \
+		africa antarctica asctime.c asia australasia \
+		backward backzone \
+		checklinks.awk checktab.awk \
+		date.1 date.c difftime.c \
+		etcetera europe factory iso3166.tab \
+		leap-seconds.list leapseconds.awk localtime.c \
+		newctime.3 newstrftime.3 newtzset.3 northamerica \
+		private.h southamerica strftime.c theory.html \
+		time2posix.3 tz-art.html tz-how-to.html tz-link.html \
+		tzfile.5 tzfile.h tzselect.8 tzselect.ksh \
+		workman.sh zdump.8 zdump.c zic.8 zic.c \
+		ziguard.awk zishrink.awk \
+		zone.tab zone1970.tab
 
 # And for the benefit of csh users on systems that assume the user
 # shell should be used to handle commands in Makefiles. . .
 
 SHELL=		/bin/sh
 
-all:		tzselect zic zdump $(LIBOBJS)
-
-ALL:		all date
-
-install:	all $(DATA) $(REDO) $(TZLIB) $(MANS) $(TABDATA)
-		$(ZIC) -y $(YEARISTYPE) \
-			-d $(TZDIR) -l $(LOCALTIME) -p $(POSIXRULES)
-		-rm -f $(TZDIR)/iso3166.tab $(TZDIR)/zone.tab
-		cp iso3166.tab zone.tab $(TZDIR)/.
-		-mkdir $(TOPDIR) $(ETCDIR)
-		cp tzselect zic zdump $(ETCDIR)/.
-		-mkdir $(TOPDIR) $(MANDIR) \
-			$(MANDIR)/man3 $(MANDIR)/man5 $(MANDIR)/man8
-		-rm -f $(MANDIR)/man3/newctime.3 \
-			$(MANDIR)/man3/newtzset.3 \
-			$(MANDIR)/man5/tzfile.5 \
-			$(MANDIR)/man8/tzselect.8 \
-			$(MANDIR)/man8/zdump.8 \
-			$(MANDIR)/man8/zic.8
-		cp newctime.3 newtzset.3 $(MANDIR)/man3/.
-		cp tzfile.5 $(MANDIR)/man5/.
-		cp tzselect.8 zdump.8 zic.8 $(MANDIR)/man8/.
+all:		tzselect zic zdump libtz.a $(TABDATA) \
+		  vanguard.zi main.zi rearguard.zi
+
+ALL:		all date $(ENCHILADA)
+
+install:	all $(DATA) $(REDO) $(MANS)
+		mkdir -p '$(DESTDIR)$(BINDIR)' \
+			'$(DESTDIR)$(ZDUMPDIR)' '$(DESTDIR)$(ZICDIR)' \
+			'$(DESTDIR)$(LIBDIR)' \
+			'$(DESTDIR)$(MANDIR)/man3' '$(DESTDIR)$(MANDIR)/man5' \
+			'$(DESTDIR)$(MANDIR)/man8'
+		$(ZIC_INSTALL) -l $(LOCALTIME) \
+			`case '$(POSIXRULES)' in ?*) echo '-p';; esac \
+			` $(POSIXRULES) \
+			-t '$(DESTDIR)$(TZDEFAULT)'
+		cp -f $(TABDATA) '$(DESTDIR)$(TZDIR)/.'
+		cp tzselect '$(DESTDIR)$(BINDIR)/.'
+		cp zdump '$(DESTDIR)$(ZDUMPDIR)/.'
+		cp zic '$(DESTDIR)$(ZICDIR)/.'
+		cp libtz.a '$(DESTDIR)$(LIBDIR)/.'
+		$(RANLIB) '$(DESTDIR)$(LIBDIR)/libtz.a'
+		cp -f newctime.3 newtzset.3 '$(DESTDIR)$(MANDIR)/man3/.'
+		cp -f tzfile.5 '$(DESTDIR)$(MANDIR)/man5/.'
+		cp -f tzselect.8 zdump.8 zic.8 '$(DESTDIR)$(MANDIR)/man8/.'
 
 INSTALL:	ALL install date.1
-		-mkdir $(TOPDIR) $(BINDIR)
-		cp date $(BINDIR)/.
-		-mkdir $(TOPDIR) $(MANDIR) $(MANDIR)/man1
-		-rm -f $(MANDIR)/man1/date.1
-		cp date.1 $(MANDIR)/man1/.
+		mkdir -p '$(DESTDIR)$(BINDIR)' '$(DESTDIR)$(MANDIR)/man1'
+		cp date '$(DESTDIR)$(BINDIR)/.'
+		cp -f date.1 '$(DESTDIR)$(MANDIR)/man1/.'
+
+# Calculate version number from git, if available.
+# Otherwise, use $(VERSION) unless it is "unknown" and there is already
+# a 'version' file, in which case reuse the existing 'version' contents
+# and append "-dirty" if the contents do not already end in "-dirty".
+version:	$(VERSION_DEPS)
+		{ (type git) >/dev/null 2>&1 && \
+		  V=`git describe --match '[0-9][0-9][0-9][0-9][a-z]*' \
+				--abbrev=7 --dirty` || \
+		  if test '$(VERSION)' = unknown && V=`cat $@`; then \
+		    case $$V in *-dirty);; *) V=$$V-dirty;; esac; \
+		  else \
+		    V='$(VERSION)'; \
+		  fi; } && \
+		printf '%s\n' "$$V" >$@.out
+		mv $@.out $@
+
+# These files can be tailored by setting BACKWARD, PACKRATDATA, PACKRATLIST.
+vanguard.zi main.zi rearguard.zi: $(DSTDATA_ZI_DEPS)
+		$(AWK) \
+		  -v DATAFORM=`expr $@ : '$.*$.zi'` \
+		  -v PACKRATDATA='$(PACKRATDATA)' \
+		  -v PACKRATLIST='$(PACKRATLIST)' \
+		  -f ziguard.awk \
+		  $(TDATA) $(PACKRATDATA) >$@.out
+		mv $@.out $@
+# This file has a version comment that attempts to capture any tailoring
+# via BACKWARD, DATAFORM, PACKRATDATA, PACKRATLIST, and REDO.
+tzdata.zi:	$(DATAFORM).zi version zishrink.awk
+		version=`sed 1q version` && \
+		  LC_ALL=C $(AWK) \
+		    -v dataform='$(DATAFORM)' \
+		    -v deps='$(DSTDATA_ZI_DEPS) zishrink.awk' \
+		    -v redo='$(REDO)' \
+		    -v version="$$version" \
+		    -f zishrink.awk \
+		    $(DATAFORM).zi >$@.out
+		mv $@.out $@
+
+version.h:	version
+		VERSION=`cat version` && printf '%s\n' \
+		  'static char const PKGVERSION[]="($(PACKAGE)) ";' \
+		  "static char const TZVERSION[]=\"$$VERSION\";" \
+		  'static char const REPORT_BUGS_TO[]="$(BUGEMAIL)";' \
+		  >$@.out
+		mv $@.out $@
 
 zdump:		$(TZDOBJS)
-		$(CC) $(CFLAGS) $(LFLAGS) $(TZDOBJS) $(LDLIBS) -o $@
+		$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(TZDOBJS) $(LDLIBS)
+
+zic:		$(TZCOBJS)
+		$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(TZCOBJS) $(LDLIBS)
+
+leapseconds:	$(LEAP_DEPS)
+		$(AWK) -v EXPIRES_LINE=$(EXPIRES_LINE) \
+		  -f leapseconds.awk leap-seconds.list >$@.out
+		mv $@.out $@
 
-zic:		$(TZCOBJS) yearistype
-		$(CC) $(CFLAGS) $(LFLAGS) $(TZCOBJS) $(LDLIBS) -o $@
+# Arguments to pass to submakes of install_data.
+# They can be overridden by later submake arguments.
+INSTALLARGS = \
+ BACKWARD='$(BACKWARD)' \
+ DESTDIR='$(DESTDIR)' \
+ LEAPSECONDS='$(LEAPSECONDS)' \
+ PACKRATDATA='$(PACKRATDATA)' \
+ PACKRATLIST='$(PACKRATLIST)' \
+ TZDEFAULT='$(TZDEFAULT)' \
+ TZDIR='$(TZDIR)' \
+ ZIC='$(ZIC)'
 
-yearistype:	yearistype.sh
-		cp yearistype.sh yearistype
-		chmod +x yearistype
+INSTALL_DATA_DEPS = zic leapseconds tzdata.zi
 
-posix_only:	zic $(TDATA)
-		$(ZIC) -y $(YEARISTYPE) -d $(TZDIR) -L /dev/null $(TDATA)
+# 'make install_data' installs one set of TZif files.
+install_data: $(INSTALL_DATA_DEPS)
+		$(ZIC_INSTALL) tzdata.zi
 
-right_only:	zic leapseconds $(TDATA)
-		$(ZIC) -y $(YEARISTYPE) -d $(TZDIR) -L leapseconds $(TDATA)
+posix_only: $(INSTALL_DATA_DEPS)
+		$(MAKE) $(INSTALLARGS) LEAPSECONDS= install_data
+
+right_only: $(INSTALL_DATA_DEPS)
+		$(MAKE) $(INSTALLARGS) LEAPSECONDS='-L leapseconds' \
+			install_data
 
 # In earlier versions of this makefile, the other two directories were
 # subdirectories of $(TZDIR).  However, this led to configuration errors.
 # For example, with posix_right under the earlier scheme,
 # TZ='right/Australia/Adelaide' got you localtime with leap seconds,
 # but gmtime without leap seconds, which led to problems with applications
 # like sendmail that subtract gmtime from localtime.
 # Therefore, the other two directories are now siblings of $(TZDIR).
 # You must replace all of $(TZDIR) to switch from not using leap seconds
 # to using them, or vice versa.
-other_two:	zic leapseconds $(TDATA)
-		$(ZIC) -y $(YEARISTYPE) -d $(TZDIR)-posix -L /dev/null $(TDATA)
-		$(ZIC) -y $(YEARISTYPE) \
-			-d $(TZDIR)-leaps -L leapseconds $(TDATA)
-
-posix_right:	posix_only other_two
+right_posix:	right_only
+		rm -fr '$(DESTDIR)$(TZDIR)-leaps'
+		ln -s '$(TZDIR_BASENAME)' '$(DESTDIR)$(TZDIR)-leaps' || \
+		  $(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-leaps' right_only
+		$(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-posix' posix_only
 
-right_posix:	right_only other_two
+posix_right:	posix_only
+		rm -fr '$(DESTDIR)$(TZDIR)-posix'
+		ln -s '$(TZDIR_BASENAME)' '$(DESTDIR)$(TZDIR)-posix' || \
+		  $(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-posix' posix_only
+		$(MAKE) $(INSTALLARGS) TZDIR='$(TZDIR)-leaps' right_only
 
 zones:		$(REDO)
 
-$(TZLIB):	$(LIBOBJS)
-		-mkdir $(TOPDIR) $(LIBDIR)
-		ar ru $@ $(LIBOBJS)
-		if [ -x /usr/ucb/ranlib -o -x /usr/bin/ranlib ] ; \
-			then ranlib $@ ; fi
+# dummy.zd is not a real file; it is mentioned here only so that the
+# top-level 'make' does not have a syntax error.
+ZDS = dummy.zd
+# Rule used only by submakes invoked by the $(TZS_NEW) rule.
+# It is separate so that GNU 'make -j' can run instances in parallel.
+$(ZDS): zdump
+		./zdump -i $(TZS_CUTOFF_FLAG) '$(wd)/'$$(expr $@ : '$.*$.zd') \
+		  >$@
+
+TZS_NEW_DEPS = tzdata.zi zdump zic
+$(TZS_NEW): $(TZS_NEW_DEPS)
+		rm -fr tzs$(TZS_YEAR).dir
+		mkdir tzs$(TZS_YEAR).dir
+		$(zic) -d tzs$(TZS_YEAR).dir tzdata.zi
+		$(AWK) '/^L/{print "Link\t" $$2 "\t" $$3}' \
+		   tzdata.zi | LC_ALL=C sort >$@.out
+		wd=`pwd` && \
+		x=`$(AWK) '/^Z/{print "tzs$(TZS_YEAR).dir/" $$2 ".zd"}' \
+				tzdata.zi \
+			| LC_ALL=C sort -t . -k 2,2` && \
+		set x $$x && \
+		shift && \
+		ZDS=$$* && \
+		$(MAKE) wd="$$wd" TZS_CUTOFF_FLAG="$(TZS_CUTOFF_FLAG)" \
+		  ZDS="$$ZDS" $$ZDS && \
+		sed 's,^TZ=".*\.dir/,TZ=",' $$ZDS >>$@.out
+		rm -fr tzs$(TZS_YEAR).dir
+		mv $@.out $@
+
+# If $(TZS) exists but 'make check_tzs' fails, a maintainer should inspect the
+# failed output and fix the inconsistency, perhaps by running 'make force_tzs'.
+$(TZS):
+		touch $@
+
+force_tzs:	$(TZS_NEW)
+		cp $(TZS_NEW) $(TZS)
+
+libtz.a:	$(LIBOBJS)
+		rm -f $@
+		$(AR) -rc $@ $(LIBOBJS)
+		$(RANLIB) $@
 
 date:		$(DATEOBJS)
-		$(CC) $(CFLAGS) date.o localtime.o asctime.o strftime.o \
-			$(LDLIBS) -lc -o $@
+		$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $(DATEOBJS) $(LDLIBS)
 
-tzselect:	tzselect.ksh
-		sed \
-			-e 's|AWK=[^}]*|AWK=$(AWK)|g' \
+tzselect:	tzselect.ksh version
+		VERSION=`cat version` && sed \
+			-e 's|#!/bin/bash|#!$(KSHELL)|g' \
+			-e 's|AWK=[^}]*|AWK='\''$(AWK)'\''|g' \
+			-e 's|$PKGVERSION$=.*|\1='\''($(PACKAGE)) '\''|' \
+			-e 's|$REPORT_BUGS_TO$=.*|\1=$(BUGEMAIL)|' \
 			-e 's|TZDIR=[^}]*|TZDIR=$(TZDIR)|' \
-			<$? >$@
-		chmod +x $@
+			-e 's|$TZVERSION$=.*|\1='"$$VERSION"'|' \
+			<$@.ksh >$@.out
+		chmod +x $@.out
+		mv $@.out $@
+
+check:		check_character_set check_white_space check_links \
+		  check_name_lengths check_slashed_abbrs check_sorted \
+		  check_tables check_web check_ziguard check_zishrink check_tzs
+
+check_character_set: $(ENCHILADA)
+	test ! '$(UTF8_LOCALE)' || \
+	! printf 'A\304\200B\n' | \
+	  LC_ALL='$(UTF8_LOCALE)' grep -q '^A.B$$' >/dev/null 2>&1 || { \
+		LC_ALL='$(UTF8_LOCALE)' && export LC_ALL && \
+		sharp='#' && \
+		! grep -Env $(SAFE_LINE) $(MANS) date.1 $(MANTXTS) \
+			$(MISC) $(SOURCES) $(WEB_PAGES) \
+			CONTRIBUTING LICENSE README SECURITY \
+			version tzdata.zi && \
+		! grep -Env $(SAFE_LINE)'|^UNUSUAL_OK_'$(OK_CHAR)'*$$' \
+			Makefile && \
+		! grep -Env $(SAFE_SHARP_LINE) $(TDATA_TO_CHECK) backzone \
+			leapseconds zone.tab && \
+		! grep -Env $(OK_LINE) $(ENCHILADA); \
+	}
+	touch $@
+
+check_white_space: $(ENCHILADA)
+		patfmt=' \t|[\f\r\v]' && pat=`printf "$$patfmt\\n"` && \
+		! grep -En "$$pat" \
+			$$(ls $(ENCHILADA) | grep -Fvx leap-seconds.list)
+		! grep -n '[$s]$$' \
+			$$(ls $(ENCHILADA) | grep -Fvx leap-seconds.list)
+		touch $@
+
+PRECEDES_FILE_NAME = ^(Zone|Link[$s]+[^$s]+)[$s]+
+FILE_NAME_COMPONENT_TOO_LONG = $(PRECEDES_FILE_NAME)[^$s]*[^/$s]{15}
+
+check_name_lengths: $(TDATA_TO_CHECK) backzone
+		! grep -En '$(FILE_NAME_COMPONENT_TOO_LONG)' \
+			$(TDATA_TO_CHECK) backzone
+		touch $@
+
+PRECEDES_STDOFF = ^(Zone[$s]+[^$s]+)?[$s]+
+STDOFF = [-+]?[0-9:.]+
+RULELESS_SAVE = (-|$(STDOFF)[sd]?)
+RULELESS_SLASHED_ABBRS = \
+  $(PRECEDES_STDOFF)$(STDOFF)[$s]+$(RULELESS_SAVE)[$s]+[^$s]*/
+
+check_slashed_abbrs: $(TDATA_TO_CHECK)
+		! grep -En '$(RULELESS_SLASHED_ABBRS)' $(TDATA_TO_CHECK)
+		touch $@
 
-check:		check_tables check_web
+CHECK_CC_LIST = { n = split($$1,a,/,/); for (i=2; i<=n; i++) print a[1], a[i]; }
 
-check_tables:	checktab.awk $(PRIMARY_YDATA)
-		$(AWK) -f checktab.awk $(PRIMARY_YDATA)
+check_sorted: backward backzone iso3166.tab zone.tab zone1970.tab
+		$(AWK) '/^Link/ {print $$3}' backward | LC_ALL=C sort -cu
+		$(AWK) '/^Zone/ {print $$2}' backzone | LC_ALL=C sort -cu
+		touch $@
 
-check_web:	$(WEB_PAGES)
-		$(VALIDATE_ENV) $(VALIDATE) $(VALIDATE_FLAGS) $(WEB_PAGES)
+check_links:	checklinks.awk $(TDATA_TO_CHECK) tzdata.zi
+		$(AWK) -f checklinks.awk $(TDATA_TO_CHECK)
+		$(AWK) -f checklinks.awk tzdata.zi
+		touch $@
 
-clean:
-		rm -f core *.o *.out tzselect zdump zic yearistype date
+check_tables:	checktab.awk $(YDATA) backward $(ZONETABLES)
+		for tab in $(ZONETABLES); do \
+		  test "$$tab" = zone.tab && links='$(BACKWARD)' || links=''; \
+		  $(AWK) -f checktab.awk -v zone_table=$$tab $(YDATA) $$links \
+		    || exit; \
+		done
+		touch $@
+
+check_tzs:	$(TZS) $(TZS_NEW)
+		if test -s $(TZS); then \
+		  diff -u $(TZS) $(TZS_NEW); \
+		else \
+		  cp $(TZS_NEW) $(TZS); \
+		fi
+		touch $@
+
+check_web:	$(CHECK_WEB_PAGES)
+check_theory.html: theory.html
+check_tz-art.html: tz-art.html
+check_tz-how-to.html: tz-how-to.html
+check_tz-link.html: tz-link.html
+check_theory.html check_tz-art.html check_tz-how-to.html check_tz-link.html:
+		$(CURL) -sS --url https://validator.w3.org/nu/ -F out=gnu \
+		    -F file=@$$(expr $@ : 'check_$.*$') -o $@.out && \
+		  test ! -s $@.out || { cat $@.out; exit 1; }
+		mv $@.out $@
+
+check_ziguard: rearguard.zi vanguard.zi ziguard.awk
+		$(AWK) -v DATAFORM=rearguard -f ziguard.awk vanguard.zi | \
+		  diff -u rearguard.zi -
+		$(AWK) -v DATAFORM=vanguard -f ziguard.awk rearguard.zi | \
+		  diff -u vanguard.zi -
+		touch $@
+
+# Check that zishrink.awk does not alter the data, and that ziguard.awk
+# preserves main-format data.
+check_zishrink: check_zishrink_posix check_zishrink_right
+check_zishrink_posix check_zishrink_right: \
+  zic leapseconds $(PACKRATDATA) $(PACKRATLIST) \
+  $(TDATA) $(DATAFORM).zi tzdata.zi
+		rm -fr $@.dir $@-t.dir $@-shrunk.dir
+		mkdir $@.dir $@-t.dir $@-shrunk.dir
+		case $@ in \
+		  *_right) leap='-L leapseconds';; \
+		  *) leap=;; \
+		esac && \
+		  $(ZIC) $$leap -d $@.dir $(DATAFORM).zi && \
+		  $(ZIC) $$leap -d $@-shrunk.dir tzdata.zi && \
+		  case $(DATAFORM),$(PACKRATLIST) in \
+		    main,) \
+		      $(ZIC) $$leap -d $@-t.dir $(TDATA) && \
+		      $(AWK) '/^Rule/' $(TDATA) | \
+			$(ZIC) $$leap -d $@-t.dir - $(PACKRATDATA) && \
+		      diff -r $@.dir $@-t.dir;; \
+		  esac
+		diff -r $@.dir $@-shrunk.dir
+		rm -fr $@.dir $@-t.dir $@-shrunk.dir
+		touch $@
+
+clean_misc:
+		rm -fr check_*.dir
+		rm -f *.o *.out $(TIME_T_ALTERNATIVES) \
+		  check_* core typecheck_* \
+		  date tzselect version.h zdump zic libtz.a
+clean:		clean_misc
+		rm -fr *.dir tzdb-*/
+		rm -f *.zi $(TZS_NEW)
 
 maintainer-clean: clean
 		@echo 'This command is intended for maintainers to use; it'
 		@echo 'deletes files that may need special tools to rebuild.'
-		rm -f *.[1-8].txt tzcode.tar.gz tzdata.tar.gz
+		rm -f leapseconds version $(MANTXTS) $(TZS) *.asc *.tar.*
 
 names:
 		@echo $(ENCHILADA)
 
+public:		check check_public $(CHECK_TIME_T_ALTERNATIVES) \
+		tarballs signatures
+
+date.1.txt:	date.1
+newctime.3.txt:	newctime.3
+newstrftime.3.txt: newstrftime.3
+newtzset.3.txt:	newtzset.3
+time2posix.3.txt: time2posix.3
+tzfile.5.txt:	tzfile.5
+tzselect.8.txt:	tzselect.8
+zdump.8.txt:	zdump.8
+zic.8.txt:	zic.8
+
+$(MANTXTS):	workman.sh
+		LC_ALL=C sh workman.sh `expr $@ : '$.*$\.txt$$'` >$@.out
+		mv $@.out $@
+
+# Set file timestamps deterministically if possible,
+# so that tarballs containing the timestamps are reproducible.
+#
+# '$(SET_TIMESTAMP_N) N DEST A B C ...' sets the timestamp of the
+# file DEST to the maximum of the timestamps of the files A B C ...,
+# plus N if GNU ls and touch are available.
+SET_TIMESTAMP_N = sh -c '\
+  n=$$0 dest=$$1; shift; \
+  touch -cmr `ls -t "$$@" | sed 1q` "$$dest" && \
+  if test $$n != 0 && \
+     lsout=`ls -n --time-style="+%s" "$$dest" 2>/dev/null`; then \
+    set x $$lsout && \
+    touch -cmd @`expr $$7 + $$n` "$$dest"; \
+  else :; fi'
+# If DEST depends on A B C ... in this Makefile, callers should use
+# $(SET_TIMESTAMP_DEP) DEST A B C ..., for the benefit of any
+# downstream 'make' that considers equal timestamps to be out of date.
+# POSIX allows this 'make' behavior, and HP-UX 'make' does it.
+# If all that matters is that the timestamp be reproducible
+# and plausible, use $(SET_TIMESTAMP).
+SET_TIMESTAMP = $(SET_TIMESTAMP_N) 0
+SET_TIMESTAMP_DEP = $(SET_TIMESTAMP_N) 1
+
+# Set the timestamps to those of the git repository, if available,
+# and if the files have not changed since then.
+# This uses GNU 'ls --time-style=+%s', which outputs the seconds count,
+# and GNU 'touch -d@N FILE', where N is the number of seconds since 1970.
+# If git or GNU is absent, don't bother to sync with git timestamps.
+# Also, set the timestamp of each prebuilt file like 'leapseconds'
+# to be the maximum of the files it depends on.
+set-timestamps.out: $(EIGHT_YARDS)
+		rm -f $@
+		if (type git) >/dev/null 2>&1 && \
+		   files=`git ls-files $(EIGHT_YARDS)` && \
+		   touch -md @1 test.out; then \
+		  rm -f test.out && \
+		  for file in $$files; do \
+		    if git diff --quiet $$file; then \
+		      time=`git log -1 --format='tformat:%ct' $$file` && \
+		      touch -cmd @$$time $$file; \
+		    else \
+		      echo >&2 "$$file: warning: does not match repository"; \
+		    fi || exit; \
+		  done; \
+		fi
+		$(SET_TIMESTAMP_DEP) leapseconds $(LEAP_DEPS)
+		for file in `ls $(MANTXTS) | sed 's/\.txt$$//'`; do \
+		  $(SET_TIMESTAMP_DEP) $$file.txt $$file workman.sh || \
+		    exit; \
+		done
+		$(SET_TIMESTAMP_DEP) version $(VERSION_DEPS)
+		$(SET_TIMESTAMP_DEP) tzdata.zi $(TZDATA_ZI_DEPS)
+		touch $@
+set-tzs-timestamp.out: $(TZS)
+		$(SET_TIMESTAMP_DEP) $(TZS) $(TZS_DEPS)
+		touch $@
+
 # The zics below ensure that each data file can stand on its own.
 # We also do an all-files run to catch links to links.
 
-public:		$(ENCHILADA)
-		make maintainer-clean
-		make "CFLAGS=$(GCC_DEBUG_FLAGS)"
-		-mkdir /tmp/,tzpublic
-		-for i in $(TDATA) ; do zic -v -d /tmp/,tzpublic $$i 2>&1 | grep -v "starting year" ; done
-		for i in $(TDATA) ; do zic -d /tmp/,tzpublic $$i || exit; done
-		zic -v -d /tmp/,tzpublic $(TDATA) || exit
-		rm -f -r /tmp/,tzpublic
-		for i in *.[1-8] ; do sh workman.sh $$i > $$i.txt || exit; done
-		$(AWK) -f checktab.awk $(PRIMARY_YDATA)
-		tar cf - $(DOCS) $(SOURCES) $(MISC) *.[1-8].txt | gzip -9 > tzcode.tar.gz
-		tar cf - $(DATA) | gzip -9 > tzdata.tar.gz
-
-typecheck:
-		make clean
-		for i in "long long" unsigned double; \
+check_public: $(VERSION_DEPS)
+		rm -fr public.dir
+		mkdir public.dir
+		ln $(VERSION_DEPS) public.dir
+		cd public.dir && $(MAKE) CFLAGS='$(GCC_DEBUG_FLAGS)' ALL
+		for i in $(TDATA_TO_CHECK) public.dir/tzdata.zi \
+		    public.dir/vanguard.zi public.dir/main.zi \
+		    public.dir/rearguard.zi; \
 		do \
-			make CFLAGS="-DTYPECHECK -D_TIME_T \"-Dtime_t=$$i\"" ; \
-			./zdump -v Europe/Rome ; \
-			make clean ; \
+		  public.dir/zic -v -d public.dir/zoneinfo $$i 2>&1 || exit; \
 		done
+		public.dir/zic -v -d public.dir/zoneinfo-all $(TDATA_TO_CHECK)
+		:
+		: Also check 'backzone' syntax.
+		rm public.dir/main.zi
+		cd public.dir && $(MAKE) PACKRATDATA=backzone main.zi
+		public.dir/zic -d public.dir/zoneinfo main.zi
+		rm public.dir/main.zi
+		cd public.dir && \
+		  $(MAKE) PACKRATDATA=backzone PACKRATLIST=zone.tab main.zi
+		public.dir/zic -d public.dir/zoneinfo main.zi
+		:
+		rm -fr public.dir
+		touch $@
+
+# Check that the code works under various alternative
+# implementations of time_t.
+check_time_t_alternatives: $(TIME_T_ALTERNATIVES)
+$(TIME_T_ALTERNATIVES_TAIL): $(TIME_T_ALTERNATIVES_HEAD)
+$(TIME_T_ALTERNATIVES): $(VERSION_DEPS)
+		rm -fr $@.dir
+		mkdir $@.dir
+		ln $(VERSION_DEPS) $@.dir
+		case $@ in \
+		  int*32_t) range=-2147483648,2147483648;; \
+		  u*) range=0,4294967296;; \
+		  *) range=-4294967296,4294967296;; \
+		esac && \
+		wd=`pwd` && \
+		zones=`$(AWK) '/^[^#]/ { print $$3 }' /dev/null; then \
+		    quiet_option='-q'; \
+		  else \
+		    quiet_option=''; \
+		  fi && \
+		    diff $$quiet_option -r $(TIME_T_ALTERNATIVES_HEAD).dir/etc \
+					   $@.dir/etc && \
+		    diff $$quiet_option -r \
+		      $(TIME_T_ALTERNATIVES_HEAD).dir/usr/share \
+		      $@.dir/usr/share; \
+		}
+		touch $@
+
+TRADITIONAL_ASC = \
+  tzcode$(VERSION).tar.gz.asc \
+  tzdata$(VERSION).tar.gz.asc
+REARGUARD_ASC = \
+  tzdata$(VERSION)-rearguard.tar.gz.asc
+ALL_ASC = $(TRADITIONAL_ASC) $(REARGUARD_ASC) \
+  tzdb-$(VERSION).tar.lz.asc
+
+tarballs rearguard_tarballs tailored_tarballs traditional_tarballs \
+signatures rearguard_signatures traditional_signatures: \
+  version set-timestamps.out rearguard.zi vanguard.zi
+		VERSION=`cat version` && \
+		$(MAKE) AWK='$(AWK)' VERSION="$$VERSION" $@_version
+
+# These *_version rules are intended for use if VERSION is set by some
+# other means.  Ordinarily these rules are used only by the above
+# non-_version rules, which set VERSION on the 'make' command line.
+tarballs_version: traditional_tarballs_version rearguard_tarballs_version \
+  tzdb-$(VERSION).tar.lz
+rearguard_tarballs_version: \
+  tzdata$(VERSION)-rearguard.tar.gz
+traditional_tarballs_version: \
+  tzcode$(VERSION).tar.gz tzdata$(VERSION).tar.gz
+tailored_tarballs_version: \
+  tzdata$(VERSION)-tailored.tar.gz
+signatures_version: $(ALL_ASC)
+rearguard_signatures_version: $(REARGUARD_ASC)
+traditional_signatures_version: $(TRADITIONAL_ASC)
+
+tzcode$(VERSION).tar.gz: set-timestamps.out
+		LC_ALL=C && export LC_ALL && \
+		tar $(TARFLAGS) -cf - \
+		    $(COMMON) $(DOCS) $(SOURCES) | \
+		  gzip $(GZIPFLAGS) >$@.out
+		mv $@.out $@
+
+tzdata$(VERSION).tar.gz: set-timestamps.out
+		LC_ALL=C && export LC_ALL && \
+		tar $(TARFLAGS) -cf - $(TZDATA_DIST) | \
+		  gzip $(GZIPFLAGS) >$@.out
+		mv $@.out $@
+
+# Create empty files with a reproducible timestamp.
+CREATE_EMPTY = TZ=UTC0 touch -mt 202010122253.00
+
+# The obsolescent *rearguard* targets and related macros are present
+# for backwards compatibility with tz releases 2018e through 2022a.
+# They should go away eventually.  To build rearguard tarballs you
+# can instead use 'make DATAFORM=rearguard tailored_tarballs'.
+tzdata$(VERSION)-rearguard.tar.gz: rearguard.zi set-timestamps.out
+		rm -fr $@.dir
+		mkdir $@.dir
+		ln $(TZDATA_DIST) $@.dir
+		cd $@.dir && rm -f $(TDATA) $(PACKRATDATA) version
+		for f in $(TDATA) $(PACKRATDATA); do \
+		  rearf=$@.dir/$$f; \
+		  $(AWK) -v DATAFORM=rearguard -f ziguard.awk $$f >$$rearf && \
+		  $(SET_TIMESTAMP_DEP) $$rearf ziguard.awk $$f || exit; \
+		done
+		sed '1s/$$/-rearguard/' $@.dir/version
+		: The dummy pacificnew pacifies TZUpdater 2.3.1 and earlier.
+		$(CREATE_EMPTY) $@.dir/pacificnew
+		touch -cmr version $@.dir/version
+		LC_ALL=C && export LC_ALL && \
+		  (cd $@.dir && \
+		   tar $(TARFLAGS) -cf - \
+			$(TZDATA_DIST) pacificnew | \
+		     gzip $(GZIPFLAGS)) >$@.out
+		mv $@.out $@
+
+# Create a tailored tarball suitable for TZUpdater and compatible tools.
+# For example, 'make DATAFORM=vanguard tailored_tarballs' makes a tarball
+# useful for testing whether TZUpdater supports vanguard form.
+# The generated tarball is not byte-for-byte equivalent to a hand-tailored
+# traditional tarball, as data entries are put into 'etcetera' even if they
+# came from some other source file.  However, the effect should be the same
+# for ordinary use, which reads all the source files.
+tzdata$(VERSION)-tailored.tar.gz: set-timestamps.out
+		rm -fr $@.dir
+		mkdir $@.dir
+		: The dummy pacificnew pacifies TZUpdater 2.3.1 and earlier.
+		cd $@.dir && \
+		  $(CREATE_EMPTY) $(PRIMARY_YDATA) $(NDATA) backward \
+		  `test $(DATAFORM) = vanguard || echo pacificnew`
+		(grep '^#' tzdata.zi && echo && cat $(DATAFORM).zi) \
+		  >$@.dir/etcetera
+		touch -cmr tzdata.zi $@.dir/etcetera
+		sed -n \
+		  -e '/^# *version  *$.*$/h' \
+		  -e '/^# *ddeps  */H' \
+		  -e '$$!d' \
+		  -e 'g' \
+		  -e 's/^# *version  *//' \
+		  -e 's/\n# *ddeps  */-/' \
+		  -e 's/ /-/g' \
+		  -e 'p' \
+		  $@.dir/version
+		touch -cmr version $@.dir/version
+		links= && \
+		  for file in $(TZDATA_DIST); do \
+		    test -f $@.dir/$$file || links="$$links $$file"; \
+		  done && \
+		  ln $$links $@.dir
+		LC_ALL=C && export LC_ALL && \
+		  (cd $@.dir && \
+		   tar $(TARFLAGS) -cf - * | gzip $(GZIPFLAGS)) >$@.out
+		mv $@.out $@
+
+tzdb-$(VERSION).tar.lz: set-timestamps.out set-tzs-timestamp.out
+		rm -fr tzdb-$(VERSION)
+		mkdir tzdb-$(VERSION)
+		ln $(ENCHILADA) tzdb-$(VERSION)
+		$(SET_TIMESTAMP) tzdb-$(VERSION) tzdb-$(VERSION)/*
+		LC_ALL=C && export LC_ALL && \
+		tar $(TARFLAGS) -cf - tzdb-$(VERSION) | lzip -9 >$@.out
+		mv $@.out $@
+
+tzcode$(VERSION).tar.gz.asc: tzcode$(VERSION).tar.gz
+tzdata$(VERSION).tar.gz.asc: tzdata$(VERSION).tar.gz
+tzdata$(VERSION)-rearguard.tar.gz.asc: tzdata$(VERSION)-rearguard.tar.gz
+tzdb-$(VERSION).tar.lz.asc: tzdb-$(VERSION).tar.lz
+$(ALL_ASC):
+		$(GPG) --armor --detach-sign $?
+
+TYPECHECK_CFLAGS = $(CFLAGS) -DTYPECHECK -D__time_t_defined -D_TIME_T
+typecheck: typecheck_long_long typecheck_unsigned
+typecheck_long_long typecheck_unsigned: $(VERSION_DEPS)
+		rm -fr $@.dir
+		mkdir $@.dir
+		ln $(VERSION_DEPS) $@.dir
+		cd $@.dir && \
+		  case $@ in \
+		    *_long_long) i="long long";; \
+		    *_unsigned ) i="unsigned" ;; \
+		  esac && \
+		  typecheck_cflags='' && \
+		  $(MAKE) \
+		    CFLAGS="$(TYPECHECK_CFLAGS) \"-Dtime_t=$$i\"" \
+		    TOPDIR="`pwd`" \
+		    install
+		$@.dir/zdump -i -c 1970,1971 Europe/Rome
+		touch $@
 
-zonenames:	$(TDATA)
-		@$(AWK) '/^Zone/ { print $$2 } /^Link/ { print $$3 }' $(TDATA)
+zonenames:	tzdata.zi
+		@$(AWK) '/^Z/ { print $$2 } /^L/ { print $$3 }' tzdata.zi
 
 asctime.o:	private.h tzfile.h
 date.o:		private.h
 difftime.o:	private.h
-ialloc.o:	private.h
 localtime.o:	private.h tzfile.h
-scheck.o:	private.h
-strftime.o:	tzfile.h
-zic.o:		private.h tzfile.h
+strftime.o:	private.h tzfile.h
+zdump.o:	version.h
+zic.o:		private.h tzfile.h version.h
 
-.KEEP_STATE:
+.PHONY: ALL INSTALL all
+.PHONY: check check_time_t_alternatives
+.PHONY: check_web check_zishrink
+.PHONY: clean clean_misc dummy.zd force_tzs
+.PHONY: install install_data maintainer-clean names
+.PHONY: posix_only posix_right public
+.PHONY: rearguard_signatures rearguard_signatures_version
+.PHONY: rearguard_tarballs rearguard_tarballs_version
+.PHONY: right_only right_posix signatures signatures_version
+.PHONY: tarballs tarballs_version
+.PHONY: traditional_signatures traditional_signatures_version
+.PHONY: traditional_tarballs traditional_tarballs_version
+.PHONY: tailored_tarballs tailored_tarballs_version
+.PHONY: typecheck
+.PHONY: zonenames zones
+.PHONY: $(ZDS)

diff --git a/NEWS b/NEWS
new file mode 100644
index 000000000000..c4abb32cd4dc
--- /dev/null
+++ b/NEWS
@@ -0,0 +1,5671 @@
+News for the tz database
+
+Release 2022c - 2022-08-15 17:47:18 -0700
+
+  Briefly:
+    Work around awk bug in FreeBSD, macOS, etc.
+    Improve tzselect on intercontinental Zones.
+
+  Changes to code
+
+    Work around a bug in onetrueawk that broke commands like
+    'make traditional_tarballs' on FreeBSD, macOS, etc.
+    (Problem reported by Deborah Goldsmith.)
+
+    Add code to tzselect that uses experimental structured comments in
+    zone1970.tab to clarify whether Zones like Africa/Abidjan and
+    Europe/Istanbul cross continent or ocean boundaries.
+    (Inspired by a problem reported by Peter Krefting.)
+
+    Fix bug with 'zic -d /a/b/c' when /a is unwritable but the
+    directory /a/b already exists.
+
+    Remove zoneinfo2tdf.pl, as it was unused and triggered false
+    malware alarms on some email servers.
+
+
+Release 2022b - 2022-08-10 15:38:32 -0700
+
+  Briefly:
+    Chile's DST is delayed by a week in September 2022.
+    Iran no longer observes DST after 2022.
+    Rename Europe/Kiev to Europe/Kyiv.
+    New zic -R option
+    Vanguard form now uses %z.
+    Finish moving duplicate-since-1970 zones to 'backzone'.
+    New build option PACKRATLIST
+    New tailored_tarballs target, replacing rearguard_tarballs
+
+  Changes to future timestamps
+
+    Chile's 2022 DST start is delayed from September 4 to September 11.
+    (Thanks to Juan Correa.)
+
+    Iran plans to stop observing DST permanently, after it falls back
+    on 2022-09-21.  (Thanks to Ali Mirjamali.)
+
+  Changes to past timestamps
+
+    Finish moving to 'backzone' the location-based zones whose
+    timestamps since 1970 are duplicates; adjust links accordingly.
+    This change ordinarily affects only pre-1970 timestamps, and with
+    the new PACKRATLIST option it does not affect any timestamps.
+    In this round the affected zones are Antarctica/Vostok,
+    Asia/Brunei, Asia/Kuala_Lumpur, Atlantic/Reykjavik,
+    Europe/Amsterdam, Europe/Copenhagen, Europe/Luxembourg,
+    Europe/Monaco, Europe/Oslo, Europe/Stockholm, Indian/Christmas,
+    Indian/Cocos, Indian/Kerguelen, Indian/Mahe, Indian/Reunion,
+    Pacific/Chuuk, Pacific/Funafuti, Pacific/Majuro, Pacific/Pohnpei,
+    Pacific/Wake and Pacific/Wallis, and the affected links are
+    Arctic/Longyearbyen, Atlantic/Jan_Mayen, Iceland, Pacific/Ponape,
+    Pacific/Truk, and Pacific/Yap.
+
+    From fall 1994 through fall 1995, Shanks wrote that Crimea's
+    DST transitions were at 02:00 standard time, not at 00:00.
+    (Thanks to Michael Deckers.)
+
+    Iran adopted standard time in 1935, not 1946.  In 1977 it observed
+    DST from 03-21 23:00 to 10-20 24:00; its 1978 transitions were on
+    03-24 and 08-05, not 03-20 and 10-20; and its spring 1979
+    transition was on 05-27, not 03-21.
+    (Thanks to Roozbeh Pournader and Francis Santoni.)
+
+    Chile's observance of -04 from 1946-08-29 through 1947-03-31 was
+    considered DST, not standard time.  Santiago and environs had moved
+    their clocks back to rejoin the rest of mainland Chile; put this
+    change at the end of 1946-08-28.  (Thanks to Michael Deckers.)
+
+    Some old, small clock transitions have been removed, as people at
+    the time did not change their clocks.  This affects Asia/Hong_Kong
+    in 1904, Asia/Ho_Chi_Minh in 1906, and Europe/Dublin in 1880.
+
+  Changes to zone name
+
+    Rename Europe/Kiev to Europe/Kyiv, as "Kyiv" is more common in
+    English now.  Spelling of other names in Ukraine has not yet
+    demonstrably changed in common English practice so for now these
+    names retain old spellings, as in other countries (e.g.,
+    Europe/Prague not "Praha", and Europe/Sofia not "Sofiya").
+
+  Changes to code
+
+    zic has a new option '-R @N' to output explicit transitions < N.
+    (Need suggested by Almaz Mingaleev.)
+
+    'zic -r @N' no longer outputs bad data when N < first transition.
+    (Problem introduced in 2021d and reported by Peter Krefting.)
+
+    zic now checks its input for NUL bytes and unterminated lines, and
+    now supports input line lengths up to 2048 (not 512) bytes.
+
+    gmtime and related code now use the abbreviation "UTC" not "GMT".
+    POSIX is being revised to require this.
+
+    When tzset and related functions set vestigial static variables
+    like tzname, they now prefer specified timestamps to unspecified ones.
+    (Problem reported by Almaz Mingaleev.)
+
+    zic no longer complains "can't determine time zone abbreviation to
+    use just after until time" when a transition to a new standard
+    time occurs simultaneously with the first DST fallback transition.
+
+  Changes to build procedure
+
+    Source data in vanguard form now uses the %z notation, introduced
+    in release 2015f.  For example, for America/Sao_Paulo vanguard
+    form contains the zone continuation line "-3:00 Brazil %z", which
+    is simpler and more reliable than the line "-3:00 Brazil -03/-02"
+    used in main and rearguard forms.  The plan is for the main form
+    to use %z eventually; in the meantime maintainers of zi parsers
+    are encouraged to test the parsers on vanguard.zi.
+
+    The Makefile has a new PACKRATLIST option to select a subset of
+    'backzone'.  For example, 'make PACKRATDATA=backzone
+    PACKRATLIST=zone.tab' now generates TZif files identical to those
+    of the global-tz project.
+
+    The Makefile has a new tailored_tarballs target for generating
+    special-purpose tarballs.  It generalizes and replaces the
+    rearguard_tarballs target and related targets and macros, which
+    are now obsolescent.
+
+    'make install' now defaults LOCALTIME to Factory not GMT,
+    which means the default abbreviation is now "-00" not "GMT".
+
+    Remove the posix_packrat target, marked obsolescent in 2016a.
+
+
+Release 2022a - 2022-03-15 23:02:01 -0700
+
+  Briefly:
+    Palestine will spring forward on 2022-03-27, not -03-26.
+    zdump -v now outputs better failure indications.
+    Bug fixes for code that reads corrupted TZif data.
+
+  Changes to future timestamps
+
+    Palestine will spring forward on 2022-03-27, not 2022-03-26.
+    (Thanks to Heba Hamad.)  Predict future transitions for first
+    Sunday >= March 25.  Additionally, predict fallbacks to be the first
+    Friday on or after October 23, not October's last Friday, to be more
+    consistent with recent practice.  The first differing fallback
+    prediction is on 2025-10-24, not 2025-10-31.
+
+  Changes to past timestamps
+
+    From 1992 through spring 1996, Ukraine's DST transitions were at
+    02:00 standard time, not at 01:00 UTC.  (Thanks to Alois Treindl.)
+
+    Chile's Santiago Mean Time and its LMT precursor have been adjusted
+    eastward by 1 second to align with past and present law.
+
+  Changes to commentary
+
+    Add several references for Chile's 1946/1947 transitions, some of
+    which only affected portions of the country.
+
+  Changes to code
+
+    Fix bug when mktime gets confused by truncated TZif files with
+    unspecified local time.  (Problem reported by Almaz Mingaleev.)
+
+    Fix bug when 32-bit time_t code reads malformed 64-bit TZif data.
+    (Problem reported by Christos Zoulas.)
+
+    When reading a version 2 or later TZif file, the TZif reader now
+    validates the version 1 header and data block only enough to skip
+    over them, as recommended by RFC 8536 section 4.  Also, the TZif
+    reader no longer mistakenly attempts to parse a version 1 TZIf
+    file header as a TZ string.
+
+    zdump -v now outputs "(localtime failed)" and "(gmtime failed)"
+    when local time and UT cannot be determined for a timestamp.
+
+  Changes to build procedure
+
+    Distribution tarballs now use standard POSIX.1-1988 ustar format
+    instead of GNU format.  Although the formats are almost identical
+    for these tarballs, ustar headers' magic fields contain "ustar"
+    instead of "ustar ", and their version fields contain "00" instead
+    of " ".  The two formats are planned to diverge more significantly
+    for tzdb releases after 2242-03-16 12:56:31 UTC, when the ustar
+    format becomes obsolete and the tarballs switch to pax format, an
+    extension of ustar.  For details about these formats, please see
+    "pax - portable archive interchange", IEEE Std 1003.1-2017,
+    .
+
+
+Release 2021e - 2021-10-21 18:41:00 -0700
+
+  Changes to future timestamps
+
+    Palestine will fall back 10-29 (not 10-30) at 01:00.
+    (Thanks to P Chan and Heba Hemad.)
+
+
+Release 2021d - 2021-10-15 13:48:18 -0700
+
+  Briefly:
+    Fiji suspends DST for the 2021/2022 season.
+    'zic -r' marks unspecified timestamps with "-00".
+
+  Changes to future timestamps
+
+    Fiji will suspend observance of DST for the 2021/2022 season.
+    Assume for now that it will return next year.  (Thanks to Jashneel
+    Kumar and P Chan.)
+
+  Changes to code
+
+    'zic -r' now uses "-00" time zone abbreviations for intervals
+    with UT offsets that are unspecified due to -r truncation.
+    This implements a change in draft Internet RFC 8536bis.
+
+
+Release 2021c - 2021-10-01 14:21:49 -0700
+
+  Briefly:
+    Revert most 2021b changes to 'backward'.
+    Fix 'zic -b fat' bug in pre-1970 32-bit data.
+    Fix two Link line typos.
+    Distribute SECURITY file.
+
+    This release is intended as a bugfix release, to fix compatibility
+    problems and typos reported since 2021b was released.
+
+  Changes to Link directives
+
+    Revert almost all of 2021b's changes to the 'backward' file,
+    by moving Link directives back to where they were in 2021a.
+    Although 'zic' doesn't care which source file contains a Link
+    directive, some downstream uses ran into trouble with the move.
+    (Problem reported by Stephen Colebourne for Joda-Time.)
+
+    Fix typo that linked Atlantic/Jan_Mayen to the wrong location
+    (problem reported by Chris Walton).
+
+    Fix 'backzone' typo that linked America/Virgin to the wrong
+    location (problem reported by Michael Deckers).
+
+  Changes to code
+
+    Fix a bug in 'zic -b fat' that caused old timestamps to be
+    mishandled in 32-bit-only readers (problem reported by Daniel
+    Fischer).
+
+  Changes to documentation
+
+    Distribute the SECURITY file (problem reported by Andreas Radke).
+
+
+Release 2021b - 2021-09-24 16:23:00 -0700
+
+  Briefly:
+    Jordan now starts DST on February's last Thursday.
+    Samoa no longer observes DST.
+    Merge more location-based Zones whose timestamps agree since 1970.
+    Move some backward-compatibility links to 'backward'.
+    Rename Pacific/Enderbury to Pacific/Kanton.
+    Correct many pre-1993 transitions in Malawi, Portugal, etc.
+    zic now creates each output file or link atomically.
+    zic -L no longer omits the POSIX TZ string in its output.
+    zic fixes for truncation and leap second table expiration.
+    zic now follows POSIX for TZ strings using all-year DST.
+    Fix some localtime crashes and bugs in obscure cases.
+    zdump -v now outputs more-useful boundary cases.
+    tzfile.5 better matches a draft successor to RFC 8536.
+    A new file SECURITY.
+
+    This release is prompted by recent announcements by Jordan and Samoa.
+    It incorporates many other changes that had accumulated since 2021a.
+    However, it omits most proposed changes that merged all Zones
+    agreeing since 1970, as concerns were raised about doing too many of
+    these changes at once.  It does keeps some of these changes in the
+    interest of making tzdb more equitable one step at a time; see
+    "Merge more location-based Zones" below.
+
+  Changes to future timestamps
+
+    Jordan now starts DST on February's last Thursday.
+    (Thanks to Steffen Thorsen.)
+
+    Samoa no longer observes DST.  (Thanks to Geoffrey D. Bennett.)
+
+  Changes to zone name
+
+    Rename Pacific/Enderbury to Pacific/Kanton.  When we added
+    Enderbury in 1993, we did not know that it is uninhabited and that
+    Kanton (population two dozen) is the only inhabited location in
+    that timezone.  The old name is now a backward-compatibility link.
+
+  Changes to past timestamps
+
+    Correct many pre-1993 transitions, fixing entries originally
+    derived from Shanks, Whitman, and Mundell.  The fixes include:
+      - Barbados: standard time was introduced in 1911, not 1932; and
+	DST was observed in 1942-1944
+      - Cook Islands: In 1899 they switched from east to west of GMT,
+	celebrating Christmas for two days.  They (and Niue) switched
+	to standard time in 1952, not 1901.
+      - Guyana: corrected LMT for Georgetown; the introduction of
+	standard time in 1911, not 1915; and corrections to 1975 and
+	1992 transitions
+      - Kanton: uninhabited before 1937-08-31
+      - Niue: only observed -11:20 from 1952 through 1964, then went to
+        -11 instead of -11:30
+      - Portugal: DST was observed in 1950
+      - Tonga: corrected LMT; the introduction of standard time in 1945,
+        not 1901; and corrections to the transition from +12:20 to +13
+        in 1961, not 1941
+    Additional fixes to entries in the 'backzone' file include:
+      - Enderbury: inhabited only 1860/1885 and 1938-03-06/1942-02-09
+      - The Gambia: 1933 and 1942 transitions
+      - Malawi: several 1911 through 1925 transitions
+      - Sierra Leone: several 1913 through 1941 transitions, and DST
+	was NOT observed in 1957 through 1962
+    (Thanks to P Chan, Michael Deckers, Alexander Krivenyshev and
+    Alois Treindl.)
+
+    Merge more location-based Zones whose timestamps agree since 1970,
+    as pre-1970 timestamps are out of scope.  This is part of a
+    process that has been ongoing since 2013.  This does not affect
+    post-1970 timestamps, and timezone historians who build with 'make
+    PACKRATDATA=backzone' should see no changes to pre-1970 timestamps.
+    When merging, keep the most-populous location's data, and move
+    data for other locations to 'backzone' with a backward
+    link in 'backward'.  For example, move America/Creston data to
+    'backzone' with a link in 'backward' from America/Phoenix because
+    the two timezones' timestamps agree since 1970; this change
+    affects some pre-1968 timestamps in America/Creston because
+    Creston and Phoenix disagreed before 1968.  The affected Zones
+    are Africa/Accra, America/Atikokan, America/Blanc-Sablon,
+    America/Creston, America/Curacao, America/Nassau,
+    America/Port_of_Spain, Antarctica/DumontDUrville, and
+    Antarctica/Syowa.
+
+  Changes to maintenance procedure
+
+    The new file SECURITY covers how to report security-related bugs.
+
+    Several backward-compatibility links have been moved to the
+    'backward' file.  These links, which range from Africa/Addis_Ababa
+    to Pacific/Saipan, are only for compatibility with now-obsolete
+    guidelines suggesting an entry for every ISO 3166 code.
+    The intercontinental convenience links Asia/Istanbul and
+    Europe/Nicosia have also been moved to 'backward'.
+
+  Changes to code
+
+    zic now creates each output file or link atomically,
+    possibly by creating a temporary file and then renaming it.
+    This avoids races where a TZ setting would temporarily stop
+    working while zic was installing a replacement file or link.
+
+    zic -L no longer omits the POSIX TZ string in its output.
+    Starting with 2020a, zic -L truncated its output according to the
+    "Expires" directive or "#expires" comment in the leapseconds file.
+    The resulting TZif files omitted daylight saving transitions after
+    the leap second table expired, which led to far less-accurate
+    predictions of times after the expiry.  Although future timestamps
+    cannot be converted accurately in the presence of leap seconds, it
+    is more accurate to convert near-future timestamps with a few
+    seconds error than with an hour error, so zic -L no longer
+    truncates output in this way.
+
+    Instead, when zic -L is given the "Expires" directive, it now
+    outputs the expiration by appending a no-change entry to the leap
+    second table.  Although this should work well with most TZif
+    readers, it does not conform to Internet RFC 8536 and some pickier
+    clients (including tzdb 2017c through 2021a) reject it, so
+    "Expires" directives are currently disabled by default.  To enable
+    them, set the EXPIRES_LINE Makefile variable.  If a TZif file uses
+    this new feature it is marked with a new TZif version number 4,
+    a format intended to be documented in a successor to RFC 8536.
+
+    zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
+    that omits leap second information for the range LO..B when LO
+    falls between two leap seconds A and B.  Instead, it generates a
+    TZif version 4 file that represents the previously-missing
+    information.
+
+    The TZif reader now allows the leap second table to begin with a
+    correction other than -1 or +1, and to contain adjacent
+    transitions with equal corrections.  This supports TZif version 4.
+
+    The TZif reader now lets leap seconds occur less than 28 days
+    apart.  This supports possible future TZif extensions.
+
+    Fix bug that caused 'localtime' etc. to crash when TZ was
+    set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
+    not conform to POSIX but does conform to Internet RFC 8536.
+
+    Fix another bug that caused 'localtime' etc. to crash when TZ was
+    set to a POSIX-conforming but unusual TZ string like
+    "EST5EDT4,0/0,J365/0", where almost all the year is DST.
+
+    Fix yet another bug that caused 'localtime' etc. to mishandle slim
+    TZif files containing leap seconds after the last explicit
+    transition in the table, or when handling far-future timestamps
+    in slim TZif files lacking leap seconds.
+
+    Fix localtime misbehavior involving positive leap seconds.
+    This change affects only behavior for "right" system time,
+    which contains leap seconds, and only if the UT offset is
+    not a multiple of 60 seconds when a positive leap second occurs.
+    (No such timezone exists in tzdb, luckily.)  Without the fix,
+    the timestamp was ambiguous during a positive leap second.
+    With the fix, any seconds occurring after a positive leap second
+    and within the same localtime minute are counted through 60, not
+    through 59; their UT offset (tm_gmtoff) is the same as before.
+    Here is how the fix affects timestamps in a timezone with UT
+    offset +01:23:45 (5025 seconds) and with a positive leap second at
+    1972-06-30 23:59:60 UTC (78796800):
+
+	time_t    without the fix      with the fix
+	78796800  1972-07-01 01:23:45  1972-07-01 01:23:45 (leap second)
+	78796801  1972-07-01 01:23:45  1972-07-01 01:23:46
+	...
+	78796815  1972-07-01 01:23:59  1972-07-01 01:23:60
+	78796816  1972-07-01 01:24:00  1972-07-01 01:24:00
+
+    Fix an unlikely bug that caused 'localtime' etc. to misbehave if
+    civil time changes a few seconds before time_t wraps around, when
+    leap seconds are enabled.
+
+    Fix bug in zic -r; in some cases, the dummy time type after the
+    last time transition disagreed with the TZ string, contrary to
+    Internet RFC 8563 section 3.3.
+
+    Fix a bug with 'zic -r @X' when X is a negative leap second that
+    has a nonnegative correction.  Without the fix, the output file
+    was truncated so that X appeared to be a positive leap second.
+    Fix a similar, even-less-likely bug when truncating at a positive
+    leap second that has a nonpositive correction.
+
+    zic -r now reports an error if given rolling leap seconds, as this
+    usage has never generally worked and is evidently unused.
+
+    zic now generates a POSIX-conforming TZ string for TZif files
+    where all-year DST is predicted for the indefinite future.
+    For example, for all-year Eastern Daylight Time, zic now generates
+    "XXX3EDT4,0/0,J365/23" where it previously generated
+    "EST5EDT,0/0,J365/25" or "".  (Thanks to Michael Deckers for
+    noting the possibility of POSIX conformance.)
+
+    zic.c no longer requires sys/wait.h (thanks to spazmodius for
+    noting it wasn't needed).
+
+    When reading slim TZif files, zdump no longer mishandles leap
+    seconds on the rare platforms where time_t counts leap seconds,
+    fixing a bug introduced in 2014g.
+
+    zdump -v now outputs timestamps at boundaries of what localtime
+    and gmtime can represent, instead of the less-useful timestamps
+    one day after the minimum and one day before the maximum.
+    (Thanks to Arthur David Olson for prototype code, and to Manuela
+    Friedrich for debugging help.)
+
+    zdump's -c and -t options are now consistently inclusive for the
+    lower time bound and exclusive for the upper.  Formerly they were
+    inconsistent.  (Confusion noted by Martin Burnicki.)
+
+  Changes to build procedure
+
+    You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
+    non-POSIX hosts where malloc doesn't set errno.
+    (Problem reported by Jan Engelhardt.)
+
+  Changes to documentation
+
+    tzfile.5 better matches a draft successor to RFC 8536
+    .
+
+
+Release 2021a - 2021-01-24 10:54:57 -0800
+
+  Changes to future timestamps
+
+    South Sudan changes from +03 to +02 on 2021-02-01 at 00:00.
+    (Thanks to Steffen Thorsen.)
+
+
+Release 2020f - 2020-12-29 00:17:46 -0800
+
+  Change to build procedure
+
+    'make rearguard_tarballs' no longer generates a bad rearguard.zi,
+    fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
+
+
+Release 2020e - 2020-12-22 15:14:34 -0800
+
+  Briefly:
+    Volgograd switches to Moscow time on 2020-12-27 at 02:00.
+
+  Changes to future timestamps
+
+    Volgograd changes time zone from +04 to +03 on 2020-12-27 at 02:00.
+    (Thanks to Alexander Krivenyshev and Stepan Golosunov.)
+
+  Changes to past timestamps
+
+    Correct many pre-1986 transitions, fixing entries originally
+    derived from Shanks.  The fixes include:
+      - Australia: several 1917 through 1971 transitions
+      - The Bahamas: several 1941 through 1945 transitions
+      - Bermuda: several 1917 through 1956 transitions
+      - Belize: several 1942 through 1968 transitions
+      - Ghana: several 1915 through 1956 transitions
+      - Israel and Palestine: several 1940 through 1985 transitions
+      - Kenya and adjacent: several 1908 through 1960 transitions
+      - Nigeria and adjacent: correcting LMT in Lagos, and several 1905
+        through 1919 transitions
+      - Seychelles: the introduction of standard time in 1907, not 1906
+      - Vanuatu: DST in 1973-1974, and a corrected 1984 transition
+    (Thanks to P Chan.)
+
+    Because of the Australia change, Australia/Currie (King Island) is
+    no longer needed, as it is identical to Australia/Hobart for all
+    timestamps since 1970 and was therefore created by mistake.
+    Australia/Currie has been moved to the 'backward' file and its
+    corrected data moved to the 'backzone' file.
+
+  Changes to past time zone abbreviations and DST flags
+
+    To better match legislation in Turks and Caicos, the 2015 shift to
+    year-round observance of -04 is now modeled as AST throughout before
+    returning to Eastern Time with US DST in 2018, rather than as
+    maintaining EDT until 2015-11-01.  (Thanks to P Chan.)
+
+  Changes to documentation
+
+    The zic man page now documents zic's coalescing of transitions
+    when a zone falls back just before DST springs forward.
+
+
+Release 2020d - 2020-10-21 11:24:13 -0700
+
+  Briefly:
+    Palestine ends DST earlier than predicted, on 2020-10-24.
+
+  Changes to past and future timestamps
+
+    Palestine ends DST on 2020-10-24 at 01:00, instead of 2020-10-31
+    as previously predicted (thanks to Sharef Mustafa.)  Its
+    2019-10-26 fall-back was at 00:00, not 01:00 (thanks to Steffen
+    Thorsen.)  Its 2015-10-23 transition was at 01:00 not 00:00, and
+    its spring 2020 transition was on March 28 at 00:00, not March 27
+    (thanks to Pierre Cashon.)  This affects Asia/Gaza and
+    Asia/Hebron.  Assume future spring and fall transitions will be on
+    the Saturday preceding the last Sunday of March and October,
+    respectively.
+
+
+Release 2020c - 2020-10-16 11:15:53 -0700
+
+  Briefly:
+    Fiji starts DST later than usual, on 2020-12-20.
+
+  Changes to future timestamps
+
+    Fiji will start DST on 2020-12-20, instead of 2020-11-08 as
+    previously predicted.  DST will still end on 2021-01-17.
+    (Thanks to Raymond Kumar and Alan Mintz.)  Assume for now that
+    the later-than-usual start date is a one-time departure from the
+    recent pattern.
+
+  Changes to build procedure
+
+    Rearguard tarballs now contain an empty file pacificnew.
+    Some older downstream software expects this file to exist.
+    (Problem reported by Mike Cullinan.)
+
+
+Release 2020b - 2020-10-06 18:35:04 -0700
+
+  Briefly:
+    Revised predictions for Morocco's changes starting in 2023.
+    Canada's Yukon changes to -07 on 2020-11-01, not 2020-03-08.
+    Macquarie Island has stayed in sync with Tasmania since 2011.
+    Casey, Antarctica is at +08 in winter and +11 in summer.
+    zic no longer supports -y, nor the TYPE field of Rules.
+
+  Changes to future timestamps
+
+    Morocco's spring-forward after Ramadan is now predicted to occur
+    no sooner than two days after Ramadan, instead of one day.
+    (Thanks to Milamber.)  The first altered prediction is for 2023,
+    now predicted to spring-forward on April 30 instead of April 23.
+
+  Changes to past and future timestamps
+
+   Casey Station, Antarctica has been using +08 in winter and +11 in
+   summer since 2018.  The most recent transition from +08 to +11 was
+   2020-10-04 00:01.  Also, Macquarie Island has been staying in
+   sync with Tasmania since 2011.  (Thanks to Steffen Thorsen.)
+
+  Changes to past and future time zone abbreviations and DST flags
+
+    Canada's Yukon, represented by America/Whitehorse and
+    America/Dawson, changes its time zone rules from -08/-07 to
+    permanent -07 on 2020-11-01, not on 2020-03-08 as 2020a had it.
+    This change affects only the time zone abbreviation (MST vs PDT)
+    and daylight saving flag for the period between the two dates.
+    (Thanks to Andrew G. Smith.)
+
+  Changes to past timestamps
+
+    Correct several transitions for Hungary for 1918/1983.
+    For example, the 1983-09-25 fall-back was at 01:00, not 03:00.
+    (Thanks to Géza Nyáry.)  Also, the 1890 transition to standard
+    time was on 11-01, not 10-01 (thanks to Michael Deckers).
+
+    The 1891 French transition was on March 16, not March 15.  The
+    1911-03-11 French transition was at midnight, not a minute later.
+    Monaco's transitions were on 1892-06-01 and 1911-03-29, not
+    1891-03-15 and 1911-03-11.  (Thanks to Michael Deckers.)
+
+  Changes to code
+
+    Support for zic's long-obsolete '-y YEARISTYPE' option has been
+    removed and, with it, so has support for the TYPE field in Rule
+    lines, which is now reserved for compatibility with earlier zic.
+    These features were previously deprecated in release 2015f.
+    (Thanks to Tim Parenti.)
+
+    zic now defaults to '-b slim' instead of to '-b fat'.
+
+    zic's new '-l -' and '-p -' options uninstall any existing
+    localtime and posixrules files, respectively.
+
+    The undocumented and ineffective tzsetwall function has been
+    removed.
+
+  Changes to build procedure
+
+    The Makefile now defaults POSIXRULES to '-', so the posixrules
+    feature (obsolete as of 2019b) is no longer installed by default.
+
+  Changes to documentation and commentary
+
+    The long-obsolete files pacificnew, systemv, and yearistype.sh have
+    been removed from the distribution.  (Thanks to Tim Parenti.)
+
+
+Release 2020a - 2020-04-23 16:03:47 -0700
+
+  Briefly:
+    Morocco springs forward on 2020-05-31, not 2020-05-24.
+    Canada's Yukon advanced to -07 year-round on 2020-03-08.
+    America/Nuuk renamed from America/Godthab.
+    zic now supports expiration dates for leap second lists.
+
+  Changes to future timestamps
+
+    Morocco's second spring-forward transition in 2020 will be May 31,
+    not May 24 as predicted earlier.  (Thanks to Semlali Naoufal.)
+    Adjust future-year predictions to use the first Sunday after the
+    day after Ramadan, not the first Sunday after Ramadan.
+
+    Canada's Yukon, represented by America/Whitehorse and
+    America/Dawson, advanced to -07 year-round, beginning with its
+    spring-forward transition on 2020-03-08, and will not fall back on
+    2020-11-01.  Although a government press release calls this
+    "permanent Pacific Daylight Saving Time", we prefer MST for
+    consistency with nearby Dawson Creek, Creston, and Fort Nelson.
+    (Thanks to Tim Parenti.)
+
+  Changes to past timestamps
+
+    Shanghai observed DST in 1919.  (Thanks to Phake Nick.)
+
+  Changes to timezone identifiers
+
+    To reflect current usage in English better, America/Godthab has
+    been renamed to America/Nuuk.  A backwards-compatibility link
+    remains for the old name.
+
+  Changes to code
+
+    localtime.c no longer mishandles timestamps after the last
+    transition in a TZif file with leap seconds and with daylight
+    saving time transitions projected into the indefinite future.
+    For example, with TZ='America/Los_Angeles' with leap seconds,
+    zdump formerly reported a DST transition on 2038-03-14
+    from 01:59:32.999... to 02:59:33 instead of the correct transition
+    from 01:59:59.999... to 03:00:00.
+
+    zic -L now supports an Expires line in the leapseconds file, and
+    truncates the TZif output accordingly.  This propagates leap
+    second expiration information into the TZif file, and avoids the
+    abovementioned localtime.c bug as well as similar bugs present in
+    many client implementations.  If no Expires line is present, zic
+    -L instead truncates the TZif output based on the #expires comment
+    present in leapseconds files distributed by tzdb 2018f and later;
+    however, this usage is obsolescent.  For now, the distributed
+    leapseconds file has an Expires line that is commented out, so
+    that the file can be fed to older versions of zic which ignore the
+    commented-out line.  Future tzdb distributions are planned to
+    contain a leapseconds file with an Expires line.
+
+    The configuration macros HAVE_TZNAME and USG_COMPAT should now be
+    set to 1 if the system library supports the feature, and 2 if not.
+    As before, these macros are nonzero if tzcode should support the
+    feature, zero otherwise.
+
+    The configuration macro ALTZONE now has the same values with the
+    same meaning as HAVE_TZNAME and USG_COMPAT.
+
+    The code's defense against CRLF in leap-seconds.list is now
+    portable to POSIX awk.  (Problem reported by Deborah Goldsmith.)
+
+    Although the undocumented tzsetwall function is not changed in
+    this release, it is now deprecated in preparation for removal in
+    future releases.  Due to POSIX requirements, tzsetwall has not
+    worked for some time.  Any code that uses it should instead use
+    tzalloc(NULL) or, if portability trumps thread-safety, should
+    unset the TZ environment variable.
+
+  Changes to commentary
+
+    The Îles-de-la-Madeleine and the Listuguj reserve are noted as
+    following America/Halifax, and comments about Yukon's "south" and
+    "north" have been corrected to say "east" and "west".  (Thanks to
+    Jeffery Nichols.)
+
+
+Release 2019c - 2019-09-11 08:59:48 -0700
+
+  Briefly:
+    Fiji observes DST from 2019-11-10 to 2020-01-12.
+    Norfolk Island starts observing Australian-style DST.
+
+  Changes to future timestamps
+
+    Fiji's next DST transitions will be 2019-11-10 and 2020-01-12
+    instead of 2019-11-03 and 2020-01-19.  (Thanks to Raymond Kumar.)
+    Adjust future guesses accordingly.
+
+    Norfolk Island will observe Australian-style DST starting in
+    spring 2019.  The first transition is on 2019-10-06.  (Thanks to
+    Kyle Czech and Michael Deckers.)
+
+  Changes to past timestamps
+
+    Many corrections to time in Turkey from 1940 through 1985.
+    (Thanks to Oya Vulaş via Alois Treindl, and to Kıvanç Yazan.)
+
+    The Norfolk Island 1975-03-02 transition was at 02:00 standard
+    time, not 02:00 DST.  (Thanks to Michael Deckers.)
+
+    South Korea observed DST from 1948 through 1951.  Although this
+    info was supposed to appear in release 2014j, a typo inadvertently
+    suppressed the change.  (Thanks to Alois Treindl.)
+
+    Detroit observed DST in 1967 and 1968 following the US DST rules,
+    except that its 1967 DST began on June 14 at 00:01.  (Thanks to
+    Alois Treindl for pointing out that the old data entries were
+    probably wrong.)
+
+    Fix several errors in pre-1970 transitions in Perry County, IN.
+    (Thanks to Alois Treindl for pointing out the 1967/9 errors.)
+
+    Edmonton did not observe DST in 1967 or 1969.  In 1946 Vancouver
+    ended DST on 09-29 not 10-13, and Vienna ended DST on 10-07 not
+    10-06.  In 1945 Königsberg (now Kaliningrad) switched from +01/+02
+    to +02/+03 on 04-10 not 01-01, and its +02/+03 is abbreviated
+    EET/EEST, not CET/CEST.  (Thanks to Alois Treindl.)  In 1946
+    Königsberg switched to +03 on 04-07 not 01-01.
+
+    In 1946 Louisville switched from CST to CDT on 04-28 at 00:01, not
+    01-01 at 00:00.  (Thanks to Alois Treindl and Michael Deckers.)
+    Also, it switched from CST to CDT on 1950-04-30, not 1947-04-27.
+
+    The 1892-05-01 transition in Brussels was at 00:17:30, not at noon.
+    (Thanks to Michael Deckers.)
+
+  Changes to past time zone abbreviations and DST flags
+
+    Hong Kong Winter Time, observed from 1941-10-01 to 1941-12-25,
+    is now flagged as DST and is abbreviated HKWT not HKT.
+
+  Changes to code
+
+    leapseconds.awk now relies only on its input data, rather than
+    also relying on its comments.  (Inspired by code from Dennis
+    Ferguson and Chris Woodbury.)
+
+    The code now defends against CRLFs in leap-seconds.list.
+    (Thanks to Brian Inglis and Chris Woodbury.)
+
+  Changes to documentation and commentary
+
+    theory.html discusses leap seconds.  (Thanks to Steve Summit.)
+
+    Nashville's newspapers dueled about the time of day in the 1950s.
+    (Thanks to John Seigenthaler.)
+
+    Liechtenstein observed Swiss DST in 1941/2.
+    (Thanks to Alois Treindl.)
+
+
+Release 2019b - 2019-07-01 00:09:53 -0700
+
+  Briefly:
+    Brazil no longer observes DST.
+    'zic -b slim' outputs smaller TZif files; please try it out.
+    Palestine's 2019 spring-forward transition was on 03-29, not 03-30.
+
+  Changes to future timestamps
+
+    Brazil has canceled DST and will stay on standard time indefinitely.
+    (Thanks to Steffen Thorsen, Marcus Diniz, and Daniel Soares de
+    Oliveira.)
+
+    Predictions for Morocco now go through 2087 instead of 2037, to
+    work around a problem on newlib when using TZif files output by
+    zic 2019a or earlier.  (Problem reported by David Gauchard.)
+
+  Changes to past and future timestamps
+
+    Palestine's 2019 spring transition was 03-29 at 00:00, not 03-30
+    at 01:00.  (Thanks to Sharef Mustafa and Even Scharning.)  Guess
+    future transitions to be March's last Friday at 00:00.
+
+  Changes to past timestamps
+
+    Hong Kong's 1941-06-15 spring-forward transition was at 03:00, not
+    03:30.  Its 1945 transition from JST to HKT was on 11-18 at 02:00,
+    not 09-15 at 00:00.  In 1946 its spring-forward transition was on
+    04-21 at 00:00, not the previous day at 03:30.  From 1946 through
+    1952 its fall-back transitions occurred at 04:30, not at 03:30.
+    In 1947 its fall-back transition was on 11-30, not 12-30.
+    (Thanks to P Chan.)
+
+  Changes to past time zone abbreviations
+
+    Italy's 1866 transition to Rome Mean Time was on December 12, not
+    September 22.  This affects only the time zone abbreviation for
+    Europe/Rome between those dates.  (Thanks to Stephen Trainor and
+    Luigi Rosa.)
+
+  Changes affecting metadata only
+
+    Add info about the Crimea situation in zone1970.tab and zone.tab.
+    (Problem reported by Serhii Demediuk.)
+
+  Changes to code
+
+    zic's new -b option supports a way to control data bloat and to
+    test for year-2038 bugs in software that reads TZif files.
+    'zic -b fat' and 'zic -b slim' generate larger and smaller output;
+    for example, changing from fat to slim shrinks the Europe/London
+    file from 3648 to 1599 bytes, saving about 56%.  Fat and slim
+    files represent the same set of timestamps and use the same TZif
+    format as documented in tzfile(5) and in Internet RFC 8536.
+    Fat format attempts to work around bugs or incompatibilities in
+    older software, notably software that mishandles 64-bit TZif data
+    or uses obsolete TZ strings like "EET-2EEST" that lack DST rules.
+    Slim format is more efficient and does not work around 64-bit bugs
+    or obsolete TZ strings.  Currently zic defaults to fat format
+    unless you compile with -DZIC_BLOAT_DEFAULT=\"slim\"; this
+    out-of-the-box default is intended to change in future releases
+    as the buggy software often mishandles timestamps anyway.
+
+    zic no longer treats a set of rules ending in 2037 specially.
+    Previously, zic assumed that such a ruleset meant that future
+    timestamps could not be predicted, and therefore omitted a
+    POSIX-like TZ string in the TZif output.  The old behavior is no
+    longer needed for current tzdata, and caused problems with newlib
+    when used with older tzdata (reported by David Gauchard).
+
+    zic no longer generates some artifact transitions.  For example,
+    Europe/London no longer has a no-op transition in January 1996.
+
+  Changes to build procedure
+
+    tzdata.zi now assumes zic 2017c or later.  This shrinks tzdata.zi
+    by a percent or so.
+
+  Changes to documentation and commentary
+
+    The Makefile now documents the POSIXRULES macro as being obsolete,
+    and similarly, zic's -p POSIXRULES option is now documented as
+    being obsolete.  Although the POSIXRULES feature still exists and
+    works as before, in practice it is rarely used for its intended
+    purpose, and it does not work either in the default reference
+    implementation (for timestamps after 2037) or in common
+    implementations such as GNU/Linux (for contemporary timestamps).
+    Since POSIXRULES was designed primarily as a temporary transition
+    facility for System V platforms that died off decades ago, it is
+    being decommissioned rather than institutionalized.
+
+    New info on Bonin Islands and Marcus (thanks to Wakaba and Phake Nick).
+
+
+Release 2019a - 2019-03-25 22:01:33 -0700
+
+  Briefly:
+    Palestine "springs forward" on 2019-03-30 instead of 2019-03-23.
+    Metlakatla "fell back" to rejoin Alaska Time on 2019-01-20 at 02:00.
+
+  Changes to past and future timestamps
+
+    Palestine will not start DST until 2019-03-30, instead of 2019-03-23 as
+    previously predicted.  Adjust our prediction by guessing that spring
+    transitions will be between 24 and 30 March, which matches recent practice
+    since 2016.  (Thanks to Even Scharning and Tim Parenti.)
+
+    Metlakatla ended its observance of Pacific standard time,
+    rejoining Alaska Time, on 2019-01-20 at 02:00.  (Thanks to Ryan
+    Stanley and Tim Parenti.)
+
+  Changes to past timestamps
+
+    Israel observed DST in 1980 (08-02/09-13) and 1984 (05-05/08-25).
+    (Thanks to Alois Treindl and Isaac Starkman.)
+
+  Changes to time zone abbreviations
+
+    Etc/UCT is now a backward-compatibility link to Etc/UTC, instead
+    of being a separate zone that generates the abbreviation "UCT",
+    which nowadays is typically a typo.  (Problem reported by Isiah
+    Meadows.)
+
+  Changes to code
+
+    zic now has an -r option to limit the time range of output data.
+    For example, 'zic -r @1000000000' limits the output data to
+    timestamps starting 1000000000 seconds after the Epoch.
+    This helps shrink output size and can be useful for applications
+    not needing the full timestamp history, such as TZDIST truncation;
+    see Internet RFC 8536 section 5.1.  (Inspired by a feature request
+    from Christopher Wong, helped along by bug reports from Wong and
+    from Tim Parenti.)
+
+  Changes to documentation
+
+    Mention Internet RFC 8536 (February 2019), which documents TZif.
+
+    tz-link.html now cites tzdata-meta
+    .
+
+
+Release 2018i - 2018-12-30 11:05:43 -0800
+
+  Briefly:
+    São Tomé and Príncipe switches from +01 to +00 on 2019-01-01.
+
+  Changes to future timestamps
+
+    Due to a change in government, São Tomé and Príncipe switches back
+    from +01 to +00 on 2019-01-01 at 02:00.  (Thanks to Vadim
+    Nasardinov and Michael Deckers.)
+
+
+Release 2018h - 2018-12-23 17:59:32 -0800
+
+  Briefly:
+    Qyzylorda, Kazakhstan moved from +06 to +05 on 2018-12-21.
+    New zone Asia/Qostanay because Qostanay, Kazakhstan didn't move.
+    Metlakatla, Alaska observes PST this winter only.
+    Guess Morocco will continue to adjust clocks around Ramadan.
+    Add predictions for Iran from 2038 through 2090.
+
+  Changes to future timestamps
+
+    Guess that Morocco will continue to fall back just before and
+    spring forward just after Ramadan, the practice since 2012.
+    (Thanks to Maamar Abdelkader.)  This means Morocco will observe
+    negative DST during Ramadan in main and vanguard formats, and in
+    rearguard format it stays in the +00 timezone and observes
+    ordinary DST in all months other than Ramadan.  As before, extend
+    this guesswork to the year 2037.  As a consequence, Morocco is
+    scheduled to observe three DST transitions in some Gregorian years
+    (e.g., 2033) due to the mismatch between the Gregorian and Islamic
+    calendars.
+
+    The table of exact transitions for Iranian DST has been extended.
+    It formerly cut off before the year 2038 in a nod to 32-bit time_t.
+    It now cuts off before 2091 as there is doubt about how the Persian
+    calendar will treat 2091.  This change predicts DST transitions in
+    2038-9, 2042-3, and 2046-7 to occur one day later than previously
+    predicted.  As before, post-cutoff transitions are approximated.
+
+  Changes to past and future timestamps
+
+    Qyzylorda (aka Kyzylorda) oblast in Kazakhstan moved from +06 to
+    +05 on 2018-12-21.  This is a zone split as Qostanay (aka
+    Kostanay) did not switch, so create a zone Asia/Qostanay.
+
+    Metlakatla moved from Alaska to Pacific standard time on 2018-11-04.
+    It did not change clocks that day and remains on -08 this winter.
+    (Thanks to Ryan Stanley.)  It will revert to the usual Alaska
+    rules next spring, so this change affects only timestamps
+    from 2018-11-04 through 2019-03-10.
+
+  Change to past timestamps
+
+    Kwajalein's 1993-08-20 transition from -12 to +12 was at 24:00,
+    not 00:00.  I transcribed the time incorrectly from Shanks.
+    (Thanks to Phake Nick.)
+
+    Nauru's 1979 transition was on 02-10 at 02:00, not 05-01 at 00:00.
+    (Thanks to Phake Nick.)
+
+    Guam observed DST irregularly from 1959 through 1977.
+    (Thanks to Phake Nick.)
+
+    Hong Kong observed DST in 1941 starting 06-15 (not 04-01), then on
+    10-01 changed standard time to +08:30 (not +08).  Its transition
+    back to +08 after WWII was on 1945-09-15, not the previous day.
+    Its 1904-10-30 change took effect at 01:00 +08 (not 00:00 LMT).
+    (Thanks to Phake Nick, Steve Allen, and Joseph Myers.)  Also,
+    its 1952 fallback was on 11-02 (not 10-25).
+
+    This release contains many changes to timestamps before 1946 due
+    to Japanese possession or occupation of Pacific/Chuuk,
+    Pacific/Guam, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro,
+    Pacific/Nauru, Pacific/Palau, and Pacific/Pohnpei.
+    (Thanks to Phake Nick.)
+
+    Assume that the Spanish East Indies was like the Philippines and
+    observed American time until the end of 1844.  This affects
+    Pacific/Chuuk, Pacific/Kosrae, Pacific/Palau, and Pacific/Pohnpei.
+
+  Changes to past tm_isdst flags
+
+    For the recent Morocco change, the tm_isdst flag should be 1 from
+    2018-10-27 00:00 to 2018-10-28 03:00.  (Thanks to Michael Deckers.)
+    Give a URL to the official decree.  (Thanks to Matt Johnson.)
+
+
+Release 2018g - 2018-10-26 22:22:45 -0700
+
+  Briefly:
+    Morocco switches to permanent +01 on 2018-10-28.
+
+  Changes to future timestamps
+
+    Morocco switches from +00/+01 to permanent +01 effective 2018-10-28,
+    so its clocks will not fall back as previously scheduled.
+    (Thanks to Mohamed Essedik Najd and Brian Inglis.)
+
+  Changes to code
+
+    When generating TZif files with leap seconds, zic no longer uses a
+    format that trips up older 32-bit clients, fixing a bug introduced
+    in 2018f.  (Reported by Daniel Fischer.)  Also, the zic workaround
+    for QTBUG-53071 now also works for TZif files with leap seconds.
+
+    The translator to rearguard format now rewrites the line
+    "Rule Japan 1948 1951 - Sep Sat>=8 25:00 0 S" to
+    "Rule Japan 1948 1951 - Sep Sun>=9  1:00 0 S".
+    This caters to zic before 2007 and to Oracle TZUpdater 2.2.0
+    and earlier.  (Reported by Christos Zoulas.)
+
+  Changes to past time zone abbreviations
+
+    Change HDT to HWT/HPT for WWII-era abbreviations in Hawaii.
+    This reverts to 2011h, as the abbreviation change in 2011i was
+    likely inadvertent.
+
+  Changes to documentation
+
+    tzfile.5 has new sections on interoperability issues.
+
+
+Release 2018f - 2018-10-18 00:14:18 -0700
+
+  Briefly:
+  Volgograd moves from +03 to +04 on 2018-10-28.
+  Fiji ends DST 2019-01-13, not 2019-01-20.
+  Most of Chile changes DST dates, effective 2019-04-06.
+
+  Changes to future timestamps
+
+    Volgograd moves from +03 to +04 on 2018-10-28 at 02:00.
+    (Thanks to Alexander Fetisov and Stepan Golosunov.)
+
+    Fiji ends DST 2019-01-13 instead of the 2019-01-20 previously
+    predicted.  (Thanks to Raymond Kumar.)  Adjust future predictions
+    accordingly.
+
+    Most of Chile will end DST on the first Saturday in April at 24:00 mainland
+    time, and resume DST on the first Saturday in September at 24:00 mainland
+    time.  The changes are effective from 2019-04-06, and do not affect the
+    Magallanes region modeled by America/Punta_Arenas.  (Thanks to Juan Correa
+    and Tim Parenti.)  Adjust future predictions accordingly.
+
+  Changes to past timestamps
+
+    The 2018-05-05 North Korea 30-minute time zone change took place
+    at 23:30 the previous day, not at 00:00 that day.
+
+    China's 1988 spring-forward transition was on April 17, not
+    April 10.  Its DST transitions in 1986/91 were at 02:00, not 00:00.
+    (Thanks to P Chan.)
+
+    Fix several issues for Macau before 1992.  Macau's pre-1904 LMT
+    was off by 10 s.  Macau switched to +08 in 1904 not 1912, and
+    temporarily switched to +09/+10 during World War II.  Macau
+    observed DST in 1942/79, not 1961/80, and there were several
+    errors for transition times and dates.  (Thanks to P Chan.)
+
+    The 1948-1951 fallback transitions in Japan were at 25:00 on
+    September's second Saturday, not at 24:00.  (Thanks to Phake Nick.)
+    zic turns this into 01:00 on the day after September's second
+    Saturday, which is the best that POSIX or C platforms can do.
+
+    Incorporate 1940-1949 Asia/Shanghai DST transitions from a 2014
+    paper by Li Yu, replacing more-questionable data from Shanks.
+
+  Changes to time zone abbreviations
+
+    Use "PST" and "PDT" for Philippine time.  (Thanks to Paul Goyette.)
+
+  Changes to code
+
+    zic now always generates TZif files where time type 0 is used for
+    timestamps before the first transition.  This simplifies the
+    reading of TZif files and should not affect behavior of existing
+    TZif readers because the same set of time types is used; only
+    their internal indexes may have changed.  This affects only the
+    legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
+    EET, which previously used nonzero types for these timestamps.
+
+    Because of the type 0 change, zic no longer outputs a dummy
+    transition at time -2**59 (before the Big Bang), as clients should
+    no longer need this to handle historical timestamps correctly.
+    This reverts a change introduced in 2013d and shrinks most TZif
+    files by a few bytes.
+
+    zic now supports negative time-of-day in Rule and Leap lines, e.g.,
+    "Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
+    occurs at 18:00 on the Saturday before the last Sunday in April.
+    This behavior was documented in 2018a but the code did not
+    entirely match the documentation.
+
+    localtime.c no longer requires at least one time type in TZif
+    files that lack transitions or have a POSIX-style TZ string.  This
+    future-proofs the code against possible future extensions to the
+    format that would allow TZif files with POSIX-style TZ strings and
+    without transitions or time types.
+
+    A read-access subscript error in localtime.c has been fixed.
+    It could occur only in TZif files with timecnt == 0, something that
+    does not happen in practice now but could happen in future versions.
+
+    localtime.c no longer ignores TZif POSIX-style TZ strings that
+    specify only standard time.  Instead, these TZ strings now
+    override the default time type for timestamps after the last
+    transition (or for all timestamps if there are no transitions),
+    just as DST strings specifying DST have always done.
+
+    leapseconds.awk now outputs "#updated" and "#expires" comments,
+    and supports leap seconds at the ends of months other than June
+    and December.  (Inspired by suggestions from Chris Woodbury.)
+
+  Changes to documentation
+
+    New restrictions: A Rule name must start with a character that
+    is neither an ASCII digit nor "-" nor "+", and an unquoted name
+    should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
+    The latter restriction makes room for future extensions (a
+    possibility noted by Tom Lane).
+
+    tzfile.5 now documents what time types apply before the first and
+    after the last transition, if any.
+
+    Documentation now uses the spelling "timezone" for a TZ setting
+    that determines timestamp history, and "time zone" for a
+    geographic region currently sharing the same standard time.
+
+    The name "TZif" is now used for the tz binary data format.
+
+    tz-link.htm now mentions the A0 TimeZone Migration utilities.
+    (Thanks to Aldrin Martoq for the link.)
+
+  Changes to build procedure
+
+    New 'make' target 'rearguard_tarballs' to build the rearguard
+    tarball only.  This is a convenience on platforms that lack lzip
+    if you want to build the rearguard tarball.  (Problem reported by
+    Deborah Goldsmith.)
+
+    tzdata.zi is now more stable from release to release.  (Problem
+    noted by Tom Lane.)  It is also a bit shorter.
+
+    tzdata.zi now can contain comment lines documenting configuration
+    information, such as which data format was selected, which input
+    files were used, and how leap seconds are treated.  (Problems
+    noted by Lester Caine and Brian Inglis.)  If the Makefile defaults
+    are used these comment lines are absent, for backward
+    compatibility.  A redistributor intending to alter its copy of the
+    files should also append "-LABEL" to the 'version' file's first
+    line, where "LABEL" identifies the redistributor's change.
+
+
+Release 2018e - 2018-05-01 23:42:51 -0700
+
+  Briefly:
+
+    North Korea switches back to +09 on 2018-05-05.
+    The main format uses negative DST again, for Ireland etc.
+    'make tarballs' now also builds a rearguard tarball.
+    New 's' and 'd' suffixes in SAVE columns of Rule and Zone lines.
+
+  Changes to past and future timestamps
+
+    North Korea switches back from +0830 to +09 on 2018-05-05.
+    (Thanks to Kang Seonghoon, Arthur David Olson, Seo Sanghyeon,
+    and Tim Parenti.)
+
+    Bring back the negative-DST changes of 2018a, except be more
+    compatible with data parsers that do not support negative DST.
+    Also, this now affects historical timestamps in Namibia and the
+    former Czechoslovakia, not just Ireland.  The main format now uses
+    negative DST to model timestamps in Europe/Dublin (from 1971 on),
+    Europe/Prague (1946/7), and Africa/Windhoek (1994/2017).  This
+    does not affect UT offsets, only time zone abbreviations and the
+    tm_isdst flag.  Also, this does not affect rearguard or vanguard
+    formats; effectively the main format now uses vanguard instead of
+    rearguard format.  Data parsers that do not support negative DST
+    can still use data from the rearguard tarball described below.
+
+  Changes to build procedure
+
+    The command 'make tarballs' now also builds the tarball
+    tzdataVERSION-rearguard.tar.gz, which is like tzdataVERSION.tar.gz
+    except that it uses rearguard format intended for trailing-edge
+    data parsers.
+
+  Changes to data format and to code
+
+    The SAVE column of Rule and Zone lines can now have an 's' or 'd'
+    suffix, which specifies whether the adjusted time is standard time
+    or daylight saving time.  If no suffix is given, daylight saving
+    time is used if and only if the SAVE column is nonzero; this is
+    the longstanding behavior.  Although this new feature is not used
+    in tzdata, it could be used to specify the legal time in Namibia
+    1994-2017, as opposed to the popular time (see below).
+
+  Changes to past timestamps
+
+    From 1994 through 2017 Namibia observed DST in winter, not summer.
+    That is, it used negative DST, as Ireland still does.  This change
+    does not affect UTC offsets; it affects only the tm_isdst flag and
+    the abbreviation used during summer, which is now CAT, not WAST.
+    Although (as noted by Michael Deckers) summer and winter time were
+    both simply called "standard time" in Namibian law, in common
+    practice winter time was considered to be DST (as noted by Stephen
+    Colebourne).  The full effect of this change is only in vanguard
+    and main format; in rearguard format, the tm_isdst flag is still
+    zero in winter and nonzero in summer.
+
+    In 1946/7 Czechoslovakia also observed negative DST in winter.
+    The full effect of this change is only in vanguard and main
+    formats; in rearguard format, it is modeled as plain GMT without
+    daylight saving.  Also, the dates of some 1944/5 DST transitions
+    in Czechoslovakia have been changed.
+
+
+Release 2018d - 2018-03-22 07:05:46 -0700
+
+  Briefly:
+
+  Palestine starts DST a week earlier in 2018.
+  Add support for vanguard and rearguard data consumers.
+  Add subsecond precision to source data format, though not to data.
+
+  Changes to future timestamps
+
+    In 2018, Palestine starts DST on March 24, not March 31.
+    Adjust future predictions accordingly.  (Thanks to Sharef Mustafa.)
+
+  Changes to past and future timestamps
+
+    Casey Station in Antarctica changed from +11 to +08 on 2018-03-11
+    at 04:00.  (Thanks to Steffen Thorsen.)
+
+  Changes to past timestamps
+
+    Historical transitions for Uruguay, represented by
+    America/Montevideo, have been updated per official legal documents,
+    replacing previous data mainly originating from the inventions of
+    Shanks & Pottenger.  This has resulted in adjustments ranging from
+    30 to 90 minutes in either direction over at least two dozen
+    distinct periods ranging from one day to several years in length.
+    A mere handful of pre-1991 transitions are unaffected; data since
+    then has come from more reliable contemporaneous reporting.  These
+    changes affect various timestamps in 1920-1923, 1936, 1939,
+    1942-1943, 1959, 1966-1970, 1972, 1974-1980, and 1988-1990.
+    Additionally, Uruguay's pre-standard-time UT offset has been
+    adjusted westward by 7 seconds, from UT-03:44:44 to UT-03:44:51, to
+    match the location of the Observatory of the National Meteorological
+    Institute in Montevideo.
+    (Thanks to Jeremie Bonjour, Tim Parenti, and Michael Deckers.)
+
+    East Kiribati skipped New Year's Eve 1994, not New Year's Day 1995.
+    (Thanks to Kerry Shetline.)
+
+    Fix the 1912-01-01 transition for Portugal and its colonies.
+    This transition was at 00:00 according to the new UT offset, not
+    according to the old one.  Also assume that Cape Verde switched on
+    the same date as the rest, not in 1907.  This affects
+    Africa/Bissau, Africa/Sao_Tome, Asia/Macau, Atlantic/Azores,
+    Atlantic/Cape_Verde, Atlantic/Madeira, and Europe/Lisbon.
+    (Thanks to Michael Deckers.)
+
+    Fix an off-by-1 error for pre-1913 timestamps in Jamaica and in
+    Turks & Caicos.
+
+  Changes to past time zone abbreviations
+
+    MMT took effect in Uruguay from 1908-06-10, not 1898-06-28.  There
+    is no clock change associated with the transition.
+
+  Changes to build procedure
+
+    The new DATAFORM macro in the Makefile lets the installer choose
+    among three source data formats.  The idea is to lessen downstream
+    disruption when data formats are improved.
+
+    * DATAFORM=vanguard installs from the latest, bleeding-edge
+      format.  DATAFORM=main (the default) installs from the format
+      used in the 'africa' etc. files.  DATAFORM=rearguard installs
+      from a trailing-edge format.  Eventually, elements of today's
+      vanguard format should move to the main format, and similarly
+      the main format's features should eventually move to the
+      rearguard format.
+
+    * In the current version, the main and rearguard formats are
+      identical and match that of 2018c, so this change does not
+      affect default behavior.  The vanguard format currently contains
+      one feature not in the main format: negative SAVE values.  This
+      improves support for Ireland, which uses Irish Standard Time
+      (IST, UTC+01) in summer and GMT (UTC) in winter.  tzcode has
+      supported negative SAVE values for decades, and this feature
+      should move to the main format soon.  However, it will not move
+      to the rearguard format for quite some time because some
+      downstream parsers do not support it.
+
+    * The build procedure constructs three files vanguard.zi, main.zi,
+      and rearguard.zi, one for each format.  Although the files
+      represent essentially the same data, they may have minor
+      discrepancies that users are not likely to notice.  The files
+      are intended for downstream data consumers and are not
+      installed.  Zoneinfo parsers that do not support negative SAVE values
+      should start using rearguard.zi, so that they will be unaffected
+      when the negative-DST feature moves from vanguard to main.
+      Bleeding-edge Zoneinfo parsers that support the new features
+      already can use vanguard.zi; in this respect, current tzcode is
+      bleeding-edge.
+
+    The Makefile should now be safe for parallelized builds, and 'make
+    -j to2050new.tzs' is now much faster on a multiprocessor host
+    with GNU Make.
+
+    When built with -DSUPPRESS_TZDIR, the tzcode library no longer
+    prepends TZDIR/ to file names that do not begin with '/'.  This is
+    not recommended for general use, due to its security implications.
+    (From a suggestion by Manuela Friedrich.)
+
+  Changes to code
+
+    zic now accepts subsecond precision in expressions like
+    00:19:32.13, which is approximately the legal time of the
+    Netherlands from 1835 to 1937.  However, because it is
+    questionable whether the few recorded uses of non-integer offsets
+    had subsecond precision in practice, there are no plans for tzdata
+    to use this feature.  (Thanks to Steve Allen for pointing out
+    the limitations of historical data in this area.)
+
+    The code is a bit more portable to MS-Windows.  Installers can
+    compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
+    reserve identifiers like 'localtime'.  (Thanks to Manuela
+    Friedrich.)
+
+  Changes to documentation and commentary
+
+    theory.html now outlines tzdb's extensions to POSIX's model for
+    civil time, and has a section "POSIX features no longer needed"
+    that lists POSIX API components that are now vestigial.
+    (From suggestions by Steve Summit.)  It also better distinguishes
+    time zones from tz regions.  (From a suggestion by Guy Harris.)
+
+    Commentary is now more consistent about using the phrase "daylight
+    saving time", to match the C name tm_isdst.  Daylight saving time
+    need not occur in summer, and need not have a positive offset from
+    standard time.
+
+    Commentary about historical transitions in Uruguay has been expanded
+    with links to many relevant legal documents.
+    (Thanks to Tim Parenti.)
+
+    Commentary now uses some non-ASCII characters with Unicode value
+    less than U+0100, as they can be useful and should work even with
+    older editors such as XEmacs.
+
+
+Release 2018c - 2018-01-22 23:00:44 -0800
+
+  Briefly:
+  Revert Irish changes that relied on negative SAVE values.
+
+  Changes to tm_isdst
+
+    Revert the 2018a change to Europe/Dublin.  As before, this change
+    does not affect UT offsets or abbreviations; it affects only
+    whether timestamps are considered to be standard time or
+    daylight-saving time, as expressed in the tm_isdst flag of C's
+    struct tm type.  This reversion is intended to be a temporary
+    workaround for problems discovered with downstream uses of
+    releases 2018a and 2018b, which implemented Irish time by using
+    negative SAVE values in the Eire rules of the 'europe' file.
+    Although negative SAVE values have been part of tzcode for many
+    years and are supported by many platforms, they were not
+    documented before 2018a and ICU and OpenJDK do not currently
+    support them.  A mechanism to export data to platforms lacking
+    support for negative DST is planned to be developed before the
+    change is reapplied.  (Problems reported by Deborah Goldsmith and
+    Stephen Colebourne.)
+
+  Changes to past timestamps
+
+    Japanese DST transitions (1948-1951) were Sundays at 00:00, not
+    Saturdays or Sundays at 02:00.  (Thanks to Takayuki Nikai.)
+
+  Changes to build procedure
+
+    The build procedure now works around mawk 1.3.3's lack of support
+    for character class expressions.  (Problem reported by Ohyama.)
+
+
+Release 2018b - 2018-01-17 23:24:48 -0800
+
+  Briefly:
+  Fix a packaging problem in tz2018a, which was missing 'pacificnew'.
+
+  Changes to build procedure
+
+    The distribution now contains the file 'pacificnew' again.
+    This file was inadvertently omitted in the 2018a distribution.
+    (Problem reported by Matias Fonzo.)
+
+
+Release 2018a - 2018-01-12 22:29:21 -0800
+
+  Briefly:
+  São Tomé and Príncipe switched from +00 to +01.
+  Brazil's DST will now start on November's first Sunday.
+  Ireland's standard time is now in the summer, not the winter.
+  Use Debian-style installation locations, instead of 4.3BSD-style.
+  New zic option -t.
+
+  Changes to past and future timestamps
+
+    São Tomé and Príncipe switched from +00 to +01 on 2018-01-01 at
+    01:00.  (Thanks to Steffen Thorsen and Michael Deckers.)
+
+  Changes to future timestamps
+
+    Starting in 2018 southern Brazil will begin DST on November's
+    first Sunday instead of October's third Sunday.  (Thanks to
+    Steffen Thorsen.)
+
+  Changes to past timestamps
+
+    A discrepancy of 4 s in timestamps before 1931 in South Sudan has
+    been corrected.  The 'backzone' and 'zone.tab' files did not agree
+    with the 'africa' and 'zone1970.tab' files.  (Problem reported by
+    Michael Deckers.)
+
+    The abbreviation invented for Bolivia Summer Time (1931-2) is now
+    BST instead of BOST, to be more consistent with the convention
+    used for Latvian Summer Time (1918-9) and for British Summer Time.
+
+  Changes to tm_isdst
+
+    Change Europe/Dublin so that it observes Irish Standard Time (UT
+    +01) in summer and GMT (as negative daylight-saving) in winter,
+    instead of observing standard time (GMT) in winter and Irish
+    Summer Time (UT +01) in summer.  This change does not affect UT
+    offsets or abbreviations; it affects only whether timestamps are
+    considered to be standard time or daylight-saving time, as
+    expressed in the tm_isdst flag of C's struct tm type.
+    (Discrepancy noted by Derick Rethans.)
+
+  Changes to build procedure
+
+    The default installation locations have been changed to mostly
+    match Debian circa 2017, instead of being designed as an add-on to
+    4.3BSD circa 1986.  This affects the Makefile macros TOPDIR,
+    TZDIR, MANDIR, and LIBDIR.  New Makefile macros TZDEFAULT, USRDIR,
+    USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
+    locations more precisely.  (This responds to suggestions from
+    Brian Inglis and from Steve Summit.)
+
+    The default installation procedure no longer creates the
+    backward-compatibility link US/Pacific-New, which causes
+    confusion during user setup (e.g., see Debian bug 815200).
+    Use 'make BACKWARD="backward pacificnew"' to create the link
+    anyway, for now.  Eventually we plan to remove the link entirely.
+
+    tzdata.zi now contains a version-number comment.
+    (Suggested by Tom Lane.)
+
+    The Makefile now quotes values like BACKWARD more carefully when
+    passing them to the shell.  (Problem reported by Zefram.)
+
+    Builders no longer need to specify -DHAVE_SNPRINTF on platforms
+    that have snprintf and use pre-C99 compilers.  (Problem reported
+    by Jon Skeet.)
+
+  Changes to code
+
+    zic has a new option -t FILE that specifies the location of the
+    file that determines local time when TZ is unset.  The default for
+    this location can be configured via the new TZDEFAULT makefile
+    macro, which defaults to /etc/localtime.
+
+    Diagnostics and commentary now distinguish UT from UTC more
+    carefully; see theory.html for more information about UT vs UTC.
+
+    zic has been ported to GCC 8's -Wstringop-truncation option.
+    (Problem reported by Martin Sebor.)
+
+  Changes to documentation and commentary
+
+    The zic man page now documents the longstanding behavior that
+    times and years can be out of the usual range, with negative times
+    counting backwards from midnight and with year 0 preceding year 1.
+    (Problem reported by Michael Deckers.)
+
+    The theory.html file now mentions the POSIX limit of six chars
+    per abbreviation, and lists alphabetic abbreviations used.
+
+    The files tz-art.htm and tz-link.htm have been renamed to
+    tz-art.html and tz-link.html, respectively, for consistency with
+    other file names and to simplify web server configuration.
+
+
+Release 2017c - 2017-10-20 14:49:34 -0700
+
+  Briefly:
+  Northern Cyprus switches from +03 to +02/+03 on 2017-10-29.
+  Fiji ends DST 2018-01-14, not 2018-01-21.
+  Namibia switches from +01/+02 to +02 on 2018-04-01.
+  Sudan switches from +03 to +02 on 2017-11-01.
+  Tonga likely switches from +13/+14 to +13 on 2017-11-05.
+  Turks & Caicos switches from -04 to -05/-04 on 2018-11-04.
+  A new file tzdata.zi now holds a small text copy of all data.
+  The zic input format has been regularized slightly.
+
+  Changes to future timestamps
+
+    Northern Cyprus has decided to resume EU rules starting
+    2017-10-29, thus reinstituting winter time.
+
+    Fiji ends DST 2018-01-14 instead of the 2018-01-21 previously
+    predicted.  (Thanks to Dominic Fok.)  Adjust future predictions
+    accordingly.
+
+    Namibia will switch from +01 with DST to +02 all year on
+    2017-09-03 at 02:00.  This affects UT offsets starting 2018-04-01
+    at 02:00.  (Thanks to Steffen Thorsen.)
+
+    Sudan will switch from +03 to +02 on 2017-11-01.  (Thanks to Ahmed
+    Atyya and Yahia Abdalla.)  South Sudan is not switching, so
+    Africa/Juba is no longer a link to Africa/Khartoum.
+
+    Tonga has likely ended its experiment with DST, and will not
+    adjust its clocks on 2017-11-05.  Although Tonga has not announced
+    whether it will continue to observe DST, the IATA is assuming that
+    it will not.  (Thanks to David Wade.)
+
+    Turks & Caicos will switch from -04 all year to -05 with US DST on
+    2018-03-11 at 03:00.  This affects UT offsets starting 2018-11-04
+    at 02:00.  (Thanks to Steffen Thorsen.)
+
+  Changes to past timestamps
+
+    Namibia switched from +02 to +01 on 1994-03-21, not 1994-04-03.
+    (Thanks to Arthur David Olson.)
+
+    Detroit did not observe DST in 1967.
+
+    Use railway time for Asia/Kolkata before 1941, by switching to
+    Madras local time (UT +052110) in 1870, then to IST (UT +0530) in
+    1906.  Also, treat 1941-2's +0630 as DST, like 1942-5.
+
+    Europe/Dublin's 1946 and 1947 fallback transitions occurred at
+    02:00 standard time, not 02:00 DST.  (Thanks to Michael Deckers.)
+
+    Pacific/Apia and Pacific/Pago_Pago switched from Antipodean to
+    American time in 1892, not 1879.  (Thanks to Michael Deckers.)
+
+    Adjust the 1867 transition in Alaska to better reflect the
+    historical record, by changing it to occur on 1867-10-18 at 15:30
+    Sitka time rather than at the start of 1867-10-17 local time.
+    Although strictly speaking this is accurate only for Sitka,
+    the rest of Alaska's blanks need to be filled in somehow.
+
+    Fix off-by-one errors in UT offsets for Adak and Nome before 1867.
+    (Thanks to Michael Deckers.)
+
+    Add 7 s to the UT offset in Asia/Yangon before 1920.
+
+  Changes to zone names
+
+    Remove Canada/East-Saskatchewan from the 'backward' file, as it
+    exceeded the 14-character limit and was an unused misnomer anyway.
+
+  Changes to build procedure
+
+    To support applications that prefer to read time zone data in text
+    form, two zic input files tzdata.zi and leapseconds are now
+    installed by default.  The commands 'zic tzdata.zi' and 'zic -L
+    leapseconds tzdata.zi' can reproduce the tzdata binary files
+    without and with leap seconds, respectively.  To prevent these two
+    new files from being installed, use 'make TZDATA_TEXT=', and to
+    suppress leap seconds from the tzdata text installation, use 'make
+    TZDATA_TEXT=tzdata.zi'.
+
+    'make BACKWARD=' now suppresses backward-compatibility names
+    like 'US/Pacific' that are defined in the 'backward' and
+    'pacificnew' files.
+
+    'make check' now works on systems that lack a UTF-8 locale,
+    or that lack the nsgmls program.  Set UTF8_LOCALE to configure
+    the name of a UTF-8 locale, if you have one.
+
+    Y2K runtime checks are no longer enabled by default.  Add
+    -DDEPRECATE_TWO_DIGIT_YEARS to CFLAGS to enable them, instead of
+    adding -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
+    to disable them.  (New name suggested by Brian Inglis.)
+
+    The build procedure for zdump now works on AIX 7.1.
+    (Problem reported by Kees Dekker.)
+
+  Changes to code
+
+    zic and the reference runtime now reject multiple leap seconds
+    within 28 days of each other, or leap seconds before the Epoch.
+    As a result, support for double leap seconds, which was
+    obsolescent and undocumented, has been removed.  Double leap
+    seconds were an error in the C89 standard; they have never existed
+    in civil timekeeping.  (Thanks to Robert Elz and Bradley White for
+    noticing glitches in the code that uncovered this problem.)
+
+    zic now warns about use of the obsolescent and undocumented -y
+    option, and about use of the obsolescent TYPE field of Rule lines.
+
+    zic now allows unambiguous abbreviations like "Sa" and "Su" for
+    weekdays; formerly it rejected them due to a bug.  Conversely, zic
+    no longer considers non-prefixes to be abbreviations; for example,
+    it no longer accepts "lF" as an abbreviation for "lastFriday".
+    Also, zic warns about the undocumented usage with a "last-"
+    prefix, e.g., "last-Fri".
+
+    Similarly, zic now accepts the unambiguous abbreviation "L" for
+    "Link" in ordinary context and for "Leap" in leap-second context.
+    Conversely, zic no longer accepts non-prefixes such as "La" as
+    abbreviations for words like "Leap".
+
+    zic no longer accepts leap second lines in ordinary input, or
+    ordinary lines in leap second input.  Formerly, zic sometimes
+    warned about this undocumented usage and handled it incorrectly.
+
+    The new macro HAVE_TZNAME governs whether the tzname external
+    variable is exported, instead of USG_COMPAT.  USG_COMPAT now
+    governs only the external variables "timezone" and "daylight".
+    This change is needed because the three variables are not in the
+    same category: although POSIX requires tzname, it specifies the
+    other two variables as optional.  Also, USG_COMPAT is now 1 or 0:
+    if not defined, the code attempts to guess it from other macros.
+
+    localtime.c and difftime.c no longer require stdio.h, and .c files
+    other than zic.c no longer require sys/wait.h.
+
+    zdump.c no longer assumes snprintf.  (Reported by Jonathan Leffler.)
+
+    Calculation of time_t extrema works around a bug in GCC 4.8.4
+    (Reported by Stan Shebs and Joseph Myers.)
+
+    zic.c no longer mistranslates formats of line numbers in non-English
+    locales.  (Problem reported by Benno Schulenberg.)
+
+    Several minor changes have been made to the code to make it a
+    bit easier to port to MS-Windows and Solaris.  (Thanks to Kees
+    Dekker for reporting the problems.)
+
+  Changes to documentation and commentary
+
+    The two new files 'theory.html' and 'calendars' contain the
+    contents of the removed file 'Theory'.  The goal is to document
+    tzdb theory more accessibly.
+
+    The zic man page now documents abbreviation rules.
+
+    tz-link.htm now covers how to apply tzdata changes to clients.
+    (Thanks to Jorge Fábregas for the AIX link.)  It also mentions MySQL.
+
+    The leap-seconds.list URL has been updated to something that is
+    more reliable for tzdb.  (Thanks to Tim Parenti and Brian Inglis.)
+
+Release 2017b - 2017-03-17 07:30:38 -0700
+
+  Briefly: Haiti has resumed DST.
+
+  Changes to past and future timestamps
+
+    Haiti resumed observance of DST in 2017.  (Thanks to Steffen Thorsen.)
+
+  Changes to past timestamps
+
+    Liberia changed from -004430 to +00 on 1972-01-07, not 1972-05-01.
+
+    Use "MMT" to abbreviate Liberia's time zone before 1972, as "-004430"
+    is one byte over the POSIX limit.  (Problem reported by Derick Rethans.)
+
+  Changes to code
+
+    The reference localtime implementation now falls back on the
+    current US daylight-saving transition rules rather than the
+    1987-2006 rules.  This fallback occurs only when (1) the TZ
+    environment variable has a value like "AST4ADT" that asks
+    for daylight saving time but does not specify the rules, (2) there
+    is no file by that name, and (3) the TZDEFRULES file cannot be
+    loaded.  (Thanks to Tom Lane.)
+
+
+Release 2017a - 2017-02-28 00:05:36 -0800
+
+  Briefly: Southern Chile moves from -04/-03 to -03, and Mongolia
+  discontinues DST.
+
+  Changes to future timestamps
+
+    Mongolia no longer observes DST.  (Thanks to Ganbold Tsagaankhuu.)
+
+    Chile's Region of Magallanes moves from -04/-03 to -03 year-round.
+    Its clocks diverge from America/Santiago starting 2017-05-13 at
+    23:00, hiving off a new zone America/Punta_Arenas.  Although the
+    Chilean government says this change expires in May 2019, for now
+    assume it's permanent.  (Thanks to Juan Correa and Deborah
+    Goldsmith.)  This also affects Antarctica/Palmer.
+
+  Changes to past timestamps
+
+    Fix many entries for historical timestamps for Europe/Madrid
+    before 1979, to agree with tables compiled by Pere Planesas of the
+    National Astronomical Observatory of Spain.  As a side effect,
+    this changes some timestamps for Africa/Ceuta before 1929, which
+    are probably guesswork anyway.  (Thanks to Steve Allen and
+    Pierpaolo Bernardi for the heads-ups, and to Michael Deckers for
+    correcting the 1901 transition.)
+
+    Ecuador observed DST from 1992-11-28 to 1993-02-05.
+    (Thanks to Alois Treindl.)
+
+    Asia/Atyrau and Asia/Oral were at +03 (not +04) before 1930-06-21.
+    (Thanks to Stepan Golosunov.)
+
+  Changes to past and future time zone abbreviations
+
+    Switch to numeric time zone abbreviations for South America, as
+    part of the ongoing project of removing invented abbreviations.
+    This avoids the need to invent an abbreviation for the new Chilean
+    new zone.  Similarly, switch from invented to numeric time zone
+    abbreviations for Afghanistan, American Samoa, the Azores,
+    Bangladesh, Bhutan, the British Indian Ocean Territory, Brunei,
+    Cape Verde, Chatham Is, Christmas I, Cocos (Keeling) Is, Cook Is,
+    Dubai, East Timor, Eucla, Fiji, French Polynesia, Greenland,
+    Indochina, Iran, Iraq, Kiribati, Lord Howe, Macquarie, Malaysia,
+    the Maldives, Marshall Is, Mauritius, Micronesia, Mongolia,
+    Myanmar, Nauru, Nepal, New Caledonia, Niue, Norfolk I, Palau,
+    Papua New Guinea, the Philippines, Pitcairn, Qatar, Réunion, St
+    Pierre & Miquelon, Samoa, Saudi Arabia, Seychelles, Singapore,
+    Solomon Is, Tokelau, Tuvalu, Wake, Vanuatu, Wallis & Futuna, and
+    Xinjiang; for 20-minute daylight saving time in Ghana before 1943;
+    for half-hour daylight saving time in Belize before 1944 and in
+    the Dominican Republic before 1975; and for Canary Islands before
+    1946, for Guinea-Bissau before 1975, for Iceland before 1969, for
+    Indian Summer Time before 1942, for Indonesia before around 1964,
+    for Kenya before 1960, for Liberia before 1973, for Madeira before
+    1967, for Namibia before 1943, for the Netherlands in 1937-9, for
+    Pakistan before 1971, for Western Sahara before 1977, and for
+    Zaporozhye in 1880-1924.
+
+    For Alaska time from 1900 through 1967, instead of "CAT" use the
+    abbreviation "AST", the abbreviation commonly used at the time
+    (Atlantic Standard Time had not been standardized yet).  Use "AWT"
+    and "APT" instead of the invented abbreviations "CAWT" and "CAPT".
+
+    Use "CST" and "CDT" instead of invented abbreviations for Macau
+    before 1999 and Taiwan before 1938, and use "JST" instead of the
+    invented abbreviation "JCST" for Japan and Korea before 1938.
+
+  Change to database entry category
+
+    Move the Pacific/Johnston link from 'australasia' to 'backward',
+    since Johnston is now uninhabited.
+
+  Changes to code
+
+    zic no longer mishandles some transitions in January 2038 when it
+    attempts to work around Qt bug 53071.  This fixes a bug affecting
+    Pacific/Tongatapu that was introduced in zic 2016e.  localtime.c
+    now contains a workaround, useful when loading a file generated by
+    a buggy zic.  (Problem and localtime.c fix reported by Bradley
+    White.)
+
+    zdump -i now outputs non-hour numeric time zone abbreviations
+    without a colon, e.g., "+0530" rather than "+05:30".  This agrees
+    with zic %z and with common practice, and simplifies auditing of
+    zdump output.
+
+    zdump is now buildable again with -DUSE_LTZ=0.
+    (Problem reported by Joseph Myers.)
+
+    zdump.c now always includes private.h, to avoid code duplication
+    with private.h.  (Problem reported by Kees Dekker.)
+
+    localtime.c no longer mishandles early or late timestamps
+    when TZ is set to a POSIX-style string that specifies DST.
+    (Problem reported by Kees Dekker.)
+
+    date and strftime now cause %z to generate "-0000" instead of
+    "+0000" when the UT offset is zero and the time zone abbreviation
+    begins with "-".
+
+  Changes to documentation and commentary
+
+    The 'Theory' file now better documents choice of historical time
+    zone abbreviations.  (Problems reported by Michael Deckers.)
+
+    tz-link.htm now covers leap smearing, which is popular in clouds.
+
+
+Release 2016j - 2016-11-22 23:17:13 -0800
+
+  Briefly: Saratov, Russia moves from +03 to +04 on 2016-12-04.
+
+  Changes to future timestamps
+
+    Saratov, Russia switches from +03 to +04 on 2016-12-04 at 02:00.
+    This hives off a new zone Europe/Saratov from Europe/Volgograd.
+    (Thanks to Yuri Konotopov and Stepan Golosunov.)
+
+  Changes to past timestamps
+
+    The new zone Asia/Atyrau for Atyraū Region, Kazakhstan, is like
+    Asia/Aqtau except it switched from +05/+06 to +04/+05 in spring
+    1999, not fall 1994.  (Thanks to Stepan Golosunov.)
+
+  Changes to past time zone abbreviations
+
+    Asia/Gaza and Asia/Hebron now use "EEST", not "EET", to denote
+    summer time before 1948.  The old use of "EET" was a typo.
+
+  Changes to code
+
+    zic no longer mishandles file systems that lack hard links, fixing
+    bugs introduced in 2016g.  (Problems reported by Tom Lane.)
+    Also, when the destination already contains symbolic links, zic
+    should now work better on systems where the 'link' system call
+    does not follow symbolic links.
+
+  Changes to documentation and commentary
+
+    tz-link.htm now documents the relationship between release version
+    numbers and development-repository commit tags.  (Suggested by
+    Paul Koning.)
+
+    The 'Theory' file now documents UT.
+
+    iso3166.tab now accents "Curaçao", and commentary now mentions
+    the names "Cabo Verde" and "Czechia".  (Thanks to Jiří Boháč.)
+
+
+Release 2016i - 2016-11-01 23:19:52 -0700
+
+  Briefly: Cyprus split into two time zones on 2016-10-30, and Tonga
+  reintroduces DST on 2016-11-06.
+
+  Changes to future timestamps
+
+    Pacific/Tongatapu begins DST on 2016-11-06 at 02:00, ending on
+    2017-01-15 at 03:00.  Assume future observances in Tonga will be
+    from the first Sunday in November through the third Sunday in
+    January, like Fiji.  (Thanks to Pulu ʻAnau.)  Switch to numeric
+    time zone abbreviations for this zone.
+
+  Changes to past and future timestamps
+
+    Northern Cyprus is now +03 year round, causing a split in Cyprus
+    time zones starting 2016-10-30 at 04:00.  This creates a zone
+    Asia/Famagusta.  (Thanks to Even Scharning and Matt Johnson.)
+
+    Antarctica/Casey switched from +08 to +11 on 2016-10-22.
+    (Thanks to Steffen Thorsen.)
+
+  Changes to past timestamps
+
+    Several corrections were made for pre-1975 timestamps in Italy.
+    These affect Europe/Malta, Europe/Rome, Europe/San_Marino, and
+    Europe/Vatican.
+
+    First, the 1893-11-01 00:00 transition in Italy used the new UT
+    offset (+01), not the old (+00:49:56).  (Thanks to Michael
+    Deckers.)
+
+    Second, rules for daylight saving in Italy were changed to agree
+    with Italy's National Institute of Metrological Research (INRiM)
+    except for 1944, as follows (thanks to Pierpaolo Bernardi, Brian
+    Inglis, and Michael Deckers):
+
+      The 1916-06-03 transition was at 24:00, not 00:00.
+
+      The 1916-10-01, 1919-10-05, and 1920-09-19 transitions were at
+      00:00, not 01:00.
+
+      The 1917-09-30 and 1918-10-06 transitions were at 24:00, not
+      01:00.
+
+      The 1944-09-17 transition was at 03:00, not 01:00.  This
+      particular change is taken from Italian law as INRiM's table,
+      (which says 02:00) appears to have a typo here.  Also, keep the
+      1944-04-03 transition for Europe/Rome, as Rome was controlled by
+      Germany then.
+
+      The 1967-1970 and 1972-1974 fallback transitions were at 01:00,
+      not 00:00.
+
+  Changes to code
+
+    The code should now be buildable on AmigaOS merely by setting the
+    appropriate Makefile variables.  (From a patch by Carsten Larsen.)
+
+
+Release 2016h - 2016-10-19 23:17:57 -0700
+
+  Changes to future timestamps
+
+    Asia/Gaza and Asia/Hebron end DST on 2016-10-29 at 01:00, not
+    2016-10-21 at 00:00.  (Thanks to Sharef Mustafa.)  Predict that
+    future fall transitions will be on the last Saturday of October
+    at 01:00, which is consistent with predicted spring transitions
+    on the last Saturday of March.  (Thanks to Tim Parenti.)
+
+  Changes to past timestamps
+
+    In Turkey, transitions in 1986-1990 were at 01:00 standard time
+    not at 02:00, and the spring 1994 transition was on March 20, not
+    March 27.  (Thanks to Kıvanç Yazan.)
+
+  Changes to past and future time zone abbreviations
+
+    Asia/Colombo now uses numeric time zone abbreviations like "+0530"
+    instead of alphabetic ones like "IST" and "LKT".  Various
+    English-language sources use "IST", "LKT" and "SLST", with no
+    working consensus.  (Usage of "SLST" mentioned by Sadika
+    Sumanapala.)
+
+  Changes to code
+
+    zic no longer mishandles relativizing file names when creating
+    symbolic links like /etc/localtime, when these symbolic links
+    are outside the usual directory hierarchy.  This fixes a bug
+    introduced in 2016g.  (Problem reported by Andreas Stieger.)
+
+  Changes to build procedure
+
+    New rules 'traditional_tarballs' and 'traditional_signatures' for
+    building just the traditional-format distribution.  (Requested by
+    Deborah Goldsmith.)
+
+    The file 'version' is now put into the tzdata tarball too.
+    (Requested by Howard Hinnant.)
+
+  Changes to documentation and commentary
+
+    The 'Theory' file now has a section on interface stability.
+    (Requested by Paul Koning.)  It also mentions features like
+    tm_zone and localtime_rz that have long been supported by the
+    reference code.
+
+    tz-link.htm has improved coverage of time zone boundaries suitable
+    for geolocation.  (Thanks to heads-ups from Evan Siroky and Matt
+    Johnson.)
+
+    The US commentary now mentions Allen and the "day of two noons".
+
+    The Fiji commentary mentions the government's 2016-10-03 press
+    release.  (Thanks to Raymond Kumar.)
+
+
+Release 2016g - 2016-09-13 08:56:38 -0700
+
+  Changes to future timestamps
+
+    Turkey switched from EET/EEST (+02/+03) to permanent +03,
+    effective 2016-09-07.  (Thanks to Burak AYDIN.)  Use "+03" rather
+    than an invented abbreviation for the new time.
+
+    New leap second 2016-12-31 23:59:60 UTC as per IERS Bulletin C 52.
+    (Thanks to Tim Parenti.)
+
+  Changes to past timestamps
+
+    For America/Los_Angeles, spring-forward transition times have been
+    corrected from 02:00 to 02:01 in 1948, and from 02:00 to 01:00 in
+    1950-1966.
+
+    For zones using Soviet time on 1919-07-01, transitions to UT-based
+    time were at 00:00 UT, not at 02:00 local time.  The affected
+    zones are Europe/Kirov, Europe/Moscow, Europe/Samara, and
+    Europe/Ulyanovsk.  (Thanks to Alexander Belopolsky.)
+
+  Changes to past and future time zone abbreviations
+
+    The Factory zone now uses the time zone abbreviation -00 instead
+    of a long English-language string, as -00 is now the normal way to
+    represent an undefined time zone.
+
+    Several zones in Antarctica and the former Soviet Union, along
+    with zones intended for ships at sea that cannot use POSIX TZ
+    strings, now use numeric time zone abbreviations instead of
+    invented or obsolete alphanumeric abbreviations.  The affected
+    zones are Antarctica/Casey, Antarctica/Davis,
+    Antarctica/DumontDUrville, Antarctica/Mawson, Antarctica/Rothera,
+    Antarctica/Syowa, Antarctica/Troll, Antarctica/Vostok,
+    Asia/Anadyr, Asia/Ashgabat, Asia/Baku, Asia/Bishkek, Asia/Chita,
+    Asia/Dushanbe, Asia/Irkutsk, Asia/Kamchatka, Asia/Khandyga,
+    Asia/Krasnoyarsk, Asia/Magadan, Asia/Omsk, Asia/Sakhalin,
+    Asia/Samarkand, Asia/Srednekolymsk, Asia/Tashkent, Asia/Tbilisi,
+    Asia/Ust-Nera, Asia/Vladivostok, Asia/Yakutsk, Asia/Yekaterinburg,
+    Asia/Yerevan, Etc/GMT-14, Etc/GMT-13, Etc/GMT-12, Etc/GMT-11,
+    Etc/GMT-10, Etc/GMT-9, Etc/GMT-8, Etc/GMT-7, Etc/GMT-6, Etc/GMT-5,
+    Etc/GMT-4, Etc/GMT-3, Etc/GMT-2, Etc/GMT-1, Etc/GMT+1, Etc/GMT+2,
+    Etc/GMT+3, Etc/GMT+4, Etc/GMT+5, Etc/GMT+6, Etc/GMT+7, Etc/GMT+8,
+    Etc/GMT+9, Etc/GMT+10, Etc/GMT+11, Etc/GMT+12, Europe/Kaliningrad,
+    Europe/Minsk, Europe/Samara, Europe/Volgograd, and
+    Indian/Kerguelen.  For Europe/Moscow the invented abbreviation MSM
+    was replaced by +05, whereas MSK and MSD were kept as they are not
+    our invention and are widely used.
+
+  Changes to zone names
+
+    Rename Asia/Rangoon to Asia/Yangon, with a backward compatibility link.
+    (Thanks to David Massoud.)
+
+  Changes to code
+
+    zic no longer generates binary files containing POSIX TZ-like
+    strings that disagree with the local time type after the last
+    explicit transition in the data.  This fixes a bug with
+    Africa/Casablanca and Africa/El_Aaiun in some year-2037 timestamps
+    on the reference platform.  (Thanks to Alexander Belopolsky for
+    reporting the bug and suggesting a way forward.)
+
+    If the installed localtime and/or posixrules files are symbolic
+    links, zic now keeps them symbolic links when updating them, for
+    compatibility with platforms like OpenSUSE where other programs
+    configure these files as symlinks.
+
+    zic now avoids hard linking to symbolic links, avoids some
+    unnecessary mkdir and stat system calls, and uses shorter file
+    names internally.
+
+    zdump has a new -i option to generate transitions in a
+    more-compact but still human-readable format.  This option is
+    experimental, and the output format may change in future versions.
+    (Thanks to Jon Skeet for suggesting that an option was needed,
+    and thanks to Tim Parenti and Chris Rovick for further comments.)
+
+  Changes to build procedure
+
+    An experimental distribution format is available, in addition
+    to the traditional format which will continue to be distributed.
+    The new format is a tarball tzdb-VERSION.tar.lz with signature
+    file tzdb-VERSION.tar.lz.asc.  It unpacks to a top-level directory
+    tzdb-VERSION containing the code and data of the traditional
+    two-tarball format, along with extra data that may be useful.
+    (Thanks to Antonio Diaz Diaz, Oscar van Vlijmen, and many others
+    for comments about the experimental format.)
+
+    The release version number is now more accurate in the usual case
+    where releases are built from a Git repository.  For example, if
+    23 commits and some working-file changes have been made since
+    release 2016g, the version number is now something like
+    '2016g-23-g50556e3-dirty' instead of the misleading '2016g'.
+    Tagged releases use the same version number format as before,
+    e.g., '2016g'.  To support the more-accurate version number, its
+    specification has moved from a line in the Makefile to a new
+    source file 'version'.
+
+    The experimental distribution contains a file to2050.tzs that
+    contains what should be the output of 'zdump -i -c 2050' on
+    primary zones.  If this file is available, 'make check' now checks
+    that zdump generates this output.
+
+    'make check_web' now works on Fedora-like distributions.
+
+  Changes to documentation and commentary
+
+    tzfile.5 now documents the new restriction on POSIX TZ-like
+    strings that is now implemented by zic.
+
+    Comments now cite URLs for some 1917-1921 Russian DST decrees.
+    (Thanks to Alexander Belopolsky.)
+
+    tz-link.htm mentions JuliaTime (thanks to Curtis Vogt) and Time4J
+    (thanks to Meno Hochschild) and ThreeTen-Extra, and its
+    description of Java 8 has been brought up to date (thanks to
+    Stephen Colebourne).  Its description of local time on Mars has
+    been updated to match current practice, and URLs have been updated
+    and some obsolete ones removed.
+
+
+Release 2016f - 2016-07-05 16:26:51 +0200
+
+  Changes affecting future timestamps
+
+    The Egyptian government changed its mind on short notice, and
+    Africa/Cairo will not introduce DST starting 2016-07-07 after all.
+    (Thanks to Mina Samuel.)
+
+    Asia/Novosibirsk switches from +06 to +07 on 2016-07-24 at 02:00.
+    (Thanks to Stepan Golosunov.)
+
+  Changes to past and future timestamps
+
+    Asia/Novokuznetsk and Asia/Novosibirsk now use numeric time zone
+    abbreviations instead of invented ones.
+
+  Changes affecting past timestamps
+
+    Europe/Minsk's 1992-03-29 spring-forward transition was at 02:00 not 00:00.
+    (Thanks to Stepan Golosunov.)
+
+
+Release 2016e - 2016-06-14 08:46:16 -0700
+
+  Changes affecting future timestamps
+
+    Africa/Cairo observes DST in 2016 from July 7 to the end of October.
+    Guess October 27 and 24:00 transitions.  (Thanks to Steffen Thorsen.)
+    For future years, guess April's last Thursday to October's last
+    Thursday except for Ramadan.
+
+  Changes affecting past timestamps
+
+    Locations while uninhabited now use '-00', not 'zzz', as a
+    placeholder time zone abbreviation.  This is inspired by Internet
+    RFC 3339 and is more consistent with numeric time zone
+    abbreviations already used elsewhere.  The change affects several
+    arctic and antarctic locations, e.g., America/Cambridge_Bay before
+    1920 and Antarctica/Troll before 2005.
+
+    Asia/Baku's 1992-09-27 transition from +04 (DST) to +04 (non-DST) was
+    at 03:00, not 23:00 the previous day.  (Thanks to Michael Deckers.)
+
+  Changes to code
+
+    zic now outputs a dummy transition at time 2**31 - 1 in zones
+    whose POSIX-style TZ strings contain a '<'.  This mostly works
+    around Qt bug 53071 .
+    (Thanks to Zhanibek Adilbekov for reporting the Qt bug.)
+
+  Changes affecting documentation and commentary
+
+    tz-link.htm says why governments should give plenty of notice for
+    time zone or DST changes, and refers to Matt Johnson's blog post.
+
+    tz-link.htm mentions Tzdata for Elixir.  (Thanks to Matt Johnson.)
+
+
+Release 2016d - 2016-04-17 22:50:29 -0700
+
+  Changes affecting future timestamps
+
+    America/Caracas switches from -0430 to -04 on 2016-05-01 at 02:30.
+    (Thanks to Alexander Krivenyshev for the heads-up.)
+
+    Asia/Magadan switches from +10 to +11 on 2016-04-24 at 02:00.
+    (Thanks to Alexander Krivenyshev and Matt Johnson.)
+
+    New zone Asia/Tomsk, split off from Asia/Novosibirsk.  It covers
+    Tomsk Oblast, Russia, which switches from +06 to +07 on 2016-05-29
+    at 02:00.  (Thanks to Stepan Golosunov.)
+
+  Changes affecting past timestamps
+
+    New zone Europe/Kirov, split off from Europe/Volgograd.  It covers
+    Kirov Oblast, Russia, which switched from +04/+05 to +03/+04 on
+    1989-03-26 at 02:00, roughly a year after Europe/Volgograd made
+    the same change.  (Thanks to Stepan Golosunov.)
+
+    Russia and nearby locations had daylight-saving transitions on
+    1992-03-29 at 02:00 and 1992-09-27 at 03:00, instead of on
+    1992-03-28 at 23:00 and 1992-09-26 at 23:00.  (Thanks to Stepan
+    Golosunov.)
+
+    Many corrections to historical time in Kazakhstan from 1991
+    through 2005.  (Thanks to Stepan Golosunov.)  Replace Kazakhstan's
+    invented time zone abbreviations with numeric abbreviations.
+
+  Changes to commentary
+
+    Mention Internet RFCs 7808 (TZDIST) and 7809 (CalDAV time zone references).
+
+
+Release 2016c - 2016-03-23 00:51:27 -0700
+
+  Changes affecting future timestamps
+
+    Azerbaijan no longer observes DST.  (Thanks to Steffen Thorsen.)
+
+    Chile reverts from permanent to seasonal DST.  (Thanks to Juan
+    Correa for the heads-up, and to Tim Parenti for corrections.)
+    Guess that future transitions are August's and May's second
+    Saturdays at 24:00 mainland time.  Also, call the period from
+    2014-09-07 through 2016-05-14 daylight saving time instead of
+    standard time, as that seems more appropriate now.
+
+  Changes affecting past timestamps
+
+    Europe/Kaliningrad and Europe/Vilnius changed from +03/+04 to
+    +02/+03 on 1989-03-26, not 1991-03-31.  Europe/Volgograd changed
+    from +04/+05 to +03/+04 on 1988-03-27, not 1989-03-26.
+    (Thanks to Stepan Golosunov.)
+
+  Changes to commentary
+
+    Several updates and URLs for historical and proposed Russian changes.
+    (Thanks to Stepan Golosunov, Matt Johnson, and Alexander Krivenyshev.)
+
+
+Release 2016b - 2016-03-12 17:30:14 -0800
+
+  Compatibility note
+
+    Starting with release 2016b, some data entries cause zic implementations
+    derived from tz releases 2005j through 2015e to issue warnings like
+    "time zone abbreviation differs from POSIX standard (+03)".
+    These warnings should not otherwise affect zic's output and can safely be
+    ignored on today's platforms, as the warnings refer to a restriction in
+    POSIX.1-1988 that was removed in POSIX.1-2001.  One way to suppress the
+    warnings is to upgrade to zic derived from tz releases 2015f and later.
+
+  Changes affecting future timestamps
+
+    New zones Europe/Astrakhan and Europe/Ulyanovsk for Astrakhan and
+    Ulyanovsk Oblasts, Russia, both of which will switch from +03 to +04 on
+    2016-03-27 at 02:00 local time.  They need distinct zones since their
+    post-1970 histories disagree.  New zone Asia/Barnaul for Altai Krai and
+    Altai Republic, Russia, which will switch from +06 to +07 on the same date
+    and local time.  The Astrakhan change is already official; the others have
+    passed the first reading in the State Duma and are extremely likely.
+    Also, Asia/Sakhalin moves from +10 to +11 on 2016-03-27 at 02:00.
+    (Thanks to Alexander Krivenyshev for the heads-up, and to Matt Johnson
+    and Stepan Golosunov for followup.)
+
+    As a trial of a new system that needs less information to be made up,
+    the new zones use numeric time zone abbreviations like "+04"
+    instead of invented abbreviations like "ASTT".
+
+    Haiti will not observe DST in 2016.  (Thanks to Jean Antoine via
+    Steffen Thorsen.)
+
+    Palestine's spring-forward transition on 2016-03-26 is at 01:00, not 00:00.
+    (Thanks to Hannah Kreitem.) Guess future transitions will be March's last
+    Saturday at 01:00, not March's last Friday at 24:00.
+
+  Changes affecting past timestamps
+
+    Europe/Chisinau observed DST during 1990, and switched from +04 to
+    +03 at 1990-05-06 02:00, instead of switching from +03 to +02.
+    (Thanks to Stepan Golosunov.)
+
+    1991 abbreviations in Europe/Samara should be SAMT/SAMST, not
+    KUYT/KUYST.  (Thanks to Stepan Golosunov.)
+
+  Changes to code
+
+    tzselect's diagnostics and checking, and checktab.awk's checking,
+    have been improved.  (Thanks to J William Piggott.)
+
+    tzcode now builds under MinGW.  (Thanks to Ian Abbott and Esben Haabendal.)
+
+    tzselect now tests Julian-date TZ settings more accurately.
+    (Thanks to J William Piggott.)
+
+  Changes to commentary
+
+    Comments in zone tables have been improved.  (Thanks to J William Piggott.)
+
+    tzselect again limits its menu comments so that menus fit on a
+    24×80 alphanumeric display.
+
+    A new web page tz-how-to.html.  (Thanks to Bill Seymour.)
+
+    In the Theory file, the description of possible time zone abbreviations in
+    tzdata has been cleaned up, as the old description was unclear and
+    inconsistent.  (Thanks to Alain Mouette for reporting the problem.)
+
+
+Release 2016a - 2016-01-26 23:28:02 -0800
+
+  Changes affecting future timestamps
+
+    America/Cayman will not observe daylight saving this year after all.
+    Revert our guess that it would.  (Thanks to Matt Johnson.)
+
+    Asia/Chita switches from +0800 to +0900 on 2016-03-27 at 02:00.
+    (Thanks to Alexander Krivenyshev.)
+
+    Asia/Tehran now has DST predictions for the year 2038 and later,
+    to be March 21 00:00 to September 21 00:00.  This is likely better
+    than predicting no DST, albeit off by a day every now and then.
+
+  Changes affecting past and future timestamps
+
+    America/Metlakatla switched from PST all year to AKST/AKDT on
+    2015-11-01 at 02:00.  (Thanks to Steffen Thorsen.)
+
+    America/Santa_Isabel has been removed, and replaced with a
+    backward compatibility link to America/Tijuana.  Its contents were
+    apparently based on a misreading of Mexican legislation.
+
+  Changes affecting past timestamps
+
+    Asia/Karachi's two transition times in 2002 were off by a minute.
+    (Thanks to Matt Johnson.)
+
+  Changes affecting build procedure
+
+    An installer can now combine leap seconds with use of the backzone file,
+    e.g., with 'make PACKRATDATA=backzone REDO=posix_right zones'.
+    The old 'make posix_packrat' rule is now marked as obsolescent.
+    (Thanks to Ian Abbott for an initial implementation.)
+
+  Changes affecting documentation and commentary
+
+    A new file LICENSE makes it easier to see that the code and data
+    are mostly public-domain.  (Thanks to James Knight.)  The three
+    non-public-domain files now use the current (3-clause) BSD license
+    instead of older versions of that license.
+
+    tz-link.htm mentions the BDE library (thanks to Andrew Paprocki),
+    CCTZ (thanks to Tim Parenti), TimeJones.com, and has a new section
+    on editing tz source files (with a mention of Sublime zoneinfo,
+    thanks to Gilmore Davidson).
+
+    The Theory and asia files now mention the 2015 book "The Global
+    Transformation of Time, 1870-1950", and cite a couple of reviews.
+
+    The America/Chicago entry now documents the informal use of US
+    central time in Fort Pierre, South Dakota.  (Thanks to Rick
+    McDermid, Matt Johnson, and Steve Jones.)
+
+
+Release 2015g - 2015-10-01 00:39:51 -0700
+
+  Changes affecting future timestamps
+
+    Turkey's 2015 fall-back transition is scheduled for Nov. 8, not Oct. 25.
+    (Thanks to Fatih.)
+
+    Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
+    (Thanks to Alexander Krivenyshev.)
+
+    Fiji's 2016 fall-back transition is scheduled for January 17, not 24.
+    (Thanks to Ken Rylander.)
+
+    Fort Nelson, British Columbia will not fall back on 2015-11-01.  It has
+    effectively been on MST (-0700) since it advanced its clocks on 2015-03-08.
+    New zone America/Fort_Nelson.  (Thanks to Matt Johnson.)
+
+  Changes affecting past timestamps
+
+    Norfolk observed DST from 1974-10-27 02:00 to 1975-03-02 02:00.
+
+  Changes affecting code
+
+    localtime no longer mishandles America/Anchorage after 2037.
+    (Thanks to Bradley White for reporting the bug.)
+
+    On hosts with signed 32-bit time_t, localtime no longer mishandles
+    Pacific/Fiji after 2038-01-16 14:00 UTC.
+
+    The localtime module allows the variables 'timezone', 'daylight',
+    and 'altzone' to be in common storage shared with other modules,
+    and declares them in case the system  does not.
+    (Problems reported by Kees Dekker.)
+
+    On platforms with tm_zone, strftime.c now assumes it is not NULL.
+    This simplifies the code and is consistent with zdump.c.
+    (Problem reported by Christos Zoulas.)
+
+  Changes affecting documentation
+
+   The tzfile man page now documents that transition times denote the
+   starts (not the ends) of the corresponding time periods.
+   (Ambiguity reported by Bill Seymour.)
+
+
+Release 2015f - 2015-08-10 18:06:56 -0700
+
+  Changes affecting future timestamps
+
+    North Korea switches to +0830 on 2015-08-15.  (Thanks to Steffen Thorsen.)
+    The abbreviation remains "KST".  (Thanks to Robert Elz.)
+
+    Uruguay no longer observes DST.  (Thanks to Steffen Thorsen
+    and Pablo Camargo.)
+
+  Changes affecting past and future timestamps
+
+    Moldova starts and ends DST at 00:00 UTC, not at 01:00 UTC.
+    (Thanks to Roman Tudos.)
+
+  Changes affecting data format and code
+
+    zic's '-y YEARISTYPE' option is no longer documented.  The TYPE
+    field of a Rule line should now be '-'; the old values 'even',
+    'odd', 'uspres', 'nonpres', 'nonuspres' were already undocumented.
+    Although the implementation has not changed, these features do not
+    work in the default installation, they are not used in the data,
+    and they are now considered obsolescent.
+
+    zic now checks that two rules don't take effect at the same time.
+    (Thanks to Jon Skeet and Arthur David Olson.)  Constraints on
+    simultaneity are now documented.
+
+    The two characters '%z' in a zone format now stand for the UT
+    offset, e.g., '-07' for seven hours behind UT and '+0530' for
+    five hours and thirty minutes ahead.  This better supports time
+    zone abbreviations conforming to POSIX.1-2001 and later.
+
+  Changes affecting installed data files
+
+    Comments for America/Halifax and America/Glace_Bay have been improved.
+    (Thanks to Brian Inglis.)
+
+    Data entries have been simplified for Atlantic/Canary, Europe/Simferopol,
+    Europe/Sofia, and Europe/Tallinn.  This yields slightly smaller
+    installed data files for Europe/Simferopol and Europe/Tallinn.
+    It does not affect timestamps.  (Thanks to Howard Hinnant.)
+
+  Changes affecting code
+
+    zdump and zic no longer warn about valid time zone abbreviations
+    like '-05'.
+
+    Some Visual Studio 2013 warnings have been suppressed.
+    (Thanks to Kees Dekker.)
+
+    'date' no longer sets the time of day and its -a, -d, -n and -t
+    options have been removed.  Long obsolescent, the implementation
+    of these features had porting problems.  Builders no longer need
+    to configure HAVE_ADJTIME, HAVE_SETTIMEOFDAY, or HAVE_UTMPX_H.
+    (Thanks to Kees Dekker for pointing out the problem.)
+
+  Changes affecting documentation
+
+    The Theory file mentions naming issues earlier, as these seem to be
+    poorly publicized (thanks to Gilmore Davidson for reporting the problem).
+
+    tz-link.htm mentions Time Zone Database Parser (thanks to Howard Hinnant).
+
+    Mention that Herbert Samuel introduced the term "Summer Time".
+
+
+Release 2015e - 2015-06-13 10:56:02 -0700
+
+  Changes affecting future timestamps
+
+    Morocco will suspend DST from 2015-06-14 03:00 through 2015-07-19 02:00,
+    not 06-13 and 07-18 as we had guessed.  (Thanks to Milamber.)
+
+    Assume Cayman Islands will observe DST starting next year, using US rules.
+    Although it isn't guaranteed, it is the most likely.
+
+  Changes affecting data format
+
+    The file 'iso3166.tab' now uses UTF-8, so that its entries can better
+    spell the names of Åland Islands, Côte d'Ivoire, and Réunion.
+
+  Changes affecting code
+
+    When displaying data, tzselect converts it to the current locale's
+    encoding if the iconv command works.  (Problem reported by random832.)
+
+    tzselect no longer mishandles Dominica, fixing a bug introduced
+    in Release 2014f.  (Problem reported by Owen Leibman.)
+
+    zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
+    This fixes a bug introduced in Release 2014f.
+    (Problem reported by Leonardo Chiquitto.)
+
+
+Release 2015d - 2015-04-24 08:09:46 -0700
+
+  Changes affecting future timestamps
+
+    Egypt will not observe DST in 2015 and will consider canceling it
+    permanently.  For now, assume no DST indefinitely.
+    (Thanks to Ahmed Nazmy and Tim Parenti.)
+
+  Changes affecting past timestamps
+
+    America/Whitehorse switched from UT -09 to -08 on 1967-05-28, not
+    1966-07-01.  Also, Yukon's time zone history is documented better.
+    (Thanks to Brian Inglis and Dennis Ferguson.)
+
+  Change affecting past and future time zone abbreviations
+
+    The abbreviations for Hawaii-Aleutian standard and daylight times
+    have been changed from HAST/HADT to HST/HDT, as per US Government
+    Printing Office style.  This affects only America/Adak since 1983,
+    as America/Honolulu was already using the new style.
+
+  Changes affecting code
+
+   zic has some minor performance improvements.
+
+
+Release 2015c - 2015-04-11 08:55:55 -0700
+
+  Changes affecting future timestamps
+
+    Egypt's spring-forward transition is at 24:00 on April's last Thursday,
+    not 00:00 on April's last Friday.  2015's transition will therefore be on
+    Thursday, April 30 at 24:00, not Friday, April 24 at 00:00.  Similar fixes
+    apply to 2026, 2037, 2043, etc.  (Thanks to Steffen Thorsen.)
+
+  Changes affecting past timestamps
+
+    The following changes affect some pre-1991 Chile-related timestamps
+    in America/Santiago, Antarctica/Palmer, and Pacific/Easter.
+
+      The 1910 transition was January 10, not January 1.
+
+      The 1918 transition was September 10, not September 1.
+
+      The UT -04 time observed from 1932 to 1942 is now considered to
+      be standard time, not year-round DST.
+
+      Santiago observed DST (UT -03) from 1946-07-15 through
+      1946-08-31, then reverted to standard time, then switched to -05
+      on 1947-04-01.
+
+      Assume transitions before 1968 were at 00:00, since we have no data
+      saying otherwise.
+
+      The spring 1988 transition was 1988-10-09, not 1988-10-02.
+      The fall 1990 transition was 1990-03-11, not 1990-03-18.
+
+      Assume no UT offset change for Pacific/Easter on 1890-01-01,
+      and omit all transitions on Pacific/Easter from 1942 through 1946
+      since we have no data suggesting that they existed.
+
+    One more zone has been turned into a link, as it differed
+    from an existing zone only for older timestamps.  As usual,
+    this change affects UT offsets in pre-1970 timestamps only.
+    The zone's old contents have been moved to the 'backzone' file.
+    The affected zone is America/Montreal.
+
+  Changes affecting commentary
+
+    Mention the TZUpdater tool.
+
+    Mention "The Time Now".  (Thanks to Brandon Ramsey.)
+
+
+Release 2015b - 2015-03-19 23:28:11 -0700
+
+  Changes affecting future timestamps
+
+    Mongolia will start observing DST again this year, from the last
+    Saturday in March at 02:00 to the last Saturday in September at 00:00.
+    (Thanks to Ganbold Tsagaankhuu.)
+
+    Palestine will start DST on March 28, not March 27.  Also,
+    correct the fall 2014 transition from September 26 to October 24.
+    Adjust future predictions accordingly.  (Thanks to Steffen Thorsen.)
+
+  Changes affecting past timestamps
+
+    The 1982 zone shift in Pacific/Easter has been corrected, fixing a 2015a
+    regression.  (Thanks to Stuart Bishop for reporting the problem.)
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older timestamps.  As usual,
+    these changes affect UT offsets in pre-1970 timestamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: America/Antigua, America/Cayman,
+    Pacific/Midway, and Pacific/Saipan.
+
+  Changes affecting time zone abbreviations
+
+    Correct the 1992-2010 DST abbreviation in Volgograd from "MSK" to "MSD".
+    (Thanks to Hank W.)
+
+  Changes affecting code
+
+    Fix integer overflow bug in reference 'mktime' implementation.
+    (Problem reported by Jörg Richter.)
+
+    Allow -Dtime_tz=time_t compilations, and allow -Dtime_tz=... libraries
+    to be used in the same executable as standard-library time_t functions.
+    (Problems reported by Bradley White.)
+
+  Changes affecting commentary
+
+    Cite the recent Mexican decree changing Quintana Roo's time zone.
+    (Thanks to Carlos Raúl Perasso.)
+
+    Likewise for the recent Chilean decree.  (Thanks to Eduardo Romero Urra.)
+
+    Update info about Mars time.
+
+
+Release 2015a - 2015-01-29 22:35:20 -0800
+
+  Changes affecting future timestamps
+
+    The Mexican state of Quintana Roo, represented by America/Cancun,
+    will shift from Central Time with DST to Eastern Time without DST
+    on 2015-02-01 at 02:00.  (Thanks to Steffen Thorsen and Gwillim Law.)
+
+    Chile will not change clocks in April or thereafter; its new standard time
+    will be its old daylight saving time.  This affects America/Santiago,
+    Pacific/Easter, and Antarctica/Palmer.  (Thanks to Juan Correa.)
+
+    New leap second 2015-06-30 23:59:60 UTC as per IERS Bulletin C 49.
+    (Thanks to Tim Parenti.)
+
+  Changes affecting past timestamps
+
+    Iceland observed DST in 1919 and 1921, and its 1939 fallback
+    transition was Oct. 29, not Nov. 29.  Remove incorrect data from
+    Shanks about time in Iceland between 1837 and 1908.
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older timestamps.  As usual,
+    these changes affect UT offsets in pre-1970 timestamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: Asia/Aden, Asia/Bahrain, Asia/Kuwait,
+    and Asia/Muscat.
+
+  Changes affecting code
+
+    tzalloc now scrubs time zone abbreviations compatibly with the way
+    that tzset always has, by replacing invalid bytes with '_' and by
+    shortening too-long abbreviations.
+
+    tzselect ports to POSIX awk implementations, no longer mishandles
+    POSIX TZ settings when GNU awk is used, and reports POSIX TZ
+    settings to the user.  (Thanks to Stefan Kuhn.)
+
+  Changes affecting build procedure
+
+    'make check' now checks for links to links in the data.
+    One such link (for Africa/Asmera) has been fixed.
+    (Thanks to Stephen Colebourne for pointing out the problem.)
+
+  Changes affecting commentary
+
+    The leapseconds file commentary now mentions the expiration date.
+    (Problem reported by Martin Burnicki.)
+
+    Update Mexican Library of Congress URL.
+
+
+Release 2014j - 2014-11-10 17:37:11 -0800
+
+  Changes affecting current and future timestamps
+
+    Turks & Caicos' switch from US eastern time to UT -04 year-round
+    did not occur on 2014-11-02 at 02:00.  It's currently scheduled
+    for 2015-11-01 at 02:00.  (Thanks to Chris Walton.)
+
+  Changes affecting past timestamps
+
+    Many pre-1989 timestamps have been corrected for Asia/Seoul and
+    Asia/Pyongyang, based on sources for the Korean-language Wikipedia
+    entry for time in Korea.  (Thanks to Sanghyuk Jung.)  Also, no
+    longer guess that Pyongyang mimicked Seoul time after World War II,
+    as this is politically implausible.
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older timestamps.  As usual,
+    these changes affect UT offsets in pre-1970 timestamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: Africa/Addis_Ababa, Africa/Asmara,
+    Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala,
+    Africa/Mogadishu, Indian/Antananarivo, Indian/Comoro, and
+    Indian/Mayotte.
+
+  Changes affecting commentary
+
+    The commentary is less enthusiastic about Shanks as a source,
+    and is more careful to distinguish UT from UTC.
+
+
+Release 2014i - 2014-10-21 22:04:57 -0700
+
+  Changes affecting future timestamps
+
+    Pacific/Fiji will observe DST from 2014-11-02 02:00 to 2015-01-18 03:00.
+    (Thanks to Ken Rylander for the heads-up.)  Guess that future
+    years will use a similar pattern.
+
+    A new Zone Pacific/Bougainville, for the part of Papua New Guinea
+    that plans to switch from UT +10 to +11 on 2014-12-28 at 02:00.
+    (Thanks to Kiley Walbom for the heads-up.)
+
+  Changes affecting time zone abbreviations
+
+    Since Belarus is not changing its clocks even though Moscow is,
+    the time zone abbreviation in Europe/Minsk is changing from FET
+    to its more-traditional value MSK on 2014-10-26 at 01:00.
+    (Thanks to Alexander Bokovoy for the heads-up about Belarus.)
+
+    The new abbreviation IDT stands for the pre-1976 use of UT +08 in
+    Indochina, to distinguish it better from ICT (+07).
+
+  Changes affecting past timestamps
+
+    Many timestamps have been corrected for Asia/Ho_Chi_Minh before 1976
+    (thanks to Trần Ngọc Quân for an indirect pointer to Trần Tiến Bình's
+    authoritative book).  Asia/Ho_Chi_Minh has been added to
+    zone1970.tab, to give tzselect users in Vietnam two choices,
+    since north and south Vietnam disagreed after our 1970 cutoff.
+
+    Asia/Phnom_Penh and Asia/Vientiane have been turned into links, as
+    they differed from existing zones only for older timestamps.  As
+    usual, these changes affect pre-1970 timestamps only.  Their old
+    contents have been moved to the 'backzone' file.
+
+  Changes affecting code
+
+    The time-related library functions now set errno on failure, and
+    some crashes in the new tzalloc-related library functions have
+    been fixed.  (Thanks to Christos Zoulas for reporting most of
+    these problems and for suggesting fixes.)
+
+    If USG_COMPAT is defined and the requested timestamp is standard time,
+    the tz library's localtime and mktime functions now set the extern
+    variable timezone to a value appropriate for that timestamp; and
+    similarly for ALTZONE, daylight saving time, and the altzone variable.
+    This change is a companion to the tzname change in 2014h, and is
+    designed to make timezone and altzone more compatible with tzname.
+
+    The tz library's functions now set errno to EOVERFLOW if they fail
+    because the result cannot be represented.  ctime and ctime_r now
+    return NULL and set errno when a timestamp is out of range, rather
+    than having undefined behavior.
+
+    Some bugs associated with the new 2014g functions have been fixed.
+    This includes a bug that largely incapacitated the new functions
+    time2posix_z and posix2time_z.  (Thanks to Christos Zoulas.)
+    It also includes some uses of uninitialized variables after tzalloc.
+    The new code uses the standard type 'ssize_t', which the Makefile
+    now gives porting advice about.
+
+  Changes affecting commentary
+
+    Updated URLs for NRC Canada (thanks to Matt Johnson and Brian Inglis).
+
+
+Release 2014h - 2014-09-25 18:59:03 -0700
+
+  Changes affecting past timestamps
+
+    America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
+
+    Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
+    not 1920-01-06.  The old entry was based on a misinterpretation of Shanks.
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older timestamps.  As usual,
+    these changes affect UT offsets in pre-1970 timestamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: Africa/Blantyre, Africa/Bujumbura,
+    Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
+    Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
+
+  Changes affecting code
+
+    zdump -V and -v now output gmtoff= values on all platforms,
+    not merely on platforms defining TM_GMTOFF.
+
+    The tz library's localtime and mktime functions now set tzname to a value
+    appropriate for the requested timestamp, and zdump now uses this
+    on platforms not defining TM_ZONE, fixing a 2014g regression.
+    (Thanks to Tim Parenti for reporting the problem.)
+
+    The tz library no longer sets tzname if localtime or mktime fails.
+
+    zdump -c no longer mishandles transitions near year boundaries.
+    (Thanks to Tim Parenti for reporting the problem.)
+
+    An access to uninitialized data has been fixed.
+    (Thanks to Jörg Richter for reporting the problem.)
+
+    When THREAD_SAFE is defined, the code ports to the C11 memory model.
+    A memory leak has been fixed if ALL_STATE and THREAD_SAFE are defined
+    and two threads race to initialize data used by gmtime-like functions.
+    (Thanks to Andy Heninger for reporting the problems.)
+
+  Changes affecting build procedure
+
+    'make check' now checks better for properly-sorted data.
+
+  Changes affecting documentation and commentary
+
+    zdump's gmtoff=N output is now documented, and its isdst=D output
+    is now documented to possibly output D values other than 0 or 1.
+
+    zdump -c's treatment of years is now documented to use the
+    Gregorian calendar and Universal Time without leap seconds,
+    and its behavior at cutoff boundaries is now documented better.
+    (Thanks to Arthur David Olson and Tim Parenti for reporting the problems.)
+
+    Programs are now documented to use the proleptic Gregorian calendar.
+    (Thanks to Alan Barrett for the suggestion.)
+
+    Fractional-second GMT offsets have been documented for civil time
+    in 19th-century Chennai, Jakarta, and New York.
+
+
+Release 2014g - 2014-08-28 12:31:23 -0700
+
+  Changes affecting future timestamps
+
+    Turks & Caicos is switching from US eastern time to UT -04
+    year-round, modeled as a switch on 2014-11-02 at 02:00.
+    [As noted in 2014j, this switch was later delayed.]
+
+  Changes affecting past timestamps
+
+    Time in Russia or the USSR before 1926 or so has been corrected by
+    a few seconds in the following zones: Asia/Irkutsk,
+    Asia/Krasnoyarsk, Asia/Omsk, Asia/Samarkand, Asia/Tbilisi,
+    Asia/Vladivostok, Asia/Yakutsk, Europe/Riga, Europe/Samara.  For
+    Asia/Yekaterinburg the correction is a few minutes.  (Thanks to
+    Vladimir Karpinsky.)
+
+    The Portuguese decree of 1911-05-26 took effect on 1912-01-01.
+    This affects 1911 timestamps in Africa/Bissau, Africa/Luanda,
+    Atlantic/Azores, and Atlantic/Madeira.  Also, Lisbon's pre-1912
+    GMT offset was -0:36:45 (rounded from -0:36:44.68), not -0:36:32.
+    (Thanks to Stephen Colebourne for pointing to the decree.)
+
+    Asia/Dhaka ended DST on 2009-12-31 at 24:00, not 23:59.
+
+    A new file 'backzone' contains data which may appeal to
+    connoisseurs of old timestamps, although it is out of scope for
+    the tz database, is often poorly sourced, and contains some data
+    that is known to be incorrect.  The new file is not recommended
+    for ordinary use and its entries are not installed by default.
+    (Thanks to Lester Caine for the high-quality Jersey, Guernsey, and
+    Isle of Man entries.)
+
+    Some more zones have been turned into links, when they differed
+    from existing zones only for older timestamps.  As usual,
+    these changes affect UT offsets in pre-1970 timestamps only.
+    Their old contents have been moved to the 'backzone' file.
+    The affected zones are: Africa/Bangui, Africa/Brazzaville,
+    Africa/Douala, Africa/Kinshasa, Africa/Libreville, Africa/Luanda,
+    Africa/Malabo, Africa/Niamey, and Africa/Porto-Novo.
+
+  Changes affecting code
+
+    Unless NETBSD_INSPIRED is defined to 0, the tz library now
+    supplies functions for creating and using objects that represent
+    timezones. The new functions are tzalloc, tzfree, localtime_rz,
+    mktime_z, and (if STD_INSPIRED is also defined) posix2time_z and
+    time2posix_z.  They are intended for performance: for example,
+    localtime_rz (unlike localtime_r) is trivially thread-safe without
+    locking.  (Thanks to Christos Zoulas for proposing NetBSD-inspired
+    functions, and to Alan Barrett and Jonathan Lennox for helping to
+    debug the change.)
+
+    zdump now builds with the tz library unless USE_LTZ is defined to 0,
+    This lets zdump use tz features even if the system library lacks them.
+    To build zdump with the system library, use 'make CFLAGS=-DUSE_LTZ=0
+    TZDOBJS=zdump.o CHECK_TIME_T_ALTERNATIVES='.
+
+    zdump now uses localtime_rz if available, as it's significantly faster,
+    and it can help zdump better diagnose invalid timezone names.
+    Define HAVE_LOCALTIME_RZ to 0 to suppress this.  HAVE_LOCALTIME_RZ
+    defaults to 1 if NETBSD_INSPIRED && USE_LTZ.  When localtime_rz is
+    not available, zdump now uses localtime_r and tzset if available,
+    as this is a bit cleaner and faster than plain localtime.  Compile
+    with -DHAVE_LOCALTIME_R=0 and/or -DHAVE_TZSET=0 if your system
+    lacks these two functions.
+
+    If THREAD_SAFE is defined to 1, the tz library is now thread-safe.
+    Although not needed for tz's own applications, which are single-threaded,
+    this supports POSIX better if the tz library is used in multithreaded apps.
+
+    Some crashes have been fixed when zdump or the tz library is given
+    invalid or outlandish input.
+
+    The tz library no longer mishandles leap seconds on platforms with
+    unsigned time_t in timezones that lack ordinary transitions after 1970.
+
+    The tz code now attempts to infer TM_GMTOFF and TM_ZONE if not
+    already defined, to make it easier to configure on common platforms.
+    Define NO_TM_GMTOFF and NO_TM_ZONE to suppress this.
+
+    Unless the new macro UNINIT_TRAP is defined to 1, the tz code now
+    assumes that reading uninitialized memory yields garbage values
+    but does not cause other problems such as traps.
+
+    If TM_GMTOFF is defined and UNINIT_TRAP is 0, mktime is now
+    more likely to guess right for ambiguous timestamps near
+    transitions where tm_isdst does not change.
+
+    If HAVE_STRFTIME_L is defined to 1, the tz library now defines
+    strftime_l for compatibility with recent versions of POSIX.
+    Only the C locale is supported, though.  HAVE_STRFTIME_L defaults
+    to 1 on recent POSIX versions, and to 0 otherwise.
+
+    tzselect -c now uses a hybrid distance measure that works better
+    in Africa.  (Thanks to Alan Barrett for noting the problem.)
+
+    The C source code now ports to NetBSD when GCC_DEBUG_FLAGS is used,
+    or when time_tz is defined.
+
+    When HAVE_UTMPX_H is set the 'date' command now builds on systems
+    whose  file does not define WTMPX_FILE, and when setting
+    the date it updates the wtmpx file if _PATH_WTMPX is defined.
+    This affects GNU/Linux and similar systems.
+
+    For easier maintenance later, some C code has been simplified,
+    some lint has been removed, and the code has been tweaked so that
+    plain 'make' is more likely to work.
+
+    The C type 'bool' is now used for boolean values, instead of 'int'.
+
+    The long-obsolete LOCALE_HOME code has been removed.
+
+    The long-obsolete 'gtime' function has been removed.
+
+  Changes affecting build procedure
+
+    'zdump' no longer links in ialloc.o, as it's not needed.
+
+    'make check_time_t_alternatives' no longer assumes GNU diff.
+
+  Changes affecting distribution tarballs
+
+    The files checktab.awk and zoneinfo2tdf.pl are now distributed in
+    the tzdata tarball instead of the tzcode tarball, since they help
+    maintain the data.  The NEWS and Theory files are now also
+    distributed in the tzdata tarball, as they're relevant for data.
+    (Thanks to Alan Barrett for pointing this out.)  Also, the
+    leapseconds.awk file is no longer distributed in the tzcode
+    tarball, since it belongs in the tzdata tarball (where 2014f
+    inadvertently also distributed it).
+
+  Changes affecting documentation and commentary
+
+    A new file CONTRIBUTING is distributed.  (Thanks to Tim Parenti for
+    suggesting a CONTRIBUTING file, and to Tony Finch and Walter Harms
+    for debugging it.)
+
+    The man pages have been updated to use function prototypes,
+    to document thread-safe variants like localtime_r, and to document
+    the NetBSD-inspired functions tzalloc, tzfree, localtime_rz, and
+    mktime_z.
+
+    The fields in Link lines have been renamed to be more descriptive
+    and more like the parameters of 'ln'.  LINK-FROM has become TARGET,
+    and LINK-TO has become LINK-NAME.
+
+    tz-link.htm mentions the IETF's tzdist working group; Windows
+    Runtime etc. (thanks to Matt Johnson); and HP-UX's tztab.
+
+    Some broken URLs have been fixed in the commentary.  (Thanks to
+    Lester Caine.)
+
+    Commentary about Philippines DST has been updated, and commentary
+    on pre-1970 time in India has been added.
+
+
+Release 2014f - 2014-08-05 17:42:36 -0700
+
+  Changes affecting future timestamps
+
+    Russia will subtract an hour from most of its time zones on 2014-10-26
+    at 02:00 local time.  (Thanks to Alexander Krivenyshev.)
+    There are a few exceptions: Magadan Oblast (Asia/Magadan) and Zabaykalsky
+    Krai are subtracting two hours; conversely, Chukotka Autonomous Okrug
+    (Asia/Anadyr), Kamchatka Krai (Asia/Kamchatka), Kemerovo Oblast
+    (Asia/Novokuznetsk), and the Samara Oblast and the Udmurt Republic
+    (Europe/Samara) are not changing their clocks.  The changed zones are
+    Europe/Kaliningrad, Europe/Moscow, Europe/Simferopol, Europe/Volgograd,
+    Asia/Yekaterinburg, Asia/Omsk, Asia/Novosibirsk, Asia/Krasnoyarsk,
+    Asia/Irkutsk, Asia/Yakutsk, Asia/Vladivostok, Asia/Khandyga,
+    Asia/Sakhalin, and Asia/Ust-Nera; Asia/Magadan will have two hours
+    subtracted; and Asia/Novokuznetsk's time zone abbreviation is affected,
+    but not its UTC offset.  Two zones are added: Asia/Chita (split
+    from Asia/Yakutsk, and also with two hours subtracted) and
+    Asia/Srednekolymsk (split from Asia/Magadan, but with only one hour
+    subtracted).  (Thanks to Tim Parenti for much of the above.)
+
+  Changes affecting time zone abbreviations
+
+    Australian eastern time zone abbreviations are now AEST/AEDT not EST,
+    and similarly for the other Australian zones.  That is, for eastern
+    standard and daylight saving time the abbreviations are AEST and AEDT
+    instead of the former EST for both; similarly, ACST/ACDT, ACWST/ACWDT,
+    and AWST/AWDT are now used instead of the former CST, CWST, and WST.
+    This change does not affect UT offsets, only time zone abbreviations.
+    (Thanks to Rich Tibbett and many others.)
+
+    Asia/Novokuznetsk shifts from NOVT to KRAT (remaining on UT +07)
+    effective 2014-10-26 at 02:00 local time.
+
+    The time zone abbreviation for Xinjiang Time (observed in Ürümqi)
+    has been changed from URUT to XJT.  (Thanks to Luther Ma.)
+
+    Prefer MSK/MSD for Moscow time in Russia, even in other cities.
+    Similarly, prefer EET/EEST for eastern European time in Russia.
+
+    Change time zone abbreviations in (western) Samoa to use "ST" and
+    "DT" suffixes, as this is more likely to match common practice.
+    Prefix "W" to (western) Samoa time when its standard-time offset
+    disagrees with that of American Samoa.
+
+    America/Metlakatla now uses PST, not MeST, to abbreviate its time zone.
+
+    Time zone abbreviations have been updated for Japan's two time
+    zones used 1896-1937.  JWST now stands for Western Standard
+    Time, and JCST for Central Standard Time (formerly this was CJT).
+    These abbreviations are now used for time in Korea, Taiwan,
+    and Sakhalin while controlled by Japan.
+
+  Changes affecting past timestamps
+
+    China's five zones have been simplified to two, since the post-1970
+    differences in the other three seem to have been imaginary.  The
+    zones Asia/Harbin, Asia/Chongqing, and Asia/Kashgar have been
+    removed; backwards-compatibility links still work, albeit with
+    different behaviors for timestamps before May 1980.  Asia/Urumqi's
+    1980 transition to UT +08 has been removed, so that it is now at
+    +06 and not +08.  (Thanks to Luther Ma and to Alois Treindl;
+    Treindl sent helpful translations of two papers by Guo Qingsheng.)
+
+    Some zones have been turned into links, when they differed from existing
+    zones only for older UT offsets where data entries were likely invented.
+    These changes affect UT offsets in pre-1970 timestamps only.  This is
+    similar to the change in release 2013e, except this time for western
+    Africa.  The affected zones are: Africa/Bamako, Africa/Banjul,
+    Africa/Conakry, Africa/Dakar, Africa/Freetown, Africa/Lome,
+    Africa/Nouakchott, Africa/Ouagadougou, Africa/Sao_Tome, and
+    Atlantic/St_Helena.  This also affects the backwards-compatibility
+    link Africa/Timbuktu.  (Thanks to Alan Barrett, Stephen Colebourne,
+    Tim Parenti, and David Patte for reporting problems in earlier
+    versions of this change.)
+
+    Asia/Shanghai's pre-standard-time UT offset has been changed from
+    8:05:57 to 8:05:43, the location of Xujiahui Observatory.  Its
+    transition to standard time has been changed from 1928 to 1901.
+
+    Asia/Taipei switched to JWST on 1896-01-01, then to JST on 1937-10-01,
+    then to CST on 1945-09-21 at 01:00, and did not observe DST in 1945.
+    In 1946 it observed DST from 05-15 through 09-30; in 1947
+    from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
+    (Thanks to Yu-Cheng Chuang.)
+
+    Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
+
+    Europe/Helsinki's 1942 fall-back transition was 10-04 at 01:00, not
+    10-03 at 00:00.  (Thanks to Konstantin Hyppönen.)
+
+    Pacific/Pago_Pago has been changed from UT -11:30 to -11 for the
+    period from 1911 to 1950.
+
+    Pacific/Chatham has been changed to New Zealand standard time plus
+    45 minutes for the period before 1957, reflecting a 1956 remark in
+    the New Zealand parliament.
+
+    Europe/Budapest has several pre-1946 corrections: in 1918 the transition
+    out of DST was on 09-16, not 09-29; in 1919 it was on 11-24, not 09-15; in
+    1945 it was on 11-01, not 11-03; in 1941 the transition to DST was 04-08
+    not 04-06 at 02:00; and there was no DST in 1920.
+
+    Africa/Accra is now assumed to have observed DST from 1920 through 1935.
+
+    Time in Russia before 1927 or so has been corrected by a few seconds in
+    the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
+    Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
+    Europe/Riga.  Also, Moscow's location has been changed to its Kilometer 0
+    point.  (Thanks to Vladimir Karpinsky for the Moscow changes.)
+
+  Changes affecting data format
+
+    A new file 'zone1970.tab' supersedes 'zone.tab' in the installed data.
+    The new file's extended format allows multiple country codes per zone.
+    The older file is still installed but is deprecated; its format is
+    not changing and it will still be distributed for a while, but new
+    applications should use the new file.
+
+    The new file format simplifies maintenance of obscure locations.
+    To test this, it adds coverage for the Crozet Islands and the
+    Scattered Islands.  (Thanks to Tobias Conradi and Antoine Leca.)
+
+    The file 'iso3166.tab' is planned to switch from ASCII to UTF-8.
+    It is still ASCII now, but commentary about the switch has been added.
+    The new file 'zone1970.tab' already uses UTF-8.
+
+  Changes affecting code
+
+    'localtime', 'mktime', etc. now use much less stack space if ALL_STATE
+    is defined.  (Thanks to Elliott Hughes for reporting the problem.)
+
+    'zic' no longer mishandles input when ignoring case in locales that
+    are not compatible with English, e.g., unibyte Turkish locales when
+    compiled with HAVE_GETTEXT.
+
+    Error diagnostics of 'zic' and 'yearistype' have been reworded so that
+    they no longer use ASCII '-' as if it were a dash.
+
+    'zic' now rejects output file names that contain '.' or '..' components.
+    (Thanks to Tim Parenti for reporting the problem.)
+
+    'zic -v' now warns about output file names that do not follow
+    POSIX rules, or that contain a digit or '.'.  (Thanks to Arthur
+    David Olson for starting the ball rolling on this.)
+
+    Some lint has been removed when using GCC_DEBUG_FLAGS with GCC 4.9.0.
+
+  Changes affecting build procedure
+
+    'zic' no longer links in localtime.o and asctime.o, as they're not needed.
+    (Thanks to John Cochran.)
+
+  Changes affecting documentation and commentary
+
+    The 'Theory' file documents legacy names, the longstanding
+    exceptions to the POSIX-inspired file name rules.
+
+    The 'zic' documentation clarifies the role of time types when
+    interpreting dates.  (Thanks to Arthur David Olson.)
+
+    Documentation and commentary now prefer UTF-8 to US-ASCII,
+    allowing the use of proper accents in foreign words and names.
+    Code and data have not changed because of this.  (Thanks to
+    Garrett Wollman, Ian Abbott, and Guy Harris for helping to debug
+    this.)
+
+    Non-HTML documentation and commentary now use plain-text URLs instead of
+    HTML insertions, and are more consistent about bracketing URLs when they
+    are not already surrounded by white space.  (Thanks to suggestions by
+    Steffen Nurpmeso.)
+
+    There is new commentary about Xujiahui Observatory, the five time-zone
+    project in China from 1918 to 1949, timekeeping in Japanese-occupied
+    Shanghai, and Tibet Time in the 1950s.  The sharp-eyed can spot the
+    warlord Jin Shuren in the data.
+
+    Commentary about the coverage of each Russian zone has been standardized.
+    (Thanks to Tim Parenti.)
+
+    There is new commentary about contemporary timekeeping in Ethiopia.
+
+    Obsolete comments about a 2007 proposal for DST in Kuwait has been removed.
+
+    There is new commentary about time in Poland in 1919.
+
+    Proper credit has been given to DST inventor George Vernon Hudson.
+
+    Commentary about time in Metlakatla, AK and Resolute, NU has been
+    improved, with a new source for the former.
+
+    In zone.tab, Pacific/Easter no longer mentions Salas y Gómez, as it
+    is uninhabited.
+
+    Commentary about permanent Antarctic bases has been updated.
+
+    Several typos have been corrected.  (Thanks to Tim Parenti for
+    contributing some of these fixes.)
+
+    tz-link.htm now mentions the JavaScript libraries Moment Timezone,
+    TimezoneJS.Date, Walltime-js, and Timezone.  (Thanks to a heads-up
+    from Matt Johnson.)  Also, it mentions the Go 'latlong' package.
+    (Thanks to a heads-up from Dirkjan Ochtman.)
+
+    The files usno1988, usno1989, usno1989a, usno1995, usno1997, and usno1998
+    have been removed.  These obsolescent US Naval Observatory entries were no
+    longer helpful for maintenance.  (Thanks to Tim Parenti for the suggestion.)
+
+
+Release 2014e - 2014-06-12 21:53:52 -0700
+
+  Changes affecting near-future timestamps
+
+    Egypt's 2014 Ramadan-based transitions are June 26 and July 31 at 24:00.
+    (Thanks to Imed Chihi.)  Guess that from 2015 on Egypt will temporarily
+    switch to standard time at 24:00 the last Thursday before Ramadan, and
+    back to DST at 00:00 the first Friday after Ramadan.
+
+    Similarly, Morocco's are June 28 at 03:00 and August 2 at 02:00.  (Thanks
+    to Milamber Space Network.)  Guess that from 2015 on Morocco will
+    temporarily switch to standard time at 03:00 the last Saturday before
+    Ramadan, and back to DST at 02:00 the first Saturday after Ramadan.
+
+  Changes affecting past timestamps
+
+    The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
+    "MSD" for Moscow's double daylight time in summer 1921.  Also, a typo
+    "VLASST" has been repaired to be "VLAST" for Vladivostok summer time
+    in 1991.  (Thanks to Hank W. for reporting the problems.)
+
+  Changes affecting commentary
+
+    tz-link.htm now cites RFC 7265 for jCal, mentions PTP and the
+    draft CalDAV extension, updates URLs for TSP, TZInfo, IATA, and
+    removes stale pointers to World Time Explorer and WORLDTIME.
+
+
+Release 2014d - 2014-05-27 21:34:40 -0700
+
+  Changes affecting code
+
+    zic no longer generates files containing timestamps before the Big Bang.
+    This works around GNOME glib bug 878
+    
+    (Thanks to Leonardo Chiquitto for reporting the bug, and to
+    Arthur David Olson and James Cloos for suggesting improvements to the fix.)
+
+  Changes affecting documentation
+
+    tz-link.htm now mentions GNOME.
+
+
+Release 2014c - 2014-05-13 07:44:13 -0700
+
+  Changes affecting near-future timestamps
+
+    Egypt observes DST starting 2014-05-15 at 24:00.
+    (Thanks to Ahmad El-Dardiry and Gunther Vermier.)
+    Details have not been announced, except that DST will not be observed
+    during Ramadan.  Guess that DST will stop during the same Ramadan dates as
+    Morocco, and that Egypt's future spring and fall transitions will be the
+    same as 2010 when it last observed DST, namely April's last Friday at
+    00:00 to September's last Thursday at 23:00 standard time.  Also, guess
+    that Ramadan transitions will be at 00:00 standard time.
+
+  Changes affecting code
+
+    zic now generates transitions for minimum time values, eliminating guesswork
+    when handling low-valued timestamps.  (Thanks to Arthur David Olson.)
+
+    Port to Cygwin sans glibc.  (Thanks to Arthur David Olson.)
+
+  Changes affecting commentary and documentation
+
+    Remove now-confusing comment about Jordan.  (Thanks to Oleksii Nochovnyi.)
+
+
+Release 2014b - 2014-03-24 21:28:50 -0700
+
+  Changes affecting near-future timestamps
+
+    Crimea switches to Moscow time on 2014-03-30 at 02:00 local time.
+    (Thanks to Alexander Krivenyshev.)  Move its zone.tab entry from UA to RU.
+
+    New entry for Troll station, Antarctica.  (Thanks to Paul-Inge Flakstad and
+    Bengt-Inge Larsson.)  This is currently an approximation; a better version
+    will require the zic and localtime fixes mentioned below, and the plan is
+    to wait for a while until at least the zic fixes propagate.
+
+  Changes affecting code
+
+    'zic' and 'localtime' no longer reject locations needing four transitions
+    per year for the foreseeable future.  (Thanks to Andrew Main (Zefram).)
+    Also, 'zic' avoids some unlikely failures due to integer overflow.
+
+  Changes affecting build procedure
+
+    'make check' now detects Rule lines defined but never used.
+    The NZAQ rules, an instance of this problem, have been removed.
+
+  Changes affecting commentary and documentation
+
+    Fix Tuesday/Thursday typo in description of time in Israel.
+    (Thanks to Bert Katz via Pavel Kharitonov and Mike Frysinger.)
+
+    Microsoft Windows 8.1 doesn't support tz database names.  (Thanks
+    to Donald MacQueen.)  Instead, the Microsoft Windows Store app
+    library supports them.
+
+    Add comments about Johnston Island time in the 1960s.
+    (Thanks to Lyle McElhaney.)
+
+    Morocco's 2014 DST start will be as predicted.
+    (Thanks to Sebastien Willemijns.)
+
+
+Release 2014a - 2014-03-07 23:30:29 -0800
+
+  Changes affecting near-future timestamps
+
+    Turkey begins DST on 2014-03-31, not 03-30.  (Thanks to Faruk Pasin for
+    the heads-up, and to Tim Parenti for simplifying the update.)
+
+  Changes affecting past timestamps
+
+    Fiji ended DST on 2014-01-19 at 02:00, not the previously-scheduled 03:00.
+    (Thanks to Steffen Thorsen.)
+
+    Ukraine switched from Moscow to Eastern European time on 1990-07-01
+    (not 1992-01-01), and observed DST during the entire next winter.
+    (Thanks to Vladimir in Moscow via Alois Treindl.)
+
+    In 1988 Israel observed DST from 04-10 to 09-04, not 04-09 to 09-03.
+    (Thanks to Avigdor Finkelstein.)
+
+  Changes affecting code
+
+    A uninitialized-storage bug in 'localtime' has been fixed.
+    (Thanks to Logan Chien.)
+
+  Changes affecting the build procedure
+
+    The settings for 'make check_web' now default to Ubuntu 13.10.
+
+  Changes affecting commentary and documentation
+
+    The boundary of the US Pacific time zone is given more accurately.
+    (Thanks to Alan Mintz.)
+
+    Chile's 2014 DST will be as predicted.  (Thanks to José Miguel Garrido.)
+
+    Paraguay's 2014 DST will be as predicted.  (Thanks to Carlos Raúl Perasso.)
+
+    Better descriptions of countries with same time zone history as
+    Trinidad and Tobago since 1970.  (Thanks to Alan Barrett for suggestion.)
+
+    Several changes affect tz-link.htm, the main web page.
+
+      Mention Time.is (thanks to Even Scharning) and WX-now (thanks to
+      David Braverman).
+
+      Mention xCal (Internet RFC 6321) and jCal.
+
+      Microsoft has some support for tz database names.
+
+      CLDR data formats include both XML and JSON.
+
+      Mention Maggiolo's map of solar vs standard time.
+      (Thanks to Arthur David Olson.)
+
+      Mention TZ4Net.  (Thanks to Matt Johnson.)
+
+      Mention the timezone-olson Haskell package.
+
+      Mention zeitverschiebung.net.  (Thanks to Martin Jäger.)
+
+      Remove moribund links to daylight-savings-time.info and to
+      Simple Timer + Clocks.
+
+      Update two links.  (Thanks to Oscar van Vlijmen.)
+
+      Fix some formatting glitches, e.g., remove random newlines from
+      abbr elements' title attributes.
+
+
+Release 2013i - 2013-12-17 07:25:23 -0800
+
+  Changes affecting near-future timestamps:
+
+    Jordan switches back to standard time at 00:00 on December 20, 2013.
+    The 2006-2011 transition schedule is planned to resume in 2014.
+    (Thanks to Steffen Thorsen.)
+
+  Changes affecting past timestamps:
+
+    In 2004, Cuba began DST on March 28, not April 4.
+    (Thanks to Steffen Thorsen.)
+
+  Changes affecting code
+
+    The compile-time flag NOSOLAR has been removed, as nowadays the
+    benefit of slightly shrinking runtime table size is outweighed by the
+    cost of disallowing potential future updates that exceed old limits.
+
+  Changes affecting documentation and commentary
+
+    The files solar87, solar88, and solar89 are no longer distributed.
+    They were a negative experiment - that is, a demonstration that
+    tz data can represent solar time only with some difficulty and error.
+    Their presence in the distribution caused confusion, as Riyadh
+    civil time was generally not solar time in those years.
+
+    tz-link.htm now mentions Noda Time.  (Thanks to Matt Johnson.)
+
+
+Release 2013h - 2013-10-25 15:32:32 -0700
+
+  Changes affecting current and future timestamps:
+
+    Libya has switched its UT offset back to +02 without DST, instead
+    of +01 with DST.  (Thanks to Even Scharning.)
+
+    Western Sahara (Africa/El_Aaiun) uses Morocco's DST rules.
+    (Thanks to Gwillim Law.)
+
+  Changes affecting future timestamps:
+
+    Acre and (we guess) western Amazonas will switch from UT -04 to -05
+    on 2013-11-10.  This affects America/Rio_Branco and America/Eirunepe.
+    (Thanks to Steffen Thorsen.)
+
+    Add entries for DST transitions in Morocco in the year 2038.
+    This avoids some year-2038 glitches introduced in 2013g.
+    (Thanks to Yoshito Umaoka for reporting the problem.)
+
+  Changes affecting API
+
+    The 'tzselect' command no longer requires the 'select' command,
+    and should now work with /bin/sh on more platforms.  It also works
+    around a bug in BusyBox awk before version 1.21.0.  (Thanks to
+    Patrick 'P. J.' McDermott and Alan Barrett.)
+
+  Changes affecting code
+
+    Fix localtime overflow bugs with 32-bit unsigned time_t.
+
+    zdump no longer assumes sscanf returns maximal values on overflow.
+
+  Changes affecting the build procedure
+
+    The builder can specify which programs to use, if any, instead of
+    'ar' and 'ranlib', and libtz.a is now built locally before being
+    installed.  (Thanks to Michael Forney.)
+
+    A dependency typo in the 'zdump' rule has been fixed.
+    (Thanks to Andrew Paprocki.)
+
+    The Makefile has been simplified by assuming that 'mkdir -p' and 'cp -f'
+    work as specified by POSIX.2-1992 or later; this is portable nowadays.
+
+    'make clean' no longer removes 'leapseconds', since it's
+    host-independent and is part of the distribution.
+
+    The unused makefile macros TZCSRCS, TZDSRCS, DATESRCS have been removed.
+
+  Changes affecting documentation and commentary
+
+    tz-link.htm now mentions TC TIMEZONE's draft time zone service protocol
+    (thanks to Mike Douglass) and TimezoneJS.Date (thanks to Jim Fehrle).
+
+    Update URLs in tz-link page.  Add URLs for Microsoft Windows, since
+    8.1 introduces tz support.  Remove URLs for Tru64 and UnixWare (no
+    longer maintained) and for old advisories.  SOFA now does C.
+
+Release 2013g - 2013-09-30 21:08:26 -0700
+
+  Changes affecting current and near-future timestamps
+
+    Morocco now observes DST from the last Sunday in March to the last
+    Sunday in October, not April to September respectively.  (Thanks
+    to Steffen Thorsen.)
+
+  Changes affecting 'zic'
+
+    'zic' now runs on platforms that lack both hard links and symlinks.
+    (Thanks to Theo Veenker for reporting the problem, for MinGW.)
+    Also, fix some bugs on platforms that lack hard links but have symlinks.
+
+    'zic -v' again warns that Asia/Tehran has no POSIX environment variable
+    to predict the far future, fixing a bug introduced in 2013e.
+
+  Changes affecting the build procedure
+
+    The 'leapseconds' file is again put into the tzdata tarball.
+    Also, 'leapseconds.awk', so tzdata is self-contained.  (Thanks to
+    Matt Burgess and Ian Abbott.)  The timestamps of these and other
+    dependent files in tarballs are adjusted more consistently.
+
+  Changes affecting documentation and commentary
+
+    The README file is now part of the data tarball as well as the code.
+    It now states that files are public domain unless otherwise specified.
+    (Thanks to Andrew Main (Zefram) for asking for clarifications.)
+    Its details about the 1989 release moved to a place of honor near
+    the end of NEWS.
+
+
+Release 2013f - 2013-09-24 23:37:36 -0700
+
+  Changes affecting near-future timestamps
+
+    Tocantins will very likely not observe DST starting this spring.
+    (Thanks to Steffen Thorsen.)
+
+    Jordan will likely stay at UT +03 indefinitely, and will not fall
+    back this fall.
+
+    Palestine will fall back at 00:00, not 01:00.  (Thanks to Steffen Thorsen.)
+
+  Changes affecting API
+
+    The types of the global variables 'timezone' and 'altzone' (if present)
+    have been changed back to 'long'.  This is required for 'timezone'
+    by POSIX, and for 'altzone' by common practice, e.g., Solaris 11.
+    These variables were originally 'long' in the tz code, but were
+    mistakenly changed to 'time_t' in 1987; nobody reported the
+    incompatibility until now.  The difference matters on x32, where
+    'long' is 32 bits and 'time_t' is 64.  (Thanks to Elliott Hughes.)
+
+  Changes affecting the build procedure
+
+    Avoid long strings in leapseconds.awk to work around a mawk bug.
+    (Thanks to Cyril Baurand.)
+
+  Changes affecting documentation and commentary
+
+    New file 'NEWS' that contains release notes like this one.
+
+    Paraguay's law does not specify DST transition time; 00:00 is customary.
+    (Thanks to Waldemar Villamayor-Venialbo.)
+
+    Minor capitalization fixes.
+
+  Changes affecting version-control only
+
+    The experimental GitHub repository now contains annotated and
+    signed tags for recent releases, e.g., '2013e' for Release 2013e.
+    Releases are tagged starting with 2012e; earlier releases were
+    done differently, and tags would either not have a simple name or
+    not exactly match what was released.
+
+    'make set-timestamps' is now simpler and a bit more portable.
+
+
+Release 2013e - 2013-09-19 23:50:04 -0700
+
+  Changes affecting near-future timestamps
+
+    This year Fiji will start DST on October 27, not October 20.
+    (Thanks to David Wheeler for the heads-up.)  For now, guess that
+    Fiji will continue to spring forward the Sunday before the fourth
+    Monday in October.
+
+  Changes affecting current and future time zone abbreviations
+
+    Use WIB/WITA/WIT rather than WIT/CIT/EIT for alphabetic Indonesian
+    time zone abbreviations since 1932.  (Thanks to George Ziegler,
+    Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and
+    Benny Lin.)  This affects Asia/Dili, Asia/Jakarta, Asia/Jayapura,
+    Asia/Makassar, and Asia/Pontianak.
+
+    Use ART (UT -03, standard time), rather than WARST (also -03, but
+    daylight saving time) for San Luis, Argentina since 2009.
+
+  Changes affecting Godthåb timestamps after 2037 if version mismatch
+
+    Allow POSIX-like TZ strings where the transition time's hour can
+    range from -167 through 167, instead of the POSIX-required 0
+    through 24.  E.g., TZ='FJT-12FJST,M10.3.1/146,M1.3.4/75' for the
+    new Fiji rules.  This is a more-compact way to represent
+    far-future timestamps for America/Godthab, America/Santiago,
+    Antarctica/Palmer, Asia/Gaza, Asia/Hebron, Asia/Jerusalem,
+    Pacific/Easter, and Pacific/Fiji.  Other zones are unaffected by
+    this change.  (Derived from a suggestion by Arthur David Olson.)
+
+    Allow POSIX-like TZ strings where daylight saving time is in
+    effect all year.  E.g., TZ='WART4WARST,J1/0,J365/25' for Western
+    Argentina Summer Time all year.  This supports a more-compact way
+    to represent the 2013d data for America/Argentina/San_Luis.
+    Because of the change for San Luis noted above this change does not
+    affect the current data.  (Thanks to Andrew Main (Zefram) for
+    suggestions that improved this change.)
+
+    Where these two TZ changes take effect, there is a minor extension
+    to the tz file format in that it allows new values for the
+    embedded TZ-format string, and the tz file format version number
+    has therefore been increased from 2 to 3 as a precaution.
+    Version-2-based client code should continue to work as before for
+    all timestamps before 2038.  Existing version-2-based client code
+    (tzcode, GNU/Linux, Solaris) has been tested on version-3-format
+    files, and typically works in practice even for timestamps after
+    2037; the only known exception is America/Godthab.
+
+  Changes affecting timestamps before 1970
+
+    Pacific/Johnston is now a link to Pacific/Honolulu.  This corrects
+    some errors before 1947.
+
+    Some zones have been turned into links, when they differ from existing
+    zones only in older data entries that were likely invented or that
+    differ only in LMT or transitions from LMT.  These changes affect
+    only timestamps before 1943.  The affected zones are:
+    Africa/Juba, America/Anguilla, America/Aruba, America/Dominica,
+    America/Grenada, America/Guadeloupe, America/Marigot,
+    America/Montserrat, America/St_Barthelemy, America/St_Kitts,
+    America/St_Lucia, America/St_Thomas, America/St_Vincent,
+    America/Tortola, and Europe/Vaduz.  (Thanks to Alois Treindl for
+    confirming that the old Europe/Vaduz zone was wrong and the new
+    link is better for WWII-era times.)
+
+    Change Kingston Mean Time from -5:07:12 to -5:07:11.  This affects
+    America/Cayman, America/Jamaica and America/Grand_Turk timestamps
+    from 1890 to 1912.
+
+    Change the UT offset of Bern Mean Time from 0:29:44 to 0:29:46.
+    This affects Europe/Zurich timestamps from 1853 to 1894.  (Thanks
+    to Alois Treindl.)
+
+    Change the date of the circa-1850 Zurich transition from 1849-09-12
+    to 1853-07-16, overriding Shanks with data from Messerli about
+    postal and telegraph time in Switzerland.
+
+  Changes affecting time zone abbreviations before 1970
+
+    For Asia/Jakarta, use BMT (not JMT) for mean time from 1923 to 1932,
+    as Jakarta was called Batavia back then.
+
+  Changes affecting API
+
+    The 'zic' command now outputs a dummy transition when far-future
+    data can't be summarized using a TZ string, and uses a 402-year
+    window rather than a 400-year window.  For the current data, this
+    affects only the Asia/Tehran file.  It does not affect any of the
+    timestamps that this file represents, so zdump outputs the same
+    information as before.  (Thanks to Andrew Main (Zefram).)
+
+    The 'date' command has a new '-r' option, which lets you specify
+    the integer time to display, a la FreeBSD.
+
+    The 'tzselect' command has two new options '-c' and '-n', which lets you
+    select a zone based on latitude and longitude.
+
+    The 'zic' command's '-v' option now warns about constructs that
+    require the new version-3 binary file format.  (Thanks to Arthur
+    David Olson for the suggestion.)
+
+    Support for floating-point time_t has been removed.
+    It was always dicey, and POSIX no longer requires it.
+    (Thanks to Eric Blake for suggesting to the POSIX committee to
+    remove it, and thanks to Alan Barrett, Clive D.W. Feather, Andy
+    Heninger, Arthur David Olson, and Alois Treindl, for reporting
+    bugs and elucidating some of the corners of the old floating-point
+    implementation.)
+
+    The signatures of 'offtime', 'timeoff', and 'gtime' have been
+    changed back to the old practice of using 'long' to represent UT
+    offsets.  This had been inadvertently and mistakenly changed to
+    'int_fast32_t'.  (Thanks to Christos Zoulas.)
+
+    The code avoids undefined behavior on integer overflow in some
+    more places, including gmtime, localtime, mktime and zdump.
+
+  Changes affecting the zdump utility
+
+    zdump now outputs "UT" when referring to Universal Time, not "UTC".
+    "UTC" does not make sense for timestamps that predate the introduction
+    of UTC, whereas "UT", a more-generic term, does.  (Thanks to Steve Allen
+    for clarifying UT vs UTC.)
+
+  Data changes affecting behavior of tzselect and similar programs
+
+    Country code BQ is now called the more-common name "Caribbean Netherlands"
+    rather than the more-official "Bonaire, St Eustatius & Saba".
+
+    Remove from zone.tab the names America/Montreal, America/Shiprock,
+    and Antarctica/South_Pole, as they are equivalent to existing
+    same-country-code zones for post-1970 timestamps.  The data entries for
+    these names are unchanged, so the names continue to work as before.
+
+  Changes affecting code internals
+
+    zic -c now runs way faster on 64-bit hosts when given large numbers.
+
+    zic now uses vfprintf to avoid allocating and freeing some memory.
+
+    tzselect now computes the list of continents from the data,
+    rather than have it hard-coded.
+
+    Minor changes pacify GCC 4.7.3 and GCC 4.8.1.
+
+  Changes affecting the build procedure
+
+    The 'leapseconds' file is now generated automatically from a
+    new file 'leap-seconds.list', which is a copy of
+    
+    A new source file 'leapseconds.awk' implements this.
+    The goal is simplification of the future maintenance of 'leapseconds'.
+
+    When building the 'posix' or 'right' subdirectories, if the
+    subdirectory would be a copy of the default subdirectory, it is
+    now made a symbolic link if that is supported.  This saves about
+    2 MB of file system space.
+
+    The links America/Shiprock and Antarctica/South_Pole have been
+    moved to the 'backward' file.  This affects only nondefault builds
+    that omit 'backward'.
+
+  Changes affecting version-control only
+
+    .gitignore now ignores 'date'.
+
+  Changes affecting documentation and commentary
+
+    Changes to the 'tzfile' man page
+
+      It now mentions that the binary file format may be extended in
+      future versions by appending data.
+
+      It now refers to the 'zdump' and 'zic' man pages.
+
+    Changes to the 'zic' man page
+
+      It lists conditions that elicit a warning with '-v'.
+
+      It says that the behavior is unspecified when duplicate names
+      are given, or if the source of one link is the target of another.
+
+      Its examples are updated to match the latest data.
+
+      The definition of white space has been clarified slightly.
+      (Thanks to Michael Deckers.)
+
+    Changes to the 'Theory' file
+
+      There is a new section about the accuracy of the tz database,
+      describing the many ways that errors can creep in, and
+      explaining why so many of the pre-1970 timestamps are wrong or
+      misleading (thanks to Steve Allen, Lester Caine, and Garrett
+      Wollman for discussions that contributed to this).
+
+      The 'Theory' file describes LMT better (this follows a
+      suggestion by Guy Harris).
+
+      It refers to the 2013 edition of POSIX rather than the 2004 edition.
+
+      It's mentioned that excluding 'backward' should not affect the
+      other data, and it suggests at least one zone.tab name per
+      inhabited country (thanks to Stephen Colebourne).
+
+      Some longstanding restrictions on names are documented, e.g.,
+      'America/New_York' precludes 'America/New_York/Bronx'.
+
+      It gives more reasons for the 1970 cutoff.
+
+      It now mentions which time_t variants are supported, such as
+      signed integer time_t.  (Thanks to Paul Goyette for reporting
+      typos in an experimental version of this change.)
+
+      (Thanks to Philip Newton for correcting typos in these changes.)
+
+    Documentation and commentary is more careful to distinguish UT in
+    general from UTC in particular.  (Thanks to Steve Allen.)
+
+    Add a better source for the Zurich 1894 transition.
+    (Thanks to Pierre-Yves Berger.)
+
+    Update shapefile citations in tz-link.htm.  (Thanks to Guy Harris.)
+
+
+Release 2013d - 2013-07-05 07:38:01 -0700
+
+  Changes affecting future timestamps:
+
+    Morocco's midsummer transitions this year are July 7 and August 10,
+    not July 9 and August 8.  (Thanks to Andrew Paprocki.)
+
+    Israel now falls back on the last Sunday of October.
+    (Thanks to Ephraim Silverberg.)
+
+  Changes affecting past timestamps:
+
+    Specify Jerusalem's location more precisely; this changes the pre-1880
+    times by 2 s.
+
+  Changing affecting metadata only:
+
+    Fix typos in the entries for country codes BQ and SX.
+
+  Changes affecting code:
+
+    Rework the code to fix a bug with handling Australia/Macquarie on
+    32-bit hosts (thanks to Arthur David Olson).
+
+    Port to platforms like NetBSD, where time_t can be wider than long.
+
+    Add support for testing time_t types other than the system's.
+    Run 'make check_time_t_alternatives' to try this out.
+    Currently, the tests fail for unsigned time_t;
+    this should get fixed at some point.
+
+  Changes affecting documentation and commentary:
+
+    Deemphasize the significance of national borders.
+
+    Update the zdump man page.
+
+    Remove obsolete NOID comment (thanks to Denis Excoffier).
+
+    Update several URLs and comments in the web pages.
+
+    Spelling fixes (thanks to Kevin Lyda and Jonathan Leffler).
+
+    Update URL for CLDR Zone->Tzid table (thanks to Yoshito Umaoka).
+
+
+Release 2013c - 2013-04-19 16:17:40 -0700
+
+  Changes affecting current and future timestamps:
+
+    Palestine observed DST starting March 29, 2013.  (Thanks to
+    Steffen Thorsen.)  From 2013 on, Gaza and Hebron both observe DST,
+    with the predicted rules being the last Thursday in March at 24:00
+    to the first Friday on or after September 21 at 01:00.
+
+    Assume that the recent change to Paraguay's DST rules is permanent,
+    by moving the end of DST to the 4th Sunday in March every year.
+    (Thanks to Carlos Raúl Perasso.)
+
+  Changes affecting past timestamps:
+
+    Fix some historical data for Palestine to agree with that of
+    timeanddate.com, as follows:
+
+	  The spring 2008 change in Gaza and Hebron was on 00:00 Mar 28, not
+	  00:00 Apr 1.
+
+	  The fall 2009 change in Gaza and Hebron on Sep 4 was at 01:00, not
+	  02:00.
+
+	  The spring 2010 change in Hebron was 00:00 Mar 26, not 00:01 Mar 27.
+
+	  The spring 2011 change in Gaza was 00:01 Apr 1, not 12:01 Apr 2.
+
+	  The spring 2011 change in Hebron on Apr 1 was at 00:01, not 12:01.
+
+	  The fall 2011 change in Hebron on Sep 30 was at 00:00, not 03:00.
+
+    Fix times of habitation for Macquarie to agree with the Tasmania
+    Parks & Wildlife Service history, which indicates that permanent
+    habitation was 1899-1919 and 1948 on.
+
+  Changing affecting metadata only:
+
+    Macquarie Island is politically part of Australia, not Antarctica.
+    (Thanks to Tobias Conradi.)
+
+    Sort Macquarie more-consistently with other parts of Australia.
+    (Thanks to Tim Parenti.)
+
+
+Release 2013b - 2013-03-10 22:33:40 -0700
+
+  Changes affecting current and future timestamps:
+
+    Haiti uses US daylight-saving rules this year, and presumably future years.
+    This changes timestamps starting today.  (Thanks to Steffen Thorsen.)
+
+    Paraguay will end DST on March 24 this year.
+    (Thanks to Steffen Thorsen.)  For now, assume it's just this year.
+
+    Morocco does not observe DST during Ramadan;
+    try to predict Ramadan in Morocco as best we can.
+    (Thanks to Erik Homoet for the heads-up.)
+
+  Changes affecting commentary:
+
+    Update URLs in tz-link page.  Add URLs for webOS, BB10, iOS.
+    Update URL for Solaris.  Mention Internet RFC 6557.
+    Update Internet RFCs 2445->5545, 2822->5322.
+    Switch from FTP to HTTP for Internet RFCs.
+
+
+Release 2013a - 2013-02-27 09:20:35 -0800
+
+  Change affecting binary data format:
+
+    The zone offset at the end of version-2-format zone files is now
+    allowed to be 24:00, as per POSIX.1-2008.  (Thanks to Arthur David Olson.)
+
+  Changes affecting current and future timestamps:
+
+    Chile's 2013 rules, and we guess rules for 2014 and later, will be
+    the same as 2012, namely Apr Sun>=23 03:00 UTC to Sep Sun>=2 04:00 UTC.
+    (Thanks to Steffen Thorsen and Robert Elz.)
+
+    New Zones Asia/Khandyga, Asia/Ust-Nera, Europe/Busingen.
+    (Thanks to Tobias Conradi and Arthur David Olson.)
+
+  Many changes affect historical timestamps before 1940.
+  These were deduced from: Milne J. Civil time. Geogr J. 1899
+  Feb;13(2):173-94 .
+
+  Changes affecting the code:
+
+    Fix zic bug that mishandled Egypt's 2010 changes (this also affected
+    the data).  (Thanks to Arthur David Olson.)
+
+    Fix localtime bug when time_t is unsigned and data files were generated
+    by a signed time_t system.  (Thanks to Doug Bailey for reporting and
+    to Arthur David Olson for fixing.)
+
+    Allow the email address for bug reports to be set by the packager.
+    The default is tz@iana.org, as before.  (Thanks to Joseph S. Myers.)
+
+    Update HTML checking to be compatible with Ubuntu 12.10.
+
+    Check that files are a safe subset of ASCII.  At some point we may
+    relax this requirement to a safe subset of UTF-8.  Without the
+    check, some non-UTF-8 encodings were leaking into the distribution.
+
+  Commentary changes:
+
+    Restore a comment about copyright notices that was inadvertently deleted.
+    (Thanks to Arthur David Olson.)
+
+    Improve the commentary about which districts observe what times
+    in Russia.  (Thanks to Oscar van Vlijmen and Arthur David Olson.)
+
+    Add web page links to tz.js.
+
+    Add "Run by the Monkeys" to tz-art.  (Thanks to Arthur David Olson.)
+
+
+Release 2012j - 2012-11-12 18:34:49 -0800
+
+  Libya moved to CET this weekend, but with DST planned next year.
+  (Thanks to Even Scharning, Steffen Thorsen, and Tim Parenti.)
+
+  Signatures now have the extension .asc, not .sign, as that's more
+  standard.  (Thanks to Phil Pennock.)
+
+  The output of 'zdump --version', and of 'zic --version', now
+  uses a format that is more typical for --version.
+  (Thanks to Joseph S. Myers.)
+
+  The output of 'tzselect --help', 'zdump --help', and 'zic --help'
+  now uses tz@iana.org rather than the old elsie address.
+
+  zic -v now complains about abbreviations that are less than 3
+  or more than 6 characters, as per Posix.  Formerly, it checked
+  for abbreviations that were more than 3.
+
+  'make public' no longer puts its temporary directory under /tmp,
+  and uses the just-built zic rather than the system zic.
+
+  Various fixes to documentation and commentary.
+
+
+Release 2012i - 2012-11-03 12:57:09 -0700
+
+  Cuba switches from DST tomorrow at 01:00.  (Thanks to Steffen Thorsen.)
+
+  Linker flags can now be specified via LDFLAGS.
+  AWK now defaults to 'awk', not 'nawk'.
+  The shell in tzselect now defaults to /bin/bash, but this can
+  be overridden by specifying KSHELL.
+  The main web page now mentions the unofficial GitHub repository.
+  (Thanks to Mike Frysinger.)
+
+  Tarball signatures can now be built by running 'make signatures'.
+  There are also new makefile rules 'tarballs', 'check_public', and
+  separate makefile rules for each tarball and signature file.
+  A few makefile rules are now more portable to strict POSIX.
+
+  The main web page now lists the canonical IANA URL.
+
+
+Release 2012h - 2012-10-26 22:49:10 -0700
+
+  Bahia no longer has DST.  (Thanks to Kelley Cook.)
+
+  Tocantins has DST.  (Thanks to Rodrigo Severo.)
+
+  Israel has new DST rules next year.  (Thanks to Ephraim Silverberg.)
+
+  Jordan stays on DST this winter.  (Thanks to Steffen Thorsen.)
+
+  Web page updates.
+
+  More C modernization, except that at Arthur David Olson's suggestion
+  the instances of 'register' were kept.
+
+
+Release 2012g - 2012-10-17 20:59:45 -0700
+
+  Samoa fall 2012 and later.  (Thanks to Nicholas Pereira and Robert Elz.)
+
+  Palestine fall 2012.  (Thanks to Steffen Thorsen.)
+
+  Assume C89.
+
+  To attack the version-number problem, this release ships the file
+  'Makefile' (which contains the release number) in both the tzcode and
+  the tzdata tarballs.  The two Makefiles are identical, and should be
+  identical in any matching pair of tarballs, so it shouldn't matter
+  which order you extract the tarballs.  Perhaps we can come up with a
+  better version-number scheme at some point; this scheme does have the
+  virtue of not adding more files.
+
+
+Release 2012f - 2012-09-12 23:17:03 -0700
+
+  * australasia (Pacific/Fiji): Fiji DST is October 21 through January
+    20 this year.  (Thanks to Steffen Thorsen.)
+
+
+Release 2012e - 2012-08-02 20:44:55 -0700
+
+  * australasia (Pacific/Fakaofo): Tokelau is UT +13, not +14.
+    (Thanks to Steffen Thorsen.)
+
+  * Use a single version number for both code and data.
+
+  * .gitignore: New file.
+
+  * Remove trailing white space.
+
+
+Release code2012c-data2012d - 2012-07-19 16:35:33 -0700
+
+  Changes for Morocco's timestamps, which take effect in a couple of
+  hours, along with infrastructure changes to accommodate how the tz
+  code and data are released on IANA.
+
+
+Release data2012c - 2012-03-27 12:17:25 -0400
+
+  africa
+	Summer time changes for Morocco (to start late April 2012)
+
+  asia
+	Changes for 2012 for Gaza & the West Bank (Hebron) and Syria
+
+  northamerica
+	Haiti following US/Canada rules for 2012 (and we're assuming,
+	for now anyway, for the future).
+
+
+Release 2012b - 2012-03-02 12:29:15 +0700
+
+  There is just one change to tzcode2012b (compared with 2012a):
+  the Makefile that was accidentally included with 2012a has been
+  replaced with the version that should have been there, which is
+  identical with the previous version (from tzcode2011i).
+
+  There are just two changes in tzdata2012b compared with 2012a.
+
+  Most significantly, summer time in Cuba has been delayed 3 weeks
+  (now starts April 1 rather than March 11).   Since Mar 11 (the old start
+  date, as listed in 2012a) is just a little over a week away, this
+  change is urgent.
+
+  Less importantly, an excess tab in one of the changes in zone.tab
+  in 2012a has been removed.
+
+
+Release 2012a - 2012-03-01 18:28:10 +0700
+
+  The changes in tzcode2012a (compared to the previous version, 2011i)
+  are entirely to the README and tz-art.htm and tz-link.htm files, if
+  none of those concern you, you can ignore the code update.  The changes
+  reflect the changed addresses for the mailing list and the code and
+  data distribution points & methods (and a link to DateTime::TimeZone::Tzfile
+  has been added to tz-link.htm).
+
+  In tzdata2012a (compared to the previous release, which was 2011n)
+  the major changes are:
+	Chile 2011/2012 and 2012/2013 summer time date adjustments.
+	Falkland Islands onto permanent summer time (we're assuming for the
+		foreseeable future, though 2012 is all we're fairly certain of.)
+	Armenia has abolished Summer Time.
+	Tokelau jumped the International Date Line back last December
+		(just the same as their near neighbour, Samoa).
+	America/Creston is a new zone for a small area of British Columbia
+	There will be a leapsecond 2012-06-30 23:59:60 UTC.
+
+  Other minor changes are:
+	Corrections to 1918 Canadian summer time end dates.
+	Updated URL for UK time zone history (in comments)
+	A few typos in Le Corre's list of free French place names (comments)
+
+
+Release data2011n - 2011-10-30 14:57:54 +0700
+
+  There are three changes of note - most urgently, Cuba (America/Havana)
+  has extended summer time by two weeks, now to end on Nov 13, rather than
+  the (already past) Oct 30.   Second, the Pridnestrovian Moldavian Republic
+  (Europe/Tiraspol) decided not to split from the rest of Moldova after
+  all, and consequently that zone has been removed (again) and reinstated
+  in the "backward" file as a link to Europe/Chisinau.   And third, the
+  end date for Fiji's summer time this summer was moved forward from the
+  earlier planned Feb 26, to Jan 22.
+
+  Apart from that, Moldova (MD) returns to a single entry in zone.tab
+  (and the incorrect syntax that was in the 2011m version of that file
+  is so fixed - it would have been fixed in a different way had this
+  change not happened - that's the "missing" sccs version id).
+
+
+Release data2011m - 2011-10-24 21:42:16 +0700
+
+  In particular, the typos in comments in the data (2011-11-17 should have
+  been 2011-10-17 as Alan Barrett noted, and spelling of Tiraspol that
+  Tim Parenti noted) have been fixed, and the change for Ukraine has been
+  made in all 4 Ukrainian zones, rather than just Kiev (again, thanks to
+  Tim Parenti, and also Denys Gavrysh)
+
+  In addition, I added Europe/Tiraspol to zone.tab.
+
+  This time, all the files have new version numbers...  (including the files
+  otherwise unchanged in 2011m that were changed in 2011l but didn't get new
+  version numbers there...)
+
+
+Release data2011l - 2011-10-10 11:15:43 +0700
+
+  There are just 2 changes that cause different generated tzdata files from
+  zic, to Asia/Hebron and Pacific/Fiji - the possible change for Bahia, Brazil
+  is included, but commented out.  Compared with the diff I sent out last week,
+  this version also includes attributions for the sources for the changes
+  (in much the same format as ado used, but the html tags have not been
+  checked, verified, or used in any way at all, so if there are errors there,
+  please let me know.)
+
+
+Release data2011k - 2011-09-20 17:54:03 -0400
+
+  [not summarized]
+
+
+Release data2011j - 2011-09-12 09:22:49 -0400
+
+  (contemporary changes for Samoa; past changes for Kenya, Uganda, and
+  Tanzania); there are also two spelling corrections to comments in
+  the australasia file (with thanks to Christos Zoulas).
+
+
+Release 2011i - 2011-08-29 05:56:32 -0400
+
+  [not summarized]
+
+
+Release data2011h - 2011-06-15 18:41:48 -0400
+
+  Russia and Curaçao changes
+
+
+Release 2011g - 2011-04-25 09:07:22 -0400
+
+  update the rules for Egypt to reflect its abandonment of DST this year
+
+
+Release 2011f - 2011-04-06 17:14:53 -0400
+
+  [not summarized]
+
+
+Release 2011e - 2011-03-31 16:04:38 -0400
+
+  Morocco, Chile, and tz-link changes
+
+
+Release 2011d - 2011-03-14 09:18:01 -0400
+
+  changes that impact present-day timestamps in Cuba, Samoa, and Turkey
+
+
+Release 2011c - 2011-03-07 09:30:09 -0500
+
+  These do affect current timestamps in Chile and Annette Island, Canada.
+
+
+Release 2011b - 2011-02-07 08:44:50 -0500
+
+  [not summarized]
+
+
+Release 2011a - 2011-01-24 10:30:16 -0500
+
+  [not summarized]
+
+
+Release data2010o - 2010-11-01 09:18:23 -0400
+
+  change to the end of DST in Fiji in 2011
+
+
+Release 2010n - 2010-10-25 08:19:17 -0400
+
+  [not summarized]
+
+
+Release 2010m - 2010-09-27 09:24:48 -0400
+
+  Hong Kong, Vostok, and zic.c changes
+
+
+Release 2010l - 2010-08-16 06:57:25 -0400
+
+  [not summarized]
+
+
+Release 2010k - 2010-07-26 10:42:27 -0400
+
+  [not summarized]
+
+
+Release 2010j - 2010-05-10 09:07:48 -0400
+
+  changes for Bahía de Banderas and for version naming
+
+
+Release data2010i - 2010-04-16 18:50:45 -0400
+
+  the end of DST in Morocco on 2010-08-08
+
+
+Release data2010h - 2010-04-05 09:58:56 -0400
+
+  [not summarized]
+
+
+Release data2010g - 2010-03-24 11:14:53 -0400
+
+  [not summarized]
+
+
+Release 2010f - 2010-03-22 09:45:46 -0400
+
+  [not summarized]
+
+
+Release data2010e - 2010-03-08 14:24:27 -0500
+
+  corrects the Dhaka bug found by Danvin Ruangchan
+
+
+Release data2010d - 2010-03-06 07:26:01 -0500
+
+  [not summarized]
+
+
+Release 2010c - 2010-03-01 09:20:58 -0500
+
+  changes including KRE's suggestion for earlier initialization of
+  "goahead" and "goback" structure elements
+
+
+Release code2010a - 2010-02-16 10:40:04 -0500
+
+  [not summarized]
+
+
+Release data2010b - 2010-01-20 12:37:01 -0500
+
+  Mexico changes
+
+
+Release data2010a - 2010-01-18 08:30:04 -0500
+
+  changes to Dhaka
+
+
+Release data2009u - 2009-12-26 08:32:28 -0500
+
+  changes to DST in Bangladesh
+
+
+Release 2009t - 2009-12-21 13:24:27 -0500
+
+  [not summarized]
+
+
+Release data2009s - 2009-11-14 10:26:32 -0500
+
+  (cosmetic) Antarctica change and the DST-in-Fiji-in-2009-and-2010 change
+
+
+Release 2009r - 2009-11-09 10:10:31 -0500
+
+  "antarctica" and "tz-link.htm" changes
+
+
+Release 2009q - 2009-11-02 09:12:40 -0500
+
+  with two corrections as reported by Eric Muller and Philip Newton
+
+
+Release data2009p - 2009-10-23 15:05:27 -0400
+
+  Argentina (including San Luis) changes (with the correction from
+  Mariano Absatz)
+
+
+Release data2009o - 2009-10-14 16:49:38 -0400
+
+  Samoa (commentary only), Pakistan, and Bangladesh changes
+
+
+Release data2009n - 2009-09-22 15:13:38 -0400
+
+  added commentary for Argentina and a change to the end of DST in
+  2009 in Pakistan
+
+
+Release data2009m - 2009-09-03 10:23:43 -0400
+
+  Samoa and Palestine changes
+
+
+Release data2009l - 2009-08-14 09:13:07 -0400
+
+  Samoa (comments only) and Egypt
+
+
+Release 2009k - 2009-07-20 09:46:08 -0400
+
+  [not summarized]
+
+
+Release data2009j - 2009-06-15 06:43:59 -0400
+
+  Bangladesh change (with a short turnaround since the DST change is
+  impending)
+
+
+Release 2009i - 2009-06-08 09:21:22 -0400
+
+  updating for DST in Bangladesh this year
+
+
+Release 2009h - 2009-05-26 09:19:14 -0400
+
+  [not summarized]
+
+
+Release data2009g - 2009-04-20 16:34:07 -0400
+
+  Cairo
+
+
+Release data2009f - 2009-04-10 11:00:52 -0400
+
+  correct DST in Pakistan
+
+
+Release 2009e - 2009-04-06 09:08:11 -0400
+
+  [not summarized]
+
+
+Release 2009d - 2009-03-23 09:38:12 -0400
+
+  Morocco, Tunisia, Argentina, and American Astronomical Society changes
+
+
+Release data2009c - 2009-03-16 09:47:51 -0400
+
+  change to the start of Cuban DST
+
+
+Release 2009b - 2009-02-09 11:15:22 -0500
+
+  [not summarized]
+
+
+Release 2009a - 2009-01-21 10:09:39 -0500
+
+  [not summarized]
+
+
+Release data2008i - 2008-10-21 12:10:25 -0400
+
+  southamerica and zone.tab files, with Argentina DST rule changes and
+  United States zone reordering and recommenting
+
+
+Release 2008h - 2008-10-13 07:33:56 -0400
+
+  [not summarized]
+
+
+Release 2008g - 2008-10-06 09:03:18 -0400
+
+  Fix a broken HTML anchor and update Brazil's DST transitions;
+  there's also a slight reordering of information in tz-art.htm.
+
+
+Release data2008f - 2008-09-09 22:33:26 -0400
+
+  [not summarized]
+
+
+Release 2008e - 2008-07-28 14:11:17 -0400
+
+  changes by Arthur David Olson and Jesper Nørgaard Welen
+
+
+Release data2008d - 2008-07-07 09:51:38 -0400
+
+  changes by Arthur David Olson, Paul Eggert, and Rodrigo Severo
+
+
+Release data2008c - 2008-05-19 17:48:03 -0400
+
+  Pakistan, Morocco, and Mongolia
+
+
+Release data2008b - 2008-03-24 08:30:59 -0400
+
+  including renaming Asia/Calcutta to Asia/Kolkata, with a backward
+  link provided
+
+
+Release 2008a - 2008-03-08 05:42:16 -0500
+
+  [not summarized]
+
+
+Release 2007k - 2007-12-31 10:25:22 -0500
+
+  most importantly, changes to the "southamerica" file based on
+  Argentina's readoption of daylight saving time
+
+
+Release 2007j - 2007-12-03 09:51:01 -0500
+
+  1. eliminate the "P" (parameter) macro;
+
+  2. the "noncontroversial" changes circulated on the time zone
+  mailing list (less the changes to "logwtmp.c");
+
+  3. eliminate "too many transition" errors when "min" is used in time
+  zone rules;
+
+  4. changes by Paul Eggert (including updated information for Venezuela).
+
+
+Release data2007i - 2007-10-30 10:28:11 -0400
+
+  changes for Cuba and Syria
+
+
+Release 2007h - 2007-10-01 10:05:51 -0400
+
+  changes by Paul Eggert, as well as an updated link to the ICU
+  project in tz-link.htm
+
+
+Release 2007g - 2007-08-20 10:47:59 -0400
+
+  changes by Paul Eggert
+
+  The "leapseconds" file has been updated to incorporate the most
+  recent International Earth Rotation and Reference Systems Service
+  (IERS) bulletin.
+
+  There's an addition to tz-art.htm regarding the television show "Medium".
+
+
+Release 2007f - 2007-05-07 10:46:46 -0400
+
+  changes by Paul Eggert (including Haiti, Turks and Caicos, and New
+  Zealand)
+
+  changes to zic.c to allow hour values greater than 24 (along with
+  Paul's improved time value overflow checking)
+
+
+Release 2007e - 2007-04-02 10:11:52 -0400
+
+  Syria and Honduras changes by Paul Eggert
+
+  zic.c variable renaming changes by Arthur David Olson
+
+
+Release 2007d - 2007-03-20 08:48:30 -0400
+
+  changes by Paul Eggert
+
+  the elimination of white space at the ends of lines
+
+
+Release 2007c - 2007-02-26 09:09:37 -0500
+
+  changes by Paul Eggert
+
+
+Release 2007b - 2007-02-12 09:34:20 -0500
+
+  Paul Eggert's proposed change to the quotation handling logic in zic.c.
+
+  changes to the commentary in "leapseconds" reflecting the IERS
+  announcement that there is to be no positive leap second at the end
+  of June 2007.
+
+
+Release 2007a - 2007-01-08 12:28:29 -0500
+
+  changes by Paul Eggert
+
+  Derick Rethans's Asmara change
+
+  Oscar van Vlijmen's Easter Island local mean time change
+
+  symbolic link changes
+
+
+Release 2006p - 2006-11-27 08:54:27 -0500
+
+  changes by Paul Eggert
+
+
+Release 2006o - 2006-11-06 09:18:07 -0500
+
+  changes by Paul Eggert
+
+
+Release 2006n - 2006-10-10 11:32:06 -0400
+
+  changes by Paul Eggert
+
+
+Release 2006m - 2006-10-02 15:32:35 -0400
+
+  changes for Uruguay, Palestine, and Egypt by Paul Eggert
+
+  (minimalist) changes to zic.8 to clarify "until" information
+
+
+Release data2006l - 2006-09-18 12:58:11 -0400
+
+  Paul's best-effort work on this coming weekend's Egypt time change
+
+
+Release 2006k - 2006-08-28 12:19:09 -0400
+
+  changes by Paul Eggert
+
+
+Release 2006j - 2006-08-21 09:56:32 -0400
+
+  changes by Paul Eggert
+
+
+Release code2006i - 2006-08-07 12:30:55 -0400
+
+  localtime.c fixes
+
+  Ken Pizzini's conversion script
+
+
+Release code2006h - 2006-07-24 09:19:37 -0400
+
+  adds public domain notices to four files
+
+  includes a fix for transition times being off by a second
+
+  adds a new recording to the "arts" file (information courtesy Colin Bowern)
+
+
+Release 2006g - 2006-05-08 17:18:09 -0400
+
+  northamerica changes by Paul Eggert
+
+
+Release 2006f - 2006-05-01 11:46:00 -0400
+
+  a missing version number problem is fixed (with thanks to Bradley
+  White for catching the problem)
+
+
+Release 2006d - 2006-04-17 14:33:43 -0400
+
+  changes by Paul Eggert
+
+  added new items to tz-arts.htm that were found by Paul
+
+
+Release 2006c - 2006-04-03 10:09:32 -0400
+
+  two sets of data changes by Paul Eggert
+
+  a fencepost error fix in zic.c
+
+  changes to zic.c and the "europe" file to minimize differences
+  between output produced by the old 32-bit zic and the new 64-bit
+  version
+
+
+Release 2006b - 2006-02-20 10:08:18 -0500
+  [tz32code2006b + tz64code2006b + tzdata2006b]
+
+  64-bit code
+
+  All SCCS IDs were bumped to "8.1" for this release.
+
+
+Release 2006a - 2006-01-30 08:59:31 -0500
+
+  changes by Paul Eggert (in particular, Indiana time zone moves)
+
+  an addition to the zic manual page to describe how special-case
+  transitions are handled
+
+
+Release 2005r - 2005-12-27 09:27:13 -0500
+
+  Canadian changes by Paul Eggert
+
+  They also add "" directives to time zone data files and reflect
+  changes to warning message logic in "zdump.c" (but with calls to
+  "gettext" kept unbundled at the suggestion of Ken Pizzini).
+
+
+Release 2005q - 2005-12-13 09:17:09 -0500
+
+  Nothing earth-shaking here:
+	1.  Electronic mail addresses have been removed.
+	2.  Casts of the return value of exit have been removed.
+	3.  Casts of the argument of is.* macros have been added.
+	4.  Indentation in one section of zic.c has been fixed.
+	5.  References to dead URLs in the data files have been dealt with.
+
+
+Release 2005p - 2005-12-05 10:30:53 -0500
+
+  "systemv", "tz-link.htm", and "zdump.c" changes
+  (less the casts of arguments to the is* macros)
+
+
+Release 2005o - 2005-11-28 10:55:26 -0500
+
+  Georgia, Cuba, Nicaragua, and Jordan changes by Paul Eggert
+
+  zdump.c lint fixes by Arthur David Olson
+
+
+Release 2005n - 2005-10-03 09:44:09 -0400
+
+  changes by Paul Eggert (both the Uruguay changes and the Kyrgyzstan
+  et al. changes)
+
+
+Release 2005m - 2005-08-29 12:15:40 -0400
+
+  changes by Paul Eggert (with a small tweak to the tz-art change)
+
+  a declaration of an unused variable has been removed from zdump.c
+
+
+Release 2005l - 2005-08-22 12:06:39 -0400
+
+  changes by Paul Eggert
+
+  overflow/underflow checks by Arthur David Olson, minus changes to
+  the "Theory" file about the pending addition of 64-bit data (I grow
+  less confident of the changes being accepted with each passing day,
+  and the changes no longer increase the data files nine-fold--there's
+  less than a doubling in size by my local Sun's reckoning)
+
+
+Release 2005k - 2005-07-14 14:14:24 -0400
+
+  The "leapseconds" file has been edited to reflect the recently
+  announced leap second at the end of 2005.
+
+  I've also deleted electronic mail addresses from the files as an
+  anti-spam measure.
+
+
+Release 2005j - 2005-06-13 14:34:13 -0400
+
+  These reflect changes to limit the length of time zone abbreviations
+  and the characters used in those abbreviations.
+
+  There are also changes to handle POSIX-style "quoted" timezone
+  environment variables.
+
+  The changes were circulated on the time zone mailing list; the only
+  change since then was the removal of a couple of minimum-length of
+  abbreviation checks.
+
+
+Release data2005i - 2005-04-21 15:04:16 -0400
+
+  changes (most importantly to Nicaragua and Haiti) by Paul Eggert
+
+
+Release 2005h - 2005-04-04 11:24:47 -0400
+
+  changes by Paul Eggert
+
+  minor changes to Makefile and zdump.c to produce more useful output
+  when doing a "make typecheck"
+
+
+Release 2005g - 2005-03-14 10:11:21 -0500
+
+  changes by Paul Eggert (a change to current DST rules in Uruguay and
+  an update to a link to time zone software)
+
+
+Release 2005f - 2005-03-01 08:45:32 -0500
+
+  data and documentation changes by Paul Eggert
+
+
+Release 2005e - 2005-02-10 15:59:44 -0500
+
+  [not summarized]
+
+
+Release code2005d - 2005-01-31 09:21:47 -0500
+
+  make zic complain about links to links if the -v flag is used
+
+  have "make public" do more code checking
+
+  add an include to "localtime.c" for the benefit of gcc systems
+
+
+Release 2005c - 2005-01-17 18:36:29 -0500
+
+  get better results when mktime runs on a system where time_t is double
+
+  changes to the data files (most importantly to Paraguay)
+
+
+Release 2005b - 2005-01-10 09:19:54 -0500
+
+  Get localtime and gmtime working on systems with exotic time_t types.
+
+  Update the leap second commentary in the "leapseconds" file.
+
+
+Release 2005a - 2005-01-01 13:13:44 -0500
+
+  [not summarized]
+
+
+Release code2004i - 2004-12-14 13:42:58 -0500
+
+  Deal with systems where time_t is unsigned.
+
+
+Release code2004h - 2004-12-07 11:40:18 -0500
+
+  64-bit-time_t changes
+
+
+Release 2004g - 2004-11-02 09:06:01 -0500
+
+  update to Cuba (taking effect this weekend)
+
+  other changes by Paul Eggert
+
+  correction of the spelling of Oslo
+
+  changed versions of difftime.c and private.h
+
+
+Release code2004f - 2004-10-21 10:25:22 -0400
+
+  Cope with wide-ranging tm_year values.
+
+
+Release 2004e - 2004-10-11 14:47:21 -0400
+
+  Brazil/Argentina/Israel changes by Paul Eggert
+
+  changes to tz-link.htm by Paul
+
+  one small fix to Makefile
+
+
+Release 2004d - 2004-09-22 08:27:29 -0400
+
+  Avoid overflow problems when TM_YEAR_BASE is added to an integer.
+
+
+Release 2004c - 2004-08-11 12:06:26 -0400
+
+  asctime-related changes
+
+  (variants of) some of the documentation changes suggested by Paul Eggert
+
+
+Release 2004b - 2004-07-19 14:33:35 -0400
+
+  data changes by Paul Eggert - most importantly, updates for Argentina
+
+
+Release 2004a - 2004-05-27 12:00:47 -0400
+
+  changes by Paul Eggert
+
+  Handle DST transitions that occur at the end of a month in some
+  years but at the start of the following month in other years.
+
+  Add a copy of the correspondence that's the basis for claims about
+  DST in the Navajo Nation.
+
+
+Release 2003e - 2003-12-15 09:36:47 -0500
+
+  changes by Arthur David Olson (primarily code changes)
+
+  changes by Paul Eggert (primarily data changes)
+
+  minor changes to "Makefile" and "northamerica" (in the latter case,
+  optimization of the "Toronto" rules)
+
+
+Release 2003d - 2003-10-06 09:34:44 -0400
+
+  changes by Paul Eggert
+
+
+Release 2003c - 2003-09-16 10:47:05 -0400
+
+  Fix bad returns in zic.c's inleap function.
+  Thanks to Bradley White for catching the problem!
+
+
+Release 2003b - 2003-09-16 07:13:44 -0400
+
+  Add a "--version" option (and documentation) to the zic and zdump commands.
+
+  changes to overflow/underflow checking in zic
+
+  a localtime typo fix.
+
+  Update the leapseconds and tz-art.htm files.
+
+
+Release 2003a - 2003-03-24 09:30:54 -0500
+
+  changes by Paul Eggert
+
+  a few additions and modifications to the tz-art.htm file
+
+
+Release 2002d - 2002-10-15 13:12:42 -0400
+
+  changes by Paul Eggert, less the "Britain (UK)" change in iso3166.tab
+
+  There's also a new time zone quote in "tz-art.htm".
+
+
+Release 2002c - 2002-04-04 11:55:20 -0500
+
+  changes by Paul Eggert
+
+  Change zic.c to avoid creating symlinks to files that don't exist.
+
+
+Release 2002b - 2002-01-28 12:56:03 -0500
+
+  [These change notes are for Release 2002a, which was corrupted.
+  2002b was a corrected version of 2002a.]
+
+  changes by Paul Eggert
+
+  Update the "leapseconds" file to note that there'll be no leap
+  second at the end of June, 2002.
+
+  Change "zic.c" to deal with a problem in handling the "Asia/Bishkek" zone.
+
+  Change to "difftime.c" to avoid sizeof problems.
+
+
+Release 2001d - 2001-10-09 13:31:32 -0400
+
+  changes by Paul Eggert
+
+
+Release 2001c - 2001-06-05 13:59:55 -0400
+
+  changes by Paul Eggert and Andrew Brown
+
+
+Release 2001b - 2001-04-05 16:44:38 -0400
+
+  changes by Paul Eggert (modulo jnorgard's typo fix)
+
+  tz-art.htm has been HTMLified.
+
+
+Release 2001a - 2001-03-13 12:57:44 -0500
+
+  changes by Paul Eggert
+
+  An addition to the "leapseconds" file: comments with the text of the
+  latest IERS leap second notice.
+
+  Trailing white space has been removed from data file lines, and
+  repeated spaces in "Rule Jordan" lines in the "asia" file have been
+  converted to tabs.
+
+
+Release 2000h - 2000-12-14 15:33:38 -0500
+
+  changes by Paul Eggert
+
+  one typo fix in the "art" file
+
+  With providence, this is the last update of the millennium.
+
+
+Release 2000g - 2000-10-10 11:35:22 -0400
+
+  changes by Paul Eggert
+
+  correction of John Mackin's name submitted by Robert Elz
+
+  Garry Shandling's Daylight Saving Time joke (!?!) from the recent
+  Emmy Awards broadcast.
+
+
+Release 2000f - 2000-08-10 09:31:58 -0400
+
+  changes by Paul Eggert
+
+  Added information in "tz-art.htm" on a Seinfeld reference to DST.
+
+  Error checking and messages in the "yearistype" script have been
+  improved.
+
+
+Release 2000e - 2000-07-31 09:27:54 -0400
+
+  data changes by Paul Eggert
+
+  a change to the default value of the defined constant HAVE_STRERROR
+
+  the addition of a Dave Barry quote on DST to the tz-arts file
+
+
+Release 2000d - 2000-04-20 15:43:04 -0400
+
+  changes to the documentation and code of strftime for C99 conformance
+
+  a bug fix for date.c
+
+  These are based on (though modified from) changes by Paul Eggert.
+
+
+Release 2000c - 2000-03-04 10:31:43 -0500
+
+  changes by Paul Eggert
+
+
+Release 2000b - 2000-02-21 12:16:29 -0500
+
+  changes by Paul Eggert and Joseph Myers
+
+  modest tweaks to the tz-art.htm and tz-link.htm files
+
+
+Release 2000a - 2000-01-18 09:21:26 -0500
+
+  changes by Paul Eggert
+
+  The two hypertext documents have also been renamed.
+
+
+Release code1999i-data1999j - 1999-11-15 18:43:22 -0500
+
+  Paul Eggert's changes
+
+  additions to the "zic" manual page and the "Arts.htm" file
+
+
+Release code1999h-data1999i - 1999-11-08 14:55:21 -0500
+
+  [not summarized]
+
+
+Release data1999h - 1999-10-07 03:50:29 -0400
+
+  changes by Paul Eggert to "europe" (most importantly, fixing
+  Lithuania and Estonia)
+
+
+Release 1999g - 1999-09-28 11:06:18 -0400
+
+  data changes by Paul Eggert (most importantly, the change for
+  Lebanon that buys correctness for this coming Sunday)
+
+  The "code" file contains changes to "Makefile" and "checktab.awk" to
+  allow better checking of time zone files before they are published.
+
+
+Release 1999f - 1999-09-23 09:48:14 -0400
+
+  changes by Arthur David Olson and Paul Eggert
+
+
+Release 1999e - 1999-08-17 15:20:54 -0400
+
+  changes circulated by Paul Eggert, although the change to handling
+  of DST-specifying timezone names has been commented out for now
+  (search for "XXX" in "localtime.c" for details).  These files also
+  do not make any changes to the start of DST in Brazil.
+
+  In addition to Paul's changes, there are updates to "Arts.htm" and
+  cleanups of URLs.
+
+
+Release 1999d - 1999-03-30 11:31:07 -0500
+
+  changes by Paul Eggert
+
+  The Makefile's "make public" rule has also been changed to do a test
+  compile of each individual time zone data file (which should help
+  avoid problems such as the one we had with Nicosia).
+
+
+Release 1999c - 1999-03-25 09:47:47 -0500
+
+  changes by Paul Eggert, most importantly the change for Chile.
+
+
+Release 1999b - 1999-02-01 17:51:44 -0500
+
+  changes by Paul Eggert
+
+  code changes (suggested by Mani Varadarajan, mani at be.com) for
+  correct handling of symbolic links when building using a relative directory
+
+  code changes to generate correct messages for failed links
+
+  updates to the URLs in Arts.htm
+
+
+Release 1999a - 1999-01-19 16:20:29 -0500
+
+  error message internationalizations and corrections in zic.c and
+  zdump.c (as suggested by Vladimir Michl, vladimir.michl at upol.cz,
+  to whom thanks!)
+
+
+Release code1998h-data1998i - 1998-10-01 09:56:10 -0400
+
+  changes for Brazil, Chile, and Germany
+
+  support for use of "24:00" in the input files for the time zone compiler
+
+
+Release code1998g-data1998h - 1998-09-24 10:50:28 -0400
+
+  changes by Paul Eggert
+
+  correction to a define in the "private.h" file
+
+
+Release data1998g - 1998-08-11 03:28:35 -0000
+  [tzdata1998g.tar.gz is missing!]
+
+  Lithuanian change provided by mgedmin at pub.osf.it
+
+  Move creation of the GMT link with Etc/GMT to "etcetera" (from
+  "backward") to ensure that the GMT file is created even where folks
+  don't want the "backward" links (as suggested by Paul Eggert).
+
+
+Release data1998f - 1998-07-20 13:50:00 -0000
+  [tzdata1998f.tar.gz is missing!]
+
+  Update the "leapseconds" file to include the newly-announced
+  insertion at the end of 1998.
+
+
+Release code1998f - 1998-06-01 10:18:31 -0400
+
+  addition to localtime.c by Guy Harris
+
+
+Release 1998e - 1998-05-28 09:56:26 -0400
+
+  The Makefile is changed to produce zoneinfo-posix rather than
+  zoneinfo/posix, and to produce zoneinfo-leaps rather than
+  zoneinfo/right.
+
+  data changes by Paul Eggert
+
+  changes from Guy Harris to provide asctime_r and ctime_r
+
+  A usno1998 file (substantially identical to usno1997) has been added.
+
+
+Release 1998d - 1998-05-14 11:58:34 -0400
+
+  changes to comments (in particular, elimination of references to CIA maps).
+  "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places
+  where changes occur.
+
+
+Release 1998c - 1998-02-28 12:32:26 -0500
+
+  changes by Paul Eggert (save the "French correction," on which I'll
+  wait for the dust to settle)
+
+  symlink changes
+
+  changes and additions to Arts.htm
+
+
+Release 1998b - 1998-01-17 14:31:51 -0500
+
+  URL cleanups and additions
+
+
+Release 1998a - 1998-01-13 12:37:35 -0500
+
+  changes by Paul Eggert
+
+
+Release code1997i-data1997k - 1997-12-29 09:53:41 -0500
+
+  changes by Paul Eggert, with minor modifications from Arthur David
+  Olson to make the files more browser friendly
+
+
+Release code1997h-data1997j - 1997-12-18 17:47:35 -0500
+
+  minor changes to put "TZif" at the start of each timezone information file
+
+  a rule has also been added to the Makefile so you can
+	make zones
+  to just recompile the zone information files (rather than doing a
+  full "make install" with its other effects).
+
+
+Release data1997i - 1997-10-07 08:45:38 -0400
+
+  changes to Africa by Paul Eggert
+
+
+Release code1997g-data1997h - 1997-09-04 16:56:54 -0400
+
+  corrections for Uruguay (and other locations)
+
+  Arthur David Olson's simple-minded fix allowing mktime to both
+  correctly handle leap seconds and correctly handle tm_sec values
+  upon which arithmetic has been performed.
+
+
+Release code1997f-data1997g - 1997-07-19 13:15:02 -0400
+
+  Paul Eggert's updates
+
+  a small change to a function prototype;
+
+  "Music" has been renamed "Arts.htm", HTMLified, and augmented to
+  include information on Around the World in Eighty Days.
+
+
+Release code1997e-data1997f - 1997-05-03 18:52:34 -0400
+
+  fixes to zic's error handling
+
+  changes inspired by the item circulated on Slovenia
+
+  The description of Web resources has been HTMLified for browsing
+  convenience.
+
+  A new piece of tz-related music has been added to the "Music" file.
+
+
+Release code1997d-data1997e - 1997-03-29 12:48:52 -0500
+
+  Paul Eggert's latest suggestions
+
+
+Release code1997c-data1997d - 1997-03-07 20:37:54 -0500
+
+  changes to "zic.c" to correct performance of the "-s" option
+
+  a new file "usno1997"
+
+
+Release data1997c - 1997-03-04 09:58:18 -0500
+
+  changes in Israel
+
+
+Release 1997b - 1997-02-27 18:34:19 -0500
+
+  The data file incorporates the 1997 leap second.
+
+  The code file incorporates Arthur David Olson's take on the
+  zic/multiprocessor/directory-creation situation.
+
+
+Release 1997a - 1997-01-21 09:11:10 -0500
+
+  Paul Eggert's Antarctica (and other changes)
+
+  Arthur David Olson finessed the "getopt" issue by checking against
+  both -1 and EOF (regardless of POSIX, SunOS 4.1.1's manual says -1
+  is returned while SunOS 5.5's manual says EOF is returned).
+
+
+Release code1996o-data1996n - 1996-12-27 21:42:05 -0500
+
+  Paul Eggert's latest changes
+
+
+Release code1996n - 1996-12-16 09:42:02 -0500
+
+  link snapping fix from Bruce Evans (via Garrett Wollman)
+
+
+Release data1996m - 1996-11-24 02:37:34 -0000
+  [tzdata1996m.tar.gz is missing!]
+
+  Paul Eggert's batch of changes
+
+
+Release code1996m-data1996l - 1996-11-05 14:00:12 -0500
+
+  No functional changes here; the files have simply been changed to
+  make more use of ISO style dates in comments. The names of the above
+  files now include the year in full.
+
+
+Release code96l - 1996-09-08 17:12:20 -0400
+
+  tzcode96k was missing a couple of pieces.
+
+
+Release 96k - 1996-09-08 16:06:22 -0400
+
+  the latest round of changes from Paul Eggert
+
+  the recent Year 2000 material
+
+
+Release code96j - 1996-07-30 13:18:53 -0400
+
+  Set sp->typecnt as suggested by Timothy Patrick Murphy.
+
+
+Release code96i - 1996-07-27 20:11:35 -0400
+
+  Paul's suggested patch for strftime %V week numbers
+
+
+Release data96i - 1996-07-01 18:13:04 -0400
+
+  "northamerica" and "europe" changes by Paul Eggert
+
+
+Release code96h - 1996-06-05 08:02:21 -0400
+
+  fix for handling transitions specified in Universal Time
+
+  Some "public domain" notices have also been added.
+
+
+Release code96g - 1996-05-16 14:00:26 -0400
+
+  fix for the simultaneous-DST-and-zone-change challenge
+
+
+Release data96h - 1996-05-09 17:40:51 -0400
+
+  changes by Paul Eggert
+
+
+Release code96f-data96g - 1996-05-03 03:09:59 -0000
+  [tzcode96f.tar.gz + tzdata96g.tar.gz are both missing!]
+
+  The changes get us some of the way to fixing the problems noted in Paul
+  Eggert's letter yesterday (in addition to a few others).  The approach
+  has been to make zic a bit smarter about figuring out what time zone
+  abbreviations apply just after the time specified in the "UNTIL" part
+  of a zone line.  Putting the smarts in zic means avoiding having
+  transition times show up in both "Zone" lines and "Rule" lines, which
+  in turn avoids multiple transition time entries in time zone files.
+  (This also makes the zic input files such as "europe" a bit shorter and
+  should ease maintenance.)
+
+
+Release data96f - 1996-04-19 19:20:03 -0000
+  [tzdata96f.tar.gz is missing!]
+
+  The only changes are to the "northamerica" file; the time zone
+  abbreviation for Denver is corrected to MST (and MDT), and the
+  comments for Mexico have been updated.
+
+
+Release data96e - 1996-03-19 17:37:26 -0500
+
+  Proposals by Paul Eggert, in particular the Portugal change that
+  comes into play at the end of this month.
+
+
+Release data96d - 1996-03-18 20:49:39 -0500
+
+  [not summarized]
+
+
+Release code96e - 1996-02-29 15:43:27 -0000
+  [tzcode96e.tar.gz is missing!]
+
+  internationalization changes and the fix to the documentation for strftime
+
+
+Release code96d-data96c - 1996-02-12 11:05:27 -0500
+
+  The "code" file simply updates Bob Kridle's electronic address.
+
+  The "data" file updates rules for Mexico.
+
+
+Release data96b - 1996-01-27 15:44:42 -0500
+
+  Kiribati change
+
+
+Release code96c - 1996-01-16 16:58:15 -0500
+
+  leap-year streamlining and binary-search changes
+
+  fix to newctime.3
+
+
+Release code96b - 1996-01-10 20:42:39 -0500
+
+  fixes and enhancements from Paul Eggert, including code that
+  emulates the behavior of recent versions of the SunOS "date"
+  command.
+
+
+Release 96a - 1996-01-06 09:08:24 -0500
+
+  Israel updates
+
+  fixes to strftime.c for correct ISO 8601 week number generation,
+  plus support for two new formats ('G' and 'g') to give ISO 8601 year
+  numbers (which are not necessarily the same as calendar year numbers)
+
+
+Release code95i-data95m - 1995-12-21 12:46:47 -0500
+
+  The latest revisions from Paul Eggert are included, the usno1995
+  file has been updated, and a new file ("WWW") covering useful URLs
+  has been added.
+
+
+Release code95h-data95l - 1995-12-19 18:10:12 -0500
+
+  A simplification of a macro definition, a change to data for Sudan,
+  and (for last minute shoppers) notes in the "Music" file on the CD
+  "Old Man Time".
+
+
+Release code95g-data95k - 1995-10-30 10:32:47 -0500
+
+  (slightly reformatted) 8-bit-clean proposed patch
+
+  minor patch: US/Eastern -> America/New_York
+
+  snapshot of the USNO's latest data ("usno1995")
+
+  some other minor cleanups
+
+
+Release code95f-data95j - 1995-10-28 21:01:34 -0000
+  [tzcode95f.tar.gz + tzdata95j.tar.gz are both missing!]
+
+  European cleanups
+
+  support for 64-bit time_t's
+
+  optimization in localtime.c
+
+
+Release code95e - 1995-10-13 13:23:57 -0400
+
+  the mktime change to scan from future to past when trying to find time zone
+  offsets
+
+
+Release data95i - 1995-09-26 10:43:26 -0400
+
+  For Canada/Central, guess that the Sun customer's "one week too
+  early" was just a approximation, and the true error is one month
+  too early.  This is consistent with the rest of Canada.
+
+
+Release data95h - 1995-09-21 11:26:48 -0400
+
+  latest changes from Paul Eggert
+
+
+Release code95d - 1995-09-14 11:14:45 -0400
+
+  the addition of a "Music" file, which documents four recorded
+  versions of the tune "Save That Time".
+
+
+Release data95g - 1995-09-01 17:21:36 -0400
+
+  "yearistype" correction
+
+
+Release data95f - 1995-08-28 20:46:56 -0400
+
+  Paul Eggert's change to the australasia file
+
+
+Release data95e - 1995-07-08 18:02:34 -0400
+
+  The only change is a leap second at the end of this year.
+  Thanks to Bradley White for forwarding news on the leap second.
+
+
+Release data95d - 1995-07-03 13:26:22 -0400
+
+  Paul Eggert's changes
+
+
+Release data95c - 1995-07-02 19:19:28 -0400
+
+  changes to "asia", "backward", "europe", and "southamerica"
+  (read: northamericacentrics need not apply)
+
+
+Release code95c - 1995-03-13 14:00:46 -0500
+
+  one-line fix for sign extension problems in detzcode
+
+
+Release 95b - 1995-03-04 11:22:38 -0500
+
+  Minor changes in both:
+
+  The "code" file contains a workaround for the lack of "unistd.h" in
+  Microsoft C++ version 7.
+
+  The "data" file contains a fixed "Link" for America/Shiprock.
+
+
+Release 94h - 1994-12-10 12:51:14 -0500
+
+  The files:
+
+  *	incorporate the changes to "zdump" and "date" to make changes to
+	the "TZ" environment variable permanent;
+
+  *	incorporate the table changes by Paul Eggert;
+
+  *	include (and document) support for universal time specifications in
+	data files - but do not (yet) include use of this feature in the
+	data files.
+
+  Think of this as "TZ Classic" - the software has been set up not to break if
+  universal time shows up in its input, and data entries have been
+  left as is so as not to break existing implementations.
+
+
+Release data94f - 1994-08-20 12:56:09 -0400
+
+  (with thanks!) the latest data updates from Paul Eggert
+
+
+Release data94e - 1994-06-04 13:13:53 -0400
+
+  [not summarized]
+
+
+Release code94g - 1994-05-05 12:14:07 -0400
+
+  fix missing "optind.c" and a reference to it in the Makefile
+
+
+Release code94f - 1994-05-05 13:00:33 -0000
+  [tzcode94f.tar.gz is missing!]
+
+  changes to avoid overflow in difftime, as well as changes to cope
+  with the 52/53 challenge in strftime
+
+
+Release code94e - 1994-03-30 23:32:59 -0500
+
+  change for the benefit of PCTS
+
+
+Release 94d - 1994-02-24 15:42:25 -0500
+
+  Avoid clashes with POSIX semantics for zones such as GMT+4.
+
+  Some other very minor housekeeping is also present.
+
+
+Release code94c - 1994-02-10 08:52:40 -0500
+
+  Fix bug where mkdirs was broken unless you compile with
+  -fwritable-strings (which is generally losing to do).
+
+
+Release 94b - 1994-02-07 10:04:33 -0500
+
+  work by Paul Eggert who notes:
+
+  I found another book of time zone histories by E W Whitman; it's not
+  as extensive as Shanks but has a few goodies of its own.  I used it
+  to update the tables.  I also fixed some more as a result of
+  correspondence with Adam David and Peter Ilieve, and move some stray
+  links from 'europe' to 'backward'.  I corrected some scanning errors
+  in usno1989.
+
+  As far as the code goes, I fixed zic to allow years in the range
+  INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900.
+  And I cleaned up the zic documentation a little bit.
+
+
+Release data94a - 1994-02-03 08:58:54 -0500
+
+  It simply incorporates the recently announced leap second into the
+  "leapseconds" file.
+
+
+Release 93g - 1993-11-22 17:28:27 -0500
+
+  Paul Eggert has provided a good deal of historic information (based
+  on Shanks), and there are some code changes to deal with the buglets
+  that crawled out in dealing with the new information.
+
+
+Release 93f - 1993-10-15 12:27:46 -0400
+
+  Paul Eggert's changes
+
+
+Release 93e - 1993-09-05 21:21:44 -0400
+
+  This has updated data for Israel, England, and Kwajalein.  There's
+  also an update to "zdump" to cope with Kwajalein's 24-hour jump.
+  Thanks to Paul Eggert and Peter Ilieve for the changes.
+
+
+Release 93d - 1993-06-17 23:34:17 -0400
+
+  new fix and new data on Israel
+
+
+Release 93c - 1993-06-06 19:31:55 -0400
+
+  [not summarized]
+
+
+Release 93b - 1993-02-02 14:53:58 -0500
+
+  updated "leapseconds" file
+
+
+Release 93 - 1993-01-08 07:01:06 -0500
+
+  At kre's suggestion, the package has been split in two - a code piece
+  (which also includes documentation) that's only of use to folks who
+  want to recompile things and a data piece useful to anyone who can
+  run "zic".
+
+  The new version has a few changes to the data files, a few
+  portability changes, and an off-by-one fix (with thanks to
+  Tom Karzes at deshaw.com for providing a description and a
+  solution).
+
+
+Release 92c - 1992-11-21 17:35:36 -0000
+  [tz92c.tar.Z is missing!]
+
+  The fallout from the latest round of DST transitions.
+
+  There are changes for Portugal, Saskatchewan, and "Pacific-New";
+  there's also a change to "zic.c" that makes it portable to more systems.
+
+
+Release 92 - 1992-04-25 18:17:03 -0000
+  [tz92.tar.Z is missing!]
+
+  By popular demand (well, at any rate, following a request by kre at munnari)
+
+
+The 1989 update of the time zone package featured:
+
+  *	POSIXization (including interpretation of POSIX-style TZ environment
+	variables, provided by Guy Harris),
+  *	ANSIfication (including versions of "mktime" and "difftime"),
+  *	SVIDulation (an "altzone" variable)
+  *	MACHination (the "gtime" function)
+  *	corrections to some time zone data (including corrections to the rules
+	for Great Britain and New Zealand)
+  *	reference data from the United States Naval Observatory for folks who
+	want to do additional time zones
+  *	and the 1989 data for Saudi Arabia.
+
+  (Since this code will be treated as "part of the implementation" in some
+  places and as "part of the application" in others, there's no good way to
+  name functions, such as timegm, that are not part of the proposed ANSI C
+  standard; such functions have kept their old, underscore-free names in this
+  update.)
+
+  And the "dysize" function has disappeared; it was present to allow
+  compilation of the "date" command on old BSD systems, and a version of "date"
+  is now provided in the package.  The "date" command is not created when you
+  "make all" since it may lack options provided by the version distributed with
+  your operating system, or may not interact with the system in the same way
+  the native version does.
+
+  Since POSIX frowns on correct leap second handling, the default behavior of
+  the "zic" command (in the absence of a "-L" option) has been changed to omit
+  leap second information from its output files.
+
+
+-----
+Notes
+
+This file contains copies of the part of each release announcement
+that talks about the changes in that release.  The text has been
+adapted and reformatted for the purposes of this file.
+
+Traditionally a release R consists of a pair of tarball files,
+tzcodeR.tar.gz and tzdataR.tar.gz.  However, some releases (e.g.,
+code2010a, data2012c) consist of just one or the other tarball, and a
+few (e.g., code2012c-data2012d) have tarballs with mixed version
+numbers.  Recent releases also come in an experimental format
+consisting of a single tarball tzdb-R.tar.lz with extra data.
+
+Release timestamps are taken from the release's commit (for newer,
+Git-based releases), from the newest file in the tarball (for older
+releases, where this info is available) or from the email announcing
+the release (if all else fails; these are marked with a time zone
+abbreviation of -0000 and an "is missing!" comment).
+
+Earlier versions of the code and data were not announced on the tz
+list and are not summarized here.
+
+This file is in the public domain.
+
+Local Variables:
+coding: utf-8
+End:
diff --git a/README b/README
index 427b6a015195..145aacd495b7 100644
--- a/README
+++ b/README
@@ -1,86 +1,52 @@
-@(#)README	8.3
-This file is in the public domain, so clarified as of
-2009-05-17 by Arthur David Olson.
+README for the tz distribution
 
-"What time is it?" -- Richard Deacon as The King
-"Any time you want it to be." -- Frank Baxter as The Scientist
+"Where do I set the hands of the clock?" -- Les Tremayne as The King
+"Oh that--you can set them any place you want." -- Frank Baxter as The Scientist
 					(from the Bell System film "About Time")
 
-The 1989 update of the time zone package featured
+The Time Zone Database (called tz, tzdb or zoneinfo) contains code and
+data that represent the history of local time for many representative
+locations around the globe.  It is updated periodically to reflect
+changes made by political bodies to time zone boundaries, UTC offsets,
+and daylight-saving rules.
 
-*	POSIXization (including interpretation of POSIX-style TZ environment
-	variables, provided by Guy Harris),
-*	ANSIfication (including versions of "mktime" and "difftime"),
-*	SVIDulation (an "altzone" variable)
-*	MACHination (the "gtime" function)
-*	corrections to some time zone data (including corrections to the rules
-	for Great Britain and New Zealand)
-*	reference data from the United States Naval Observatory for folks who
-	want to do additional time zones
-*	and the 1989 data for Saudi Arabia.
-
-(Since this code will be treated as "part of the implementation" in some places
-and as "part of the application" in others, there's no good way to name
-functions, such as timegm, that are not part of the proposed ANSI C standard;
-such functions have kept their old, underscore-free names in this update.)
-
-And the "dysize" function has disappeared; it was present to allow compilation
-of the "date" command on old BSD systems, and a version of "date" is now
-provided in the package.  The "date" command is not created when you "make all"
-since it may lack options provided by the version distributed with your
-operating system, or may not interact with the system in the same way the
-native version does.
-
-Since POSIX frowns on correct leap second handling, the default behavior of
-the "zic" command (in the absence of a "-L" option) has been changed to omit
-leap second information from its output files.
-
-Here is a recipe for acquiring, building, installing, and testing the
-tz distribution on a GNU/Linux or similar host.
-
-	mkdir tz
-	cd tz
-	wget 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz'
-	gzip -dc tzcode*.tar.gz | tar -xf -
-	gzip -dc tzdata*.tar.gz | tar -xf -
-
-Be sure to read the comments in "Makefile" and make any changes needed
+See  or the
+file tz-link.html for how to acquire the code and data.  Once acquired,
+read the comments in the file 'Makefile' and make any changes needed
 to make things right for your system, especially if you are using some
 platform other than GNU/Linux.  Then run the following commands,
 substituting your desired installation directory for "$HOME/tzdir":
 
 	make TOPDIR=$HOME/tzdir install
-	$HOME/tzdir/etc/zdump -v America/Los_Angeles
+	$HOME/tzdir/usr/bin/zdump -v America/Los_Angeles
 
-To use the new functions, use a "-ltz" option when compiling or linking.
+See the file tz-how-to.html for examples of how to read the data files.
 
-Historical local time information has been included here to:
+This database of historical local time information has several goals:
 
-*	provide a compendium of data about the history of civil time
-	that is useful even if the data are not 100% accurate;
+ * Provide a compendium of data about the history of civil time that
+   is useful even if not 100% accurate.
 
-*	give an idea of the variety of local time rules that have
-	existed in the past and thus an idea of the variety that may be
-	expected in the future;
+ * Give an idea of the variety of local time rules that have existed
+   in the past and thus may be expected in the future.
 
-*	provide a test of the generality of the local time rule description
-	system.
+ * Test the generality of the local time rule description system.
 
 The information in the time zone data files is by no means authoritative;
-the files currently do not even attempt to cover all time stamps before
-1970, and there are undoubtedly errors even for time stamps since 1970.
-If you know that the rules are different from those in a file, by all means
-feel free to change file (and please send the changed version to
-tz@elsie.nci.nih.gov for use in the future).  Europeans take note!
+fixes and enhancements are welcome.  Please see the file CONTRIBUTING
+for details.
 
-Thanks to these Timezone Caballeros who've made major contributions to the
-time conversion package:  Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
+Thanks to these Time Zone Caballeros who've made major contributions to the
+time conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
 Guy Harris; Mark Horton; John Mackin; and Bradley White.  Thanks also to
 Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
 for testing work, and to Gwillim Law for checking local mean time data.
+Thanks in particular to Arthur David Olson, the project's founder and first
+maintainer, to whom the time zone community owes the greatest debt of all.
 None of them are responsible for remaining errors.
 
-Look in the ~ftp/pub directory of elsie.nci.nih.gov
-for updated versions of these files.
+-----
 
-Please send comments or information to tz@elsie.nci.nih.gov.
+This file is in the public domain, so clarified as of 2009-05-17 by
+Arthur David Olson.  The other files in this distribution are either
+public domain or BSD licensed; see the file LICENSE for details.
diff --git a/SECURITY b/SECURITY
new file mode 100644
index 000000000000..40128bc86dd2
--- /dev/null
+++ b/SECURITY
@@ -0,0 +1,15 @@
+Please report any sensitive security-related bugs via email to the
+tzdb designated coordinators, currently Paul Eggert
+ and Tim Parenti .
+Put "tzdb security" at the start of your email's subject line.
+We prefer communications to be in English.
+
+You should receive a response within a week. If not, please follow up
+via email to make sure we received your original message.
+
+If we confirm the bug, we plan to notify affected third-party services
+or software that we know about, prepare an advisory, commit fixes to
+the main development branch as quickly as is practical, and finally
+publish the advisory on tz@iana.org.  As with all tzdb contributions,
+we give credit to security contributors unless they wish to remain
+anonymous.
diff --git a/Theory b/Theory
deleted file mode 100644
index b1e6bd5c9d5d..000000000000
--- a/Theory
+++ /dev/null
@@ -1,568 +0,0 @@
-@(#)Theory	8.5
-This file is in the public domain, so clarified as of
-2009-05-17 by Arthur David Olson.
-
------ Outline -----
-
-	Time and date functions
-	Names of time zone regions
-	Time zone abbreviations
-	Calendrical issues
-	Time and time zones on Mars
-
------ Time and date functions -----
-
-These time and date functions are upwards compatible with POSIX,
-an international standard for UNIX-like systems.
-As of this writing, the current edition of POSIX is:
-
-  Standard for Information technology
-  -- Portable Operating System Interface (POSIX (R))
-  -- System Interfaces
-  IEEE Std 1003.1, 2004 Edition
-  
-  
-
-POSIX has the following properties and limitations.
-
-*	In POSIX, time display in a process is controlled by the
-	environment variable TZ.  Unfortunately, the POSIX TZ string takes
-	a form that is hard to describe and is error-prone in practice.
-	Also, POSIX TZ strings can't deal with other (for example, Israeli)
-	daylight saving time rules, or situations where more than two
-	time zone abbreviations are used in an area.
-
-	The POSIX TZ string takes the following form:
-
-		stdoffset[dst[offset],date[/time],date[/time]]
-
-	where:
-
-	std and dst
-		are 3 or more characters specifying the standard
-		and daylight saving time (DST) zone names.
-		Starting with POSIX.1-2001, std and dst may also be
-		in a quoted form like ""; this allows
-		"+" and "-" in the names.
-	offset
-		is of the form `[-]hh:[mm[:ss]]' and specifies the
-		offset west of UTC.  The default DST offset is one hour
-		ahead of standard time.
-	date[/time],date[/time]
-		specifies the beginning and end of DST.  If this is absent,
-		the system supplies its own rules for DST, and these can
-		differ from year to year; typically US DST rules are used.
-	time
-		takes the form `hh:[mm[:ss]]' and defaults to 02:00.
-	date
-		takes one of the following forms:
-		Jn (1<=n<=365)
-			origin-1 day number not counting February 29
-		n (0<=n<=365)
-			origin-0 day number counting February 29 if present
-		Mm.n.d (0[Sunday]<=d<=6[Saturday], 1<=n<=5, 1<=m<=12)
-			for the dth day of week n of month m of the year,
-			where week 1 is the first week in which day d appears,
-			and `5' stands for the last week in which day d appears
-			(which may be either the 4th or 5th week).
-
-	Here is an example POSIX TZ string, for US Pacific time using rules
-	appropriate from 1987 through 2006:
-
-		TZ='PST8PDT,M4.1.0/02:00,M10.5.0/02:00'
-
-	This POSIX TZ string is hard to remember, and mishandles time stamps
-	before 1987 and after 2006.  With this package you can use this
-	instead:
-
-		TZ='America/Los_Angeles'
-
-*	POSIX does not define the exact meaning of TZ values like "EST5EDT".
-	Typically the current US DST rules are used to interpret such values,
-	but this means that the US DST rules are compiled into each program
-	that does time conversion.  This means that when US time conversion
-	rules change (as in the United States in 1987), all programs that
-	do time conversion must be recompiled to ensure proper results.
-
-*	In POSIX, there's no tamper-proof way for a process to learn the
-	system's best idea of local wall clock.  (This is important for
-	applications that an administrator wants used only at certain times--
-	without regard to whether the user has fiddled the "TZ" environment
-	variable.  While an administrator can "do everything in UTC" to get
-	around the problem, doing so is inconvenient and precludes handling
-	daylight saving time shifts--as might be required to limit phone
-	calls to off-peak hours.)
-
-*	POSIX requires that systems ignore leap seconds.
-
-These are the extensions that have been made to the POSIX functions:
-
-*	The "TZ" environment variable is used in generating the name of a file
-	from which time zone information is read (or is interpreted a la
-	POSIX); "TZ" is no longer constrained to be a three-letter time zone
-	name followed by a number of hours and an optional three-letter
-	daylight time zone name.  The daylight saving time rules to be used
-	for a particular time zone are encoded in the time zone file;
-	the format of the file allows U.S., Australian, and other rules to be
-	encoded, and allows for situations where more than two time zone
-	abbreviations are used.
-
-	It was recognized that allowing the "TZ" environment variable to
-	take on values such as "America/New_York" might cause "old" programs
-	(that expect "TZ" to have a certain form) to operate incorrectly;
-	consideration was given to using some other environment variable
-	(for example, "TIMEZONE") to hold the string used to generate the
-	time zone information file name.  In the end, however, it was decided
-	to continue using "TZ":  it is widely used for time zone purposes;
-	separately maintaining both "TZ" and "TIMEZONE" seemed a nuisance;
-	and systems where "new" forms of "TZ" might cause problems can simply
-	use TZ values such as "EST5EDT" which can be used both by
-	"new" programs (a la POSIX) and "old" programs (as zone names and
-	offsets).
-
-*	To handle places where more than two time zone abbreviations are used,
-	the functions "localtime" and "gmtime" set tzname[tmp->tm_isdst]
-	(where "tmp" is the value the function returns) to the time zone
-	abbreviation to be used.  This differs from POSIX, where the elements
-	of tzname are only changed as a result of calls to tzset.
-
-*	Since the "TZ" environment variable can now be used to control time
-	conversion, the "daylight" and "timezone" variables are no longer
-	needed.  (These variables are defined and set by "tzset"; however, their
-	values will not be used by "localtime.")
-
-*	The "localtime" function has been set up to deliver correct results
-	for near-minimum or near-maximum time_t values.  (A comment in the
-	source code tells how to get compatibly wrong results).
-
-*	A function "tzsetwall" has been added to arrange for the system's
-	best approximation to local wall clock time to be delivered by
-	subsequent calls to "localtime."  Source code for portable
-	applications that "must" run on local wall clock time should call
-	"tzsetwall();" if such code is moved to "old" systems that don't
-	provide tzsetwall, you won't be able to generate an executable program.
-	(These time zone functions also arrange for local wall clock time to be
-	used if tzset is called--directly or indirectly--and there's no "TZ"
-	environment variable; portable applications should not, however, rely
-	on this behavior since it's not the way SVR2 systems behave.)
-
-*	These functions can account for leap seconds, thanks to Bradley White.
-
-Points of interest to folks with other systems:
-
-*	This package is already part of many POSIX-compliant hosts,
-	including BSD, HP, Linux, Network Appliance, SCO, SGI, and Sun.
-	On such hosts, the primary use of this package
-	is to update obsolete time zone rule tables.
-	To do this, you may need to compile the time zone compiler
-	`zic' supplied with this package instead of using the system `zic',
-	since the format of zic's input changed slightly in late 1994,
-	and many vendors still do not support the new input format.
-
-*	The UNIX Version 7 "timezone" function is not present in this package;
-	it's impossible to reliably map timezone's arguments (a "minutes west
-	of GMT" value and a "daylight saving time in effect" flag) to a
-	time zone abbreviation, and we refuse to guess.
-	Programs that in the past used the timezone function may now examine
-	tzname[localtime(&clock)->tm_isdst] to learn the correct time
-	zone abbreviation to use.  Alternatively, use
-	localtime(&clock)->tm_zone if this has been enabled.
-
-*	The 4.2BSD gettimeofday function is not used in this package.
-	This formerly let users obtain the current UTC offset and DST flag,
-	but this functionality was removed in later versions of BSD.
-
-*	In SVR2, time conversion fails for near-minimum or near-maximum
-	time_t values when doing conversions for places that don't use UTC.
-	This package takes care to do these conversions correctly.
-
-The functions that are conditionally compiled if STD_INSPIRED is defined
-should, at this point, be looked on primarily as food for thought.  They are
-not in any sense "standard compatible"--some are not, in fact, specified in
-*any* standard.  They do, however, represent responses of various authors to
-standardization proposals.
-
-Other time conversion proposals, in particular the one developed by folks at
-Hewlett Packard, offer a wider selection of functions that provide capabilities
-beyond those provided here.  The absence of such functions from this package
-is not meant to discourage the development, standardization, or use of such
-functions.  Rather, their absence reflects the decision to make this package
-contain valid extensions to POSIX, to ensure its broad acceptability.  If
-more powerful time conversion functions can be standardized, so much the
-better.
-
-
------ Names of time zone rule files -----
-
-The time zone rule file naming conventions attempt to strike a balance
-among the following goals:
-
- * Uniquely identify every national region where clocks have all
-   agreed since 1970.  This is essential for the intended use: static
-   clocks keeping local civil time.
-
- * Indicate to humans as to where that region is.  This simplifes use.
-
- * Be robust in the presence of political changes.  This reduces the
-   number of updates and backward-compatibility hacks.  For example,
-   names of countries are ordinarily not used, to avoid
-   incompatibilities when countries change their name
-   (e.g. Zaire->Congo) or when locations change countries
-   (e.g. Hong Kong from UK colony to China).
-
- * Be portable to a wide variety of implementations.
-   This promotes use of the technology.
-
- * Use a consistent naming convention over the entire world.
-   This simplifies both use and maintenance.
-
-This naming convention is not intended for use by inexperienced users
-to select TZ values by themselves (though they can of course examine
-and reuse existing settings).  Distributors should provide
-documentation and/or a simple selection interface that explains the
-names; see the 'tzselect' program supplied with this distribution for
-one example.
-
-Names normally have the form AREA/LOCATION, where AREA is the name
-of a continent or ocean, and LOCATION is the name of a specific
-location within that region.  North and South America share the same
-area, `America'.  Typical names are `Africa/Cairo', `America/New_York',
-and `Pacific/Honolulu'.
-
-Here are the general rules used for choosing location names,
-in decreasing order of importance:
-
-	Use only valid POSIX file name components (i.e., the parts of
-		names other than `/').  Within a file name component,
-		use only ASCII letters, `.', `-' and `_'.  Do not use
-		digits, as that might create an ambiguity with POSIX
-		TZ strings.  A file name component must not exceed 14
-		characters or start with `-'.  E.g., prefer `Brunei'
-		to `Bandar_Seri_Begawan'.
-	Include at least one location per time zone rule set per country.
-		One such location is enough.  Use ISO 3166 (see the file
-		iso3166.tab) to help decide whether something is a country.
-		However, uninhabited ISO 3166 regions like Bouvet Island
-		do not need locations, since local time is not defined there.
-	If all the clocks in a country's region have agreed since 1970,
-		don't bother to include more than one location
-		even if subregions' clocks disagreed before 1970.
-		Otherwise these tables would become annoyingly large.
-	If a name is ambiguous, use a less ambiguous alternative;
-		e.g. many cities are named San Jose and Georgetown, so
-		prefer `Costa_Rica' to `San_Jose' and `Guyana' to `Georgetown'.
-	Keep locations compact.  Use cities or small islands, not countries
-		or regions, so that any future time zone changes do not split
-		locations into different time zones.  E.g. prefer `Paris'
-		to `France', since France has had multiple time zones.
-	Use mainstream English spelling, e.g. prefer `Rome' to `Roma', and
-		prefer `Athens' to the true name (which uses Greek letters).
-		The POSIX file name restrictions encourage this rule.
-	Use the most populous among locations in a country's time zone,
-		e.g. prefer `Shanghai' to `Beijing'.  Among locations with
-		similar populations, pick the best-known location,
-		e.g. prefer `Rome' to `Milan'.
-	Use the singular form, e.g. prefer `Canary' to `Canaries'.
-	Omit common suffixes like `_Islands' and `_City', unless that
-		would lead to ambiguity.  E.g. prefer `Cayman' to
-		`Cayman_Islands' and `Guatemala' to `Guatemala_City',
-		but prefer `Mexico_City' to `Mexico' because the country
-		of Mexico has several time zones.
-	Use `_' to represent a space.
-	Omit `.' from abbreviations in names, e.g. prefer `St_Helena'
-		to `St._Helena'.
-	Do not change established names if they only marginally
-		violate the above rules.  For example, don't change
-		the existing name `Rome' to `Milan' merely because
-		Milan's population has grown to be somewhat greater
-		than Rome's.
-	If a name is changed, put its old spelling in the `backward' file.
-
-The file `zone.tab' lists the geographical locations used to name
-time zone rule files.  It is intended to be an exhaustive list
-of canonical names for geographic regions.
-
-Older versions of this package used a different naming scheme,
-and these older names are still supported.
-See the file `backward' for most of these older names
-(e.g. `US/Eastern' instead of `America/New_York').
-The other old-fashioned names still supported are
-`WET', `CET', `MET', and `EET' (see the file `europe').
-
-
------ Time zone abbreviations -----
-
-When this package is installed, it generates time zone abbreviations
-like `EST' to be compatible with human tradition and POSIX.
-Here are the general rules used for choosing time zone abbreviations,
-in decreasing order of importance:
-
-	Use abbreviations that consist of three or more ASCII letters.
-		Previous editions of this database also used characters like
-		' ' and '?', but these characters have a special meaning to
-		the shell and cause commands like
-			set `date`
-		to have unexpected effects.
-		Previous editions of this rule required upper-case letters,
-		but the Congressman who introduced Chamorro Standard Time
-		preferred "ChST", so the rule has been relaxed.
-
-		This rule guarantees that all abbreviations could have
-		been specified by a POSIX TZ string.  POSIX
-		requires at least three characters for an
-		abbreviation.  POSIX through 2000 says that an abbreviation
-		cannot start with ':', and cannot contain ',', '-',
-		'+', NUL, or a digit.  POSIX from 2001 on changes this
-		rule to say that an abbreviation can contain only '-', '+',
-		and alphanumeric characters from the portable character set
-		in the current locale.  To be portable to both sets of
-		rules, an abbreviation must therefore use only ASCII
-		letters.
-
-	Use abbreviations that are in common use among English-speakers,
-		e.g. `EST' for Eastern Standard Time in North America.
-		We assume that applications translate them to other languages
-		as part of the normal localization process; for example,
-		a French application might translate `EST' to `HNE'.
-
-	For zones whose times are taken from a city's longitude, use the
-		traditional xMT notation, e.g. `PMT' for Paris Mean Time.
-		The only name like this in current use is `GMT'.
-
-	If there is no common English abbreviation, abbreviate the English
-		translation of the usual phrase used by native speakers.
-		If this is not available or is a phrase mentioning the country
-		(e.g. ``Cape Verde Time''), then:
-
-		When a country has a single or principal time zone region,
-			append `T' to the country's ISO	code, e.g. `CVT' for
-			Cape Verde Time.  For summer time append `ST';
-			for double summer time append `DST'; etc.
-		When a country has multiple time zones, take the first three
-			letters of an English place name identifying each zone
-			and then append `T', `ST', etc. as before;
-			e.g. `VLAST' for VLAdivostok Summer Time.
-
-	Use UTC (with time zone abbreviation "zzz") for locations while
-		uninhabited.  The "zzz" mnemonic is that these locations are,
-		in some sense, asleep.
-
-Application writers should note that these abbreviations are ambiguous
-in practice: e.g. `EST' has a different meaning in Australia than
-it does in the United States.  In new applications, it's often better
-to use numeric UTC offsets like `-0500' instead of time zone
-abbreviations like `EST'; this avoids the ambiguity.
-
-
------ Calendrical issues -----
-
-Calendrical issues are a bit out of scope for a time zone database,
-but they indicate the sort of problems that we would run into if we
-extended the time zone database further into the past.  An excellent
-resource in this area is Nachum Dershowitz and Edward M. Reingold,
-
-Calendrical Calculations: Third Edition
-, Cambridge University Press (2008).  Other information and
-sources are given below.  They sometimes disagree.
-
-
-France
-
-Gregorian calendar adopted 1582-12-20.
-French Revolutionary calendar used 1793-11-24 through 1805-12-31,
-and (in Paris only) 1871-05-06 through 1871-05-23.
-
-
-Russia
-
-From Chris Carrier (1996-12-02):
-On 1929-10-01 the Soviet Union instituted an ``Eternal Calendar''
-with 30-day months plus 5 holidays, with a 5-day week.
-On 1931-12-01 it changed to a 6-day week; in 1934 it reverted to the
-Gregorian calendar while retaining the 6-day week; on 1940-06-27 it
-reverted to the 7-day week.  With the 6-day week the usual days
-off were the 6th, 12th, 18th, 24th and 30th of the month.
-(Source: Evitiar Zerubavel, _The Seven Day Circle_)
-
-
-Mark Brader reported a similar story in "The Book of Calendars", edited
-by Frank Parise (1982, Facts on File, ISBN 0-8719-6467-8), page 377.  But:
-
-From: Petteri Sulonen (via Usenet)
-Date: 14 Jan 1999 00:00:00 GMT
-...
-
-If your source is correct, how come documents between 1929 -- 1940 were
-still dated using the conventional, Gregorian calendar?
-
-I can post a scan of a document dated December 1, 1934, signed by
-Yenukidze, the secretary, on behalf of Kalinin, the President of the
-Executive Committee of the Supreme Soviet, if you like.
-
-
-
-Sweden (and Finland)
-
-From: Mark Brader
-
-Subject: Re: Gregorian reform -- a part of locale?
-
-Date: 1996-07-06
-
-In 1700, Denmark made the transition from Julian to Gregorian.  Sweden
-decided to *start* a transition in 1700 as well, but rather than have one of
-those unsightly calendar gaps :-), they simply decreed that the next leap
-year after 1696 would be in 1744 -- putting the whole country on a calendar
-different from both Julian and Gregorian for a period of 40 years.
-
-However, in 1704 something went wrong and the plan was not carried through;
-they did, after all, have a leap year that year.  And one in 1708.  In 1712
-they gave it up and went back to Julian, putting 30 days in February that
-year!...
-
-Then in 1753, Sweden made the transition to Gregorian in the usual manner,
-getting there only 13 years behind the original schedule.
-
-(A previous posting of this story was challenged, and Swedish readers
-produced the following references to support it: "Tiderakning och historia"
-by Natanael Beckman (1924) and "Tid, en bok om tiderakning och
-kalendervasen" by Lars-Olof Lode'n (no date was given).)
-
-
-Grotefend's data
-
-From: "Michael Palmer" [with one obvious typo fixed]
-Subject: Re: Gregorian Calendar (was Re: Another FHC related question
-Newsgroups: soc.genealogy.german
-Date: Tue, 9 Feb 1999 02:32:48 -800
-...
-
-The following is a(n incomplete) listing, arranged chronologically, of
-European states, with the date they converted from the Julian to the
-Gregorian calendar:
-
-04/15 Oct 1582 - Italy (with exceptions), Spain, Portugal, Poland (Roman
-                 Catholics and Danzig only)
-09/20 Dec 1582 - France, Lorraine
-
-21 Dec 1582/
-   01 Jan 1583 - Holland, Brabant, Flanders, Hennegau
-10/21 Feb 1583 - bishopric of Liege (L"uttich)
-13/24 Feb 1583 - bishopric of Augsburg
-04/15 Oct 1583 - electorate of Trier
-05/16 Oct 1583 - Bavaria, bishoprics of Freising, Eichstedt, Regensburg,
-                 Salzburg, Brixen
-13/24 Oct 1583 - Austrian Oberelsass and Breisgau
-20/31 Oct 1583 - bishopric of Basel
-02/13 Nov 1583 - duchy of J"ulich-Berg
-02/13 Nov 1583 - electorate and city of K"oln
-04/15 Nov 1583 - bishopric of W"urzburg
-11/22 Nov 1583 - electorate of Mainz
-16/27 Nov 1583 - bishopric of Strassburg and the margraviate of Baden
-17/28 Nov 1583 - bishopric of M"unster and duchy of Cleve
-14/25 Dec 1583 - Steiermark
-
-06/17 Jan 1584 - Austria and Bohemia
-11/22 Jan 1584 - Luzern, Uri, Schwyz, Zug, Freiburg, Solothurn
-12/23 Jan 1584 - Silesia and the Lausitz
-22 Jan/
-   02 Feb 1584 - Hungary (legally on 21 Oct 1587)
-      Jun 1584 - Unterwalden
-01/12 Jul 1584 - duchy of Westfalen
-
-16/27 Jun 1585 - bishopric of Paderborn
-
-14/25 Dec 1590 - Transylvania
-
-22 Aug/
-   02 Sep 1612 - duchy of Prussia
-
-13/24 Dec 1614 - Pfalz-Neuburg
-
-          1617 - duchy of Kurland (reverted to the Julian calendar in
-                 1796)
-
-          1624 - bishopric of Osnabr"uck
-
-          1630 - bishopric of Minden
-
-15/26 Mar 1631 - bishopric of Hildesheim
-
-          1655 - Kanton Wallis
-
-05/16 Feb 1682 - city of Strassburg
-
-18 Feb/
-   01 Mar 1700 - Protestant Germany (including Swedish possessions in
-                 Germany), Denmark, Norway
-30 Jun/
-   12 Jul 1700 - Gelderland, Zutphen
-10 Nov/
-   12 Dec 1700 - Utrecht, Overijssel
-
-31 Dec 1700/
-   12 Jan 1701 - Friesland, Groningen, Z"urich, Bern, Basel, Geneva,
-                 Turgau, and Schaffhausen
-
-          1724 - Glarus, Appenzell, and the city of St. Gallen
-
-01 Jan 1750    - Pisa and Florence
-
-02/14 Sep 1752 - Great Britain
-
-17 Feb/
-   01 Mar 1753 - Sweden
-
-1760-1812      - Graub"unden
-
-The Russian empire (including Finland and the Baltic states) did not
-convert to the Gregorian calendar until the Soviet revolution of 1917.
-
-Source:  H. Grotefend, _Taschenbuch der Zeitrechnung des deutschen
-Mittelalters und der Neuzeit_, herausgegeben von Dr. O. Grotefend
-(Hannover:  Hahnsche Buchhandlung, 1941), pp. 26-28.
-
-
------ Time and time zones on Mars -----
-
-Some people have adjusted their work schedules to fit Mars time.
-Dozens of special Mars watches were built for Jet Propulsion
-Laboratory workers who kept Mars time during the Mars Exploration
-Rovers mission (2004).  These timepieces look like normal Seikos and
-Citizens but use Mars seconds rather than terrestrial seconds.
-
-A Mars solar day is called a "sol" and has a mean period equal to
-about 24 hours 39 minutes 35.244 seconds in terrestrial time.  It is
-divided into a conventional 24-hour clock, so each Mars second equals
-about 1.02749125 terrestrial seconds.
-
-The prime meridian of Mars goes through the center of the crater
-Airy-0, named in honor of the British astronomer who built the
-Greenwich telescope that defines Earth's prime meridian.  Mean solar
-time on the Mars prime meridian is called Mars Coordinated Time (MTC).
-
-Each landed mission on Mars has adopted a different reference for
-solar time keeping, so there is no real standard for Mars time zones.
-For example, the Mars Exploration Rover project (2004) defined two
-time zones "Local Solar Time A" and "Local Solar Time B" for its two
-missions, each zone designed so that its time equals local true solar
-time at approximately the middle of the nominal mission.  Such a "time
-zone" is not particularly suited for any application other than the
-mission itself.
-
-Many calendars have been proposed for Mars, but none have achieved
-wide acceptance.  Astronomers often use Mars Sol Date (MSD) which is a
-sequential count of Mars solar days elapsed since about 1873-12-29
-12:00 GMT.
-
-The tz database does not currently support Mars time, but it is
-documented here in the hopes that support will be added eventually.
-
-Sources:
-
-Michael Allison and Robert Schmunk,
-"Technical Notes on Mars Solar Time as Adopted by the Mars24 Sunclock"
- (2004-07-30).
-
-Jia-Rui Chong, "Workdays Fit for a Martian", Los Angeles Times
-(2004-01-14), pp A1, A20-A21.
diff --git a/asctime.c b/asctime.c
index 52586c6aedf2..f0159f8324fa 100644
--- a/asctime.c
+++ b/asctime.c
@@ -1,141 +1,106 @@
+/* asctime and asctime_r a la POSIX and ISO C, except pad years before 1000.  */
+
 /*
 ** This file is in the public domain, so clarified as of
 ** 1996-06-05 by Arthur David Olson.
 */
 
 /*
 ** Avoid the temptation to punt entirely to strftime;
 ** the output of strftime is supposed to be locale specific
 ** whereas the output of asctime is supposed to be constant.
 */
 
-#ifndef lint
-#ifndef NOID
-static char	elsieid[] = "@(#)asctime.c	8.5";
-#endif /* !defined NOID */
-#endif /* !defined lint */
-
 /*LINTLIBRARY*/
 
 #include "private.h"
-#include "tzfile.h"
+#include 
 
-/*
-** Some systems only handle "%.2d"; others only handle "%02d";
-** "%02.2d" makes (most) everybody happy.
-** At least some versions of gcc warn about the %02.2d;
-** we conditionalize below to avoid the warning.
-*/
 /*
 ** All years associated with 32-bit time_t values are exactly four digits long;
 ** some years associated with 64-bit time_t values are not.
 ** Vintage programs are coded for years that are always four digits long
 ** and may assume that the newline always lands in the same place.
 ** For years that are less than four digits, we pad the output with
 ** leading zeroes to get the newline in the traditional place.
 ** The -4 ensures that we get four characters of output even if
 ** we call a strftime variant that produces fewer characters for some years.
-** The ISO C 1999 and POSIX 1003.1-2004 standards prohibit padding the year,
+** The ISO C and POSIX standards prohibit padding the year,
 ** but many implementations pad anyway; most likely the standards are buggy.
 */
-#ifdef __GNUC__
-#define ASCTIME_FMT	"%.3s %.3s%3d %2.2d:%2.2d:%2.2d %-4s\n"
-#else /* !defined __GNUC__ */
-#define ASCTIME_FMT	"%.3s %.3s%3d %02.2d:%02.2d:%02.2d %-4s\n"
-#endif /* !defined __GNUC__ */
+static char const ASCTIME_FMT[] = "%s %s%3d %.2d:%.2d:%.2d %-4s\n";
 /*
 ** For years that are more than four digits we put extra spaces before the year
 ** so that code trying to overwrite the newline won't end up overwriting
 ** a digit within a year and truncating the year (operating on the assumption
 ** that no output is better than wrong output).
 */
-#ifdef __GNUC__
-#define ASCTIME_FMT_B	"%.3s %.3s%3d %2.2d:%2.2d:%2.2d     %s\n"
-#else /* !defined __GNUC__ */
-#define ASCTIME_FMT_B	"%.3s %.3s%3d %02.2d:%02.2d:%02.2d     %s\n"
-#endif /* !defined __GNUC__ */
+static char const ASCTIME_FMT_B[] = "%s %s%3d %.2d:%.2d:%.2d     %s\n";
 
-#define STD_ASCTIME_BUF_SIZE	26
+enum { STD_ASCTIME_BUF_SIZE = 26 };
 /*
 ** Big enough for something such as
 ** ??? ???-2147483648 -2147483648:-2147483648:-2147483648     -2147483648\n
 ** (two three-character abbreviations, five strings denoting integers,
 ** seven explicit spaces, two explicit colons, a newline,
-** and a trailing ASCII nul).
+** and a trailing NUL byte).
 ** The values above are for systems where an int is 32 bits and are provided
-** as an example; the define below calculates the maximum for the system at
+** as an example; the size expression below is a bound for the system at
 ** hand.
 */
-#define MAX_ASCTIME_BUF_SIZE	(2*3+5*INT_STRLEN_MAXIMUM(int)+7+2+1+1)
-
-static char	buf_asctime[MAX_ASCTIME_BUF_SIZE];
-
-/*
-** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
-*/
+static char buf_asctime[2*3 + 5*INT_STRLEN_MAXIMUM(int) + 7 + 2 + 1 + 1];
 
 char *
-asctime_r(timeptr, buf)
-register const struct tm *	timeptr;
-char *				buf;
+asctime_r(register const struct tm *timeptr, char *buf)
 {
-	static const char	wday_name[][3] = {
+	static const char	wday_name[][4] = {
 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 	};
-	static const char	mon_name[][3] = {
+	static const char	mon_name[][4] = {
 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 	};
 	register const char *	wn;
 	register const char *	mn;
 	char			year[INT_STRLEN_MAXIMUM(int) + 2];
-	char			result[MAX_ASCTIME_BUF_SIZE];
+	char result[sizeof buf_asctime];
 
 	if (timeptr == NULL) {
 		errno = EINVAL;
 		return strcpy(buf, "??? ??? ?? ??:??:?? ????\n");
 	}
 	if (timeptr->tm_wday < 0 || timeptr->tm_wday >= DAYSPERWEEK)
 		wn = "???";
 	else	wn = wday_name[timeptr->tm_wday];
 	if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR)
 		mn = "???";
 	else	mn = mon_name[timeptr->tm_mon];
 	/*
 	** Use strftime's %Y to generate the year, to avoid overflow problems
 	** when computing timeptr->tm_year + TM_YEAR_BASE.
 	** Assume that strftime is unaffected by other out-of-range members
 	** (e.g., timeptr->tm_mday) when processing "%Y".
 	*/
-	(void) strftime(year, sizeof year, "%Y", timeptr);
+	strftime(year, sizeof year, "%Y", timeptr);
 	/*
 	** We avoid using snprintf since it's not available on all systems.
 	*/
-	(void) sprintf(result,
+	sprintf(result,
 		((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B),
 		wn, mn,
 		timeptr->tm_mday, timeptr->tm_hour,
 		timeptr->tm_min, timeptr->tm_sec,
 		year);
 	if (strlen(result) < STD_ASCTIME_BUF_SIZE || buf == buf_asctime)
 		return strcpy(buf, result);
 	else {
-#ifdef EOVERFLOW
 		errno = EOVERFLOW;
-#else /* !defined EOVERFLOW */
-		errno = EINVAL;
-#endif /* !defined EOVERFLOW */
 		return NULL;
 	}
 }
 
-/*
-** A la ISO/IEC 9945-1, ANSI/IEEE Std 1003.1, 2004 Edition.
-*/
-
 char *
-asctime(timeptr)
-register const struct tm *	timeptr;
+asctime(register const struct tm *timeptr)
 {
 	return asctime_r(timeptr, buf_asctime);
 }
diff --git a/calendars b/calendars
new file mode 100644
index 000000000000..f4ed9e434e50
--- /dev/null
+++ b/calendars
@@ -0,0 +1,173 @@
+----- Calendrical issues -----
+
+As mentioned in Theory.html, although calendrical issues are out of
+scope for tzdb, they indicate the sort of problems that we would run
+into if we extended tzdb further into the past.  The following
+information and sources go beyond Theory.html's brief discussion.
+They sometimes disagree.
+
+
+France
+
+Gregorian calendar adopted 1582-12-20.
+French Revolutionary calendar used 1793-11-24 through 1805-12-31,
+and (in Paris only) 1871-05-06 through 1871-05-23.
+
+
+Russia
+
+From Chris Carrier (1996-12-02):
+On 1929-10-01 the Soviet Union instituted an "Eternal Calendar"
+with 30-day months plus 5 holidays, with a 5-day week.
+On 1931-12-01 it changed to a 6-day week; in 1934 it reverted to the
+Gregorian calendar while retaining the 6-day week; on 1940-06-27 it
+reverted to the 7-day week.  With the 6-day week the usual days
+off were the 6th, 12th, 18th, 24th and 30th of the month.
+(Source: Evitiar Zerubavel, _The Seven Day Circle_)
+
+
+Mark Brader reported a similar story in "The Book of Calendars", edited
+by Frank Parise (1982, Facts on File, ISBN 0-8719-6467-8), page 377.  But:
+
+From: Petteri Sulonen (via Usenet)
+Date: 14 Jan 1999 00:00:00 GMT
+...
+
+If your source is correct, how come documents between 1929 and 1940 were
+still dated using the conventional, Gregorian calendar?
+
+I can post a scan of a document dated December 1, 1934, signed by
+Yenukidze, the secretary, on behalf of Kalinin, the President of the
+Executive Committee of the Supreme Soviet, if you like.
+
+
+
+Sweden (and Finland)
+
+From: Mark Brader
+Subject: Re: Gregorian reform - a part of locale?
+
+Date: 1996-07-06
+
+In 1700, Denmark made the transition from Julian to Gregorian.  Sweden
+decided to *start* a transition in 1700 as well, but rather than have one of
+those unsightly calendar gaps :-), they simply decreed that the next leap
+year after 1696 would be in 1744 - putting the whole country on a calendar
+different from both Julian and Gregorian for a period of 40 years.
+
+However, in 1704 something went wrong and the plan was not carried through;
+they did, after all, have a leap year that year.  And one in 1708.  In 1712
+they gave it up and went back to Julian, putting 30 days in February that
+year!...
+
+Then in 1753, Sweden made the transition to Gregorian in the usual manner,
+getting there only 13 years behind the original schedule.
+
+(A previous posting of this story was challenged, and Swedish readers
+produced the following references to support it: "Tideräkning och historia"
+by Natanael Beckman (1924) and "Tid, en bok om tideräkning och
+kalenderväsen" by Lars-Olof Lodén (1968).
+
+
+Grotefend's data
+
+From: "Michael Palmer" [with two obvious typos fixed]
+Subject: Re: Gregorian Calendar (was Re: Another FHC related question
+Newsgroups: soc.genealogy.german
+Date: Tue, 9 Feb 1999 02:32:48 -800
+...
+
+The following is a(n incomplete) listing, arranged chronologically, of
+European states, with the date they converted from the Julian to the
+Gregorian calendar:
+
+04/15 Oct 1582 - Italy (with exceptions), Spain, Portugal, Poland (Roman
+                 Catholics and Danzig only)
+09/20 Dec 1582 - France, Lorraine
+
+21 Dec 1582/
+   01 Jan 1583 - Holland, Brabant, Flanders, Hennegau
+10/21 Feb 1583 - bishopric of Liege (Lüttich)
+13/24 Feb 1583 - bishopric of Augsburg
+04/15 Oct 1583 - electorate of Trier
+05/16 Oct 1583 - Bavaria, bishoprics of Freising, Eichstedt, Regensburg,
+                 Salzburg, Brixen
+13/24 Oct 1583 - Austrian Oberelsaß and Breisgau
+20/31 Oct 1583 - bishopric of Basel
+02/13 Nov 1583 - duchy of Jülich-Berg
+02/13 Nov 1583 - electorate and city of Köln
+04/15 Nov 1583 - bishopric of Würzburg
+11/22 Nov 1583 - electorate of Mainz
+16/27 Nov 1583 - bishopric of Strassburg and the margraviate of Baden
+17/28 Nov 1583 - bishopric of Münster and duchy of Cleve
+14/25 Dec 1583 - Steiermark
+
+06/17 Jan 1584 - Austria and Bohemia
+11/22 Jan 1584 - Lucerne, Uri, Schwyz, Zug, Freiburg, Solothurn
+12/23 Jan 1584 - Silesia and the Lausitz
+22 Jan/
+   02 Feb 1584 - Hungary (legally on 21 Oct 1587)
+      Jun 1584 - Unterwalden
+01/12 Jul 1584 - duchy of Westfalen
+
+16/27 Jun 1585 - bishopric of Paderborn
+
+14/25 Dec 1590 - Transylvania
+
+22 Aug/
+   02 Sep 1612 - duchy of Prussia
+
+13/24 Dec 1614 - Pfalz-Neuburg
+
+          1617 - duchy of Kurland (reverted to the Julian calendar in
+                 1796)
+
+          1624 - bishopric of Osnabrück
+
+          1630 - bishopric of Minden
+
+15/26 Mar 1631 - bishopric of Hildesheim
+
+          1655 - Kanton Wallis
+
+05/16 Feb 1682 - city of Strassburg
+
+18 Feb/
+   01 Mar 1700 - Protestant Germany (including Swedish possessions in
+                 Germany), Denmark, Norway
+30 Jun/
+   12 Jul 1700 - Gelderland, Zutphen
+10 Nov/
+   12 Dec 1700 - Utrecht, Overijssel
+
+31 Dec 1700/
+   12 Jan 1701 - Friesland, Groningen, Zürich, Bern, Basel, Geneva,
+                 Thurgau, and Schaffhausen
+
+          1724 - Glarus, Appenzell, and the city of St. Gallen
+
+01 Jan 1750    - Pisa and Florence
+
+02/14 Sep 1752 - Great Britain
+
+17 Feb/
+   01 Mar 1753 - Sweden
+
+1760-1812      - Graubünden
+
+The Russian empire (including Finland and the Baltic states) did not
+convert to the Gregorian calendar until the Soviet revolution of 1917.
+
+Source: H. Grotefend, _Taschenbuch der Zeitrechnung des deutschen
+Mittelalters und der Neuzeit_, herausgegeben von Dr. O. Grotefend
+(Hannover: Hahnsche Buchhandlung, 1941), pp. 26-28.
+
+-----
+
+This file is in the public domain, so clarified as of 2009-05-17 by
+Arthur David Olson.
+
+-----
+Local Variables:
+coding: utf-8
+End:
diff --git a/checktab.awk b/checktab.awk
deleted file mode 100644
index 80ad7d570158..000000000000
--- a/checktab.awk
+++ /dev/null
@@ -1,159 +0,0 @@
-# Check tz tables for consistency.
-
-# @(#)checktab.awk	8.1
-
-# Contributed by Paul Eggert.
-
-BEGIN {
-	FS = "\t"
-
-	if (!iso_table) iso_table = "iso3166.tab"
-	if (!zone_table) zone_table = "zone.tab"
-	if (!want_warnings) want_warnings = -1
-
-	while (getline >"/dev/stderr"
-			status = 1
-		}
-		cc = $1
-		name = $2
-		if (cc !~ /^[A-Z][A-Z]$/) {
-			printf "%s:%d: invalid country code `%s'\n", \
-				iso_table, iso_NR, cc >>"/dev/stderr"
-			status = 1
-		}
-		if (cc <= cc0) {
-			if (cc == cc0) {
-				s = "duplicate";
-			} else {
-				s = "out of order";
-			}
-
-			printf "%s:%d: country code `%s' is %s\n", \
-				iso_table, iso_NR, cc, s \
-				>>"/dev/stderr"
-			status = 1
-		}
-		cc0 = cc
-		if (name2cc[name]) {
-			printf "%s:%d: `%s' and `%s' have the sname name\n", \
-				iso_table, iso_NR, name2cc[name], cc \
-				>>"/dev/stderr"
-			status = 1
-		}
-		name2cc[name] = cc
-		cc2name[cc] = name
-		cc2NR[cc] = iso_NR
-	}
-
-	zone_table = "zone.tab"
-	cc0 = ""
-
-	while (getline >"/dev/stderr"
-			status = 1
-		}
-		cc = $1
-		coordinates = $2
-		tz = $3
-		comments = $4
-		if (cc < cc0) {
-			printf "%s:%d: country code `%s' is out of order\n", \
-				zone_table, zone_NR, cc >>"/dev/stderr"
-			status = 1
-		}
-		cc0 = cc
-		if (tz2cc[tz]) {
-			printf "%s:%d: %s: duplicate TZ column\n", \
-				zone_table, zone_NR, tz >>"/dev/stderr"
-			status = 1
-		}
-		tz2cc[tz] = cc
-		tz2comments[tz] = comments
-		tz2NR[tz] = zone_NR
-		if (cc2name[cc]) {
-			cc_used[cc]++
-		} else {
-			printf "%s:%d: %s: unknown country code\n", \
-				zone_table, zone_NR, cc >>"/dev/stderr"
-			status = 1
-		}
-		if (coordinates !~ /^[-+][0-9][0-9][0-5][0-9][-+][01][0-9][0-9][0-5][0-9]$/ \
-		    && coordinates !~ /^[-+][0-9][0-9][0-5][0-9][0-5][0-9][-+][01][0-9][0-9][0-5][0-9][0-5][0-9]$/) {
-			printf "%s:%d: %s: invalid coordinates\n", \
-				zone_table, zone_NR, coordinates >>"/dev/stderr"
-			status = 1
-		}
-	}
-
-	for (tz in tz2cc) {
-		if (cc_used[tz2cc[tz]] == 1) {
-			if (tz2comments[tz]) {
-				printf "%s:%d: unnecessary comment `%s'\n", \
-					zone_table, tz2NR[tz], tz2comments[tz] \
-					>>"/dev/stderr"
-				status = 1
-			}
-		} else {
-			if (!tz2comments[tz]) {
-				printf "%s:%d: missing comment\n", \
-					zone_table, tz2NR[tz] >>"/dev/stderr"
-				status = 1
-			}
-		}
-	}
-
-	FS = " "
-}
-
-{
-	tz = ""
-	if ($1 == "Zone") tz = $2
-	if ($1 == "Link") {
-		# Ignore Link commands if source and destination basenames
-		# are identical, e.g. Europe/Istanbul versus Asia/Istanbul.
-		src = $2
-		dst = $3
-		while ((i = index(src, "/"))) src = substr(src, i+1)
-		while ((i = index(dst, "/"))) dst = substr(dst, i+1)
-		if (src != dst) tz = $3
-	}
-	if (tz && tz ~ /\//) {
-		if (!tz2cc[tz]) {
-			printf "%s: no data for `%s'\n", zone_table, tz \
-				>>"/dev/stderr"
-			status = 1
-		}
-		zoneSeen[tz] = 1
-	}
-}
-
-END {
-	for (tz in tz2cc) {
-		if (!zoneSeen[tz]) {
-			printf "%s:%d: no Zone table for `%s'\n", \
-				zone_table, tz2NR[tz], tz >>"/dev/stderr"
-			status = 1
-		}
-	}
-
-	if (0 < want_warnings) {
-		for (cc in cc2name) {
-			if (!cc_used[cc]) {
-				printf "%s:%d: warning: " \
-					"no Zone entries for %s (%s)\n", \
-					iso_table, cc2NR[cc], cc, cc2name[cc]
-			}
-		}
-	}
-
-	exit status
-}
diff --git a/date.1 b/date.1
index a3e00731f955..1ecd63a3d90c 100644
--- a/date.1
+++ b/date.1
@@ -1,177 +1,167 @@
 .TH DATE 1
 .SH NAME
 date \- show and set date and time
 .SH SYNOPSIS
 .if n .nh
 .if n .na
+.ie \n(.g .ds - \f(CW-\fP
+.el .ds - \-
 .B date
 [
-.B \-u
+.B \*-u
 ] [
-.B \-c
+.B \*-c
 ] [
-.B \-n
-] [
-.B \-d
-dsttype
-] [
-.B \-t
-minutes-west
-] [
-\fB\-a \fR[\fB+\fR|\fB-]\fIsss\fB.\fIfff\fR
+.B \*-r
+.I seconds
 ] [
 .BI + format
 ] [
 \fR[\fIyyyy\fR]\fImmddhhmm\fR[\fIyy\fR][\fB.\fIss\fR]
 ]
 .SH DESCRIPTION
-.I Date
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+The
+.B date
+command
 without arguments writes the date and time to the standard output in
 the form
 .ce 1
 Wed Mar  8 14:54:40 EST 1989
 .br
 with
 .B EST
 replaced by the local time zone's abbreviation
 (or by the abbreviation for the time zone specified in the
 .B TZ
 environment variable if set).
 The exact output format depends on the locale.
 .PP
-If a command-line argument starts with a plus sign
-.RB (` + '),
+If a command-line argument starts with a plus sign (\c
+.q "\fB+\fP" ),
 the rest of the argument is used as a
 .I format
 that controls what appears in the output.
-In the format, when a percent sign
-.RB (` % ')
+In the format, when a percent sign (\c
+.q "\fB%\fP"
 appears,
 it and the character after it are not output,
 but rather identify part of the date or time
 to be output in a particular way
 (or identify a special character to output):
 .nf
 .sp
 .if t .in +.5i
 .if n .in +2
 .ta \w'%M\0\0'u +\w'Wed Mar  8 14:54:40 EST 1989\0\0'u
 	Sample output	Explanation
 %a	Wed	Abbreviated weekday name*
 %A	Wednesday	Full weekday name*
 %b	Mar	Abbreviated month name*
 %B	March	Full month name*
 %c	Wed Mar 08 14:54:40 1989	Date and time*
 %C	19	Century
 %d	08	Day of month (always two digits)
 %D	03/08/89	Month/day/year (eight characters)
 %e	 8	Day of month (leading zero blanked)
 %h	Mar	Abbreviated month name*
 %H	14	24-hour-clock hour (two digits)
 %I	02	12-hour-clock hour (two digits)
 %j	067	Julian day number (three digits)
 %k	 2	12-hour-clock hour (leading zero blanked)
 %l	14	24-hour-clock hour (leading zero blanked)
 %m	03	Month number (two digits)
 %M	54	Minute (two digits)
 %n	\\n	newline character
 %p	PM	AM/PM designation
 %r	02:54:40 PM	Hour:minute:second AM/PM designation
 %R	14:54	Hour:minute
 %S	40	Second (two digits)
 %t	\\t	tab character
 %T	14:54:40	Hour:minute:second
 %U	10	Sunday-based week number (two digits)
 %w	3	Day number (one digit, Sunday is 0)
 %W	10	Monday-based week number (two digits)
 %x	03/08/89	Date*
 %X	14:54:40	Time*
 %y	89	Last two digits of year
 %Y	1989	Year in full
+%z	-0500	Numeric time zone
 %Z	EST	Time zone abbreviation
 %+	Wed Mar  8 14:54:40 EST 1989	Default output format*
 .if t .in -.5i
 .if n .in -2
 * The exact output depends on the locale.
 .sp
 .fi
 If a character other than one of those shown above appears after
 a percent sign in the format,
 that following character is output.
 All other characters in the format are copied unchanged to the output;
 a newline character is always added at the end of the output.
 .PP
 In Sunday-based week numbering,
 the first Sunday of the year begins week 1;
-days preceding it are part of ``week 0.''
+days preceding it are part of
+.q "week 0" .
 In Monday-based week numbering,
 the first Monday of the year begins week 1.
 .PP
 To set the date, use a command line argument with one of the following forms:
 .nf
 .if t .in +.5i
 .if n .in +2
 .ta \w'198903081454\0'u
 1454	24-hour-clock hours (first two digits) and minutes
 081454	Month day (first two digits), hours, and minutes
 03081454	Month (two digits, January is 01), month day, hours, minutes
 8903081454	Year, month, month day, hours, minutes
 0308145489	Month, month day, hours, minutes, year
 	(on System V-compatible systems)
 030814541989	Month, month day, hours, minutes, four-digit year
 198903081454	Four-digit year, month, month day, hours, minutes
 .if t .in -.5i
 .if n .in -2
 .fi
 If the century, year, month, or month day is not given,
 the current value is used.
 Any of the above forms may be followed by a period and two digits that give
 the seconds part of the new time; if no seconds are given, zero is assumed.
 .PP
 These options are available:
 .TP
-.BR \-u " or " \-c
-Use UTC when setting and showing the date and time.
-.TP
-.B \-n
-Do not notify other networked systems of the time change.
+.BR \*-u " or " \*-c
+Use Universal Time when setting and showing the date and time.
 .TP
-.BI "\-d " dsttype
-Set the kernel-stored Daylight Saving Time type to the given value.
-(The kernel-stored DST type is used mostly by ``old'' binaries.)
-.TP
-.BI "\-t " minutes-west
-Set the kernel-stored ``minutes west of UTC'' value to the one given on the
-command line.
-(The kernel-stored DST type is used mostly by ``old'' binaries.)
-.TP
-.BI "\-a " adjustment
-Change the time forward (or backward) by the number of seconds
-(and fractions thereof) specified in the
-.I adjustment\^
-argument.
-Either the seconds part or the fractions part of the argument (but not both)
-may be omitted.
-On BSD-based systems,
-the adjustment is made by changing the rate at which time advances;
-on System-V-based systems, the adjustment is made by changing the time.
+.BI "\*-r " seconds
+Output the date that corresponds to
+.I seconds
+past the epoch of 1970-01-01 00:00:00 UTC, where
+.I seconds
+should be an integer, either decimal, octal (leading 0), or
+hexadecimal (leading 0x), preceded by an optional sign.
 .SH FILES
-.ta \w'/usr/local/etc/zoneinfo/posixrules\0\0'u
-/usr/lib/locale/\f2L\fP/LC_TIME	description of time locale \f2L\fP
+.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+/etc/localtime	local timezone file
 .br
-/usr/local/etc/zoneinfo	time zone information directory
+/usr/lib/locale/\f2L\fP/LC_TIME	description of time locale \f2L\fP
 .br
-/usr/local/etc/zoneinfo/localtime	local time zone file
+/usr/share/zoneinfo	timezone information directory
 .br
-/usr/local/etc/zoneinfo/posixrules	used with POSIX-style TZ's
+/usr/share/zoneinfo/posixrules	used with POSIX-style TZ's
 .br
-/usr/local/etc/zoneinfo/GMT	for UTC leap seconds
+/usr/share/zoneinfo/GMT	for UTC leap seconds
 .sp
 If
-.B /usr/local/etc/zoneinfo/GMT
+.B /usr/share/zoneinfo/GMT
 is absent,
 UTC leap seconds are loaded from
-.BR /usr/local/etc/zoneinfo/posixrules .
-.\" @(#)date.1	8.2
+.BR /usr/share/zoneinfo/posixrules .
 .\" This file is in the public domain, so clarified as of
 .\" 2009-05-17 by Arthur David Olson.
diff --git a/date.1.txt b/date.1.txt
index 2910aaac370c..5affca23b2f0 100644
--- a/date.1.txt
+++ b/date.1.txt
@@ -1,127 +1,107 @@
-NAME
+DATE(1)                     General Commands Manual                    DATE(1)
 
-     date - show and set date and time
+NAME
+       date - show and set date and time
 
 SYNOPSIS
-     date [ -u ] [ -c ] [ -n ] [ -d dsttype ] [ -t minutes-west ]
-     [ -a [+|-]sss.fff ] [ +format ] [ [yyyy]mmddhhmm[yy][.ss] ]
+       date [ -u ] [ -c ] [ -r seconds ] [ +format ] [ [yyyy]mmddhhmm[yy][.ss]
+       ]
 
 DESCRIPTION
-     Date without arguments writes the date and time to the
-     standard output in the form
-                     Wed Mar  8 14:54:40 EST 1989
-     with EST replaced by the local time zone's abbreviation (or
-     by the abbreviation for the time zone specified in the TZ
-     environment variable if set).  The exact output format
-     depends on the locale.
-
-     If a command-line argument starts with a plus sign (`+'),
-     the rest of the argument is used as a format that controls
-     what appears in the output.  In the format, when a percent
-     sign (`%') appears, it and the character after it are not
-     output, but rather identify part of the date or time to be
-     output in a particular way (or identify a special character
-     to output):
+       The date command without arguments writes the date and time to the
+       standard output in the form
+                            Wed Mar  8 14:54:40 EST 1989
+       with EST replaced by the local time zone's abbreviation (or by the
+       abbreviation for the time zone specified in the TZ environment variable
+       if set).  The exact output format depends on the locale.
 
-           Sample output                 Explanation
-       %a  Wed                           Abbreviated weekday name*
-       %A  Wednesday                     Full weekday name*
-       %b  Mar                           Abbreviated month name*
-       %B  March                         Full month name*
-       %c  Wed Mar 08 14:54:40 1989      Date and time*
-       %C  19                            Century
-       %d  08                            Day of month (always two digits)
-       %D  03/08/89                      Month/day/year (eight characters)
-       %e   8                            Day of month (leading zero blanked)
-       %h  Mar                           Abbreviated month name*
-       %H  14                            24-hour-clock hour (two digits)
-       %I  02                            12-hour-clock hour (two digits)
-       %j  067                           Julian day number (three digits)
-       %k   2                            12-hour-clock hour (leading zero blanked)
-       %l  14                            24-hour-clock hour (leading zero blanked)
-       %m  03                            Month number (two digits)
-       %M  54                            Minute (two digits)
-       %n  \n                            newline character
-       %p  PM                            AM/PM designation
-       %r  02:54:40 PM                   Hour:minute:second AM/PM designation
-       %R  14:54                         Hour:minute
-       %S  40                            Second (two digits)
-       %t  \t                            tab character
-       %T  14:54:40                      Hour:minute:second
-       %U  10                            Sunday-based week number (two digits)
-       %w  3                             Day number (one digit, Sunday is 0)
-       %W  10                            Monday-based week number (two digits)
-       %x  03/08/89                      Date*
-       %X  14:54:40                      Time*
-       %y  89                            Last two digits of year
-       %Y  1989                          Year in full
-       %Z  EST                           Time zone abbreviation
-       %+  Wed Mar  8 14:54:40 EST 1989  Default output format*
-     * The exact output depends on the locale.
+       If a command-line argument starts with a plus sign ("+"), the rest of
+       the argument is used as a format that controls what appears in the
+       output.  In the format, when a percent sign ("%" appears, it and the
+       character after it are not output, but rather identify part of the date
+       or time to be output in a particular way (or identify a special
+       character to output):
 
-     If a character other than one of those shown above appears
-     after a percent sign in the format, that following character
-     is output.  All other characters in the format are copied
-     unchanged to the output; a newline character is always added
-     at the end of the output.
-     In Sunday-based week numbering, the first Sunday of the year
-     begins week 1; days preceding it are part of ``week 0.''  In
-     Monday-based week numbering, the first Monday of the year
-     begins week 1.
+             Sample output                 Explanation
+         %a  Wed                           Abbreviated weekday name*
+         %A  Wednesday                     Full weekday name*
+         %b  Mar                           Abbreviated month name*
+         %B  March                         Full month name*
+         %c  Wed Mar 08 14:54:40 1989      Date and time*
+         %C  19                            Century
+         %d  08                            Day of month (always two digits)
+         %D  03/08/89                      Month/day/year (eight characters)
+         %e   8                            Day of month (leading zero blanked)
+         %h  Mar                           Abbreviated month name*
+         %H  14                            24-hour-clock hour (two digits)
+         %I  02                            12-hour-clock hour (two digits)
+         %j  067                           Julian day number (three digits)
+         %k   2                            12-hour-clock hour (leading zero blanked)
+         %l  14                            24-hour-clock hour (leading zero blanked)
+         %m  03                            Month number (two digits)
+         %M  54                            Minute (two digits)
+         %n  \n                            newline character
+         %p  PM                            AM/PM designation
+         %r  02:54:40 PM                   Hour:minute:second AM/PM designation
+         %R  14:54                         Hour:minute
+         %S  40                            Second (two digits)
+         %t  \t                            tab character
+         %T  14:54:40                      Hour:minute:second
+         %U  10                            Sunday-based week number (two digits)
+         %w  3                             Day number (one digit, Sunday is 0)
+         %W  10                            Monday-based week number (two digits)
+         %x  03/08/89                      Date*
+         %X  14:54:40                      Time*
+         %y  89                            Last two digits of year
+         %Y  1989                          Year in full
+         %z  -0500                         Numeric time zone
+         %Z  EST                           Time zone abbreviation
+         %+  Wed Mar  8 14:54:40 EST 1989  Default output format*
+       * The exact output depends on the locale.
 
-     To set the date, use a command line argument with one of the
-     following forms:
-       1454         24-hour-clock hours (first two digits) and minutes
-       081454       Month day (first two digits), hours, and minutes
-       03081454     Month (two digits, January is 01), month day, hours, minutes
-       8903081454   Year, month, month day, hours, minutes
-       0308145489   Month, month day, hours, minutes, year
-                    (on System V-compatible systems)
-       030814541989 Month, month day, hours, minutes, four-digit year
-       198903081454 Four-digit year, month, month day, hours, minutes
-     If the century, year, month, or month day is not given, the
-     current value is used.  Any of the above forms may be
-     followed by a period and two digits that give the seconds
-     part of the new time; if no seconds are given, zero is
-     assumed.
+       If a character other than one of those shown above appears after a
+       percent sign in the format, that following character is output.  All
+       other characters in the format are copied unchanged to the output; a
+       newline character is always added at the end of the output.
 
-     These options are available:
+       In Sunday-based week numbering, the first Sunday of the year begins
+       week 1; days preceding it are part of "week 0".  In Monday-based week
+       numbering, the first Monday of the year begins week 1.
 
-     -u or -c
-          Use UTC when setting and showing the date and time.
+       To set the date, use a command line argument with one of the following
+       forms:
+         1454         24-hour-clock hours (first two digits) and minutes
+         081454       Month day (first two digits), hours, and minutes
+         03081454     Month (two digits, January is 01), month day, hours, minutes
+         8903081454   Year, month, month day, hours, minutes
+         0308145489   Month, month day, hours, minutes, year
+                      (on System V-compatible systems)
+         030814541989 Month, month day, hours, minutes, four-digit year
+         198903081454 Four-digit year, month, month day, hours, minutes
+       If the century, year, month, or month day is not given, the current
+       value is used.  Any of the above forms may be followed by a period and
+       two digits that give the seconds part of the new time; if no seconds
+       are given, zero is assumed.
 
-     -n   Do not notify other networked systems of the time
-          change.
+       These options are available:
 
-     -d dsttype
-          Set the kernel-stored Daylight Saving Time type to the
-          given value.  (The kernel-stored DST type is used
-          mostly by ``old'' binaries.)
+       -u or -c
+              Use Universal Time when setting and showing the date and time.
 
-     -t minutes-west
-          Set the kernel-stored ``minutes west of UTC'' value to
-          the one given on the command line.  (The kernel-stored
-          DST type is used mostly by ``old'' binaries.)
-
-     -a adjustment
-          Change the time forward (or backward) by the number of
-          seconds (and fractions thereof) specified in the
-          adjustment argument.  Either the seconds part or the
-          fractions part of the argument (but not both) may be
-          omitted.  On BSD-based systems, the adjustment is made
-          by changing the rate at which time advances; on System-
-          V-based systems, the adjustment is made by changing the
-          time.
+       -r seconds
+              Output the date that corresponds to seconds past the epoch of
+              1970-01-01 00:00:00 UTC, where seconds should be an integer,
+              either decimal, octal (leading 0), or hexadecimal (leading 0x),
+              preceded by an optional sign.
 
 FILES
-     /usr/lib/locale/L/LC_TIME           description of time
-     locale L
-     /usr/local/etc/zoneinfo             time zone information
-     directory
-     /usr/local/etc/zoneinfo/localtime   local time zone file
-     /usr/local/etc/zoneinfo/posixrules  used with POSIX-style
-     TZ's
-     /usr/local/etc/zoneinfo/GMT         for UTC leap seconds
+       /etc/localtime                  local timezone file
+       /usr/lib/locale/L/LC_TIME       description of time locale L
+       /usr/share/zoneinfo             timezone information directory
+       /usr/share/zoneinfo/posixrules  used with POSIX-style TZ's
+       /usr/share/zoneinfo/GMT         for UTC leap seconds
+
+       If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+       /usr/share/zoneinfo/posixrules.
 
-     If /usr/local/etc/zoneinfo/GMT is absent, UTC leap seconds
-     are loaded from /usr/local/etc/zoneinfo/posixrules.
+                                                                       DATE(1)
diff --git a/date.c b/date.c
index 6a6d2cdaffcd..4e4b355af03f 100644
--- a/date.c
+++ b/date.c
@@ -1,945 +1,216 @@
-#ifndef lint
-#ifndef NOID
-static char	elsieid[] = "@(#)date.c	8.4";
-/*
-** Modified from the UCB version with the SCCS ID appearing below.
-*/
-#endif /* !defined NOID */
-#endif /* !defined lint */
-
-/*
- * Copyright (c) 1985, 1987, 1988 The Regents of the University of California.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms are permitted
- * provided that the above copyright notice and this paragraph are
- * duplicated in all such forms and that any documentation,
- * advertising materials, and other materials related to such
- * distribution and use acknowledge that the software was developed
- * by the University of California, Berkeley.  The name of the
- * University may not be used to endorse or promote products derived
- * from this software without specific prior written permission.
- * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
- * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
- * WARRANTIES OF MERCHANT[A]BILITY AND FITNESS FOR A PARTICULAR PURPOSE.
- */
-
-#ifndef lint
-char copyright[] =
-"@(#) Copyright (c) 1985, 1987, 1988 The Regents of the University of California.\n\
- All rights reserved.\n";
-#endif /* not lint */
-
-#ifndef lint
-static char sccsid[] = "@(#)date.c	4.23 (Berkeley) 9/20/88";
-#endif /* not lint */
+/* Display or set the current time and date.  */
+
+/* Copyright 1985, 1987, 1988 The Regents of the University of California.
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+   1. Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+   2. Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+   3. Neither the name of the University nor the names of its contributors
+      may be used to endorse or promote products derived from this software
+      without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
+   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+   ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+   SUCH DAMAGE.  */
 
 #include "private.h"
-#if HAVE_ADJTIME || HAVE_SETTIMEOFDAY
-#include "sys/time.h"	/* for struct timeval, struct timezone */
-#endif /* HAVE_ADJTIME || HAVE_SETTIMEOFDAY */
-#include "locale.h"
-#include "utmp.h"	/* for OLD_TIME (or its absence) */
-#if HAVE_UTMPX_H
-#include "utmpx.h"
-#endif
-
-#ifndef OTIME_MSG
-#define OTIME_MSG "old time"
-#endif
-#ifndef NTIME_MSG
-#define NTIME_MSG "new time"
-#endif
-
-/*
-** The two things date knows about time are. . .
-*/
-
-#ifndef TM_YEAR_BASE
-#define TM_YEAR_BASE	1900
-#endif /* !defined TM_YEAR_BASE */
+#include 
+#include 
 
-#ifndef SECSPERMIN
-#define SECSPERMIN	60
-#endif /* !defined SECSPERMIN */
-
-extern double		atof();
-extern char **		environ;
-extern char *		getlogin();
-extern time_t		mktime();
+#if !HAVE_POSIX_DECLS
 extern char *		optarg;
 extern int		optind;
-extern char *		strchr();
-extern time_t		time();
-extern char *		tzname[2];
+#endif
 
 static int		retval = EXIT_SUCCESS;
 
-static void		checkfinal(const char *, int, time_t, time_t);
-static int		comptm(const struct tm *, const struct tm *);
-static time_t		convert(const char *, int, time_t);
-static void		display(const char *);
+static void		display(const char *, time_t);
 static void		dogmt(void);
 static void		errensure(void);
-static void		iffy(time_t, time_t, const char *, const char *);
-int			main(int, char**);
-static const char *	nondigit(const char *);
-static void		oops(const char *);
-static void		reset(time_t, int);
 static void		timeout(FILE *, const char *, const struct tm *);
-static void		usage(void);
-static void		wildinput(const char *, const char *,
-				const char *);
+static _Noreturn void	usage(void);
 
 int
-main(argc, argv)
-const int	argc;
-char *		argv[];
+main(const int argc, char *argv[])
 {
-	register const char *	format;
-	register const char *	value;
-	register const char *	cp;
+	register const char *	format = "+%+";
 	register int		ch;
-	register int		dousg;
-	register int		aflag = 0;
-	register int		dflag = 0;
-	register int		nflag = 0;
-	register int		tflag = 0;
-	register int		minuteswest;
-	register int		dsttime;
-	register double		adjust;
-	time_t			now;
+	register bool		rflag = false;
 	time_t			t;
+	intmax_t		secs;
+	char *			endarg;
 
-	INITIALIZE(dousg);
-	INITIALIZE(minuteswest);
-	INITIALIZE(dsttime);
-	INITIALIZE(adjust);
-	INITIALIZE(t);
 #ifdef LC_ALL
-	(void) setlocale(LC_ALL, "");
+	setlocale(LC_ALL, "");
 #endif /* defined(LC_ALL) */
 #if HAVE_GETTEXT
-#ifdef TZ_DOMAINDIR
-	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
-#endif /* defined(TEXTDOMAINDIR) */
-	(void) textdomain(TZ_DOMAIN);
+# ifdef TZ_DOMAINDIR
+	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
+# endif /* defined(TEXTDOMAINDIR) */
+	textdomain(TZ_DOMAIN);
 #endif /* HAVE_GETTEXT */
-	(void) time(&now);
-	format = value = NULL;
-	while ((ch = getopt(argc, argv, "ucnd:t:a:")) != EOF && ch != -1) {
+	t = time(NULL);
+	while ((ch = getopt(argc, argv, "ucr:")) != EOF && ch != -1) {
 		switch (ch) {
 		default:
 			usage();
-		case 'u':		/* do it in UTC */
+		case 'u':		/* do it in UT */
 		case 'c':
 			dogmt();
 			break;
-		case 'n':		/* don't set network */
-			nflag = 1;
-			break;
-		case 'd':		/* daylight saving time */
-			if (dflag) {
-				(void) fprintf(stderr,
-					_("date: error: multiple -d's used"));
+		case 'r':		/* seconds since 1970 */
+			if (rflag) {
+				fprintf(stderr,
+					_("date: error: multiple -r's used"));
 				usage();
 			}
-			dflag = 1;
-			cp = optarg;
-			dsttime = atoi(cp);
-			if (*cp == '\0' || *nondigit(cp) != '\0')
-				wildinput(_("-t value"), optarg,
-					_("must be a non-negative number"));
-			break;
-		case 't':		/* minutes west of UTC */
-			if (tflag) {
-				(void) fprintf(stderr,
-					_("date: error: multiple -t's used"));
-				usage();
+			rflag = true;
+			errno = 0;
+			secs = strtoimax(optarg, &endarg, 0);
+			if (*endarg || optarg == endarg)
+				errno = EINVAL;
+			else if (! (TIME_T_MIN <= secs && secs <= TIME_T_MAX))
+				errno = ERANGE;
+			if (errno) {
+				perror(optarg);
+				errensure();
+				exit(retval);
 			}
-			tflag = 1;
-			cp = optarg;
-			minuteswest = atoi(cp);
-			if (*cp == '+' || *cp == '-')
-				++cp;
-			if (*cp == '\0' || *nondigit(cp) != '\0')
-				wildinput(_("-d value"), optarg,
-					_("must be a number"));
+			t = secs;
 			break;
-		case 'a':		/* adjustment */
-			if (aflag) {
-				(void) fprintf(stderr,
-					_("date: error: multiple -a's used"));
-				usage();
-			}
-			aflag = 1;
-			cp = optarg;
-			adjust = atof(cp);
-			if (*cp == '+' || *cp == '-')
-				++cp;
-			if (*cp == '\0' || strcmp(cp, ".") == 0)
-				wildinput(_("-a value"), optarg,
-					_("must be a number"));
-			cp = nondigit(cp);
-			if (*cp == '.')
-				++cp;
-			if (*nondigit(cp) != '\0')
-				wildinput(_("-a value"), optarg,
-					_("must be a number"));
-			break;
-		}
-	}
-	while (optind < argc) {
-		cp = argv[optind++];
-		if (*cp == '+')
-			if (format == NULL)
-				format = cp + 1;
-			else {
-				(void) fprintf(stderr,
-_("date: error: multiple formats in command line\n"));
-				usage();
-			}
-		else	if (value == NULL)
-				value = cp;
-			else {
-				(void) fprintf(stderr,
-_("date: error: multiple values in command line\n"));
-				usage();
-			}
-	}
-	if (value != NULL) {
-		/*
-		** This order ensures that "reasonable" twelve-digit inputs
-		** (such as 120203042006) won't be misinterpreted
-		** even if time_t's range all the way back to the thirteenth
-		** century.  Do not change the order.
-		*/
-		t = convert(value, (dousg = TRUE), now);
-		if (t == -1)
-			t = convert(value, (dousg = FALSE), now);
-		if (t == -1) {
-			/*
-			** Out of range values,
-			** or time that falls in a DST transition hole?
-			*/
-			if ((cp = strchr(value, '.')) != NULL) {
-				/*
-				** Ensure that the failure of
-				**	TZ=America/New_York date 8712312359.60
-				** doesn't get misdiagnosed.  (It was
-				**	TZ=America/New_York date 8712311859.60
-				** when the leap second was inserted.)
-				** The normal check won't work since
-				** the given time is valid in UTC.
-				*/
-				if (atoi(cp + 1) >= SECSPERMIN)
-					wildinput(_("time"), value,
-					    _("out of range seconds given"));
-			}
-			dogmt();
-			t = convert(value, FALSE, now);
-			if (t == -1)
-				t = convert(value, TRUE, now);
-			wildinput(_("time"), value,
-				(t == -1) ?
-				_("out of range value given") :
-				_("time skipped when clock springs forward"));
 		}
 	}
-	/*
-	** Entire command line has now been checked.
-	*/
-	if (aflag) {
-#if HAVE_ADJTIME
-		struct timeval	tv;
-
-		tv.tv_sec = (int) adjust;
-		tv.tv_usec = (int) ((adjust - tv.tv_sec) * 1000000L);
-		if (adjtime(&tv, (struct timeval *) NULL) != 0)
-			oops("adjtime");
-#endif /* HAVE_ADJTIME */
-#if !HAVE_ADJTIME
-		reset((time_t) (now + adjust), nflag);
-#endif /* !HAVE_ADJTIME */
-		/*
-		** Sun silently ignores everything else; we follow suit.
-		*/
-		exit(retval);
-	}
-	if (dflag || tflag) {
-#if HAVE_SETTIMEOFDAY == 2
-		struct timezone	tz;
-
-		if (!dflag || !tflag)
-			if (gettimeofday((struct timeval *) NULL, &tz) != 0)
-				oops("gettimeofday");
-		if (dflag)
-			tz.tz_dsttime = dsttime;
-		if (tflag)
-			tz.tz_minuteswest = minuteswest;
-		if (settimeofday((struct timeval *) NULL, &tz) != 0)
-			oops("settimeofday");
-#endif /* HAVE_SETTIMEOFDAY == 2 */
-#if HAVE_SETTIMEOFDAY != 2
-		(void) fprintf(stderr,
-_("date: warning: kernel doesn't keep -d/-t information, option ignored\n"));
-#endif /* HAVE_SETTIMEOFDAY != 2 */
+	if (optind < argc) {
+	  if (argc - optind != 1) {
+	    fprintf(stderr,
+		    _("date: error: multiple operands in command line\n"));
+	    usage();
+	  }
+	  format = argv[optind];
+	  if (*format != '+') {
+	    fprintf(stderr, _("date: unknown operand: %s\n"), format);
+	    usage();
+	  }
 	}
 
-	if (value == NULL)
-		display(format);
-
-	reset(t, nflag);
-
-	checkfinal(value, dousg, t, now);
-
-#ifdef EBUG
-	{
-		struct tm	tm;
-
-		tm = *localtime(&t);
-		timeout(stdout, "%c\n", &tm);
-		exit(retval);
-	}
-#endif /* defined EBUG */
-
-	display(format);
-
-	/* gcc -Wall pacifier */
-	for ( ; ; )
-		continue;
+	display(format, t);
+	return retval;
 }
 
 static void
 dogmt(void)
 {
 	static char **	fakeenv;
 
 	if (fakeenv == NULL) {
 		register int	from;
 		register int	to;
 		register int	n;
-		static char	tzegmt0[] = "TZ=GMT0";
+		static char	tzeutc0[] = "TZ=UTC0";
 
 		for (n = 0;  environ[n] != NULL;  ++n)
 			continue;
-		fakeenv = (char **) malloc((size_t) (n + 2) * sizeof *fakeenv);
+		fakeenv = malloc((n + 2) * sizeof *fakeenv);
 		if (fakeenv == NULL) {
-			(void) perror(_("Memory exhausted"));
+			fprintf(stderr, _("date: Memory exhausted\n"));
 			errensure();
 			exit(retval);
 		}
 		to = 0;
-		fakeenv[to++] = tzegmt0;
+		fakeenv[to++] = tzeutc0;
 		for (from = 1; environ[from] != NULL; ++from)
 			if (strncmp(environ[from], "TZ=", 3) != 0)
 				fakeenv[to++] = environ[from];
 		fakeenv[to] = NULL;
 		environ = fakeenv;
 	}
 }
 
-#ifdef OLD_TIME
-
-/*
-** We assume we're on a System-V-based system,
-** should use stime,
-** should write System-V-format utmp entries,
-** and don't have network notification to worry about.
-*/
-
-#include "fcntl.h"	/* for O_WRONLY, O_APPEND */
-
-/*ARGSUSED*/
-static void
-reset(const time_t newt, const int nflag)
-{
-	register int		fid;
-	time_t			oldt;
-	static struct {
-		struct utmp	before;
-		struct utmp	after;
-	} s;
-#if HAVE_UTMPX_H
-	static struct {
-		struct utmpx	before;
-		struct utmpx	after;
-	} sx;
-#endif
-
-	/*
-	** Wouldn't it be great if stime returned the old time?
-	*/
-	(void) time(&oldt);
-	if (stime(&newt) != 0)
-		oops("stime");
-	s.before.ut_type = OLD_TIME;
-	s.before.ut_time = oldt;
-	(void) strcpy(s.before.ut_line, OTIME_MSG);
-	s.after.ut_type = NEW_TIME;
-	s.after.ut_time = newt;
-	(void) strcpy(s.after.ut_line, NTIME_MSG);
-	fid = open(WTMP_FILE, O_WRONLY | O_APPEND);
-	if (fid < 0)
-		oops(_("log file open"));
-	if (write(fid, (char *) &s, sizeof s) != sizeof s)
-		oops(_("log file write"));
-	if (close(fid) != 0)
-		oops(_("log file close"));
-#if !HAVE_UTMPX_H
-	pututline(&s.before);
-	pututline(&s.after);
-#endif /* !HAVE_UTMPX_H */
-#if HAVE_UTMPX_H
-	sx.before.ut_type = OLD_TIME;
-	sx.before.ut_tv.tv_sec = oldt;
-	(void) strcpy(sx.before.ut_line, OTIME_MSG);
-	sx.after.ut_type = NEW_TIME;
-	sx.after.ut_tv.tv_sec = newt;
-	(void) strcpy(sx.after.ut_line, NTIME_MSG);
-#if !SUPPRESS_WTMPX_FILE_UPDATE
-	/* In Solaris 2.5 (and presumably other systems),
-	   `date' does not update /var/adm/wtmpx.
-	   This must be a bug.  If you'd like to reproduce the bug,
-	   define SUPPRESS_WTMPX_FILE_UPDATE to be nonzero.  */
-	fid = open(WTMPX_FILE, O_WRONLY | O_APPEND);
-	if (fid < 0)
-		oops(_("log file open"));
-	if (write(fid, (char *) &sx, sizeof sx) != sizeof sx)
-		oops(_("log file write"));
-	if (close(fid) != 0)
-		oops(_("log file close"));
-#endif /* !SUPPRESS_WTMPX_FILE_UPDATE */
-	pututxline(&sx.before);
-	pututxline(&sx.after);
-#endif /* HAVE_UTMPX_H */
-}
-
-#endif /* defined OLD_TIME */
-#ifndef OLD_TIME
-
-/*
-** We assume we're on a BSD-based system,
-** should use settimeofday,
-** should write BSD-format utmp entries (using logwtmp),
-** and may get to worry about network notification.
-** The "time name" changes between 4.3-tahoe and 4.4;
-** we include sys/param.h to determine which we should use.
-*/
-
-#ifndef TIME_NAME
-#include "sys/param.h"
-#ifdef BSD4_4
-#define TIME_NAME	"date"
-#endif /* defined BSD4_4 */
-#ifndef BSD4_4
-#define TIME_NAME	""
-#endif /* !defined BSD4_4 */
-#endif /* !defined TIME_NAME */
-
-#include "syslog.h"
-#include "sys/socket.h"
-#include "netinet/in.h"
-#include "netdb.h"
-#define TSPTYPES
-#include "protocols/timed.h"
-
-extern int		logwtmp();
-
-#if HAVE_SETTIMEOFDAY == 1
-#define settimeofday(t, tz) (settimeofday)(t)
-#endif /* HAVE_SETTIMEOFDAY == 1 */
-
-#ifndef TSP_SETDATE
-/*ARGSUSED*/
-#endif /* !defined TSP_SETDATE */
-static void
-reset(newt, nflag)
-const time_t	newt;
-const int	nflag;
-{
-	register const char *	username;
-	static struct timeval	tv;	/* static so tv_usec is 0 */
-
-#ifdef EBUG
-	return;
-#endif /* defined EBUG */
-	username = getlogin();
-	if (username == NULL || *username == '\0') /* single-user or no tty */
-		username = "root";
-	tv.tv_sec = newt;
-#ifdef TSP_SETDATE
-	if (nflag || !netsettime(tv))
-#endif /* defined TSP_SETDATE */
-	{
-		/*
-		** "old" entry is always written, for compatibility.
-		*/
-		logwtmp("|", TIME_NAME, "");
-		if (settimeofday(&tv, (struct timezone *) NULL) == 0) {
-			logwtmp("{", TIME_NAME, "");	/* } */
-			syslog(LOG_AUTH | LOG_NOTICE, _("date set by %s"),
-				username);
-		} else	oops("settimeofday");
-	}
-}
-
-#endif /* !defined OLD_TIME */
-
-static void
-wildinput(item, value, reason)
-const char * const	item;
-const char * const	value;
-const char * const	reason;
-{
-	(void) fprintf(stderr,
-		_("date: error: bad command line %s \"%s\", %s\n"),
-		item, value, reason);
-	usage();
-}
-
 static void
 errensure(void)
 {
 	if (retval == EXIT_SUCCESS)
 		retval = EXIT_FAILURE;
 }
 
-static const char *
-nondigit(cp)
-register const char *	cp;
-{
-	while (is_digit(*cp))
-		++cp;
-	return cp;
-}
-
 static void
 usage(void)
 {
-	(void) fprintf(stderr, _("date: usage is date [-u] [-c] [-n] [-d dst] \
-[-t min-west] [-a sss.fff] [[yyyy]mmddhhmm[yyyy][.ss]] [+format]\n"));
+	fprintf(stderr,
+		       _("date: usage: date [-u] [-c] [-r seconds]"
+			 " [+format]\n"));
 	errensure();
 	exit(retval);
 }
 
 static void
-oops(string)
-const char * const	string;
+display(char const *format, time_t now)
 {
-	int		e = errno;
-
-	(void) fprintf(stderr, _("date: error: "));
-	errno = e;
-	(void) perror(string);
-	errensure();
-	display((char *) NULL);
-}
+	struct tm *tmp;
 
-static void
-display(format)
-const char * const	format;
-{
-	struct tm	tm;
-	time_t		now;
-
-	(void) time(&now);
-	tm = *localtime(&now);
-	timeout(stdout, format ? format : "%+", &tm);
-	(void) putchar('\n');
-	(void) fflush(stdout);
-	(void) fflush(stderr);
+	tmp = localtime(&now);
+	if (!tmp) {
+		fprintf(stderr,
+			_("date: error: time out of range\n"));
+		errensure();
+		return;
+	}
+	timeout(stdout, format, tmp);
+	putchar('\n');
+	fflush(stdout);
+	fflush(stderr);
 	if (ferror(stdout) || ferror(stderr)) {
-		(void) fprintf(stderr,
+		fprintf(stderr,
 			_("date: error: couldn't write results\n"));
 		errensure();
 	}
-	exit(retval);
 }
 
-extern size_t	strftime();
-
-#define INCR	1024
-
 static void
-timeout(fp, format, tmp)
-FILE * const		fp;
-const char * const	format;
-const struct tm * const	tmp;
+timeout(FILE *fp, char const *format, struct tm const *tmp)
 {
 	char *	cp;
 	size_t	result;
 	size_t	size;
+	struct tm tm;
+	int INCR = 1024;
 
-	if (*format == '\0')
+	if (!tmp) {
+		fprintf(stderr, _("date: error: time out of range\n"));
+		errensure();
 		return;
+	}
+	tm = *tmp;
+	tmp = &tm;
 	size = INCR;
-	cp = malloc((size_t) size);
+	cp = malloc(size);
 	for ( ; ; ) {
 		if (cp == NULL) {
-			(void) fprintf(stderr,
+			fprintf(stderr,
 				_("date: error: can't get memory\n"));
 			errensure();
 			exit(retval);
 		}
-		cp[0] = '\1';
 		result = strftime(cp, size, format, tmp);
-		if (result != 0 || cp[0] == '\0')
+		if (result != 0)
 			break;
 		size += INCR;
-		cp = realloc(cp, (size_t) size);
+		cp = realloc(cp, size);
 	}
-	(void) fwrite(cp, 1, result, fp);
+	fwrite(cp + 1, 1, result - 1, fp);
 	free(cp);
 }
-
-static int
-comptm(atmp, btmp)
-register const struct tm * const atmp;
-register const struct tm * const btmp;
-{
-	register int	result;
-
-	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
-		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
-		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
-		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
-		(result = (atmp->tm_min - btmp->tm_min)) == 0)
-			result = atmp->tm_sec - btmp->tm_sec;
-	return result;
-}
-
-/*
-** convert --
-**	convert user's input into a time_t.
-*/
-
-#define ATOI2(ar)	(ar[0] - '0') * 10 + (ar[1] - '0'); ar += 2;
-
-static time_t
-convert(register const char * const value, const int dousg, const time_t t)
-{
-	register const char *	cp;
-	register const char *	dotp;
-	register int	cent, year_in_cent, month, hour, day, mins, secs;
-	struct tm	tm, outtm;
-	time_t		outt;
-
-	tm = *localtime(&t);
-#define DIVISOR	100
-	year_in_cent = tm.tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
-	cent = tm.tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
-		year_in_cent / DIVISOR;
-	year_in_cent %= DIVISOR;
-	if (year_in_cent < 0) {
-		year_in_cent += DIVISOR;
-		--cent;
-	}
-	month = tm.tm_mon + 1;
-	day = tm.tm_mday;
-	hour = tm.tm_hour;
-	mins = tm.tm_min;
-	secs = 0;
-
-	dotp = strchr(value, '.');
-	for (cp = value; *cp != '\0'; ++cp)
-		if (!is_digit(*cp) && cp != dotp)
-			wildinput(_("time"), value, _("contains a nondigit"));
-
-	if (dotp == NULL)
-		dotp = strchr(value, '\0');
-	else {
-		cp = dotp + 1;
-		if (strlen(cp) != 2)
-			wildinput(_("time"), value,
-				_("seconds part is not two digits"));
-		secs = ATOI2(cp);
-	}
-
-	cp = value;
-	switch (dotp - cp) {
-		default:
-			wildinput(_("time"), value,
-				_("main part is wrong length"));
-		case 12:
-			if (!dousg) {
-				cent = ATOI2(cp);
-				year_in_cent = ATOI2(cp);
-			}
-			month = ATOI2(cp);
-			day = ATOI2(cp);
-			hour = ATOI2(cp);
-			mins = ATOI2(cp);
-			if (dousg) {
-				cent = ATOI2(cp);
-				year_in_cent = ATOI2(cp);
-			}
-			break;
-		case 8:	/* mmddhhmm */
-			month = ATOI2(cp);
-			/* fall through to. . . */
-		case 6:	/* ddhhmm */
-			day = ATOI2(cp);
-			/* fall through to. . . */
-		case 4:	/* hhmm */
-			hour = ATOI2(cp);
-			mins = ATOI2(cp);
-			break;
-		case 10:
-			if (!dousg) {
-				year_in_cent = ATOI2(cp);
-			}
-			month = ATOI2(cp);
-			day = ATOI2(cp);
-			hour = ATOI2(cp);
-			mins = ATOI2(cp);
-			if (dousg) {
-				year_in_cent = ATOI2(cp);
-			}
-			break;
-	}
-
-	tm.tm_year = cent * 100 + year_in_cent - TM_YEAR_BASE;
-	tm.tm_mon = month - 1;
-	tm.tm_mday = day;
-	tm.tm_hour = hour;
-	tm.tm_min = mins;
-	tm.tm_sec = secs;
-	tm.tm_isdst = -1;
-	outtm = tm;
-	outt = mktime(&outtm);
-	return (comptm(&tm, &outtm) == 0) ? outt : -1;
-}
-
-/*
-** Code from here on out is either based on code provided by UCB
-** or is only called just before the program exits.
-*/
-
-/*
-** Check for iffy input.
-*/
-
-static void
-checkfinal(const char * const	value,
-	   const int		didusg,
-	   const time_t		t,
-	   const time_t		oldnow)
-{
-	time_t		othert;
-	struct tm	tm;
-	struct tm	othertm;
-	register int	pass;
-	register long	offset;
-
-	/*
-	** See if there's both a USG and a BSD interpretation.
-	*/
-	othert = convert(value, !didusg, oldnow);
-	if (othert != -1 && othert != t)
-		iffy(t, othert, value, _("year could be at start or end"));
-	/*
-	** See if there's both a DST and a STD version.
-	*/
-	tm = *localtime(&t);
-	othertm = tm;
-	othertm.tm_isdst = !tm.tm_isdst;
-	othert = mktime(&othertm);
-	if (othert != -1 && othertm.tm_isdst != tm.tm_isdst &&
-		comptm(&tm, &othertm) == 0)
-			iffy(t, othert, value,
-			    _("both standard and summer time versions exist"));
-/*
-** Final check.
-**
-** If a jurisdiction shifts time *without* shifting whether time is
-** summer or standard (as Hawaii, the United Kingdom, and Saudi Arabia
-** have done), routine checks for iffy times may not work.
-** So we perform this final check, deferring it until after the time has
-** been set--it may take a while, and we don't want to introduce an unnecessary
-** lag between the time the user enters their command and the time that
-** stime/settimeofday is called.
-**
-** We just check nearby times to see if any have the same representation
-** as the time that convert returned.  We work our way out from the center
-** for quick response in solar time situations.  We only handle common cases--
-** offsets of at most a minute, and offsets of exact numbers of minutes
-** and at most an hour.
-*/
-	for (offset = 1; offset <= 60; ++offset)
-		for (pass = 1; pass <= 4; ++pass) {
-			if (pass == 1)
-				othert = t + offset;
-			else if (pass == 2)
-				othert = t - offset;
-			else if (pass == 3)
-				othert = t + 60 * offset;
-			else	othert = t - 60 * offset;
-			othertm = *localtime(&othert);
-			if (comptm(&tm, &othertm) == 0)
-				iffy(t, othert, value,
-					_("multiple matching times exist"));
-		}
-}
-
-static void
-iffy(const time_t thist, const time_t thatt,
-	const char * const value, const char * const reason)
-{
-	struct tm	tm;
-
-	(void) fprintf(stderr, _("date: warning: ambiguous time \"%s\", %s.\n"),
-		value, reason);
-	tm = *gmtime(&thist);
-	/*
-	** Avoid running afoul of SCCS!
-	*/
-	timeout(stderr, _("Time was set as if you used\n\tdate -u %m%d%H\
-%M\
-%Y.%S\n"), &tm);
-	tm = *localtime(&thist);
-	timeout(stderr, _("to get %c"), &tm);
-	(void) fprintf(stderr, _(" (%s).  Use\n"),
-		tm.tm_isdst ? _("summer time") : _("standard time"));
-	tm = *gmtime(&thatt);
-	timeout(stderr, _("\tdate -u %m%d%H\
-%M\
-%Y.%S\n"), &tm);
-	tm = *localtime(&thatt);
-	timeout(stderr, _("to get %c"), &tm);
-	(void) fprintf(stderr, _(" (%s).\n"),
-		tm.tm_isdst ? _("summer time") : _("standard time"));
-	errensure();
-	exit(retval);
-}
-
-#ifdef TSP_SETDATE
-#define WAITACK		2	/* seconds */
-#define WAITDATEACK	5	/* seconds */
-
-/*
- * Set the date in the machines controlled by timedaemons
- * by communicating the new date to the local timedaemon.
- * If the timedaemon is in the master state, it performs the
- * correction on all slaves.  If it is in the slave state, it
- * notifies the master that a correction is needed.
- * Returns 1 on success, 0 on failure.
- */
-netsettime(ntv)
-	struct timeval ntv;
-{
-	int s, length, port, timed_ack, found, err;
-	long waittime;
-	fd_set ready;
-	char hostname[MAXHOSTNAMELEN];
-	struct timeval tout;
-	struct servent *sp;
-	struct tsp msg;
-	struct sockaddr_in sin, dest, from;
-
-	sp = getservbyname("timed", "udp");
-	if (sp == 0) {
-		fputs(_("udp/timed: unknown service\n"), stderr);
-		retval = 2;
-		return (0);
-	}
-	dest.sin_port = sp->s_port;
-	dest.sin_family = AF_INET;
-	dest.sin_addr.s_addr = htonl((u_long)INADDR_ANY);
-	s = socket(AF_INET, SOCK_DGRAM, 0);
-	if (s < 0) {
-		if (errno != EPROTONOSUPPORT)
-			perror("date: socket");
-		goto bad;
-	}
-	bzero((char *)&sin, sizeof (sin));
-	sin.sin_family = AF_INET;
-	for (port = IPPORT_RESERVED - 1; port > IPPORT_RESERVED / 2; port--) {
-		sin.sin_port = htons((u_short)port);
-		if (bind(s, (struct sockaddr *)&sin, sizeof (sin)) >= 0)
-			break;
-		if (errno != EADDRINUSE) {
-			if (errno != EADDRNOTAVAIL)
-				perror("date: bind");
-			goto bad;
-		}
-	}
-	if (port == IPPORT_RESERVED / 2) {
-		fputs(_("date: All ports in use\n"), stderr);
-		goto bad;
-	}
-	msg.tsp_type = TSP_SETDATE;
-	msg.tsp_vers = TSPVERSION;
-	if (gethostname(hostname, sizeof (hostname))) {
-		perror("gethostname");
-		goto bad;
-	}
-	(void) strncpy(msg.tsp_name, hostname, sizeof (hostname));
-	msg.tsp_seq = htons((u_short)0);
-	msg.tsp_time.tv_sec = htonl((u_long)ntv.tv_sec);
-	msg.tsp_time.tv_usec = htonl((u_long)ntv.tv_usec);
-	length = sizeof (struct sockaddr_in);
-	if (connect(s, &dest, length) < 0) {
-		perror("date: connect");
-		goto bad;
-	}
-	if (send(s, (char *)&msg, sizeof (struct tsp), 0) < 0) {
-		if (errno != ECONNREFUSED)
-			perror("date: send");
-		goto bad;
-	}
-	timed_ack = -1;
-	waittime = WAITACK;
-loop:
-	tout.tv_sec = waittime;
-	tout.tv_usec = 0;
-	FD_ZERO(&ready);
-	FD_SET(s, &ready);
-	found = select(FD_SETSIZE, &ready, (fd_set *)0, (fd_set *)0, &tout);
-	length = sizeof err;
-	if (getsockopt(s, SOL_SOCKET, SO_ERROR, (char *)&err, &length) == 0
-	    && err) {
-		errno = err;
-		if (errno != ECONNREFUSED)
-			perror(_("date: send (delayed error)"));
-		goto bad;
-	}
-	if (found > 0 && FD_ISSET(s, &ready)) {
-		length = sizeof (struct sockaddr_in);
-		if (recvfrom(s, (char *)&msg, sizeof (struct tsp), 0, &from,
-		    &length) < 0) {
-			if (errno != ECONNREFUSED)
-				perror("date: recvfrom");
-			goto bad;
-		}
-		msg.tsp_seq = ntohs(msg.tsp_seq);
-		msg.tsp_time.tv_sec = ntohl(msg.tsp_time.tv_sec);
-		msg.tsp_time.tv_usec = ntohl(msg.tsp_time.tv_usec);
-		switch (msg.tsp_type) {
-
-		case TSP_ACK:
-			timed_ack = TSP_ACK;
-			waittime = WAITDATEACK;
-			goto loop;
-
-		case TSP_DATEACK:
-			(void)close(s);
-			return (1);
-
-		default:
-			fprintf(stderr,
-				_("date: Wrong ack received from timed: %s\n"),
-				tsptype[msg.tsp_type]);
-			timed_ack = -1;
-			break;
-		}
-	}
-	if (timed_ack == -1)
-		fputs(_("date: Can't reach time daemon, time set locally.\n"),
-			stderr);
-bad:
-	(void)close(s);
-	retval = 2;
-	return (0);
-}
-#endif /* defined TSP_SETDATE */
diff --git a/difftime.c b/difftime.c
index da779773bfdd..ff78f03c5705 100644
--- a/difftime.c
+++ b/difftime.c
@@ -1,65 +1,60 @@
+/* Return the difference between two timestamps.  */
+
 /*
 ** This file is in the public domain, so clarified as of
 ** 1996-06-05 by Arthur David Olson.
 */
 
-#ifndef lint
-#ifndef NOID
-static char	elsieid[] = "@(#)difftime.c	8.1";
-#endif /* !defined NOID */
-#endif /* !defined lint */
-
 /*LINTLIBRARY*/
 
-#include "private.h"	/* for time_t, TYPE_INTEGRAL, and TYPE_SIGNED */
+#include "private.h"	/* for time_t and TYPE_SIGNED */
+
+/* Return -X as a double.  Using this avoids casting to 'double'.  */
+static double
+dminus(double x)
+{
+  return -x;
+}
 
 double
-difftime(time1, time0)
-const time_t	time1;
-const time_t	time0;
+difftime(time_t time1, time_t time0)
 {
 	/*
-	** If (sizeof (double) > sizeof (time_t)) simply convert and subtract
+	** If double is large enough, simply convert and subtract
 	** (assuming that the larger type has more precision).
-	** This is the common real-world case circa 2004.
 	*/
-	if (sizeof (double) > sizeof (time_t))
-		return (double) time1 - (double) time0;
-	if (!TYPE_INTEGRAL(time_t)) {
-		/*
-		** time_t is floating.
-		*/
-		return time1 - time0;
+	if (sizeof(time_t) < sizeof(double)) {
+	  double t1 = time1, t0 = time0;
+	  return t1 - t0;
 	}
-	if (!TYPE_SIGNED(time_t)) {
-		/*
-		** time_t is integral and unsigned.
-		** The difference of two unsigned values can't overflow
-		** if the minuend is greater than or equal to the subtrahend.
-		*/
-		if (time1 >= time0)
-			return time1 - time0;
-		else	return -((double) (time0 - time1));
+
+	/*
+	** The difference of two unsigned values can't overflow
+	** if the minuend is greater than or equal to the subtrahend.
+	*/
+	if (!TYPE_SIGNED(time_t))
+	  return time0 <= time1 ? time1 - time0 : dminus(time0 - time1);
+
+	/* Use uintmax_t if wide enough.  */
+	if (sizeof(time_t) <= sizeof(uintmax_t)) {
+	  uintmax_t t1 = time1, t0 = time0;
+	  return time0 <= time1 ? t1 - t0 : dminus(t0 - t1);
 	}
+
 	/*
-	** time_t is integral and signed.
 	** Handle cases where both time1 and time0 have the same sign
 	** (meaning that their difference cannot overflow).
 	*/
 	if ((time1 < 0) == (time0 < 0))
-		return time1 - time0;
-	/*
-	** time1 and time0 have opposite signs.
-	** Punt if unsigned long is too narrow.
-	*/
-	if (sizeof (unsigned long) < sizeof (time_t))
-		return (double) time1 - (double) time0;
+	  return time1 - time0;
+
 	/*
-	** Stay calm...decent optimizers will eliminate the complexity below.
+	** The values have opposite signs and uintmax_t is too narrow.
+	** This suffers from double rounding; attempt to lessen that
+	** by using long double temporaries.
 	*/
-	if (time1 >= 0 /* && time0 < 0 */)
-		return (unsigned long) time1 +
-			(unsigned long) (-(time0 + 1)) + 1;
-	return -(double) ((unsigned long) time0 +
-		(unsigned long) (-(time1 + 1)) + 1);
+	{
+	  long double t1 = time1, t0 = time0;
+	  return t1 - t0;
+	}
 }
diff --git a/ialloc.c b/ialloc.c
deleted file mode 100644
index 1fc2035f4529..000000000000
--- a/ialloc.c
+++ /dev/null
@@ -1,86 +0,0 @@
-/*
-** This file is in the public domain, so clarified as of
-** 2006-07-17 by Arthur David Olson.
-*/
-
-#ifndef lint
-#ifndef NOID
-static char	elsieid[] = "@(#)ialloc.c	8.30";
-#endif /* !defined NOID */
-#endif /* !defined lint */
-
-/*LINTLIBRARY*/
-
-#include "private.h"
-
-#define nonzero(n)	(((n) == 0) ? 1 : (n))
-
-char *
-imalloc(n)
-const int	n;
-{
-	return malloc((size_t) nonzero(n));
-}
-
-char *
-icalloc(nelem, elsize)
-int	nelem;
-int	elsize;
-{
-	if (nelem == 0 || elsize == 0)
-		nelem = elsize = 1;
-	return calloc((size_t) nelem, (size_t) elsize);
-}
-
-void *
-irealloc(pointer, size)
-void * const	pointer;
-const int	size;
-{
-	if (pointer == NULL)
-		return imalloc(size);
-	return realloc((void *) pointer, (size_t) nonzero(size));
-}
-
-char *
-icatalloc(old, new)
-char * const		old;
-const char * const	new;
-{
-	register char *	result;
-	register int	oldsize, newsize;
-
-	newsize = (new == NULL) ? 0 : strlen(new);
-	if (old == NULL)
-		oldsize = 0;
-	else if (newsize == 0)
-		return old;
-	else	oldsize = strlen(old);
-	if ((result = irealloc(old, oldsize + newsize + 1)) != NULL)
-		if (new != NULL)
-			(void) strcpy(result + oldsize, new);
-	return result;
-}
-
-char *
-icpyalloc(string)
-const char * const	string;
-{
-	return icatalloc((char *) NULL, string);
-}
-
-void
-ifree(p)
-char * const	p;
-{
-	if (p != NULL)
-		(void) free(p);
-}
-
-void
-icfree(p)
-char * const	p;
-{
-	if (p != NULL)
-		(void) free(p);
-}
diff --git a/itca.jpg b/itca.jpg
deleted file mode 100644
index 89a7119c0ccc..000000000000
Binary files a/itca.jpg and /dev/null differ
diff --git a/localtime.c b/localtime.c
index 13c11aa928df..073b09669648 100644
--- a/localtime.c
+++ b/localtime.c
@@ -1,2084 +1,2449 @@
+/* Convert timestamp from time_t to struct tm.  */
+
 /*
 ** This file is in the public domain, so clarified as of
 ** 1996-06-05 by Arthur David Olson.
 */
 
-#ifndef lint
-#ifndef NOID
-static char	elsieid[] = "@(#)localtime.c	8.15";
-#endif /* !defined NOID */
-#endif /* !defined lint */
-
 /*
 ** Leap second handling from Bradley White.
 ** POSIX-style TZ environment variable handling from Guy Harris.
 */
 
 /*LINTLIBRARY*/
 
+#define LOCALTIME_IMPLEMENTATION
 #include "private.h"
+
 #include "tzfile.h"
-#include "fcntl.h"
-#include "float.h"	/* for FLT_MAX and DBL_MAX */
+#include 
+
+#if defined THREAD_SAFE && THREAD_SAFE
+# include 
+static pthread_mutex_t locallock = PTHREAD_MUTEX_INITIALIZER;
+static int lock(void) { return pthread_mutex_lock(&locallock); }
+static void unlock(void) { pthread_mutex_unlock(&locallock); }
+#else
+static int lock(void) { return 0; }
+static void unlock(void) { }
+#endif
 
 #ifndef TZ_ABBR_MAX_LEN
-#define TZ_ABBR_MAX_LEN	16
+# define TZ_ABBR_MAX_LEN 16
 #endif /* !defined TZ_ABBR_MAX_LEN */
 
 #ifndef TZ_ABBR_CHAR_SET
-#define TZ_ABBR_CHAR_SET \
+# define TZ_ABBR_CHAR_SET \
 	"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 :+-._"
 #endif /* !defined TZ_ABBR_CHAR_SET */
 
 #ifndef TZ_ABBR_ERR_CHAR
-#define TZ_ABBR_ERR_CHAR	'_'
+# define TZ_ABBR_ERR_CHAR '_'
 #endif /* !defined TZ_ABBR_ERR_CHAR */
 
 /*
-** SunOS 4.1.1 headers lack O_BINARY.
+** Support non-POSIX platforms that distinguish between text and binary files.
 */
 
-#ifdef O_BINARY
-#define OPEN_MODE	(O_RDONLY | O_BINARY)
-#endif /* defined O_BINARY */
 #ifndef O_BINARY
-#define OPEN_MODE	O_RDONLY
-#endif /* !defined O_BINARY */
+# define O_BINARY 0
+#endif
 
 #ifndef WILDABBR
 /*
 ** Someone might make incorrect use of a time zone abbreviation:
 **	1.	They might reference tzname[0] before calling tzset (explicitly
 **		or implicitly).
 **	2.	They might reference tzname[1] before calling tzset (explicitly
 **		or implicitly).
 **	3.	They might reference tzname[1] after setting to a time zone
 **		in which Daylight Saving Time is never observed.
 **	4.	They might reference tzname[0] after setting to a time zone
 **		in which Standard Time is never observed.
 **	5.	They might reference tm.TM_ZONE after calling offtime.
 ** What's best to do in the above cases is open to debate;
 ** for now, we just set things up so that in any of the five cases
 ** WILDABBR is used. Another possibility: initialize tzname[0] to the
 ** string "tzname[0] used before set", and similarly for the other cases.
 ** And another: initialize tzname[0] to "ERA", with an explanation in the
 ** manual page of what this "time zone abbreviation" means (doing this so
 ** that tzname[0] has the "normal" length of three characters).
 */
-#define WILDABBR	"   "
+# define WILDABBR "   "
 #endif /* !defined WILDABBR */
 
-static char		wildabbr[] = WILDABBR;
+static const char	wildabbr[] = WILDABBR;
 
-static const char	gmt[] = "GMT";
+static char const etc_utc[] = "Etc/UTC";
+static char const *utc = etc_utc + sizeof "Etc/" - 1;
 
 /*
 ** The DST rules to use if TZ has no rules and we can't load TZDEFRULES.
-** We default to US rules as of 1999-08-17.
-** POSIX 1003.1 section 8.1.1 says that the default DST rules are
-** implementation dependent; for historical reasons, US rules are a
-** common default.
+** Default to US rules as of 2017-05-07.
+** POSIX does not specify the default DST rules;
+** for historical reasons, US rules are a common default.
 */
 #ifndef TZDEFRULESTRING
-#define TZDEFRULESTRING ",M4.1.0,M10.5.0"
-#endif /* !defined TZDEFDST */
+# define TZDEFRULESTRING ",M3.2.0,M11.1.0"
+#endif
 
 struct ttinfo {				/* time type information */
-	long		tt_gmtoff;	/* UTC offset in seconds */
-	int		tt_isdst;	/* used to set tm_isdst */
-	int		tt_abbrind;	/* abbreviation list index */
-	int		tt_ttisstd;	/* TRUE if transition is std time */
-	int		tt_ttisgmt;	/* TRUE if transition is UTC */
+	int_fast32_t	tt_utoff;	/* UT offset in seconds */
+	bool		tt_isdst;	/* used to set tm_isdst */
+	int		tt_desigidx;	/* abbreviation list index */
+	bool		tt_ttisstd;	/* transition is std time */
+	bool		tt_ttisut;	/* transition is UT */
 };
 
 struct lsinfo {				/* leap second information */
 	time_t		ls_trans;	/* transition time */
-	long		ls_corr;	/* correction to apply */
+	int_fast32_t	ls_corr;	/* correction to apply */
 };
 
-#define BIGGEST(a, b)	(((a) > (b)) ? (a) : (b))
+/* This abbreviation means local time is unspecified.  */
+static char const UNSPEC[] = "-00";
+
+/* How many extra bytes are needed at the end of struct state's chars array.
+   This needs to be at least 1 for null termination in case the input
+   data isn't properly terminated, and it also needs to be big enough
+   for ttunspecified to work without crashing.  */
+enum { CHARS_EXTRA = max(sizeof UNSPEC, 2) - 1 };
 
 #ifdef TZNAME_MAX
-#define MY_TZNAME_MAX	TZNAME_MAX
+# define MY_TZNAME_MAX TZNAME_MAX
 #endif /* defined TZNAME_MAX */
 #ifndef TZNAME_MAX
-#define MY_TZNAME_MAX	255
+# define MY_TZNAME_MAX 255
 #endif /* !defined TZNAME_MAX */
 
 struct state {
 	int		leapcnt;
 	int		timecnt;
 	int		typecnt;
 	int		charcnt;
-	int		goback;
-	int		goahead;
+	bool		goback;
+	bool		goahead;
 	time_t		ats[TZ_MAX_TIMES];
 	unsigned char	types[TZ_MAX_TIMES];
 	struct ttinfo	ttis[TZ_MAX_TYPES];
-	char		chars[BIGGEST(BIGGEST(TZ_MAX_CHARS + 1, sizeof gmt),
-				(2 * (MY_TZNAME_MAX + 1)))];
+	char chars[max(max(TZ_MAX_CHARS + CHARS_EXTRA, sizeof "UTC"),
+		       2 * (MY_TZNAME_MAX + 1))];
 	struct lsinfo	lsis[TZ_MAX_LEAPS];
+
+	/* The time type to use for early times or if no transitions.
+	   It is always zero for recent tzdb releases.
+	   It might be nonzero for data from tzdb 2018e or earlier.  */
+	int defaulttype;
+};
+
+enum r_type {
+  JULIAN_DAY,		/* Jn = Julian day */
+  DAY_OF_YEAR,		/* n = day of year */
+  MONTH_NTH_DAY_OF_WEEK	/* Mm.n.d = month, week, day of week */
 };
 
 struct rule {
-	int		r_type;		/* type of rule--see below */
+	enum r_type	r_type;		/* type of rule */
 	int		r_day;		/* day number of rule */
 	int		r_week;		/* week number of rule */
 	int		r_mon;		/* month number of rule */
-	long		r_time;		/* transition time of rule */
+	int_fast32_t	r_time;		/* transition time of rule */
 };
 
-#define JULIAN_DAY		0	/* Jn - Julian day */
-#define DAY_OF_YEAR		1	/* n - day of year */
-#define MONTH_NTH_DAY_OF_WEEK	2	/* Mm.n.d - month, week, day of week */
-
-/*
-** Prototypes for static functions.
-*/
-
-static long		detzcode(const char * codep);
-static time_t		detzcode64(const char * codep);
-static int		differ_by_repeat(time_t t1, time_t t0);
-static const char *	getzname(const char * strp);
-static const char *	getqzname(const char * strp, const int delim);
-static const char *	getnum(const char * strp, int * nump, int min,
-				int max);
-static const char *	getsecs(const char * strp, long * secsp);
-static const char *	getoffset(const char * strp, long * offsetp);
-static const char *	getrule(const char * strp, struct rule * rulep);
-static void		gmtload(struct state * sp);
-static struct tm *	gmtsub(const time_t * timep, long offset,
-				struct tm * tmp);
-static struct tm *	localsub(const time_t * timep, long offset,
-				struct tm * tmp);
-static int		increment_overflow(int * number, int delta);
-static int		leaps_thru_end_of(int y);
-static int		long_increment_overflow(long * number, int delta);
-static int		long_normalize_overflow(long * tensptr,
-				int * unitsptr, int base);
-static int		normalize_overflow(int * tensptr, int * unitsptr,
-				int base);
-static void		settzname(void);
-static time_t		time1(struct tm * tmp,
-				struct tm * (*funcp)(const time_t *,
-				long, struct tm *),
-				long offset);
-static time_t		time2(struct tm *tmp,
-				struct tm * (*funcp)(const time_t *,
-				long, struct tm*),
-				long offset, int * okayp);
-static time_t		time2sub(struct tm *tmp,
-				struct tm * (*funcp)(const time_t *,
-				long, struct tm*),
-				long offset, int * okayp, int do_norm_secs);
-static struct tm *	timesub(const time_t * timep, long offset,
-				const struct state * sp, struct tm * tmp);
-static int		tmcomp(const struct tm * atmp,
-				const struct tm * btmp);
-static time_t		transtime(time_t janfirst, int year,
-				const struct rule * rulep, long offset);
-static int		typesequiv(const struct state * sp, int a, int b);
-static int		tzload(const char * name, struct state * sp,
-				int doextend);
-static int		tzparse(const char * name, struct state * sp,
-				int lastditch);
+static struct tm *gmtsub(struct state const *, time_t const *, int_fast32_t,
+			 struct tm *);
+static bool increment_overflow(int *, int);
+static bool increment_overflow_time(time_t *, int_fast32_t);
+static int_fast32_t leapcorr(struct state const *, time_t);
+static bool normalize_overflow32(int_fast32_t *, int *, int);
+static struct tm *timesub(time_t const *, int_fast32_t, struct state const *,
+			  struct tm *);
+static bool typesequiv(struct state const *, int, int);
+static bool tzparse(char const *, struct state *, struct state *);
 
 #ifdef ALL_STATE
 static struct state *	lclptr;
 static struct state *	gmtptr;
 #endif /* defined ALL_STATE */
 
 #ifndef ALL_STATE
 static struct state	lclmem;
 static struct state	gmtmem;
-#define lclptr		(&lclmem)
-#define gmtptr		(&gmtmem)
+static struct state *const lclptr = &lclmem;
+static struct state *const gmtptr = &gmtmem;
 #endif /* State Farm */
 
 #ifndef TZ_STRLEN_MAX
-#define TZ_STRLEN_MAX 255
+# define TZ_STRLEN_MAX 255
 #endif /* !defined TZ_STRLEN_MAX */
 
 static char		lcl_TZname[TZ_STRLEN_MAX + 1];
 static int		lcl_is_set;
-static int		gmt_is_set;
-
-char *			tzname[2] = {
-	wildabbr,
-	wildabbr
-};
 
 /*
 ** Section 4.12.3 of X3.159-1989 requires that
 **	Except for the strftime function, these functions [asctime,
 **	ctime, gmtime, localtime] return values in one of two static
 **	objects: a broken-down time structure and an array of char.
 ** Thanks to Paul Eggert for noting this.
 */
 
 static struct tm	tm;
 
-#ifdef USG_COMPAT
-time_t			timezone = 0;
-int			daylight = 0;
-#endif /* defined USG_COMPAT */
-
-#ifdef ALTZONE
-time_t			altzone = 0;
-#endif /* defined ALTZONE */
+#if 2 <= HAVE_TZNAME + TZ_TIME_T
+char *			tzname[2] = {
+	(char *) wildabbr,
+	(char *) wildabbr
+};
+#endif
+#if 2 <= USG_COMPAT + TZ_TIME_T
+long			timezone;
+int			daylight;
+#endif
+#if 2 <= ALTZONE + TZ_TIME_T
+long			altzone;
+#endif
+
+/* Initialize *S to a value based on UTOFF, ISDST, and DESIGIDX.  */
+static void
+init_ttinfo(struct ttinfo *s, int_fast32_t utoff, bool isdst, int desigidx)
+{
+  s->tt_utoff = utoff;
+  s->tt_isdst = isdst;
+  s->tt_desigidx = desigidx;
+  s->tt_ttisstd = false;
+  s->tt_ttisut = false;
+}
 
-static long
-detzcode(codep)
-const char * const	codep;
+/* Return true if SP's time type I does not specify local time.  */
+static bool
+ttunspecified(struct state const *sp, int i)
 {
-	register long	result;
-	register int	i;
+  char const *abbr = &sp->chars[sp->ttis[i].tt_desigidx];
+  /* memcmp is likely faster than strcmp, and is safe due to CHARS_EXTRA.  */
+  return memcmp(abbr, UNSPEC, sizeof UNSPEC) == 0;
+}
 
-	result = (codep[0] & 0x80) ? ~0L : 0;
-	for (i = 0; i < 4; ++i)
+static int_fast32_t
+detzcode(const char *const codep)
+{
+	register int_fast32_t	result;
+	register int		i;
+	int_fast32_t one = 1;
+	int_fast32_t halfmaxval = one << (32 - 2);
+	int_fast32_t maxval = halfmaxval - 1 + halfmaxval;
+	int_fast32_t minval = -1 - maxval;
+
+	result = codep[0] & 0x7f;
+	for (i = 1; i < 4; ++i)
 		result = (result << 8) | (codep[i] & 0xff);
+
+	if (codep[0] & 0x80) {
+	  /* Do two's-complement negation even on non-two's-complement machines.
+	     If the result would be minval - 1, return minval.  */
+	  result -= !TWOS_COMPLEMENT(int_fast32_t) && result != 0;
+	  result += minval;
+	}
 	return result;
 }
 
-static time_t
-detzcode64(codep)
-const char * const	codep;
+static int_fast64_t
+detzcode64(const char *const codep)
 {
-	register time_t	result;
+	register int_fast64_t result;
 	register int	i;
+	int_fast64_t one = 1;
+	int_fast64_t halfmaxval = one << (64 - 2);
+	int_fast64_t maxval = halfmaxval - 1 + halfmaxval;
+	int_fast64_t minval = -TWOS_COMPLEMENT(int_fast64_t) - maxval;
 
-	result = (codep[0] & 0x80) ?  (~(int_fast64_t) 0) : 0;
-	for (i = 0; i < 8; ++i)
-		result = result * 256 + (codep[i] & 0xff);
+	result = codep[0] & 0x7f;
+	for (i = 1; i < 8; ++i)
+		result = (result << 8) | (codep[i] & 0xff);
+
+	if (codep[0] & 0x80) {
+	  /* Do two's-complement negation even on non-two's-complement machines.
+	     If the result would be minval - 1, return minval.  */
+	  result -= !TWOS_COMPLEMENT(int_fast64_t) && result != 0;
+	  result += minval;
+	}
 	return result;
 }
 
+static void
+update_tzname_etc(struct state const *sp, struct ttinfo const *ttisp)
+{
+#if HAVE_TZNAME
+  tzname[ttisp->tt_isdst] = (char *) &sp->chars[ttisp->tt_desigidx];
+#endif
+#if USG_COMPAT
+  if (!ttisp->tt_isdst)
+    timezone = - ttisp->tt_utoff;
+#endif
+#if ALTZONE
+  if (ttisp->tt_isdst)
+    altzone = - ttisp->tt_utoff;
+#endif
+}
+
+/* If STDDST_MASK indicates that SP's TYPE provides useful info,
+   update tzname, timezone, and/or altzone and return STDDST_MASK,
+   diminished by the provided info if it is a specified local time.
+   Otherwise, return STDDST_MASK.  See settzname for STDDST_MASK.  */
+static int
+may_update_tzname_etc(int stddst_mask, struct state *sp, int type)
+{
+  struct ttinfo *ttisp = &sp->ttis[type];
+  int this_bit = 1 << ttisp->tt_isdst;
+  if (stddst_mask & this_bit) {
+    update_tzname_etc(sp, ttisp);
+    if (!ttunspecified(sp, type))
+      return stddst_mask & ~this_bit;
+  }
+  return stddst_mask;
+}
+
 static void
 settzname(void)
 {
 	register struct state * const	sp = lclptr;
 	register int			i;
 
-	tzname[0] = wildabbr;
-	tzname[1] = wildabbr;
-#ifdef USG_COMPAT
-	daylight = 0;
+	/* If STDDST_MASK & 1 we need info about a standard time.
+	   If STDDST_MASK & 2 we need info about a daylight saving time.
+	   When STDDST_MASK becomes zero we can stop looking.  */
+	int stddst_mask = 0;
+
+#if HAVE_TZNAME
+	tzname[0] = tzname[1] = (char *) (sp ? wildabbr : utc);
+	stddst_mask = 3;
+#endif
+#if USG_COMPAT
 	timezone = 0;
-#endif /* defined USG_COMPAT */
-#ifdef ALTZONE
+	stddst_mask = 3;
+#endif
+#if ALTZONE
 	altzone = 0;
-#endif /* defined ALTZONE */
-#ifdef ALL_STATE
-	if (sp == NULL) {
-		tzname[0] = tzname[1] = gmt;
-		return;
-	}
-#endif /* defined ALL_STATE */
+	stddst_mask |= 2;
+#endif
 	/*
-	** And to get the latest zone names into tzname. . .
+	** And to get the latest time zone abbreviations into tzname. . .
 	*/
-	for (i = 0; i < sp->timecnt; ++i) {
-		register const struct ttinfo * const	ttisp =
-							&sp->ttis[
-								sp->types[i]];
-
-		tzname[ttisp->tt_isdst] =
-			&sp->chars[ttisp->tt_abbrind];
-#ifdef USG_COMPAT
-		if (ttisp->tt_isdst)
-			daylight = 1;
-		if (!ttisp->tt_isdst)
-			timezone = -(ttisp->tt_gmtoff);
-#endif /* defined USG_COMPAT */
-#ifdef ALTZONE
-		if (ttisp->tt_isdst)
-			altzone = -(ttisp->tt_gmtoff);
-#endif /* defined ALTZONE */
+	if (sp) {
+	  for (i = sp->timecnt - 1; stddst_mask && 0 <= i; i--)
+	    stddst_mask = may_update_tzname_etc(stddst_mask, sp, sp->types[i]);
+	  for (i = sp->typecnt - 1; stddst_mask && 0 <= i; i--)
+	    stddst_mask = may_update_tzname_etc(stddst_mask, sp, i);
 	}
+#if USG_COMPAT
+	daylight = stddst_mask >> 1 ^ 1;
+#endif
+}
+
+static void
+scrub_abbrs(struct state *sp)
+{
+	int i;
 	/*
-	** Finally, scrub the abbreviations.
 	** First, replace bogus characters.
 	*/
 	for (i = 0; i < sp->charcnt; ++i)
 		if (strchr(TZ_ABBR_CHAR_SET, sp->chars[i]) == NULL)
 			sp->chars[i] = TZ_ABBR_ERR_CHAR;
 	/*
 	** Second, truncate long abbreviations.
 	*/
 	for (i = 0; i < sp->typecnt; ++i) {
 		register const struct ttinfo * const	ttisp = &sp->ttis[i];
-		register char *				cp = &sp->chars[ttisp->tt_abbrind];
+		char *cp = &sp->chars[ttisp->tt_desigidx];
 
 		if (strlen(cp) > TZ_ABBR_MAX_LEN &&
 			strcmp(cp, GRANDPARENTED) != 0)
 				*(cp + TZ_ABBR_MAX_LEN) = '\0';
 	}
 }
 
-static int
-differ_by_repeat(t1, t0)
-const time_t	t1;
-const time_t	t0;
-{
-	if (TYPE_INTEGRAL(time_t) &&
-		TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS)
-			return 0;
-	return t1 - t0 == SECSPERREPEAT;
-}
+/* Input buffer for data read from a compiled tz file.  */
+union input_buffer {
+  /* The first part of the buffer, interpreted as a header.  */
+  struct tzhead tzhead;
+
+  /* The entire buffer.  */
+  char buf[2 * sizeof(struct tzhead) + 2 * sizeof(struct state)
+	   + 4 * TZ_MAX_TIMES];
+};
+
+/* TZDIR with a trailing '/' rather than a trailing '\0'.  */
+static char const tzdirslash[sizeof TZDIR] = TZDIR "/";
+
+/* Local storage needed for 'tzloadbody'.  */
+union local_storage {
+  /* The results of analyzing the file's contents after it is opened.  */
+  struct file_analysis {
+    /* The input buffer.  */
+    union input_buffer u;
 
+    /* A temporary state used for parsing a TZ string in the file.  */
+    struct state st;
+  } u;
+
+  /* The file name to be opened.  */
+  char fullname[max(sizeof(struct file_analysis), sizeof tzdirslash + 1024)];
+};
+
+/* Load tz data from the file named NAME into *SP.  Read extended
+   format if DOEXTEND.  Use *LSP for temporary storage.  Return 0 on
+   success, an errno value on failure.  */
 static int
-tzload(name, sp, doextend)
-register const char *		name;
-register struct state * const	sp;
-register const int		doextend;
+tzloadbody(char const *name, struct state *sp, bool doextend,
+	   union local_storage *lsp)
 {
-	register const char *		p;
 	register int			i;
 	register int			fid;
 	register int			stored;
-	register int			nread;
-	union {
-		struct tzhead	tzhead;
-		char		buf[2 * sizeof(struct tzhead) +
-					2 * sizeof *sp +
-					4 * TZ_MAX_TIMES];
-	} u;
-
-	sp->goback = sp->goahead = FALSE;
-	if (name == NULL && (name = TZDEFAULT) == NULL)
-		return -1;
-	{
-		register int	doaccess;
-		/*
-		** Section 4.9.1 of the C standard says that
-		** "FILENAME_MAX expands to an integral constant expression
-		** that is the size needed for an array of char large enough
-		** to hold the longest file name string that the implementation
-		** guarantees can be opened."
-		*/
-		char		fullname[FILENAME_MAX + 1];
+	register ssize_t		nread;
+	register bool doaccess;
+	register union input_buffer *up = &lsp->u.u;
+	register int tzheadsize = sizeof(struct tzhead);
 
-		if (name[0] == ':')
-			++name;
-		doaccess = name[0] == '/';
-		if (!doaccess) {
-			if ((p = TZDIR) == NULL)
-				return -1;
-			if ((strlen(p) + strlen(name) + 1) >= sizeof fullname)
-				return -1;
-			(void) strcpy(fullname, p);
-			(void) strcat(fullname, "/");
-			(void) strcat(fullname, name);
-			/*
-			** Set doaccess if '.' (as in "../") shows up in name.
-			*/
-			if (strchr(name, '.') != NULL)
-				doaccess = TRUE;
-			name = fullname;
-		}
-		if (doaccess && access(name, R_OK) != 0)
-			return -1;
-		if ((fid = open(name, OPEN_MODE)) == -1)
-			return -1;
+	sp->goback = sp->goahead = false;
+
+	if (! name) {
+		name = TZDEFAULT;
+		if (! name)
+		  return EINVAL;
 	}
-	nread = read(fid, u.buf, sizeof u.buf);
-	if (close(fid) < 0 || nread <= 0)
-		return -1;
+
+	if (name[0] == ':')
+		++name;
+#ifdef SUPPRESS_TZDIR
+	/* Do not prepend TZDIR.  This is intended for specialized
+	   applications only, due to its security implications.  */
+	doaccess = true;
+#else
+	doaccess = name[0] == '/';
+#endif
+	if (!doaccess) {
+		char const *dot;
+		size_t namelen = strlen(name);
+		if (sizeof lsp->fullname - sizeof tzdirslash <= namelen)
+		  return ENAMETOOLONG;
+
+		/* Create a string "TZDIR/NAME".  Using sprintf here
+		   would pull in stdio (and would fail if the
+		   resulting string length exceeded INT_MAX!).  */
+		memcpy(lsp->fullname, tzdirslash, sizeof tzdirslash);
+		strcpy(lsp->fullname + sizeof tzdirslash, name);
+
+		/* Set doaccess if NAME contains a ".." file name
+		   component, as such a name could read a file outside
+		   the TZDIR virtual subtree.  */
+		for (dot = name; (dot = strchr(dot, '.')); dot++)
+		  if ((dot == name || dot[-1] == '/') && dot[1] == '.'
+		      && (dot[2] == '/' || !dot[2])) {
+		    doaccess = true;
+		    break;
+		  }
+
+		name = lsp->fullname;
+	}
+	if (doaccess && access(name, R_OK) != 0)
+	  return errno;
+	fid = open(name, O_RDONLY | O_BINARY);
+	if (fid < 0)
+	  return errno;
+
+	nread = read(fid, up->buf, sizeof up->buf);
+	if (nread < tzheadsize) {
+	  int err = nread < 0 ? errno : EINVAL;
+	  close(fid);
+	  return err;
+	}
+	if (close(fid) < 0)
+	  return errno;
 	for (stored = 4; stored <= 8; stored *= 2) {
-		int		ttisstdcnt;
-		int		ttisgmtcnt;
-
-		ttisstdcnt = (int) detzcode(u.tzhead.tzh_ttisstdcnt);
-		ttisgmtcnt = (int) detzcode(u.tzhead.tzh_ttisgmtcnt);
-		sp->leapcnt = (int) detzcode(u.tzhead.tzh_leapcnt);
-		sp->timecnt = (int) detzcode(u.tzhead.tzh_timecnt);
-		sp->typecnt = (int) detzcode(u.tzhead.tzh_typecnt);
-		sp->charcnt = (int) detzcode(u.tzhead.tzh_charcnt);
-		p = u.tzhead.tzh_charcnt + sizeof u.tzhead.tzh_charcnt;
-		if (sp->leapcnt < 0 || sp->leapcnt > TZ_MAX_LEAPS ||
-			sp->typecnt <= 0 || sp->typecnt > TZ_MAX_TYPES ||
-			sp->timecnt < 0 || sp->timecnt > TZ_MAX_TIMES ||
-			sp->charcnt < 0 || sp->charcnt > TZ_MAX_CHARS ||
-			(ttisstdcnt != sp->typecnt && ttisstdcnt != 0) ||
-			(ttisgmtcnt != sp->typecnt && ttisgmtcnt != 0))
-				return -1;
-		if (nread - (p - u.buf) <
-			sp->timecnt * stored +		/* ats */
-			sp->timecnt +			/* types */
-			sp->typecnt * 6 +		/* ttinfos */
-			sp->charcnt +			/* chars */
-			sp->leapcnt * (stored + 4) +	/* lsinfos */
-			ttisstdcnt +			/* ttisstds */
-			ttisgmtcnt)			/* ttisgmts */
-				return -1;
+	    char version = up->tzhead.tzh_version[0];
+	    bool skip_datablock = stored == 4 && version;
+	    int_fast32_t datablock_size;
+	    int_fast32_t ttisstdcnt = detzcode(up->tzhead.tzh_ttisstdcnt);
+	    int_fast32_t ttisutcnt = detzcode(up->tzhead.tzh_ttisutcnt);
+	    int_fast64_t prevtr = -1;
+	    int_fast32_t prevcorr;
+	    int_fast32_t leapcnt = detzcode(up->tzhead.tzh_leapcnt);
+	    int_fast32_t timecnt = detzcode(up->tzhead.tzh_timecnt);
+	    int_fast32_t typecnt = detzcode(up->tzhead.tzh_typecnt);
+	    int_fast32_t charcnt = detzcode(up->tzhead.tzh_charcnt);
+	    char const *p = up->buf + tzheadsize;
+	    /* Although tzfile(5) currently requires typecnt to be nonzero,
+	       support future formats that may allow zero typecnt
+	       in files that have a TZ string and no transitions.  */
+	    if (! (0 <= leapcnt && leapcnt < TZ_MAX_LEAPS
+		   && 0 <= typecnt && typecnt < TZ_MAX_TYPES
+		   && 0 <= timecnt && timecnt < TZ_MAX_TIMES
+		   && 0 <= charcnt && charcnt < TZ_MAX_CHARS
+		   && 0 <= ttisstdcnt && ttisstdcnt < TZ_MAX_TYPES
+		   && 0 <= ttisutcnt && ttisutcnt < TZ_MAX_TYPES))
+	      return EINVAL;
+	    datablock_size
+		    = (timecnt * stored		/* ats */
+		       + timecnt		/* types */
+		       + typecnt * 6		/* ttinfos */
+		       + charcnt		/* chars */
+		       + leapcnt * (stored + 4)	/* lsinfos */
+		       + ttisstdcnt		/* ttisstds */
+		       + ttisutcnt);		/* ttisuts */
+	    if (nread < tzheadsize + datablock_size)
+	      return EINVAL;
+	    if (skip_datablock)
+		p += datablock_size;
+	    else {
+		if (! ((ttisstdcnt == typecnt || ttisstdcnt == 0)
+		       && (ttisutcnt == typecnt || ttisutcnt == 0)))
+		  return EINVAL;
+
+		sp->leapcnt = leapcnt;
+		sp->timecnt = timecnt;
+		sp->typecnt = typecnt;
+		sp->charcnt = charcnt;
+
+		/* Read transitions, discarding those out of time_t range.
+		   But pretend the last transition before TIME_T_MIN
+		   occurred at TIME_T_MIN.  */
+		timecnt = 0;
 		for (i = 0; i < sp->timecnt; ++i) {
-			sp->ats[i] = (stored == 4) ?
-				detzcode(p) : detzcode64(p);
+			int_fast64_t at
+			  = stored == 4 ? detzcode(p) : detzcode64(p);
+			sp->types[i] = at <= TIME_T_MAX;
+			if (sp->types[i]) {
+			  time_t attime
+			    = ((TYPE_SIGNED(time_t) ? at < TIME_T_MIN : at < 0)
+			       ? TIME_T_MIN : at);
+			  if (timecnt && attime <= sp->ats[timecnt - 1]) {
+			    if (attime < sp->ats[timecnt - 1])
+			      return EINVAL;
+			    sp->types[i - 1] = 0;
+			    timecnt--;
+			  }
+			  sp->ats[timecnt++] = attime;
+			}
 			p += stored;
 		}
+
+		timecnt = 0;
 		for (i = 0; i < sp->timecnt; ++i) {
-			sp->types[i] = (unsigned char) *p++;
-			if (sp->types[i] >= sp->typecnt)
-				return -1;
+			unsigned char typ = *p++;
+			if (sp->typecnt <= typ)
+			  return EINVAL;
+			if (sp->types[i])
+				sp->types[timecnt++] = typ;
 		}
+		sp->timecnt = timecnt;
 		for (i = 0; i < sp->typecnt; ++i) {
 			register struct ttinfo *	ttisp;
+			unsigned char isdst, desigidx;
 
 			ttisp = &sp->ttis[i];
-			ttisp->tt_gmtoff = detzcode(p);
+			ttisp->tt_utoff = detzcode(p);
 			p += 4;
-			ttisp->tt_isdst = (unsigned char) *p++;
-			if (ttisp->tt_isdst != 0 && ttisp->tt_isdst != 1)
-				return -1;
-			ttisp->tt_abbrind = (unsigned char) *p++;
-			if (ttisp->tt_abbrind < 0 ||
-				ttisp->tt_abbrind > sp->charcnt)
-					return -1;
+			isdst = *p++;
+			if (! (isdst < 2))
+			  return EINVAL;
+			ttisp->tt_isdst = isdst;
+			desigidx = *p++;
+			if (! (desigidx < sp->charcnt))
+			  return EINVAL;
+			ttisp->tt_desigidx = desigidx;
 		}
 		for (i = 0; i < sp->charcnt; ++i)
 			sp->chars[i] = *p++;
-		sp->chars[i] = '\0';	/* ensure '\0' at end */
-		for (i = 0; i < sp->leapcnt; ++i) {
-			register struct lsinfo *	lsisp;
+		/* Ensure '\0'-terminated, and make it safe to call
+		   ttunspecified later.  */
+		memset(&sp->chars[i], 0, CHARS_EXTRA);
 
-			lsisp = &sp->lsis[i];
-			lsisp->ls_trans = (stored == 4) ?
-				detzcode(p) : detzcode64(p);
-			p += stored;
-			lsisp->ls_corr = detzcode(p);
-			p += 4;
+		/* Read leap seconds, discarding those out of time_t range.  */
+		leapcnt = 0;
+		for (i = 0; i < sp->leapcnt; ++i) {
+		  int_fast64_t tr = stored == 4 ? detzcode(p) : detzcode64(p);
+		  int_fast32_t corr = detzcode(p + stored);
+		  p += stored + 4;
+
+		  /* Leap seconds cannot occur before the Epoch,
+		     or out of order.  */
+		  if (tr <= prevtr)
+		    return EINVAL;
+
+		  /* To avoid other botches in this code, each leap second's
+		     correction must differ from the previous one's by 1
+		     second or less, except that the first correction can be
+		     any value; these requirements are more generous than
+		     RFC 8536, to allow future RFC extensions.  */
+		  if (! (i == 0
+			 || (prevcorr < corr
+			     ? corr == prevcorr + 1
+			     : (corr == prevcorr
+				|| corr == prevcorr - 1))))
+		    return EINVAL;
+		  prevtr = tr;
+		  prevcorr = corr;
+
+		  if (tr <= TIME_T_MAX) {
+		    sp->lsis[leapcnt].ls_trans = tr;
+		    sp->lsis[leapcnt].ls_corr = corr;
+		    leapcnt++;
+		  }
 		}
+		sp->leapcnt = leapcnt;
+
 		for (i = 0; i < sp->typecnt; ++i) {
 			register struct ttinfo *	ttisp;
 
 			ttisp = &sp->ttis[i];
 			if (ttisstdcnt == 0)
-				ttisp->tt_ttisstd = FALSE;
+				ttisp->tt_ttisstd = false;
 			else {
+				if (*p != true && *p != false)
+				  return EINVAL;
 				ttisp->tt_ttisstd = *p++;
-				if (ttisp->tt_ttisstd != TRUE &&
-					ttisp->tt_ttisstd != FALSE)
-						return -1;
 			}
 		}
 		for (i = 0; i < sp->typecnt; ++i) {
 			register struct ttinfo *	ttisp;
 
 			ttisp = &sp->ttis[i];
-			if (ttisgmtcnt == 0)
-				ttisp->tt_ttisgmt = FALSE;
+			if (ttisutcnt == 0)
+				ttisp->tt_ttisut = false;
 			else {
-				ttisp->tt_ttisgmt = *p++;
-				if (ttisp->tt_ttisgmt != TRUE &&
-					ttisp->tt_ttisgmt != FALSE)
-						return -1;
+				if (*p != true && *p != false)
+						return EINVAL;
+				ttisp->tt_ttisut = *p++;
 			}
 		}
-		/*
-		** Out-of-sort ats should mean we're running on a
-		** signed time_t system but using a data file with
-		** unsigned values (or vice versa).
-		*/
-		for (i = 0; i < sp->timecnt - 2; ++i)
-			if (sp->ats[i] > sp->ats[i + 1]) {
-				++i;
-				if (TYPE_SIGNED(time_t)) {
-					/*
-					** Ignore the end (easy).
-					*/
-					sp->timecnt = i;
-				} else {
-					/*
-					** Ignore the beginning (harder).
-					*/
-					register int	j;
+	    }
 
-					for (j = 0; j + i < sp->timecnt; ++j) {
-						sp->ats[j] = sp->ats[j + i];
-						sp->types[j] = sp->types[j + i];
-					}
-					sp->timecnt = j;
-				}
-				break;
-			}
-		/*
-		** If this is an old file, we're done.
-		*/
-		if (u.tzhead.tzh_version[0] == '\0')
-			break;
-		nread -= p - u.buf;
-		for (i = 0; i < nread; ++i)
-			u.buf[i] = p[i];
-		/*
-		** If this is a narrow integer time_t system, we're done.
-		*/
-		if (stored >= (int) sizeof(time_t) && TYPE_INTEGRAL(time_t))
-			break;
+	    nread -= p - up->buf;
+	    memmove(up->buf, p, nread);
+
+	    /* If this is an old file, we're done.  */
+	    if (!version)
+	      break;
 	}
 	if (doextend && nread > 2 &&
-		u.buf[0] == '\n' && u.buf[nread - 1] == '\n' &&
+		up->buf[0] == '\n' && up->buf[nread - 1] == '\n' &&
 		sp->typecnt + 2 <= TZ_MAX_TYPES) {
-			struct state	ts;
-			register int	result;
-
-			u.buf[nread - 1] = '\0';
-			result = tzparse(&u.buf[1], &ts, FALSE);
-			if (result == 0 && ts.typecnt == 2 &&
-				sp->charcnt + ts.charcnt <= TZ_MAX_CHARS) {
-					for (i = 0; i < 2; ++i)
-						ts.ttis[i].tt_abbrind +=
-							sp->charcnt;
-					for (i = 0; i < ts.charcnt; ++i)
-						sp->chars[sp->charcnt++] =
-							ts.chars[i];
-					i = 0;
-					while (i < ts.timecnt &&
-						ts.ats[i] <=
-						sp->ats[sp->timecnt - 1])
-							++i;
-					while (i < ts.timecnt &&
-					    sp->timecnt < TZ_MAX_TIMES) {
-						sp->ats[sp->timecnt] =
-							ts.ats[i];
-						sp->types[sp->timecnt] =
-							sp->typecnt +
-							ts.types[i];
-						++sp->timecnt;
-						++i;
-					}
-					sp->ttis[sp->typecnt++] = ts.ttis[0];
-					sp->ttis[sp->typecnt++] = ts.ttis[1];
+			struct state	*ts = &lsp->u.st;
+
+			up->buf[nread - 1] = '\0';
+			if (tzparse(&up->buf[1], ts, sp)) {
+
+			  /* Attempt to reuse existing abbreviations.
+			     Without this, America/Anchorage would be right on
+			     the edge after 2037 when TZ_MAX_CHARS is 50, as
+			     sp->charcnt equals 40 (for LMT AST AWT APT AHST
+			     AHDT YST AKDT AKST) and ts->charcnt equals 10
+			     (for AKST AKDT).  Reusing means sp->charcnt can
+			     stay 40 in this example.  */
+			  int gotabbr = 0;
+			  int charcnt = sp->charcnt;
+			  for (i = 0; i < ts->typecnt; i++) {
+			    char *tsabbr = ts->chars + ts->ttis[i].tt_desigidx;
+			    int j;
+			    for (j = 0; j < charcnt; j++)
+			      if (strcmp(sp->chars + j, tsabbr) == 0) {
+				ts->ttis[i].tt_desigidx = j;
+				gotabbr++;
+				break;
+			      }
+			    if (! (j < charcnt)) {
+			      int tsabbrlen = strlen(tsabbr);
+			      if (j + tsabbrlen < TZ_MAX_CHARS) {
+				strcpy(sp->chars + j, tsabbr);
+				charcnt = j + tsabbrlen + 1;
+				ts->ttis[i].tt_desigidx = j;
+				gotabbr++;
+			      }
+			    }
+			  }
+			  if (gotabbr == ts->typecnt) {
+			    sp->charcnt = charcnt;
+
+			    /* Ignore any trailing, no-op transitions generated
+			       by zic as they don't help here and can run afoul
+			       of bugs in zic 2016j or earlier.  */
+			    while (1 < sp->timecnt
+				   && (sp->types[sp->timecnt - 1]
+				       == sp->types[sp->timecnt - 2]))
+			      sp->timecnt--;
+
+			    for (i = 0;
+				 i < ts->timecnt && sp->timecnt < TZ_MAX_TIMES;
+				 i++) {
+			      time_t t = ts->ats[i];
+			      if (increment_overflow_time(&t, leapcorr(sp, t))
+				  || (0 < sp->timecnt
+				      && t <= sp->ats[sp->timecnt - 1]))
+				continue;
+			      sp->ats[sp->timecnt] = t;
+			      sp->types[sp->timecnt] = (sp->typecnt
+							+ ts->types[i]);
+			      sp->timecnt++;
+			    }
+			    for (i = 0; i < ts->typecnt; i++)
+			      sp->ttis[sp->typecnt++] = ts->ttis[i];
+			  }
 			}
 	}
+	if (sp->typecnt == 0)
+	  return EINVAL;
 	if (sp->timecnt > 1) {
+	    if (sp->ats[0] <= TIME_T_MAX - SECSPERREPEAT) {
+		time_t repeatat = sp->ats[0] + SECSPERREPEAT;
+		int repeattype = sp->types[0];
 		for (i = 1; i < sp->timecnt; ++i)
-			if (typesequiv(sp, sp->types[i], sp->types[0]) &&
-				differ_by_repeat(sp->ats[i], sp->ats[0])) {
-					sp->goback = TRUE;
+		  if (sp->ats[i] == repeatat
+		      && typesequiv(sp, sp->types[i], repeattype)) {
+					sp->goback = true;
 					break;
-				}
+		  }
+	    }
+	    if (TIME_T_MIN + SECSPERREPEAT <= sp->ats[sp->timecnt - 1]) {
+		time_t repeatat = sp->ats[sp->timecnt - 1] - SECSPERREPEAT;
+		int repeattype = sp->types[sp->timecnt - 1];
 		for (i = sp->timecnt - 2; i >= 0; --i)
-			if (typesequiv(sp, sp->types[sp->timecnt - 1],
-				sp->types[i]) &&
-				differ_by_repeat(sp->ats[sp->timecnt - 1],
-				sp->ats[i])) {
-					sp->goahead = TRUE;
+		  if (sp->ats[i] == repeatat
+		      && typesequiv(sp, sp->types[i], repeattype)) {
+					sp->goahead = true;
 					break;
-		}
+		  }
+	    }
+	}
+
+	/* Infer sp->defaulttype from the data.  Although this default
+	   type is always zero for data from recent tzdb releases,
+	   things are trickier for data from tzdb 2018e or earlier.
+
+	   The first set of heuristics work around bugs in 32-bit data
+	   generated by tzdb 2013c or earlier.  The workaround is for
+	   zones like Australia/Macquarie where timestamps before the
+	   first transition have a time type that is not the earliest
+	   standard-time type.  See:
+	   https://mm.icann.org/pipermail/tz/2013-May/019368.html */
+	/*
+	** If type 0 does not specify local time, or is unused in transitions,
+	** it's the type to use for early times.
+	*/
+	for (i = 0; i < sp->timecnt; ++i)
+		if (sp->types[i] == 0)
+			break;
+	i = i < sp->timecnt && ! ttunspecified(sp, 0) ? -1 : 0;
+	/*
+	** Absent the above,
+	** if there are transition times
+	** and the first transition is to a daylight time
+	** find the standard type less than and closest to
+	** the type of the first transition.
+	*/
+	if (i < 0 && sp->timecnt > 0 && sp->ttis[sp->types[0]].tt_isdst) {
+		i = sp->types[0];
+		while (--i >= 0)
+			if (!sp->ttis[i].tt_isdst)
+				break;
 	}
+	/* The next heuristics are for data generated by tzdb 2018e or
+	   earlier, for zones like EST5EDT where the first transition
+	   is to DST.  */
+	/*
+	** If no result yet, find the first standard type.
+	** If there is none, punt to type zero.
+	*/
+	if (i < 0) {
+		i = 0;
+		while (sp->ttis[i].tt_isdst)
+			if (++i >= sp->typecnt) {
+				i = 0;
+				break;
+			}
+	}
+	/* A simple 'sp->defaulttype = 0;' would suffice here if we
+	   didn't have to worry about 2018e-or-earlier data.  Even
+	   simpler would be to remove the defaulttype member and just
+	   use 0 in its place.  */
+	sp->defaulttype = i;
+
 	return 0;
 }
 
+/* Load tz data from the file named NAME into *SP.  Read extended
+   format if DOEXTEND.  Return 0 on success, an errno value on failure.  */
 static int
-typesequiv(sp, a, b)
-const struct state * const	sp;
-const int			a;
-const int			b;
+tzload(char const *name, struct state *sp, bool doextend)
 {
-	register int	result;
+#ifdef ALL_STATE
+  union local_storage *lsp = malloc(sizeof *lsp);
+  if (!lsp) {
+    return HAVE_MALLOC_ERRNO ? errno : ENOMEM;
+  } else {
+    int err = tzloadbody(name, sp, doextend, lsp);
+    free(lsp);
+    return err;
+  }
+#else
+  union local_storage ls;
+  return tzloadbody(name, sp, doextend, &ls);
+#endif
+}
+
+static bool
+typesequiv(const struct state *sp, int a, int b)
+{
+	register bool result;
 
 	if (sp == NULL ||
 		a < 0 || a >= sp->typecnt ||
 		b < 0 || b >= sp->typecnt)
-			result = FALSE;
+			result = false;
 	else {
 		register const struct ttinfo *	ap = &sp->ttis[a];
 		register const struct ttinfo *	bp = &sp->ttis[b];
-		result = ap->tt_gmtoff == bp->tt_gmtoff &&
-			ap->tt_isdst == bp->tt_isdst &&
-			ap->tt_ttisstd == bp->tt_ttisstd &&
-			ap->tt_ttisgmt == bp->tt_ttisgmt &&
-			strcmp(&sp->chars[ap->tt_abbrind],
-			&sp->chars[bp->tt_abbrind]) == 0;
+		result = (ap->tt_utoff == bp->tt_utoff
+			  && ap->tt_isdst == bp->tt_isdst
+			  && ap->tt_ttisstd == bp->tt_ttisstd
+			  && ap->tt_ttisut == bp->tt_ttisut
+			  && (strcmp(&sp->chars[ap->tt_desigidx],
+				     &sp->chars[bp->tt_desigidx])
+			      == 0));
 	}
 	return result;
 }
 
 static const int	mon_lengths[2][MONSPERYEAR] = {
 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
 };
 
 static const int	year_lengths[2] = {
 	DAYSPERNYEAR, DAYSPERLYEAR
 };
 
+/* Is C an ASCII digit?  */
+static bool
+is_digit(char c)
+{
+  return '0' <= c && c <= '9';
+}
+
 /*
-** Given a pointer into a time zone string, scan until a character that is not
-** a valid character in a zone name is found. Return a pointer to that
-** character.
+** Given a pointer into a timezone string, scan until a character that is not
+** a valid character in a time zone abbreviation is found.
+** Return a pointer to that character.
 */
 
-static const char *
-getzname(strp)
-register const char *	strp;
+static ATTRIBUTE_PURE const char *
+getzname(register const char *strp)
 {
 	register char	c;
 
 	while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' &&
 		c != '+')
 			++strp;
 	return strp;
 }
 
 /*
-** Given a pointer into an extended time zone string, scan until the ending
-** delimiter of the zone name is located. Return a pointer to the delimiter.
+** Given a pointer into an extended timezone string, scan until the ending
+** delimiter of the time zone abbreviation is located.
+** Return a pointer to the delimiter.
 **
 ** As with getzname above, the legal character set is actually quite
 ** restricted, with other characters producing undefined results.
 ** We don't do any checking here; checking is done later in common-case code.
 */
 
-static const char *
+static ATTRIBUTE_PURE const char *
 getqzname(register const char *strp, const int delim)
 {
 	register int	c;
 
 	while ((c = *strp) != '\0' && c != delim)
 		++strp;
 	return strp;
 }
 
 /*
-** Given a pointer into a time zone string, extract a number from that string.
+** Given a pointer into a timezone string, extract a number from that string.
 ** Check that the number is within a specified range; if it is not, return
 ** NULL.
 ** Otherwise, return a pointer to the first character not part of the number.
 */
 
 static const char *
-getnum(strp, nump, min, max)
-register const char *	strp;
-int * const		nump;
-const int		min;
-const int		max;
+getnum(register const char *strp, int *const nump, const int min, const int max)
 {
 	register char	c;
 	register int	num;
 
 	if (strp == NULL || !is_digit(c = *strp))
 		return NULL;
 	num = 0;
 	do {
 		num = num * 10 + (c - '0');
 		if (num > max)
 			return NULL;	/* illegal value */
 		c = *++strp;
 	} while (is_digit(c));
 	if (num < min)
 		return NULL;		/* illegal value */
 	*nump = num;
 	return strp;
 }
 
 /*
-** Given a pointer into a time zone string, extract a number of seconds,
+** Given a pointer into a timezone string, extract a number of seconds,
 ** in hh[:mm[:ss]] form, from the string.
 ** If any error occurs, return NULL.
 ** Otherwise, return a pointer to the first character not part of the number
 ** of seconds.
 */
 
 static const char *
-getsecs(strp, secsp)
-register const char *	strp;
-long * const		secsp;
+getsecs(register const char *strp, int_fast32_t *const secsp)
 {
 	int	num;
+	int_fast32_t secsperhour = SECSPERHOUR;
 
 	/*
-	** `HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
+	** 'HOURSPERDAY * DAYSPERWEEK - 1' allows quasi-Posix rules like
 	** "M10.4.6/26", which does not conform to Posix,
 	** but which specifies the equivalent of
-	** ``02:00 on the first Sunday on or after 23 Oct''.
+	** "02:00 on the first Sunday on or after 23 Oct".
 	*/
 	strp = getnum(strp, &num, 0, HOURSPERDAY * DAYSPERWEEK - 1);
 	if (strp == NULL)
 		return NULL;
-	*secsp = num * (long) SECSPERHOUR;
+	*secsp = num * secsperhour;
 	if (*strp == ':') {
 		++strp;
 		strp = getnum(strp, &num, 0, MINSPERHOUR - 1);
 		if (strp == NULL)
 			return NULL;
 		*secsp += num * SECSPERMIN;
 		if (*strp == ':') {
 			++strp;
-			/* `SECSPERMIN' allows for leap seconds. */
+			/* 'SECSPERMIN' allows for leap seconds.  */
 			strp = getnum(strp, &num, 0, SECSPERMIN);
 			if (strp == NULL)
 				return NULL;
 			*secsp += num;
 		}
 	}
 	return strp;
 }
 
 /*
-** Given a pointer into a time zone string, extract an offset, in
+** Given a pointer into a timezone string, extract an offset, in
 ** [+-]hh[:mm[:ss]] form, from the string.
 ** If any error occurs, return NULL.
 ** Otherwise, return a pointer to the first character not part of the time.
 */
 
 static const char *
-getoffset(strp, offsetp)
-register const char *	strp;
-long * const		offsetp;
+getoffset(register const char *strp, int_fast32_t *const offsetp)
 {
-	register int	neg = 0;
+	register bool neg = false;
 
 	if (*strp == '-') {
-		neg = 1;
+		neg = true;
 		++strp;
 	} else if (*strp == '+')
 		++strp;
 	strp = getsecs(strp, offsetp);
 	if (strp == NULL)
 		return NULL;		/* illegal time */
 	if (neg)
 		*offsetp = -*offsetp;
 	return strp;
 }
 
 /*
-** Given a pointer into a time zone string, extract a rule in the form
+** Given a pointer into a timezone string, extract a rule in the form
 ** date[/time]. See POSIX section 8 for the format of "date" and "time".
 ** If a valid rule is not found, return NULL.
 ** Otherwise, return a pointer to the first character not part of the rule.
 */
 
 static const char *
-getrule(strp, rulep)
-const char *			strp;
-register struct rule * const	rulep;
+getrule(const char *strp, register struct rule *const rulep)
 {
 	if (*strp == 'J') {
 		/*
 		** Julian day.
 		*/
 		rulep->r_type = JULIAN_DAY;
 		++strp;
 		strp = getnum(strp, &rulep->r_day, 1, DAYSPERNYEAR);
 	} else if (*strp == 'M') {
 		/*
 		** Month, week, day.
 		*/
 		rulep->r_type = MONTH_NTH_DAY_OF_WEEK;
 		++strp;
 		strp = getnum(strp, &rulep->r_mon, 1, MONSPERYEAR);
 		if (strp == NULL)
 			return NULL;
 		if (*strp++ != '.')
 			return NULL;
 		strp = getnum(strp, &rulep->r_week, 1, 5);
 		if (strp == NULL)
 			return NULL;
 		if (*strp++ != '.')
 			return NULL;
 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1);
 	} else if (is_digit(*strp)) {
 		/*
 		** Day of year.
 		*/
 		rulep->r_type = DAY_OF_YEAR;
 		strp = getnum(strp, &rulep->r_day, 0, DAYSPERLYEAR - 1);
 	} else	return NULL;		/* invalid format */
 	if (strp == NULL)
 		return NULL;
 	if (*strp == '/') {
 		/*
 		** Time specified.
 		*/
 		++strp;
-		strp = getsecs(strp, &rulep->r_time);
+		strp = getoffset(strp, &rulep->r_time);
 	} else	rulep->r_time = 2 * SECSPERHOUR;	/* default = 2:00:00 */
 	return strp;
 }
 
 /*
-** Given the Epoch-relative time of January 1, 00:00:00 UTC, in a year, the
-** year, a rule, and the offset from UTC at the time that rule takes effect,
-** calculate the Epoch-relative time that rule takes effect.
+** Given a year, a rule, and the offset from UT at the time that rule takes
+** effect, calculate the year-relative time that rule takes effect.
 */
 
-static time_t
-transtime(janfirst, year, rulep, offset)
-const time_t				janfirst;
-const int				year;
-register const struct rule * const	rulep;
-const long				offset;
+static int_fast32_t
+transtime(const int year, register const struct rule *const rulep,
+	  const int_fast32_t offset)
 {
-	register int	leapyear;
-	register time_t	value;
+	register bool	leapyear;
+	register int_fast32_t value;
 	register int	i;
 	int		d, m1, yy0, yy1, yy2, dow;
 
-	INITIALIZE(value);
 	leapyear = isleap(year);
 	switch (rulep->r_type) {
 
 	case JULIAN_DAY:
 		/*
 		** Jn - Julian day, 1 == January 1, 60 == March 1 even in leap
 		** years.
 		** In non-leap years, or if the day number is 59 or less, just
 		** add SECSPERDAY times the day number-1 to the time of
 		** January 1, midnight, to get the day.
 		*/
-		value = janfirst + (rulep->r_day - 1) * SECSPERDAY;
+		value = (rulep->r_day - 1) * SECSPERDAY;
 		if (leapyear && rulep->r_day >= 60)
 			value += SECSPERDAY;
 		break;
 
 	case DAY_OF_YEAR:
 		/*
 		** n - day of year.
 		** Just add SECSPERDAY times the day number to the time of
 		** January 1, midnight, to get the day.
 		*/
-		value = janfirst + rulep->r_day * SECSPERDAY;
+		value = rulep->r_day * SECSPERDAY;
 		break;
 
 	case MONTH_NTH_DAY_OF_WEEK:
 		/*
 		** Mm.n.d - nth "dth day" of month m.
 		*/
-		value = janfirst;
-		for (i = 0; i < rulep->r_mon - 1; ++i)
-			value += mon_lengths[leapyear][i] * SECSPERDAY;
 
 		/*
 		** Use Zeller's Congruence to get day-of-week of first day of
 		** month.
 		*/
 		m1 = (rulep->r_mon + 9) % 12 + 1;
 		yy0 = (rulep->r_mon <= 2) ? (year - 1) : year;
 		yy1 = yy0 / 100;
 		yy2 = yy0 % 100;
 		dow = ((26 * m1 - 2) / 10 +
 			1 + yy2 + yy2 / 4 + yy1 / 4 - 2 * yy1) % 7;
 		if (dow < 0)
 			dow += DAYSPERWEEK;
 
 		/*
 		** "dow" is the day-of-week of the first day of the month. Get
 		** the day-of-month (zero-origin) of the first "dow" day of the
 		** month.
 		*/
 		d = rulep->r_day - dow;
 		if (d < 0)
 			d += DAYSPERWEEK;
 		for (i = 1; i < rulep->r_week; ++i) {
 			if (d + DAYSPERWEEK >=
 				mon_lengths[leapyear][rulep->r_mon - 1])
 					break;
 			d += DAYSPERWEEK;
 		}
 
 		/*
 		** "d" is the day-of-month (zero-origin) of the day we want.
 		*/
-		value += d * SECSPERDAY;
+		value = d * SECSPERDAY;
+		for (i = 0; i < rulep->r_mon - 1; ++i)
+			value += mon_lengths[leapyear][i] * SECSPERDAY;
 		break;
+
+	default: UNREACHABLE();
 	}
 
 	/*
-	** "value" is the Epoch-relative time of 00:00:00 UTC on the day in
-	** question. To get the Epoch-relative time of the specified local
+	** "value" is the year-relative time of 00:00:00 UT on the day in
+	** question. To get the year-relative time of the specified local
 	** time on that day, add the transition time and the current offset
-	** from UTC.
+	** from UT.
 	*/
 	return value + rulep->r_time + offset;
 }
 
 /*
 ** Given a POSIX section 8-style TZ string, fill in the rule tables as
 ** appropriate.
 */
 
-static int
-tzparse(name, sp, lastditch)
-const char *			name;
-register struct state * const	sp;
-const int			lastditch;
+static bool
+tzparse(const char *name, struct state *sp, struct state *basep)
 {
 	const char *			stdname;
 	const char *			dstname;
 	size_t				stdlen;
 	size_t				dstlen;
-	long				stdoffset;
-	long				dstoffset;
-	register time_t *		atp;
-	register unsigned char *	typep;
+	size_t				charcnt;
+	int_fast32_t			stdoffset;
+	int_fast32_t			dstoffset;
 	register char *			cp;
-	register int			load_result;
-	static struct ttinfo		zttinfo;
+	register bool			load_ok;
+	time_t atlo = TIME_T_MIN, leaplo = TIME_T_MIN;
 
-	INITIALIZE(dstname);
 	stdname = name;
-	if (lastditch) {
-		stdlen = strlen(name);	/* length of standard zone name */
-		name += stdlen;
-		if (stdlen >= sizeof sp->chars)
-			stdlen = (sizeof sp->chars) - 1;
-		stdoffset = 0;
+	if (*name == '<') {
+	  name++;
+	  stdname = name;
+	  name = getqzname(name, '>');
+	  if (*name != '>')
+	    return false;
+	  stdlen = name - stdname;
+	  name++;
 	} else {
-		if (*name == '<') {
-			name++;
-			stdname = name;
-			name = getqzname(name, '>');
-			if (*name != '>')
-				return (-1);
-			stdlen = name - stdname;
-			name++;
-		} else {
-			name = getzname(name);
-			stdlen = name - stdname;
-		}
-		if (*name == '\0')
-			return -1;
-		name = getoffset(name, &stdoffset);
-		if (name == NULL)
-			return -1;
+	  name = getzname(name);
+	  stdlen = name - stdname;
+	}
+	if (!stdlen)
+	  return false;
+	name = getoffset(name, &stdoffset);
+	if (name == NULL)
+	  return false;
+	charcnt = stdlen + 1;
+	if (sizeof sp->chars < charcnt)
+	  return false;
+	if (basep) {
+	  if (0 < basep->timecnt)
+	    atlo = basep->ats[basep->timecnt - 1];
+	  load_ok = false;
+	  sp->leapcnt = basep->leapcnt;
+	  memcpy(sp->lsis, basep->lsis, sp->leapcnt * sizeof *sp->lsis);
+	} else {
+	  load_ok = tzload(TZDEFRULES, sp, false) == 0;
+	  if (!load_ok)
+	    sp->leapcnt = 0;	/* So, we're off a little.  */
 	}
-	load_result = tzload(TZDEFRULES, sp, FALSE);
-	if (load_result != 0)
-		sp->leapcnt = 0;		/* so, we're off a little */
+	if (0 < sp->leapcnt)
+	  leaplo = sp->lsis[sp->leapcnt - 1].ls_trans;
 	if (*name != '\0') {
 		if (*name == '<') {
 			dstname = ++name;
 			name = getqzname(name, '>');
 			if (*name != '>')
-				return -1;
+			  return false;
 			dstlen = name - dstname;
 			name++;
 		} else {
 			dstname = name;
 			name = getzname(name);
-			dstlen = name - dstname; /* length of DST zone name */
+			dstlen = name - dstname; /* length of DST abbr. */
 		}
+		if (!dstlen)
+		  return false;
+		charcnt += dstlen + 1;
+		if (sizeof sp->chars < charcnt)
+		  return false;
 		if (*name != '\0' && *name != ',' && *name != ';') {
 			name = getoffset(name, &dstoffset);
 			if (name == NULL)
-				return -1;
+			  return false;
 		} else	dstoffset = stdoffset - SECSPERHOUR;
-		if (*name == '\0' && load_result != 0)
+		if (*name == '\0' && !load_ok)
 			name = TZDEFRULESTRING;
 		if (*name == ',' || *name == ';') {
 			struct rule	start;
 			struct rule	end;
 			register int	year;
-			register time_t	janfirst;
-			time_t		starttime;
-			time_t		endtime;
+			register int	timecnt;
+			time_t		janfirst;
+			int_fast32_t janoffset = 0;
+			int yearbeg, yearlim;
 
 			++name;
 			if ((name = getrule(name, &start)) == NULL)
-				return -1;
+			  return false;
 			if (*name++ != ',')
-				return -1;
+			  return false;
 			if ((name = getrule(name, &end)) == NULL)
-				return -1;
+			  return false;
 			if (*name != '\0')
-				return -1;
+			  return false;
 			sp->typecnt = 2;	/* standard time and DST */
 			/*
 			** Two transitions per year, from EPOCH_YEAR forward.
 			*/
-			sp->ttis[0] = sp->ttis[1] = zttinfo;
-			sp->ttis[0].tt_gmtoff = -dstoffset;
-			sp->ttis[0].tt_isdst = 1;
-			sp->ttis[0].tt_abbrind = stdlen + 1;
-			sp->ttis[1].tt_gmtoff = -stdoffset;
-			sp->ttis[1].tt_isdst = 0;
-			sp->ttis[1].tt_abbrind = 0;
-			atp = sp->ats;
-			typep = sp->types;
+			init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
+			init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
+			sp->defaulttype = 0;
+			timecnt = 0;
 			janfirst = 0;
-			sp->timecnt = 0;
-			for (year = EPOCH_YEAR;
-			    sp->timecnt + 2 <= TZ_MAX_TIMES;
-			    ++year) {
-			    	time_t	newfirst;
-
-				starttime = transtime(janfirst, year, &start,
-					stdoffset);
-				endtime = transtime(janfirst, year, &end,
-					dstoffset);
-				if (starttime > endtime) {
-					*atp++ = endtime;
-					*typep++ = 1;	/* DST ends */
-					*atp++ = starttime;
-					*typep++ = 0;	/* DST begins */
-				} else {
-					*atp++ = starttime;
-					*typep++ = 0;	/* DST begins */
-					*atp++ = endtime;
-					*typep++ = 1;	/* DST ends */
+			yearbeg = EPOCH_YEAR;
+
+			do {
+			  int_fast32_t yearsecs
+			    = year_lengths[isleap(yearbeg - 1)] * SECSPERDAY;
+			  yearbeg--;
+			  if (increment_overflow_time(&janfirst, -yearsecs)) {
+			    janoffset = -yearsecs;
+			    break;
+			  }
+			} while (atlo < janfirst
+				 && EPOCH_YEAR - YEARSPERREPEAT / 2 < yearbeg);
+
+			while (true) {
+			  int_fast32_t yearsecs
+			    = year_lengths[isleap(yearbeg)] * SECSPERDAY;
+			  int yearbeg1 = yearbeg;
+			  time_t janfirst1 = janfirst;
+			  if (increment_overflow_time(&janfirst1, yearsecs)
+			      || increment_overflow(&yearbeg1, 1)
+			      || atlo <= janfirst1)
+			    break;
+			  yearbeg = yearbeg1;
+			  janfirst = janfirst1;
+			}
+
+			yearlim = yearbeg;
+			if (increment_overflow(&yearlim, YEARSPERREPEAT + 1))
+			  yearlim = INT_MAX;
+			for (year = yearbeg; year < yearlim; year++) {
+				int_fast32_t
+				  starttime = transtime(year, &start, stdoffset),
+				  endtime = transtime(year, &end, dstoffset);
+				int_fast32_t
+				  yearsecs = (year_lengths[isleap(year)]
+					      * SECSPERDAY);
+				bool reversed = endtime < starttime;
+				if (reversed) {
+					int_fast32_t swap = starttime;
+					starttime = endtime;
+					endtime = swap;
+				}
+				if (reversed
+				    || (starttime < endtime
+					&& endtime - starttime < yearsecs)) {
+					if (TZ_MAX_TIMES - 2 < timecnt)
+						break;
+					sp->ats[timecnt] = janfirst;
+					if (! increment_overflow_time
+					    (&sp->ats[timecnt],
+					     janoffset + starttime)
+					    && atlo <= sp->ats[timecnt])
+					  sp->types[timecnt++] = !reversed;
+					sp->ats[timecnt] = janfirst;
+					if (! increment_overflow_time
+					    (&sp->ats[timecnt],
+					     janoffset + endtime)
+					    && atlo <= sp->ats[timecnt]) {
+					  sp->types[timecnt++] = reversed;
+					}
 				}
-				sp->timecnt += 2;
-				newfirst = janfirst;
-				newfirst += year_lengths[isleap(year)] *
-					SECSPERDAY;
-				if (newfirst <= janfirst)
+				if (endtime < leaplo) {
+				  yearlim = year;
+				  if (increment_overflow(&yearlim,
+							 YEARSPERREPEAT + 1))
+				    yearlim = INT_MAX;
+				}
+				if (increment_overflow_time
+				    (&janfirst, janoffset + yearsecs))
 					break;
-				janfirst = newfirst;
+				janoffset = 0;
 			}
+			sp->timecnt = timecnt;
+			if (! timecnt) {
+				sp->ttis[0] = sp->ttis[1];
+				sp->typecnt = 1;	/* Perpetual DST.  */
+			} else if (YEARSPERREPEAT < year - yearbeg)
+				sp->goback = sp->goahead = true;
 		} else {
-			register long	theirstdoffset;
-			register long	theirdstoffset;
-			register long	theiroffset;
-			register int	isdst;
-			register int	i;
-			register int	j;
+			register int_fast32_t	theirstdoffset;
+			register int_fast32_t	theirdstoffset;
+			register int_fast32_t	theiroffset;
+			register bool		isdst;
+			register int		i;
+			register int		j;
 
 			if (*name != '\0')
-				return -1;
+			  return false;
 			/*
 			** Initial values of theirstdoffset and theirdstoffset.
 			*/
 			theirstdoffset = 0;
 			for (i = 0; i < sp->timecnt; ++i) {
 				j = sp->types[i];
 				if (!sp->ttis[j].tt_isdst) {
 					theirstdoffset =
-						-sp->ttis[j].tt_gmtoff;
+						- sp->ttis[j].tt_utoff;
 					break;
 				}
 			}
 			theirdstoffset = 0;
 			for (i = 0; i < sp->timecnt; ++i) {
 				j = sp->types[i];
 				if (sp->ttis[j].tt_isdst) {
 					theirdstoffset =
-						-sp->ttis[j].tt_gmtoff;
+						- sp->ttis[j].tt_utoff;
 					break;
 				}
 			}
 			/*
 			** Initially we're assumed to be in standard time.
 			*/
-			isdst = FALSE;
-			theiroffset = theirstdoffset;
+			isdst = false;
 			/*
 			** Now juggle transition times and types
 			** tracking offsets as you do.
 			*/
 			for (i = 0; i < sp->timecnt; ++i) {
 				j = sp->types[i];
 				sp->types[i] = sp->ttis[j].tt_isdst;
-				if (sp->ttis[j].tt_ttisgmt) {
+				if (sp->ttis[j].tt_ttisut) {
 					/* No adjustment to transition time */
 				} else {
 					/*
-					** If summer time is in effect, and the
-					** transition time was not specified as
-					** standard time, add the summer time
-					** offset to the transition time;
-					** otherwise, add the standard time
-					** offset to the transition time.
+					** If daylight saving time is in
+					** effect, and the transition time was
+					** not specified as standard time, add
+					** the daylight saving time offset to
+					** the transition time; otherwise, add
+					** the standard time offset to the
+					** transition time.
 					*/
 					/*
 					** Transitions from DST to DDST
 					** will effectively disappear since
 					** POSIX provides for only one DST
 					** offset.
 					*/
 					if (isdst && !sp->ttis[j].tt_ttisstd) {
 						sp->ats[i] += dstoffset -
 							theirdstoffset;
 					} else {
 						sp->ats[i] += stdoffset -
 							theirstdoffset;
 					}
 				}
-				theiroffset = -sp->ttis[j].tt_gmtoff;
+				theiroffset = -sp->ttis[j].tt_utoff;
 				if (sp->ttis[j].tt_isdst)
 					theirdstoffset = theiroffset;
 				else	theirstdoffset = theiroffset;
 			}
 			/*
 			** Finally, fill in ttis.
 			*/
-			sp->ttis[0] = sp->ttis[1] = zttinfo;
-			sp->ttis[0].tt_gmtoff = -stdoffset;
-			sp->ttis[0].tt_isdst = FALSE;
-			sp->ttis[0].tt_abbrind = 0;
-			sp->ttis[1].tt_gmtoff = -dstoffset;
-			sp->ttis[1].tt_isdst = TRUE;
-			sp->ttis[1].tt_abbrind = stdlen + 1;
+			init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
+			init_ttinfo(&sp->ttis[1], -dstoffset, true, stdlen + 1);
 			sp->typecnt = 2;
+			sp->defaulttype = 0;
 		}
 	} else {
 		dstlen = 0;
 		sp->typecnt = 1;		/* only standard time */
 		sp->timecnt = 0;
-		sp->ttis[0] = zttinfo;
-		sp->ttis[0].tt_gmtoff = -stdoffset;
-		sp->ttis[0].tt_isdst = 0;
-		sp->ttis[0].tt_abbrind = 0;
+		init_ttinfo(&sp->ttis[0], -stdoffset, false, 0);
+		sp->defaulttype = 0;
 	}
-	sp->charcnt = stdlen + 1;
-	if (dstlen != 0)
-		sp->charcnt += dstlen + 1;
-	if ((size_t) sp->charcnt > sizeof sp->chars)
-		return -1;
+	sp->charcnt = charcnt;
 	cp = sp->chars;
-	(void) strncpy(cp, stdname, stdlen);
+	memcpy(cp, stdname, stdlen);
 	cp += stdlen;
 	*cp++ = '\0';
 	if (dstlen != 0) {
-		(void) strncpy(cp, dstname, dstlen);
+		memcpy(cp, dstname, dstlen);
 		*(cp + dstlen) = '\0';
 	}
-	return 0;
+	return true;
 }
 
 static void
-gmtload(sp)
-struct state * const	sp;
+gmtload(struct state *const sp)
 {
-	if (tzload(gmt, sp, TRUE) != 0)
-		(void) tzparse(gmt, sp, TRUE);
+	if (tzload(etc_utc, sp, true) != 0)
+	  tzparse("UTC0", sp, NULL);
 }
 
-#ifndef STD_INSPIRED
-/*
-** A non-static declaration of tzsetwall in a system header file
-** may cause a warning about this upcoming static declaration...
-*/
-static
-#endif /* !defined STD_INSPIRED */
-void
-tzsetwall(void)
+/* Initialize *SP to a value appropriate for the TZ setting NAME.
+   Return 0 on success, an errno value on failure.  */
+static int
+zoneinit(struct state *sp, char const *name)
 {
-	if (lcl_is_set < 0)
-		return;
-	lcl_is_set = -1;
+  if (name && ! name[0]) {
+    /*
+    ** User wants it fast rather than right.
+    */
+    sp->leapcnt = 0;		/* so, we're off a little */
+    sp->timecnt = 0;
+    sp->typecnt = 0;
+    sp->charcnt = 0;
+    sp->goback = sp->goahead = false;
+    init_ttinfo(&sp->ttis[0], 0, false, 0);
+    strcpy(sp->chars, utc);
+    sp->defaulttype = 0;
+    return 0;
+  } else {
+    int err = tzload(name, sp, true);
+    if (err != 0 && name && name[0] != ':' && tzparse(name, sp, NULL))
+      err = 0;
+    if (err == 0)
+      scrub_abbrs(sp);
+    return err;
+  }
+}
 
+static void
+tzset_unlocked(void)
+{
+  char const *name = getenv("TZ");
+  struct state *sp = lclptr;
+  int lcl = name ? strlen(name) < sizeof lcl_TZname : -1;
+  if (lcl < 0
+      ? lcl_is_set < 0
+      : 0 < lcl_is_set && strcmp(lcl_TZname, name) == 0)
+    return;
 #ifdef ALL_STATE
-	if (lclptr == NULL) {
-		lclptr = (struct state *) calloc(1, sizeof *lclptr);
-		if (lclptr == NULL) {
-			settzname();	/* all we can do */
-			return;
-		}
-	}
+  if (! sp)
+    lclptr = sp = malloc(sizeof *lclptr);
 #endif /* defined ALL_STATE */
-	if (tzload((char *) NULL, lclptr, TRUE) != 0)
-		gmtload(lclptr);
-	settzname();
+  if (sp) {
+    if (zoneinit(sp, name) != 0)
+      zoneinit(sp, "");
+    if (0 < lcl)
+      strcpy(lcl_TZname, name);
+  }
+  settzname();
+  lcl_is_set = lcl;
 }
 
 void
 tzset(void)
 {
-	register const char *	name;
+  if (lock() != 0)
+    return;
+  tzset_unlocked();
+  unlock();
+}
 
-	name = getenv("TZ");
-	if (name == NULL) {
-		tzsetwall();
-		return;
-	}
+static void
+gmtcheck(void)
+{
+  static bool gmt_is_set;
+  if (lock() != 0)
+    return;
+  if (! gmt_is_set) {
+#ifdef ALL_STATE
+    gmtptr = malloc(sizeof *gmtptr);
+#endif
+    if (gmtptr)
+      gmtload(gmtptr);
+    gmt_is_set = true;
+  }
+  unlock();
+}
 
-	if (lcl_is_set > 0 && strcmp(lcl_TZname, name) == 0)
-		return;
-	lcl_is_set = strlen(name) < sizeof lcl_TZname;
-	if (lcl_is_set)
-		(void) strcpy(lcl_TZname, name);
+#if NETBSD_INSPIRED
 
-#ifdef ALL_STATE
-	if (lclptr == NULL) {
-		lclptr = (struct state *) calloc(1, sizeof *lclptr);
-		if (lclptr == NULL) {
-			settzname();	/* all we can do */
-			return;
-		}
-	}
-#endif /* defined ALL_STATE */
-	if (*name == '\0') {
-		/*
-		** User wants it fast rather than right.
-		*/
-		lclptr->leapcnt = 0;		/* so, we're off a little */
-		lclptr->timecnt = 0;
-		lclptr->typecnt = 0;
-		lclptr->ttis[0].tt_isdst = 0;
-		lclptr->ttis[0].tt_gmtoff = 0;
-		lclptr->ttis[0].tt_abbrind = 0;
-		(void) strcpy(lclptr->chars, gmt);
-	} else if (tzload(name, lclptr, TRUE) != 0)
-		if (name[0] == ':' || tzparse(name, lclptr, FALSE) != 0)
-			(void) gmtload(lclptr);
-	settzname();
+timezone_t
+tzalloc(char const *name)
+{
+  timezone_t sp = malloc(sizeof *sp);
+  if (sp) {
+    int err = zoneinit(sp, name);
+    if (err != 0) {
+      free(sp);
+      errno = err;
+      return NULL;
+    }
+  } else if (!HAVE_MALLOC_ERRNO)
+    errno = ENOMEM;
+  return sp;
+}
+
+void
+tzfree(timezone_t sp)
+{
+  free(sp);
 }
 
+/*
+** NetBSD 6.1.4 has ctime_rz, but omit it because POSIX says ctime and
+** ctime_r are obsolescent and have potential security problems that
+** ctime_rz would share.  Callers can instead use localtime_rz + strftime.
+**
+** NetBSD 6.1.4 has tzgetname, but omit it because it doesn't work
+** in zones with three or more time zone abbreviations.
+** Callers can instead use localtime_rz + strftime.
+*/
+
+#endif
+
 /*
 ** The easy way to behave "as if no library function calls" localtime
-** is to not call it--so we drop its guts into "localsub", which can be
-** freely called. (And no, the PANS doesn't require the above behavior--
+** is to not call it, so we drop its guts into "localsub", which can be
+** freely called. (And no, the PANS doesn't require the above behavior,
 ** but it *is* desirable.)
 **
-** The unused offset argument is for the benefit of mktime variants.
+** If successful and SETNAME is nonzero,
+** set the applicable parts of tzname, timezone and altzone;
+** however, it's OK to omit this step if the timezone is POSIX-compatible,
+** since in that case tzset should have already done this step correctly.
+** SETNAME's type is int_fast32_t for compatibility with gmtsub,
+** but it is actually a boolean and its value should be 0 or 1.
 */
 
 /*ARGSUSED*/
 static struct tm *
-localsub(timep, offset, tmp)
-const time_t * const	timep;
-const long		offset;
-struct tm * const	tmp;
+localsub(struct state const *sp, time_t const *timep, int_fast32_t setname,
+	 struct tm *const tmp)
 {
-	register struct state *		sp;
 	register const struct ttinfo *	ttisp;
 	register int			i;
 	register struct tm *		result;
 	const time_t			t = *timep;
 
-	sp = lclptr;
-#ifdef ALL_STATE
-	if (sp == NULL)
-		return gmtsub(timep, offset, tmp);
-#endif /* defined ALL_STATE */
+	if (sp == NULL) {
+	  /* Don't bother to set tzname etc.; tzset has already done it.  */
+	  return gmtsub(gmtptr, timep, 0, tmp);
+	}
 	if ((sp->goback && t < sp->ats[0]) ||
 		(sp->goahead && t > sp->ats[sp->timecnt - 1])) {
-			time_t			newt = t;
+			time_t newt;
 			register time_t		seconds;
-			register time_t		tcycles;
-			register int_fast64_t	icycles;
+			register time_t		years;
 
 			if (t < sp->ats[0])
 				seconds = sp->ats[0] - t;
 			else	seconds = t - sp->ats[sp->timecnt - 1];
 			--seconds;
-			tcycles = seconds / YEARSPERREPEAT / AVGSECSPERYEAR;
-			++tcycles;
-			icycles = tcycles;
-			if (tcycles - icycles >= 1 || icycles - tcycles >= 1)
-				return NULL;
-			seconds = icycles;
-			seconds *= YEARSPERREPEAT;
-			seconds *= AVGSECSPERYEAR;
+
+			/* Beware integer overflow, as SECONDS might
+			   be close to the maximum time_t.  */
+			years = seconds / SECSPERREPEAT * YEARSPERREPEAT;
+			seconds = years * AVGSECSPERYEAR;
+			years += YEARSPERREPEAT;
 			if (t < sp->ats[0])
-				newt += seconds;
-			else	newt -= seconds;
+			  newt = t + seconds + SECSPERREPEAT;
+			else
+			  newt = t - seconds - SECSPERREPEAT;
+
 			if (newt < sp->ats[0] ||
 				newt > sp->ats[sp->timecnt - 1])
 					return NULL;	/* "cannot happen" */
-			result = localsub(&newt, offset, tmp);
-			if (result == tmp) {
-				register time_t	newy;
+			result = localsub(sp, &newt, setname, tmp);
+			if (result) {
+				register int_fast64_t newy;
 
-				newy = tmp->tm_year;
+				newy = result->tm_year;
 				if (t < sp->ats[0])
-					newy -= icycles * YEARSPERREPEAT;
-				else	newy += icycles * YEARSPERREPEAT;
-				tmp->tm_year = newy;
-				if (tmp->tm_year != newy)
+					newy -= years;
+				else	newy += years;
+				if (! (INT_MIN <= newy && newy <= INT_MAX))
 					return NULL;
+				result->tm_year = newy;
 			}
 			return result;
 	}
 	if (sp->timecnt == 0 || t < sp->ats[0]) {
-		i = 0;
-		while (sp->ttis[i].tt_isdst)
-			if (++i >= sp->typecnt) {
-				i = 0;
-				break;
-			}
+		i = sp->defaulttype;
 	} else {
 		register int	lo = 1;
 		register int	hi = sp->timecnt;
 
 		while (lo < hi) {
 			register int	mid = (lo + hi) >> 1;
 
 			if (t < sp->ats[mid])
 				hi = mid;
 			else	lo = mid + 1;
 		}
-		i = (int) sp->types[lo - 1];
+		i = sp->types[lo - 1];
 	}
 	ttisp = &sp->ttis[i];
 	/*
 	** To get (wrong) behavior that's compatible with System V Release 2.0
 	** you'd replace the statement below with
-	**	t += ttisp->tt_gmtoff;
+	**	t += ttisp->tt_utoff;
 	**	timesub(&t, 0L, sp, tmp);
 	*/
-	result = timesub(&t, ttisp->tt_gmtoff, sp, tmp);
-	tmp->tm_isdst = ttisp->tt_isdst;
-	tzname[tmp->tm_isdst] = &sp->chars[ttisp->tt_abbrind];
+	result = timesub(&t, ttisp->tt_utoff, sp, tmp);
+	if (result) {
+	  result->tm_isdst = ttisp->tt_isdst;
 #ifdef TM_ZONE
-	tmp->TM_ZONE = &sp->chars[ttisp->tt_abbrind];
+	  result->TM_ZONE = (char *) &sp->chars[ttisp->tt_desigidx];
 #endif /* defined TM_ZONE */
+	  if (setname)
+	    update_tzname_etc(sp, ttisp);
+	}
 	return result;
 }
 
+#if NETBSD_INSPIRED
+
 struct tm *
-localtime(timep)
-const time_t * const	timep;
+localtime_rz(struct state *sp, time_t const *timep, struct tm *tmp)
 {
-	tzset();
-	return localsub(timep, 0L, &tm);
+  return localsub(sp, timep, 0, tmp);
 }
 
-/*
-** Re-entrant version of localtime.
-*/
+#endif
+
+static struct tm *
+localtime_tzset(time_t const *timep, struct tm *tmp, bool setname)
+{
+  int err = lock();
+  if (err) {
+    errno = err;
+    return NULL;
+  }
+  if (setname || !lcl_is_set)
+    tzset_unlocked();
+  tmp = localsub(lclptr, timep, setname, tmp);
+  unlock();
+  return tmp;
+}
+
+struct tm *
+localtime(const time_t *timep)
+{
+  return localtime_tzset(timep, &tm, true);
+}
 
 struct tm *
-localtime_r(timep, tmp)
-const time_t * const	timep;
-struct tm *		tmp;
+localtime_r(const time_t *timep, struct tm *tmp)
 {
-	return localsub(timep, 0L, tmp);
+  return localtime_tzset(timep, tmp, false);
 }
 
 /*
 ** gmtsub is to gmtime as localsub is to localtime.
 */
 
 static struct tm *
-gmtsub(timep, offset, tmp)
-const time_t * const	timep;
-const long		offset;
-struct tm * const	tmp;
+gmtsub(struct state const *sp, time_t const *timep, int_fast32_t offset,
+       struct tm *tmp)
 {
 	register struct tm *	result;
 
-	if (!gmt_is_set) {
-		gmt_is_set = TRUE;
-#ifdef ALL_STATE
-		gmtptr = (struct state *) calloc(1, sizeof *gmtptr);
-		if (gmtptr != NULL)
-#endif /* defined ALL_STATE */
-			gmtload(gmtptr);
-	}
 	result = timesub(timep, offset, gmtptr, tmp);
 #ifdef TM_ZONE
 	/*
 	** Could get fancy here and deliver something such as
-	** "UTC+xxxx" or "UTC-xxxx" if offset is non-zero,
+	** "+xx" or "-xx" if offset is non-zero,
 	** but this is no time for a treasure hunt.
 	*/
-	if (offset != 0)
-		tmp->TM_ZONE = wildabbr;
-	else {
-#ifdef ALL_STATE
-		if (gmtptr == NULL)
-			tmp->TM_ZONE = gmt;
-		else	tmp->TM_ZONE = gmtptr->chars;
-#endif /* defined ALL_STATE */
-#ifndef ALL_STATE
-		tmp->TM_ZONE = gmtptr->chars;
-#endif /* State Farm */
-	}
+	tmp->TM_ZONE = ((char *)
+			(offset ? wildabbr : gmtptr ? gmtptr->chars : utc));
 #endif /* defined TM_ZONE */
 	return result;
 }
 
-struct tm *
-gmtime(timep)
-const time_t * const	timep;
-{
-	return gmtsub(timep, 0L, &tm);
-}
-
 /*
 * Re-entrant version of gmtime.
 */
 
 struct tm *
-gmtime_r(timep, tmp)
-const time_t * const	timep;
-struct tm *		tmp;
+gmtime_r(const time_t *timep, struct tm *tmp)
 {
-	return gmtsub(timep, 0L, tmp);
+  gmtcheck();
+  return gmtsub(gmtptr, timep, 0, tmp);
+}
+
+struct tm *
+gmtime(const time_t *timep)
+{
+  return gmtime_r(timep, &tm);
 }
 
 #ifdef STD_INSPIRED
 
 struct tm *
-offtime(timep, offset)
-const time_t * const	timep;
-const long		offset;
+offtime(const time_t *timep, long offset)
 {
-	return gmtsub(timep, offset, &tm);
+  gmtcheck();
+  return gmtsub(gmtptr, timep, offset, &tm);
 }
 
 #endif /* defined STD_INSPIRED */
 
 /*
 ** Return the number of leap years through the end of the given year
 ** where, to make the math easy, the answer for year zero is defined as zero.
 */
 
-static int
-leaps_thru_end_of(y)
-register const int	y;
+static time_t
+leaps_thru_end_of_nonneg(time_t y)
+{
+  return y / 4 - y / 100 + y / 400;
+}
+
+static time_t
+leaps_thru_end_of(time_t y)
 {
-	return (y >= 0) ? (y / 4 - y / 100 + y / 400) :
-		-(leaps_thru_end_of(-(y + 1)) + 1);
+  return (y < 0
+	  ? -1 - leaps_thru_end_of_nonneg(-1 - y)
+	  : leaps_thru_end_of_nonneg(y));
 }
 
 static struct tm *
-timesub(timep, offset, sp, tmp)
-const time_t * const			timep;
-const long				offset;
-register const struct state * const	sp;
-register struct tm * const		tmp;
+timesub(const time_t *timep, int_fast32_t offset,
+	const struct state *sp, struct tm *tmp)
 {
 	register const struct lsinfo *	lp;
 	register time_t			tdays;
-	register int			idays;	/* unsigned would be so 2003 */
-	register long			rem;
-	int				y;
 	register const int *		ip;
-	register long			corr;
-	register int			hit;
+	register int_fast32_t		corr;
 	register int			i;
+	int_fast32_t idays, rem, dayoff, dayrem;
+	time_t y;
+
+	/* If less than SECSPERMIN, the number of seconds since the
+	   most recent positive leap second; otherwise, do not add 1
+	   to localtime tm_sec because of leap seconds.  */
+	time_t secs_since_posleap = SECSPERMIN;
 
 	corr = 0;
-	hit = 0;
-#ifdef ALL_STATE
 	i = (sp == NULL) ? 0 : sp->leapcnt;
-#endif /* defined ALL_STATE */
-#ifndef ALL_STATE
-	i = sp->leapcnt;
-#endif /* State Farm */
 	while (--i >= 0) {
 		lp = &sp->lsis[i];
 		if (*timep >= lp->ls_trans) {
-			if (*timep == lp->ls_trans) {
-				hit = ((i == 0 && lp->ls_corr > 0) ||
-					lp->ls_corr > sp->lsis[i - 1].ls_corr);
-				if (hit)
-					while (i > 0 &&
-						sp->lsis[i].ls_trans ==
-						sp->lsis[i - 1].ls_trans + 1 &&
-						sp->lsis[i].ls_corr ==
-						sp->lsis[i - 1].ls_corr + 1) {
-							++hit;
-							--i;
-					}
-			}
 			corr = lp->ls_corr;
+			if ((i == 0 ? 0 : lp[-1].ls_corr) < corr)
+			  secs_since_posleap = *timep - lp->ls_trans;
 			break;
 		}
 	}
-	y = EPOCH_YEAR;
+
+	/* Calculate the year, avoiding integer overflow even if
+	   time_t is unsigned.  */
 	tdays = *timep / SECSPERDAY;
-	rem = *timep - tdays * SECSPERDAY;
-	while (tdays < 0 || tdays >= year_lengths[isleap(y)]) {
-		int		newy;
-		register time_t	tdelta;
-		register int	idelta;
+	rem = *timep % SECSPERDAY;
+	rem += offset % SECSPERDAY - corr % SECSPERDAY + 3 * SECSPERDAY;
+	dayoff = offset / SECSPERDAY - corr / SECSPERDAY + rem / SECSPERDAY - 3;
+	rem %= SECSPERDAY;
+	/* y = (EPOCH_YEAR
+	        + floor((tdays + dayoff) / DAYSPERREPEAT) * YEARSPERREPEAT),
+	   sans overflow.  But calculate against 1570 (EPOCH_YEAR -
+	   YEARSPERREPEAT) instead of against 1970 so that things work
+	   for localtime values before 1970 when time_t is unsigned.  */
+	dayrem = tdays % DAYSPERREPEAT;
+	dayrem += dayoff % DAYSPERREPEAT;
+	y = (EPOCH_YEAR - YEARSPERREPEAT
+	     + ((1 + dayoff / DAYSPERREPEAT + dayrem / DAYSPERREPEAT
+		 - ((dayrem % DAYSPERREPEAT) < 0)
+		 + tdays / DAYSPERREPEAT)
+		* YEARSPERREPEAT));
+	/* idays = (tdays + dayoff) mod DAYSPERREPEAT, sans overflow.  */
+	idays = tdays % DAYSPERREPEAT;
+	idays += dayoff % DAYSPERREPEAT + 2 * DAYSPERREPEAT;
+	idays %= DAYSPERREPEAT;
+	/* Increase Y and decrease IDAYS until IDAYS is in range for Y.  */
+	while (year_lengths[isleap(y)] <= idays) {
+		int tdelta = idays / DAYSPERLYEAR;
+		int_fast32_t ydelta = tdelta + !tdelta;
+		time_t newy = y + ydelta;
 		register int	leapdays;
-
-		tdelta = tdays / DAYSPERLYEAR;
-		idelta = tdelta;
-		if (tdelta - idelta >= 1 || idelta - tdelta >= 1)
-			return NULL;
-		if (idelta == 0)
-			idelta = (tdays < 0) ? -1 : 1;
-		newy = y;
-		if (increment_overflow(&newy, idelta))
-			return NULL;
 		leapdays = leaps_thru_end_of(newy - 1) -
 			leaps_thru_end_of(y - 1);
-		tdays -= ((time_t) newy - y) * DAYSPERNYEAR;
-		tdays -= leapdays;
+		idays -= ydelta * DAYSPERNYEAR;
+		idays -= leapdays;
 		y = newy;
 	}
-	{
-		register long	seconds;
 
-		seconds = tdays * SECSPERDAY + 0.5;
-		tdays = seconds / SECSPERDAY;
-		rem += seconds - tdays * SECSPERDAY;
-	}
-	/*
-	** Given the range, we can now fearlessly cast...
-	*/
-	idays = tdays;
-	rem += offset - corr;
-	while (rem < 0) {
-		rem += SECSPERDAY;
-		--idays;
-	}
-	while (rem >= SECSPERDAY) {
-		rem -= SECSPERDAY;
-		++idays;
-	}
-	while (idays < 0) {
-		if (increment_overflow(&y, -1))
-			return NULL;
-		idays += year_lengths[isleap(y)];
-	}
-	while (idays >= year_lengths[isleap(y)]) {
-		idays -= year_lengths[isleap(y)];
-		if (increment_overflow(&y, 1))
-			return NULL;
+	if (!TYPE_SIGNED(time_t) && y < TM_YEAR_BASE) {
+	  int signed_y = y;
+	  tmp->tm_year = signed_y - TM_YEAR_BASE;
+	} else if ((!TYPE_SIGNED(time_t) || INT_MIN + TM_YEAR_BASE <= y)
+		   && y - TM_YEAR_BASE <= INT_MAX)
+	  tmp->tm_year = y - TM_YEAR_BASE;
+	else {
+	  errno = EOVERFLOW;
+	  return NULL;
 	}
-	tmp->tm_year = y;
-	if (increment_overflow(&tmp->tm_year, -TM_YEAR_BASE))
-		return NULL;
 	tmp->tm_yday = idays;
 	/*
 	** The "extra" mods below avoid overflow problems.
 	*/
-	tmp->tm_wday = EPOCH_WDAY +
-		((y - EPOCH_YEAR) % DAYSPERWEEK) *
-		(DAYSPERNYEAR % DAYSPERWEEK) +
-		leaps_thru_end_of(y - 1) -
-		leaps_thru_end_of(EPOCH_YEAR - 1) +
-		idays;
+	tmp->tm_wday = (TM_WDAY_BASE
+			+ ((tmp->tm_year % DAYSPERWEEK)
+			   * (DAYSPERNYEAR % DAYSPERWEEK))
+			+ leaps_thru_end_of(y - 1)
+			- leaps_thru_end_of(TM_YEAR_BASE - 1)
+			+ idays);
 	tmp->tm_wday %= DAYSPERWEEK;
 	if (tmp->tm_wday < 0)
 		tmp->tm_wday += DAYSPERWEEK;
-	tmp->tm_hour = (int) (rem / SECSPERHOUR);
+	tmp->tm_hour = rem / SECSPERHOUR;
 	rem %= SECSPERHOUR;
-	tmp->tm_min = (int) (rem / SECSPERMIN);
-	/*
-	** A positive leap second requires a special
-	** representation. This uses "... ??:59:60" et seq.
-	*/
-	tmp->tm_sec = (int) (rem % SECSPERMIN) + hit;
+	tmp->tm_min = rem / SECSPERMIN;
+	tmp->tm_sec = rem % SECSPERMIN;
+
+	/* Use "... ??:??:60" at the end of the localtime minute containing
+	   the second just before the positive leap second.  */
+	tmp->tm_sec += secs_since_posleap <= tmp->tm_sec;
+
 	ip = mon_lengths[isleap(y)];
 	for (tmp->tm_mon = 0; idays >= ip[tmp->tm_mon]; ++(tmp->tm_mon))
 		idays -= ip[tmp->tm_mon];
-	tmp->tm_mday = (int) (idays + 1);
+	tmp->tm_mday = idays + 1;
 	tmp->tm_isdst = 0;
 #ifdef TM_GMTOFF
 	tmp->TM_GMTOFF = offset;
 #endif /* defined TM_GMTOFF */
 	return tmp;
 }
 
 char *
-ctime(timep)
-const time_t * const	timep;
+ctime(const time_t *timep)
 {
 /*
 ** Section 4.12.3.2 of X3.159-1989 requires that
 **	The ctime function converts the calendar time pointed to by timer
 **	to local time in the form of a string. It is equivalent to
 **		asctime(localtime(timer))
 */
-	return asctime(localtime(timep));
+  struct tm *tmp = localtime(timep);
+  return tmp ? asctime(tmp) : NULL;
 }
 
 char *
-ctime_r(timep, buf)
-const time_t * const	timep;
-char *			buf;
+ctime_r(const time_t *timep, char *buf)
 {
-	struct tm	mytm;
-
-	return asctime_r(localtime_r(timep, &mytm), buf);
+  struct tm mytm;
+  struct tm *tmp = localtime_r(timep, &mytm);
+  return tmp ? asctime_r(tmp, buf) : NULL;
 }
 
 /*
 ** Adapted from code provided by Robert Elz, who writes:
 **	The "best" way to do mktime I think is based on an idea of Bob
 **	Kridle's (so its said...) from a long time ago.
 **	It does a binary search of the time_t space. Since time_t's are
 **	just 32 bits, its a max of 32 iterations (even at 64 bits it
 **	would still be very reasonable).
 */
 
 #ifndef WRONG
-#define WRONG	(-1)
+# define WRONG (-1)
 #endif /* !defined WRONG */
 
 /*
-** Simplified normalize logic courtesy Paul Eggert.
+** Normalize logic courtesy Paul Eggert.
 */
 
-static int
-increment_overflow(number, delta)
-int *	number;
-int	delta;
+static bool
+increment_overflow(int *ip, int j)
 {
-	int	number0;
+	register int const	i = *ip;
 
-	number0 = *number;
-	*number += delta;
-	return (*number < number0) != (delta < 0);
+	/*
+	** If i >= 0 there can only be overflow if i + j > INT_MAX
+	** or if j > INT_MAX - i; given i >= 0, INT_MAX - i cannot overflow.
+	** If i < 0 there can only be overflow if i + j < INT_MIN
+	** or if j < INT_MIN - i; given i < 0, INT_MIN - i cannot overflow.
+	*/
+	if ((i >= 0) ? (j > INT_MAX - i) : (j < INT_MIN - i))
+		return true;
+	*ip += j;
+	return false;
 }
 
-static int
-long_increment_overflow(number, delta)
-long *	number;
-int	delta;
+static bool
+increment_overflow32(int_fast32_t *const lp, int const m)
 {
-	long	number0;
+	register int_fast32_t const	l = *lp;
 
-	number0 = *number;
-	*number += delta;
-	return (*number < number0) != (delta < 0);
+	if ((l >= 0) ? (m > INT_FAST32_MAX - l) : (m < INT_FAST32_MIN - l))
+		return true;
+	*lp += m;
+	return false;
 }
 
-static int
-normalize_overflow(tensptr, unitsptr, base)
-int * const	tensptr;
-int * const	unitsptr;
-const int	base;
+static bool
+increment_overflow_time(time_t *tp, int_fast32_t j)
+{
+	/*
+	** This is like
+	** 'if (! (TIME_T_MIN <= *tp + j && *tp + j <= TIME_T_MAX)) ...',
+	** except that it does the right thing even if *tp + j would overflow.
+	*/
+	if (! (j < 0
+	       ? (TYPE_SIGNED(time_t) ? TIME_T_MIN - j <= *tp : -1 - j < *tp)
+	       : *tp <= TIME_T_MAX - j))
+		return true;
+	*tp += j;
+	return false;
+}
+
+static bool
+normalize_overflow(int *const tensptr, int *const unitsptr, const int base)
 {
 	register int	tensdelta;
 
 	tensdelta = (*unitsptr >= 0) ?
 		(*unitsptr / base) :
 		(-1 - (-1 - *unitsptr) / base);
 	*unitsptr -= tensdelta * base;
 	return increment_overflow(tensptr, tensdelta);
 }
 
-static int
-long_normalize_overflow(tensptr, unitsptr, base)
-long * const	tensptr;
-int * const	unitsptr;
-const int	base;
+static bool
+normalize_overflow32(int_fast32_t *tensptr, int *unitsptr, int base)
 {
 	register int	tensdelta;
 
 	tensdelta = (*unitsptr >= 0) ?
 		(*unitsptr / base) :
 		(-1 - (-1 - *unitsptr) / base);
 	*unitsptr -= tensdelta * base;
-	return long_increment_overflow(tensptr, tensdelta);
+	return increment_overflow32(tensptr, tensdelta);
 }
 
 static int
-tmcomp(atmp, btmp)
-register const struct tm * const atmp;
-register const struct tm * const btmp;
+tmcomp(register const struct tm *const atmp,
+       register const struct tm *const btmp)
 {
 	register int	result;
 
-	if ((result = (atmp->tm_year - btmp->tm_year)) == 0 &&
-		(result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
+	if (atmp->tm_year != btmp->tm_year)
+		return atmp->tm_year < btmp->tm_year ? -1 : 1;
+	if ((result = (atmp->tm_mon - btmp->tm_mon)) == 0 &&
 		(result = (atmp->tm_mday - btmp->tm_mday)) == 0 &&
 		(result = (atmp->tm_hour - btmp->tm_hour)) == 0 &&
 		(result = (atmp->tm_min - btmp->tm_min)) == 0)
 			result = atmp->tm_sec - btmp->tm_sec;
 	return result;
 }
 
 static time_t
-time2sub(tmp, funcp, offset, okayp, do_norm_secs)
-struct tm * const	tmp;
-struct tm * (* const	funcp)(const time_t*, long, struct tm*);
-const long		offset;
-int * const		okayp;
-const int		do_norm_secs;
+time2sub(struct tm *const tmp,
+	 struct tm *(*funcp)(struct state const *, time_t const *,
+			     int_fast32_t, struct tm *),
+	 struct state const *sp,
+	 const int_fast32_t offset,
+	 bool *okayp,
+	 bool do_norm_secs)
 {
-	register const struct state *	sp;
 	register int			dir;
 	register int			i, j;
 	register int			saved_seconds;
-	register long			li;
+	register int_fast32_t		li;
 	register time_t			lo;
 	register time_t			hi;
-	long				y;
+	int_fast32_t			y;
 	time_t				newt;
 	time_t				t;
 	struct tm			yourtm, mytm;
 
-	*okayp = FALSE;
+	*okayp = false;
 	yourtm = *tmp;
 	if (do_norm_secs) {
 		if (normalize_overflow(&yourtm.tm_min, &yourtm.tm_sec,
 			SECSPERMIN))
 				return WRONG;
 	}
 	if (normalize_overflow(&yourtm.tm_hour, &yourtm.tm_min, MINSPERHOUR))
 		return WRONG;
 	if (normalize_overflow(&yourtm.tm_mday, &yourtm.tm_hour, HOURSPERDAY))
 		return WRONG;
 	y = yourtm.tm_year;
-	if (long_normalize_overflow(&y, &yourtm.tm_mon, MONSPERYEAR))
+	if (normalize_overflow32(&y, &yourtm.tm_mon, MONSPERYEAR))
 		return WRONG;
 	/*
 	** Turn y into an actual year number for now.
 	** It is converted back to an offset from TM_YEAR_BASE later.
 	*/
-	if (long_increment_overflow(&y, TM_YEAR_BASE))
+	if (increment_overflow32(&y, TM_YEAR_BASE))
 		return WRONG;
 	while (yourtm.tm_mday <= 0) {
-		if (long_increment_overflow(&y, -1))
+		if (increment_overflow32(&y, -1))
 			return WRONG;
 		li = y + (1 < yourtm.tm_mon);
 		yourtm.tm_mday += year_lengths[isleap(li)];
 	}
 	while (yourtm.tm_mday > DAYSPERLYEAR) {
 		li = y + (1 < yourtm.tm_mon);
 		yourtm.tm_mday -= year_lengths[isleap(li)];
-		if (long_increment_overflow(&y, 1))
+		if (increment_overflow32(&y, 1))
 			return WRONG;
 	}
 	for ( ; ; ) {
 		i = mon_lengths[isleap(y)][yourtm.tm_mon];
 		if (yourtm.tm_mday <= i)
 			break;
 		yourtm.tm_mday -= i;
 		if (++yourtm.tm_mon >= MONSPERYEAR) {
 			yourtm.tm_mon = 0;
-			if (long_increment_overflow(&y, 1))
+			if (increment_overflow32(&y, 1))
 				return WRONG;
 		}
 	}
-	if (long_increment_overflow(&y, -TM_YEAR_BASE))
+	if (increment_overflow32(&y, -TM_YEAR_BASE))
 		return WRONG;
-	yourtm.tm_year = y;
-	if (yourtm.tm_year != y)
+	if (! (INT_MIN <= y && y <= INT_MAX))
 		return WRONG;
+	yourtm.tm_year = y;
 	if (yourtm.tm_sec >= 0 && yourtm.tm_sec < SECSPERMIN)
 		saved_seconds = 0;
 	else if (y + TM_YEAR_BASE < EPOCH_YEAR) {
 		/*
 		** We can't set tm_sec to 0, because that might push the
 		** time below the minimum representable time.
 		** Set tm_sec to 59 instead.
 		** This assumes that the minimum representable time is
 		** not in the same minute that a leap second was deleted from,
 		** which is a safer assumption than using 58 would be.
 		*/
 		if (increment_overflow(&yourtm.tm_sec, 1 - SECSPERMIN))
 			return WRONG;
 		saved_seconds = yourtm.tm_sec;
 		yourtm.tm_sec = SECSPERMIN - 1;
 	} else {
 		saved_seconds = yourtm.tm_sec;
 		yourtm.tm_sec = 0;
 	}
 	/*
 	** Do a binary search (this works whatever time_t's type is).
 	*/
-	if (!TYPE_SIGNED(time_t)) {
-		lo = 0;
-		hi = lo - 1;
-	} else if (!TYPE_INTEGRAL(time_t)) {
-		if (sizeof(time_t) > sizeof(float))
-			hi = (time_t) DBL_MAX;
-		else	hi = (time_t) FLT_MAX;
-		lo = -hi;
-	} else {
-		lo = 1;
-		for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i)
-			lo *= 2;
-		hi = -(lo + 1);
-	}
+	lo = TIME_T_MIN;
+	hi = TIME_T_MAX;
 	for ( ; ; ) {
 		t = lo / 2 + hi / 2;
 		if (t < lo)
 			t = lo;
 		else if (t > hi)
 			t = hi;
-		if ((*funcp)(&t, offset, &mytm) == NULL) {
+		if (! funcp(sp, &t, offset, &mytm)) {
 			/*
 			** Assume that t is too extreme to be represented in
 			** a struct tm; arrange things so that it is less
 			** extreme on the next pass.
 			*/
 			dir = (t > 0) ? 1 : -1;
 		} else	dir = tmcomp(&mytm, &yourtm);
 		if (dir != 0) {
 			if (t == lo) {
-				++t;
-				if (t <= lo)
+				if (t == TIME_T_MAX)
 					return WRONG;
+				++t;
 				++lo;
 			} else if (t == hi) {
-				--t;
-				if (t >= hi)
+				if (t == TIME_T_MIN)
 					return WRONG;
+				--t;
 				--hi;
 			}
 			if (lo > hi)
 				return WRONG;
 			if (dir > 0)
 				hi = t;
 			else	lo = t;
 			continue;
 		}
+#if defined TM_GMTOFF && ! UNINIT_TRAP
+		if (mytm.TM_GMTOFF != yourtm.TM_GMTOFF
+		    && (yourtm.TM_GMTOFF < 0
+			? (-SECSPERDAY <= yourtm.TM_GMTOFF
+			   && (mytm.TM_GMTOFF <=
+			       (min(INT_FAST32_MAX, LONG_MAX)
+				+ yourtm.TM_GMTOFF)))
+			: (yourtm.TM_GMTOFF <= SECSPERDAY
+			   && ((max(INT_FAST32_MIN, LONG_MIN)
+				+ yourtm.TM_GMTOFF)
+			       <= mytm.TM_GMTOFF)))) {
+		  /* MYTM matches YOURTM except with the wrong UT offset.
+		     YOURTM.TM_GMTOFF is plausible, so try it instead.
+		     It's OK if YOURTM.TM_GMTOFF contains uninitialized data,
+		     since the guess gets checked.  */
+		  time_t altt = t;
+		  int_fast32_t diff = mytm.TM_GMTOFF - yourtm.TM_GMTOFF;
+		  if (!increment_overflow_time(&altt, diff)) {
+		    struct tm alttm;
+		    if (funcp(sp, &altt, offset, &alttm)
+			&& alttm.tm_isdst == mytm.tm_isdst
+			&& alttm.TM_GMTOFF == yourtm.TM_GMTOFF
+			&& tmcomp(&alttm, &yourtm) == 0) {
+		      t = altt;
+		      mytm = alttm;
+		    }
+		  }
+		}
+#endif
 		if (yourtm.tm_isdst < 0 || mytm.tm_isdst == yourtm.tm_isdst)
 			break;
 		/*
 		** Right time, wrong type.
 		** Hunt for right time, right type.
 		** It's okay to guess wrong since the guess
 		** gets checked.
 		*/
-		sp = (const struct state *)
-			((funcp == localsub) ? lclptr : gmtptr);
-#ifdef ALL_STATE
 		if (sp == NULL)
 			return WRONG;
-#endif /* defined ALL_STATE */
 		for (i = sp->typecnt - 1; i >= 0; --i) {
 			if (sp->ttis[i].tt_isdst != yourtm.tm_isdst)
 				continue;
 			for (j = sp->typecnt - 1; j >= 0; --j) {
 				if (sp->ttis[j].tt_isdst == yourtm.tm_isdst)
 					continue;
-				newt = t + sp->ttis[j].tt_gmtoff -
-					sp->ttis[i].tt_gmtoff;
-				if ((*funcp)(&newt, offset, &mytm) == NULL)
+				if (ttunspecified(sp, j))
+				  continue;
+				newt = (t + sp->ttis[j].tt_utoff
+					- sp->ttis[i].tt_utoff);
+				if (! funcp(sp, &newt, offset, &mytm))
 					continue;
 				if (tmcomp(&mytm, &yourtm) != 0)
 					continue;
 				if (mytm.tm_isdst != yourtm.tm_isdst)
 					continue;
 				/*
 				** We have a match.
 				*/
 				t = newt;
 				goto label;
 			}
 		}
 		return WRONG;
 	}
 label:
 	newt = t + saved_seconds;
 	if ((newt < t) != (saved_seconds < 0))
 		return WRONG;
 	t = newt;
-	if ((*funcp)(&t, offset, tmp))
-		*okayp = TRUE;
+	if (funcp(sp, &t, offset, tmp))
+		*okayp = true;
 	return t;
 }
 
 static time_t
-time2(tmp, funcp, offset, okayp)
-struct tm * const	tmp;
-struct tm * (* const	funcp)(const time_t*, long, struct tm*);
-const long		offset;
-int * const		okayp;
+time2(struct tm * const	tmp,
+      struct tm *(*funcp)(struct state const *, time_t const *,
+			  int_fast32_t, struct tm *),
+      struct state const *sp,
+      const int_fast32_t offset,
+      bool *okayp)
 {
 	time_t	t;
 
 	/*
 	** First try without normalization of seconds
 	** (in case tm_sec contains a value associated with a leap second).
 	** If that fails, try with normalization of seconds.
 	*/
-	t = time2sub(tmp, funcp, offset, okayp, FALSE);
-	return *okayp ? t : time2sub(tmp, funcp, offset, okayp, TRUE);
+	t = time2sub(tmp, funcp, sp, offset, okayp, false);
+	return *okayp ? t : time2sub(tmp, funcp, sp, offset, okayp, true);
 }
 
 static time_t
-time1(tmp, funcp, offset)
-struct tm * const	tmp;
-struct tm * (* const	funcp)(const time_t *, long, struct tm *);
-const long		offset;
+time1(struct tm *const tmp,
+      struct tm *(*funcp)(struct state const *, time_t const *,
+			  int_fast32_t, struct tm *),
+      struct state const *sp,
+      const int_fast32_t offset)
 {
 	register time_t			t;
-	register const struct state *	sp;
 	register int			samei, otheri;
 	register int			sameind, otherind;
 	register int			i;
 	register int			nseen;
-	int				seen[TZ_MAX_TYPES];
-	int				types[TZ_MAX_TYPES];
-	int				okay;
+	char				seen[TZ_MAX_TYPES];
+	unsigned char			types[TZ_MAX_TYPES];
+	bool				okay;
 
 	if (tmp == NULL) {
 		errno = EINVAL;
 		return WRONG;
 	}
 	if (tmp->tm_isdst > 1)
 		tmp->tm_isdst = 1;
-	t = time2(tmp, funcp, offset, &okay);
-#ifdef PCTS
-	/*
-	** PCTS code courtesy Grant Sullivan.
-	*/
+	t = time2(tmp, funcp, sp, offset, &okay);
 	if (okay)
 		return t;
 	if (tmp->tm_isdst < 0)
+#ifdef PCTS
+		/*
+		** POSIX Conformance Test Suite code courtesy Grant Sullivan.
+		*/
 		tmp->tm_isdst = 0;	/* reset to std and try again */
-#endif /* defined PCTS */
-#ifndef PCTS
-	if (okay || tmp->tm_isdst < 0)
+#else
 		return t;
 #endif /* !defined PCTS */
 	/*
 	** We're supposed to assume that somebody took a time of one type
 	** and did some math on it that yielded a "struct tm" that's bad.
 	** We try to divine the type they started from and adjust to the
 	** type they need.
 	*/
-	sp = (const struct state *) ((funcp == localsub) ?  lclptr : gmtptr);
-#ifdef ALL_STATE
 	if (sp == NULL)
 		return WRONG;
-#endif /* defined ALL_STATE */
 	for (i = 0; i < sp->typecnt; ++i)
-		seen[i] = FALSE;
+		seen[i] = false;
 	nseen = 0;
 	for (i = sp->timecnt - 1; i >= 0; --i)
-		if (!seen[sp->types[i]]) {
-			seen[sp->types[i]] = TRUE;
+		if (!seen[sp->types[i]] && !ttunspecified(sp, sp->types[i])) {
+			seen[sp->types[i]] = true;
 			types[nseen++] = sp->types[i];
 		}
 	for (sameind = 0; sameind < nseen; ++sameind) {
 		samei = types[sameind];
 		if (sp->ttis[samei].tt_isdst != tmp->tm_isdst)
 			continue;
 		for (otherind = 0; otherind < nseen; ++otherind) {
 			otheri = types[otherind];
 			if (sp->ttis[otheri].tt_isdst == tmp->tm_isdst)
 				continue;
-			tmp->tm_sec += sp->ttis[otheri].tt_gmtoff -
-					sp->ttis[samei].tt_gmtoff;
+			tmp->tm_sec += (sp->ttis[otheri].tt_utoff
+					- sp->ttis[samei].tt_utoff);
 			tmp->tm_isdst = !tmp->tm_isdst;
-			t = time2(tmp, funcp, offset, &okay);
+			t = time2(tmp, funcp, sp, offset, &okay);
 			if (okay)
 				return t;
-			tmp->tm_sec -= sp->ttis[otheri].tt_gmtoff -
-					sp->ttis[samei].tt_gmtoff;
+			tmp->tm_sec -= (sp->ttis[otheri].tt_utoff
+					- sp->ttis[samei].tt_utoff);
 			tmp->tm_isdst = !tmp->tm_isdst;
 		}
 	}
 	return WRONG;
 }
 
+static time_t
+mktime_tzname(struct state *sp, struct tm *tmp, bool setname)
+{
+  if (sp)
+    return time1(tmp, localsub, sp, setname);
+  else {
+    gmtcheck();
+    return time1(tmp, gmtsub, gmtptr, 0);
+  }
+}
+
+#if NETBSD_INSPIRED
+
 time_t
-mktime(tmp)
-struct tm * const	tmp;
+mktime_z(struct state *sp, struct tm *tmp)
 {
-	tzset();
-	return time1(tmp, localsub, 0L);
+  return mktime_tzname(sp, tmp, false);
+}
+
+#endif
+
+time_t
+mktime(struct tm *tmp)
+{
+  time_t t;
+  int err = lock();
+  if (err) {
+    errno = err;
+    return -1;
+  }
+  tzset_unlocked();
+  t = mktime_tzname(lclptr, tmp, true);
+  unlock();
+  return t;
 }
 
 #ifdef STD_INSPIRED
 
 time_t
-timelocal(tmp)
-struct tm * const	tmp;
+timelocal(struct tm *tmp)
 {
 	if (tmp != NULL)
 		tmp->tm_isdst = -1;	/* in case it wasn't initialized */
 	return mktime(tmp);
 }
 
 time_t
-timegm(tmp)
-struct tm * const	tmp;
+timegm(struct tm *tmp)
 {
-	if (tmp != NULL)
-		tmp->tm_isdst = 0;
-	return time1(tmp, gmtsub, 0L);
+  return timeoff(tmp, 0);
 }
 
 time_t
-timeoff(tmp, offset)
-struct tm * const	tmp;
-const long		offset;
+timeoff(struct tm *tmp, long offset)
 {
-	if (tmp != NULL)
-		tmp->tm_isdst = 0;
-	return time1(tmp, gmtsub, offset);
+  if (tmp)
+    tmp->tm_isdst = 0;
+  gmtcheck();
+  return time1(tmp, gmtsub, gmtptr, offset);
 }
 
 #endif /* defined STD_INSPIRED */
 
-#ifdef CMUCS
-
-/*
-** The following is supplied for compatibility with
-** previous versions of the CMUCS runtime library.
-*/
-
-long
-gtime(tmp)
-struct tm * const	tmp;
+static int_fast32_t
+leapcorr(struct state const *sp, time_t t)
 {
-	const time_t	t = mktime(tmp);
+	register struct lsinfo const *	lp;
+	register int			i;
 
-	if (t == WRONG)
-		return -1;
-	return t;
+	i = sp->leapcnt;
+	while (--i >= 0) {
+		lp = &sp->lsis[i];
+		if (t >= lp->ls_trans)
+			return lp->ls_corr;
+	}
+	return 0;
 }
 
-#endif /* defined CMUCS */
-
 /*
 ** XXX--is the below the right way to conditionalize??
 */
 
 #ifdef STD_INSPIRED
 
+/* NETBSD_INSPIRED_EXTERN functions are exported to callers if
+   NETBSD_INSPIRED is defined, and are private otherwise.  */
+# if NETBSD_INSPIRED
+#  define NETBSD_INSPIRED_EXTERN
+# else
+#  define NETBSD_INSPIRED_EXTERN static
+# endif
+
 /*
-** IEEE Std 1003.1-1988 (POSIX) legislates that 536457599
+** IEEE Std 1003.1 (POSIX) says that 536457599
 ** shall correspond to "Wed Dec 31 23:59:59 UTC 1986", which
 ** is not the case if we are accounting for leap seconds.
 ** So, we provide the following conversion routines for use
 ** when exchanging timestamps with POSIX conforming systems.
 */
 
-static long
-leapcorr(timep)
-time_t *	timep;
+NETBSD_INSPIRED_EXTERN time_t
+time2posix_z(struct state *sp, time_t t)
 {
-	register struct state *		sp;
-	register struct lsinfo *	lp;
-	register int			i;
-
-	sp = lclptr;
-	i = sp->leapcnt;
-	while (--i >= 0) {
-		lp = &sp->lsis[i];
-		if (*timep >= lp->ls_trans)
-			return lp->ls_corr;
-	}
-	return 0;
+  return t - leapcorr(sp, t);
 }
 
 time_t
-time2posix(t)
-time_t	t;
+time2posix(time_t t)
 {
-	tzset();
-	return t - leapcorr(&t);
+  int err = lock();
+  if (err) {
+    errno = err;
+    return -1;
+  }
+  if (!lcl_is_set)
+    tzset_unlocked();
+  if (lclptr)
+    t = time2posix_z(lclptr, t);
+  unlock();
+  return t;
 }
 
-time_t
-posix2time(t)
-time_t	t;
+NETBSD_INSPIRED_EXTERN time_t
+posix2time_z(struct state *sp, time_t t)
 {
 	time_t	x;
 	time_t	y;
-
-	tzset();
 	/*
 	** For a positive leap second hit, the result
 	** is not unique. For a negative leap second
 	** hit, the corresponding time doesn't exist,
 	** so we return an adjacent second.
 	*/
-	x = t + leapcorr(&t);
-	y = x - leapcorr(&x);
+	x = t + leapcorr(sp, t);
+	y = x - leapcorr(sp, x);
 	if (y < t) {
 		do {
 			x++;
-			y = x - leapcorr(&x);
+			y = x - leapcorr(sp, x);
 		} while (y < t);
-		if (t != y)
-			return x - 1;
+		x -= y != t;
 	} else if (y > t) {
 		do {
 			--x;
-			y = x - leapcorr(&x);
+			y = x - leapcorr(sp, x);
 		} while (y > t);
-		if (t != y)
-			return x + 1;
+		x += y != t;
 	}
 	return x;
 }
 
+time_t
+posix2time(time_t t)
+{
+  int err = lock();
+  if (err) {
+    errno = err;
+    return -1;
+  }
+  if (!lcl_is_set)
+    tzset_unlocked();
+  if (lclptr)
+    t = posix2time_z(lclptr, t);
+  unlock();
+  return t;
+}
+
 #endif /* defined STD_INSPIRED */
+
+#if TZ_TIME_T
+
+# if !USG_COMPAT
+#  define daylight 0
+#  define timezone 0
+# endif
+# if !ALTZONE
+#  define altzone 0
+# endif
+
+/* Convert from the underlying system's time_t to the ersatz time_tz,
+   which is called 'time_t' in this file.  Typically, this merely
+   converts the time's integer width.  On some platforms, the system
+   time is local time not UT, or uses some epoch other than the POSIX
+   epoch.
+
+   Although this code appears to define a function named 'time' that
+   returns time_t, the macros in private.h cause this code to actually
+   define a function named 'tz_time' that returns tz_time_t.  The call
+   to sys_time invokes the underlying system's 'time' function.  */
+
+time_t
+time(time_t *p)
+{
+  time_t r = sys_time(0);
+  if (r != (time_t) -1) {
+    int_fast32_t offset = EPOCH_LOCAL ? (daylight ? timezone : altzone) : 0;
+    if (increment_overflow32(&offset, -EPOCH_OFFSET)
+	|| increment_overflow_time(&r, offset)) {
+      errno = EOVERFLOW;
+      r = -1;
+    }
+  }
+  if (p)
+    *p = r;
+  return r;
+}
+
+#endif
diff --git a/newctime.3 b/newctime.3
index a0239de5c0a4..866154986dab 100644
--- a/newctime.3
+++ b/newctime.3
@@ -1,241 +1,344 @@
 .TH NEWCTIME 3
 .SH NAME
-asctime, ctime, difftime, gmtime, localtime, mktime \- convert date and time to ASCII
+asctime, ctime, difftime, gmtime, localtime, mktime \- convert date and time
 .SH SYNOPSIS
 .nf
-.B extern char *tzname[2];
+.ie \n(.g .ds - \f(CW-\fP
+.el .ds - \-
+.B #include 
 .PP
-.B void tzset()
+.BR "extern char *tzname[];" " /\(** (optional) \(**/"
 .PP
-.B #include 
+.B char *ctime(time_t const *clock);
 .PP
-.B char *ctime(clock)
-.B const time_t *clock;
+.B char *ctime_r(time_t const *clock, char *buf);
 .PP
-.B double difftime(time1, time0)
-.B time_t time1;
-.B time_t time0;
+.B double difftime(time_t time1, time_t time0);
 .PP
-.B #include 
+.B char *asctime(struct tm const *tm);
+.PP
+.B "char *asctime_r(struct tm const *restrict tm,"
+.B "    char *restrict result);"
+.PP
+.B struct tm *localtime(time_t const *clock);
+.PP
+.B "struct tm *localtime_r(time_t const *restrict clock,"
+.B "    struct tm *restrict result);"
+.PP
+.B "struct tm *localtime_rz(timezone_t restrict zone,"
+.B "    time_t const *restrict clock,"
+.B "    struct tm *restrict result);"
 .PP
-.B char *asctime(tm)
-.B const struct tm *tm;
+.B struct tm *gmtime(time_t const *clock);
 .PP
-.B struct tm *localtime(clock)
-.B const time_t *clock;
+.B "struct tm *gmtime_r(time_t const *restrict clock,"
+.B "    struct tm *restrict result);"
 .PP
-.B struct tm *gmtime(clock)
-.B const time_t *clock;
+.B time_t mktime(struct tm *tm);
 .PP
-.B time_t mktime(tm)
-.B struct tm *tm;
+.B "time_t mktime_z(timezone_t restrict zone,"
+.B "    struct tm *restrict tm);"
 .PP
-.B cc ... -ltz
+.B cc ... \*-ltz
 .fi
 .SH DESCRIPTION
-.I Ctime\^
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+The
+.B ctime
+function
 converts a long integer, pointed to by
 .IR clock ,
-representing the time in seconds since
-00:00:00 UTC, 1970-01-01,
 and returns a pointer to a
 string of the form
 .br
 .ce
 .eo
 Thu Nov 24 18:22:48 1986\n\0
 .br
 .ec
 Years requiring fewer than four characters are padded with leading zeroes.
 For years longer than four characters, the string is of the form
 .br
 .ce
 .eo
 Thu Nov 24 18:22:48     81986\n\0
 .ec
 .br
 with five spaces before the year.
 These unusual formats are designed to make it less likely that older
 software that expects exactly 26 bytes of output will mistakenly output
 misleading values for out-of-range years.
 .PP
-.I Localtime\^
+The
+.BI * clock
+timestamp represents the time in seconds since 1970-01-01 00:00:00
+Coordinated Universal Time (UTC).
+The POSIX standard says that timestamps must be nonnegative
+and must ignore leap seconds.
+Many implementations extend POSIX by allowing negative timestamps,
+and can therefore represent timestamps that predate the
+introduction of UTC and are some other flavor of Universal Time (UT).
+Some implementations support leap seconds, in contradiction to POSIX.
+.PP
+The
+.B localtime
 and
-.I gmtime\^
-return pointers to ``tm'' structures, described below.
-.I Localtime\^
+.B gmtime
+functions
+return pointers to
+.q "tm"
+structures, described below.
+The
+.B localtime
+function
 corrects for the time zone and any time zone adjustments
 (such as Daylight Saving Time in the United States).
-After filling in the ``tm'' structure,
-.I localtime
+After filling in the
+.q "tm"
+structure,
+.B localtime
 sets the
 .BR tm_isdst 'th
 element of
 .B tzname
-to a pointer to an
-ASCII string that's the time zone abbreviation to be used with
-.IR localtime 's
+to a pointer to a string that's the time zone abbreviation to be used with
+.BR localtime 's
 return value.
 .PP
-.I Gmtime\^
+The
+.B gmtime
+function
 converts to Coordinated Universal Time.
 .PP
-.I Asctime\^
+The
+.B asctime
+function
 converts a time value contained in a
-``tm'' structure to a string,
+.q "tm"
+structure to a string,
 as shown in the above example,
 and returns a pointer to the string.
 .PP
-.I Mktime\^
+The
+.B mktime
+function
 converts the broken-down time,
 expressed as local time,
 in the structure pointed to by
 .I tm
 into a calendar time value with the same encoding as that of the values
 returned by the
-.I time
+.B time
 function.
 The original values of the
 .B tm_wday
 and
 .B tm_yday
 components of the structure are ignored,
 and the original values of the other components are not restricted
 to their normal ranges.
 (A positive or zero value for
 .B tm_isdst
 causes
-.I mktime
-to presume initially that summer time (for example, Daylight Saving Time
-in the U.S.A.)
+.B mktime
+to presume initially that daylight saving time
 respectively,
 is or is not in effect for the specified time.
 A negative value for
 .B tm_isdst
 causes the
-.I mktime
-function to attempt to divine whether summer time is in effect
+.B mktime
+function to attempt to divine whether daylight saving time is in effect
 for the specified time; in this case it does not use a consistent
 rule and may give a different answer when later
 presented with the same argument.)
 On successful completion, the values of the
 .B tm_wday
 and
 .B tm_yday
 components of the structure are set appropriately,
 and the other components are set to represent the specified calendar time,
 but with their values forced to their normal ranges; the final value of
 .B tm_mday
 is not set until
 .B tm_mon
 and
 .B tm_year
 are determined.
-.I Mktime\^
+The
+.B mktime
+function
 returns the specified calendar time;
 If the calendar time cannot be represented,
-it returns
-.BR -1 .
+it returns \-1.
 .PP
-.I Difftime\^
+The
+.B difftime
+function
 returns the difference between two calendar times,
 .RI ( time1
--
+\-
 .IR time0 ),
 expressed in seconds.
 .PP
-Declarations of all the functions and externals, and the ``tm'' structure,
+The
+.BR ctime_r ,
+.BR localtime_r ,
+.BR gmtime_r ,
+and
+.B asctime_r
+functions
+are like their unsuffixed counterparts, except that they accept an
+additional argument specifying where to store the result if successful.
+.PP
+The
+.B localtime_rz
+and
+.B mktime_z
+functions
+are like their unsuffixed counterparts, except that they accept an
+extra initial
+.B zone
+argument specifying the timezone to be used for conversion.
+If
+.B zone
+is null, UT is used; otherwise,
+.B zone
+should be have been allocated by
+.B tzalloc
+and should not be freed until after all uses (e.g., by calls to
+.BR strftime )
+of the filled-in
+.B tm_zone
+fields.
+.PP
+Declarations of all the functions and externals, and the
+.q "tm"
+structure,
 are in the
-.B \^
+.B 
 header file.
 The structure (of type)
 .B struct tm
 includes the following fields:
 .RS
 .PP
 .nf
-.ta .5i +\w'long tm_gmtoff;\0\0'u
-	int tm_sec;	/\(** seconds (0 - 60) \(**/
-	int tm_min;	/\(** minutes (0 - 59) \(**/
-	int tm_hour;	/\(** hours (0 - 23) \(**/
-	int tm_mday;	/\(** day of month (1 - 31) \(**/
-	int tm_mon;	/\(** month of year (0 - 11) \(**/
+.ta 2n +\w'long tm_gmtoff;nn'u
+	int tm_sec;	/\(** seconds (0\*(en60) \(**/
+	int tm_min;	/\(** minutes (0\*(en59) \(**/
+	int tm_hour;	/\(** hours (0\*(en23) \(**/
+	int tm_mday;	/\(** day of month (1\*(en31) \(**/
+	int tm_mon;	/\(** month of year (0\*(en11) \(**/
 	int tm_year;	/\(** year \- 1900 \(**/
 	int tm_wday;	/\(** day of week (Sunday = 0) \(**/
-	int tm_yday;	/\(** day of year (0 - 365) \(**/
-	int tm_isdst;	/\(** is summer time in effect? \(**/
-	char \(**tm_zone;	/\(** abbreviation of timezone name \(**/
-	long tm_gmtoff;	/\(** offset from UTC in seconds \(**/
+	int tm_yday;	/\(** day of year (0\*(en365) \(**/
+	int tm_isdst;	/\(** is daylight saving time in effect? \(**/
+	char \(**tm_zone;	/\(** time zone abbreviation (optional) \(**/
+	long tm_gmtoff;	/\(** offset from UT in seconds (optional) \(**/
 .fi
 .RE
 .PP
 The
-.I tm_zone
+.B tm_isdst
+field
+is non-zero if daylight saving time is in effect.
+.PP
+The
+.B tm_gmtoff
+field
+is the offset (in seconds) of the time represented
+from UT, with positive values indicating east
+of the Prime Meridian.
+The field's name is derived from Greenwich Mean Time, a precursor of UT.
+.PP
+In
+.B "struct tm"
+the
+.B tm_zone
 and
-.I tm_gmtoff
+.B tm_gmtoff
 fields exist, and are filled in, only if arrangements to do
 so were made when the library containing these functions was
 created.
-There is no guarantee that these fields will continue to exist
-in this form in future releases of this code.
-.PP
-.I Tm_isdst\^
-is non-zero if summer time is in effect.
-.PP
-.I Tm_gmtoff
-is the offset (in seconds) of the time represented
-from UTC, with positive values indicating east
-of the Prime Meridian.
+Similarly, the
+.B tzname
+variable is optional; also, there is no guarantee that
+.B tzname
+will
+continue to exist in this form in future releases of this code.
 .SH FILES
-.ta \w'/usr/local/etc/zoneinfo/posixrules\0\0'u
-/usr/local/etc/zoneinfo	time zone information directory
+.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+/usr/share/zoneinfo	timezone information directory
 .br
-/usr/local/etc/zoneinfo/localtime	local time zone file
+/usr/share/zoneinfo/localtime	local timezone file
 .br
-/usr/local/etc/zoneinfo/posixrules	used with POSIX-style TZ's
+/usr/share/zoneinfo/posixrules	used with POSIX-style TZ's
 .br
-/usr/local/etc/zoneinfo/GMT	for UTC leap seconds
+/usr/share/zoneinfo/GMT	for UTC leap seconds
 .sp
 If
-.B /usr/local/etc/zoneinfo/GMT
+.B /usr/share/zoneinfo/GMT
 is absent,
 UTC leap seconds are loaded from
-.BR /usr/local/etc/zoneinfo/posixrules .
+.BR /usr/share/zoneinfo/posixrules .
 .SH SEE ALSO
 getenv(3),
 newstrftime(3),
 newtzset(3),
 time(2),
 tzfile(5)
 .SH NOTES
-The return values point to static data;
-the data is overwritten by each call.
+The return values of
+.BR asctime ,
+.BR ctime ,
+.BR gmtime ,
+and
+.B localtime
+point to static data
+overwritten by each call.
 The
+.B tzname
+variable (once set) and the
 .B tm_zone
 field of a returned
 .B "struct tm"
-points to a static array of characters, which
-will also be overwritten at the next call
-(and by calls to
-.IR tzset ).
+both point to an array of characters that
+can be freed or overwritten by later calls to the functions
+.BR localtime ,
+.BR tzfree ,
+and
+.BR tzset ,
+if these functions affect the timezone information that specifies the
+abbreviation in question.
+The remaining functions and data are thread-safe.
 .PP
-.I Asctime\^
+The
+.BR asctime ,
+.BR asctime_r ,
+.BR ctime ,
 and
-.I ctime\^
+.B ctime_r
+functions
 behave strangely for years before 1000 or after 9999.
 The 1989 and 1999 editions of the C Standard say
 that years from \-99 through 999 are converted without
 extra spaces, but this conflicts with longstanding
 tradition and with this implementation.
+The 2011 edition says that the behavior
+is undefined if the year is before 1000 or after 9999.
 Traditional implementations of these two functions are
 restricted to years in the range 1900 through 2099.
 To avoid this portability mess, new programs should use
-.I strftime\^
+.B strftime
 instead.
-.PP
-Avoid using out-of-range values with
-.I mktime
-when setting up lunch with promptness sticklers in Riyadh.
-.\" @(#)newctime.3	8.3
 .\" This file is in the public domain, so clarified as of
 .\" 2009-05-17 by Arthur David Olson.
diff --git a/newctime.3.txt b/newctime.3.txt
index ba311400474a..2076491d925e 100644
--- a/newctime.3.txt
+++ b/newctime.3.txt
@@ -1,149 +1,172 @@
-NAME
+NEWCTIME(3)                Library Functions Manual                NEWCTIME(3)
 
-     asctime, ctime, difftime, gmtime, localtime, mktime -
-     convert date and time to ASCII
+NAME
+       asctime, ctime, difftime, gmtime, localtime, mktime - convert date and
+       time
 
 SYNOPSIS
-     extern char *tzname[2];
+       #include 
+
+       extern char *tzname[]; /* (optional) */
+
+       char *ctime(time_t const *clock);
+
+       char *ctime_r(time_t const *clock, char *buf);
+
+       double difftime(time_t time1, time_t time0);
 
-     void tzset()
+       char *asctime(struct tm const *tm);
 
-     #include 
+       char *asctime_r(struct tm const *restrict tm,
+           char *restrict result);
 
-     char *ctime(clock)
-     const time_t *clock;
+       struct tm *localtime(time_t const *clock);
 
-     double difftime(time1, time0)
-     time_t time1;
-     time_t time0;
+       struct tm *localtime_r(time_t const *restrict clock,
+           struct tm *restrict result);
 
-     #include 
+       struct tm *localtime_rz(timezone_t restrict zone,
+           time_t const *restrict clock,
+           struct tm *restrict result);
 
-     char *asctime(tm)
-     const struct tm *tm;
+       struct tm *gmtime(time_t const *clock);
 
-     struct tm *localtime(clock)
-     const time_t *clock;
+       struct tm *gmtime_r(time_t const *restrict clock,
+           struct tm *restrict result);
 
-     struct tm *gmtime(clock)
-     const time_t *clock;
+       time_t mktime(struct tm *tm);
 
-     time_t mktime(tm)
-     struct tm *tm;
+       time_t mktime_z(timezone_t restrict zone,
+           struct tm *restrict tm);
 
-     cc ... -ltz
+       cc ... -ltz
 
 DESCRIPTION
-     Ctime converts a long integer, pointed to by clock,
-     representing the time in seconds since 00:00:00 UTC,
-     1970-01-01, and returns a pointer to a string of the form
-                     Thu Nov 24 18:22:48 1986\n\0
-     Years requiring fewer than four characters are padded with
-     leading zeroes.  For years longer than four characters, the
-     string is of the form
-                  Thu Nov 24 18:22:48     81986\n\0
-     with five spaces before the year.  These unusual formats are
-     designed to make it less likely that older software that
-     expects exactly 26 bytes of output will mistakenly output
-     misleading values for out-of-range years.
-
-     Localtime and gmtime return pointers to ``tm'' structures,
-     described below.  Localtime corrects for the time zone and
-     any time zone adjustments (such as Daylight Saving Time in
-     the United States).  After filling in the ``tm'' structure,
-     localtime sets the tm_isdst'th element of tzname to a
-     pointer to an ASCII string that's the time zone abbreviation
-     to be used with localtime's return value.
-
-     Gmtime converts to Coordinated Universal Time.
-
-     Asctime converts a time value contained in a ``tm''
-     structure to a string, as shown in the above example, and
-     returns a pointer to the string.
-
-     Mktime converts the broken-down time, expressed as local
-     time, in the structure pointed to by tm into a calendar time
-     value with the same encoding as that of the values returned
-     by the time function.  The original values of the tm_wday
-     and tm_yday components of the structure are ignored, and the
-     original values of the other components are not restricted
-     to their normal ranges.  (A positive or zero value for
-     tm_isdst causes mktime to presume initially that summer time
-     (for example, Daylight Saving Time in the U.S.A.)
-     respectively, is or is not in effect for the specified time.
-     A negative value for tm_isdst causes the mktime function to
-     attempt to divine whether summer time is in effect for the
-     specified time; in this case it does not use a consistent
-     rule and may give a different answer when later presented
-     with the same argument.)  On successful completion, the
-     values of the tm_wday and tm_yday components of the
-     structure are set appropriately, and the other components
-     are set to represent the specified calendar time, but with
-     their values forced to their normal ranges; the final value
-     of tm_mday is not set until tm_mon and tm_year are
-     determined.  Mktime returns the specified calendar time; If
-     the calendar time cannot be represented, it returns -1.
-
-     Difftime returns the difference between two calendar times,
-     (time1 - time0), expressed in seconds.
-
-     Declarations of all the functions and externals, and the
-     ``tm'' structure, are in the  header file.  The
-     structure (of type) struct tm includes the following fields:
-
-               int tm_sec;      /* seconds (0 - 60) */
-               int tm_min;      /* minutes (0 - 59) */
-               int tm_hour;     /* hours (0 - 23) */
-               int tm_mday;     /* day of month (1 - 31) */
-               int tm_mon;      /* month of year (0 - 11) */
-               int tm_year;     /* year - 1900 */
-               int tm_wday;     /* day of week (Sunday = 0) */
-               int tm_yday;     /* day of year (0 - 365) */
-               int tm_isdst;    /* is summer time in effect? */
-               char *tm_zone;   /* abbreviation of timezone name */
-               long tm_gmtoff;  /* offset from UTC in seconds */
-
-     The tm_zone and tm_gmtoff fields exist, and are filled in,
-     only if arrangements to do so were made when the library
-     containing these functions was created.  There is no
-     guarantee that these fields will continue to exist in this
-     form in future releases of this code.
-
-     Tm_isdst is non-zero if summer time is in effect.
-
-     Tm_gmtoff is the offset (in seconds) of the time represented
-     from UTC, with positive values indicating east of the Prime
-     Meridian.
+       The ctime function converts a long integer, pointed to by clock, and
+       returns a pointer to a string of the form
+                            Thu Nov 24 18:22:48 1986\n\0
+       Years requiring fewer than four characters are padded with leading
+       zeroes.  For years longer than four characters, the string is of the
+       form
+                          Thu Nov 24 18:22:48     81986\n\0
+       with five spaces before the year.  These unusual formats are designed
+       to make it less likely that older software that expects exactly 26
+       bytes of output will mistakenly output misleading values for out-of-
+       range years.
+
+       The *clock timestamp represents the time in seconds since 1970-01-01
+       00:00:00 Coordinated Universal Time (UTC).  The POSIX standard says
+       that timestamps must be nonnegative and must ignore leap seconds.  Many
+       implementations extend POSIX by allowing negative timestamps, and can
+       therefore represent timestamps that predate the introduction of UTC and
+       are some other flavor of Universal Time (UT).  Some implementations
+       support leap seconds, in contradiction to POSIX.
+
+       The localtime and gmtime functions return pointers to "tm" structures,
+       described below.  The localtime function corrects for the time zone and
+       any time zone adjustments (such as Daylight Saving Time in the United
+       States).  After filling in the "tm" structure, localtime sets the
+       tm_isdst'th element of tzname to a pointer to a string that's the time
+       zone abbreviation to be used with localtime's return value.
+
+       The gmtime function converts to Coordinated Universal Time.
+
+       The asctime function converts a time value contained in a "tm"
+       structure to a string, as shown in the above example, and returns a
+       pointer to the string.
+
+       The mktime function converts the broken-down time, expressed as local
+       time, in the structure pointed to by tm into a calendar time value with
+       the same encoding as that of the values returned by the time function.
+       The original values of the tm_wday and tm_yday components of the
+       structure are ignored, and the original values of the other components
+       are not restricted to their normal ranges.  (A positive or zero value
+       for tm_isdst causes mktime to presume initially that daylight saving
+       time respectively, is or is not in effect for the specified time.  A
+       negative value for tm_isdst causes the mktime function to attempt to
+       divine whether daylight saving time is in effect for the specified
+       time; in this case it does not use a consistent rule and may give a
+       different answer when later presented with the same argument.)  On
+       successful completion, the values of the tm_wday and tm_yday components
+       of the structure are set appropriately, and the other components are
+       set to represent the specified calendar time, but with their values
+       forced to their normal ranges; the final value of tm_mday is not set
+       until tm_mon and tm_year are determined.  The mktime function returns
+       the specified calendar time; If the calendar time cannot be
+       represented, it returns -1.
+
+       The difftime function returns the difference between two calendar
+       times, (time1 - time0), expressed in seconds.
+
+       The ctime_r, localtime_r, gmtime_r, and asctime_r functions are like
+       their unsuffixed counterparts, except that they accept an additional
+       argument specifying where to store the result if successful.
+
+       The localtime_rz and mktime_z functions are like their unsuffixed
+       counterparts, except that they accept an extra initial zone argument
+       specifying the timezone to be used for conversion.  If zone is null, UT
+       is used; otherwise, zone should be have been allocated by tzalloc and
+       should not be freed until after all uses (e.g., by calls to strftime)
+       of the filled-in tm_zone fields.
+
+       Declarations of all the functions and externals, and the "tm"
+       structure, are in the  header file.  The structure (of type)
+       struct tm includes the following fields:
+
+                int tm_sec;      /* seconds (0-60) */
+                int tm_min;      /* minutes (0-59) */
+                int tm_hour;     /* hours (0-23) */
+                int tm_mday;     /* day of month (1-31) */
+                int tm_mon;      /* month of year (0-11) */
+                int tm_year;     /* year - 1900 */
+                int tm_wday;     /* day of week (Sunday = 0) */
+                int tm_yday;     /* day of year (0-365) */
+                int tm_isdst;    /* is daylight saving time in effect? */
+                char *tm_zone;   /* time zone abbreviation (optional) */
+                long tm_gmtoff;  /* offset from UT in seconds (optional) */
+
+       The tm_isdst field is non-zero if daylight saving time is in effect.
+
+       The tm_gmtoff field is the offset (in seconds) of the time represented
+       from UT, with positive values indicating east of the Prime Meridian.
+       The field's name is derived from Greenwich Mean Time, a precursor of
+       UT.
+
+       In struct tm the tm_zone and tm_gmtoff fields exist, and are filled in,
+       only if arrangements to do so were made when the library containing
+       these functions was created.  Similarly, the tzname variable is
+       optional; also, there is no guarantee that tzname will continue to
+       exist in this form in future releases of this code.
 
 FILES
-     /usr/local/etc/zoneinfo             time zone information
-     directory
-     /usr/local/etc/zoneinfo/localtime   local time zone file
-     /usr/local/etc/zoneinfo/posixrules  used with POSIX-style
-     TZ's
-     /usr/local/etc/zoneinfo/GMT         for UTC leap seconds
+       /usr/share/zoneinfo             timezone information directory
+       /usr/share/zoneinfo/localtime   local timezone file
+       /usr/share/zoneinfo/posixrules  used with POSIX-style TZ's
+       /usr/share/zoneinfo/GMT         for UTC leap seconds
 
-     If /usr/local/etc/zoneinfo/GMT is absent, UTC leap seconds
-     are loaded from /usr/local/etc/zoneinfo/posixrules.
+       If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+       /usr/share/zoneinfo/posixrules.
 
 SEE ALSO
-     getenv(3), newstrftime(3), newtzset(3), time(2), tzfile(5)
+       getenv(3), newstrftime(3), newtzset(3), time(2), tzfile(5)
 
 NOTES
-     The return values point to static data; the data is
-     overwritten by each call.  The tm_zone field of a returned
-     struct tm points to a static array of characters, which will
-     also be overwritten at the next call (and by calls to
-     tzset).
-
-     Asctime and ctime behave strangely for years before 1000 or
-     after 9999.  The 1989 and 1999 editions of the C Standard
-     say that years from -99 through 999 are converted without
-     extra spaces, but this conflicts with longstanding tradition
-     and with this implementation.  Traditional implementations
-     of these two functions are restricted to years in the range
-     1900 through 2099.  To avoid this portability mess, new
-     programs should use strftime instead.
-
-     Avoid using out-of-range values with mktime when setting up
-     lunch with promptness sticklers in Riyadh.
+       The return values of asctime, ctime, gmtime, and localtime point to
+       static data overwritten by each call.  The tzname variable (once set)
+       and the tm_zone field of a returned struct tm both point to an array of
+       characters that can be freed or overwritten by later calls to the
+       functions localtime, tzfree, and tzset, if these functions affect the
+       timezone information that specifies the abbreviation in question.  The
+       remaining functions and data are thread-safe.
+
+       The asctime, asctime_r, ctime, and ctime_r functions behave strangely
+       for years before 1000 or after 9999.  The 1989 and 1999 editions of the
+       C Standard say that years from -99 through 999 are converted without
+       extra spaces, but this conflicts with longstanding tradition and with
+       this implementation.  The 2011 edition says that the behavior is
+       undefined if the year is before 1000 or after 9999.  Traditional
+       implementations of these two functions are restricted to years in the
+       range 1900 through 2099.  To avoid this portability mess, new programs
+       should use strftime instead.
+
+                                                                   NEWCTIME(3)
diff --git a/newstrftime.3 b/newstrftime.3
index cd70974b8e15..d68bc33783a1 100644
--- a/newstrftime.3
+++ b/newstrftime.3
@@ -1,232 +1,290 @@
-.\" Based on the UCB file whose copyright information appears below.
-.\" Copyright (c) 1989, 1991 The Regents of the University of California.
+.\" strftime man page
+.\"
+.\" Based on the UCB file whose corrected copyright information appears below.
+.\" Copyright 1989, 1991 The Regents of the University of California.
 .\" All rights reserved.
 .\"
 .\" This code is derived from software contributed to Berkeley by
 .\" the American National Standards Committee X3, on Information
 .\" Processing Systems.
 .\"
 .\" Redistribution and use in source and binary forms, with or without
 .\" modification, are permitted provided that the following conditions
 .\" are met:
 .\" 1. Redistributions of source code must retain the above copyright
 .\"    notice, this list of conditions and the following disclaimer.
 .\" 2. Redistributions in binary form must reproduce the above copyright
 .\"    notice, this list of conditions and the following disclaimer in the
 .\"    documentation and/or other materials provided with the distribution.
-.\" 3. All advertising materials mentioning features or use of this software
-.\"    must display the following acknowledgement:
-.\"	This product includes software developed by the University of
-.\"	California, Berkeley and its contributors.
-.\" 4. Neither the name of the University nor the names of its contributors
+.\" 3. Neither the name of the University nor the names of its contributors
 .\"    may be used to endorse or promote products derived from this software
 .\"    without specific prior written permission.
 .\"
-.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
 .\"     from: @(#)strftime.3	5.12 (Berkeley) 6/29/91
 .\"	$Id: strftime.3,v 1.4 1993/12/15 20:33:00 jtc Exp $
 .\"
 .TH NEWSTRFTIME 3
 .SH NAME
 strftime \- format date and time
 .SH SYNOPSIS
 .nf
-.B #include 
+.ie \n(.g .ds - \f(CW-\fP
+.el .ds - \-
 .B #include 
 .PP
-.B size_t strftime(buf, maxsize, format, timeptr)
-.B char *buf;
-.B size_t maxsize;
-.B const char *format;
-.B const struct tm *timeptr
+.B "size_t strftime(char *restrict buf, size_t maxsize,"
+.B "    char const *restrict format, struct tm const *restrict timeptr);"
 .PP
-.B cc ... -ltz
+.B cc ... \-ltz
 .fi
 .SH DESCRIPTION
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de c
+.ie \n(.g \f(CW\\$1\fP\\$2
+.el \\$1\\$2
+..
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
 The
-.I strftime\^
+.B strftime
 function formats the information from
-.I timeptr\^
-into the buffer
-.I buf\^
+.I timeptr
+into the array pointed to by
+.I buf
 according to the string pointed to by
-.IR format\^ .
+.IR format .
 .PP
 The
-.I format\^
+.I format
 string consists of zero or more conversion specifications and
 ordinary characters.
-All ordinary characters are copied directly into the buffer.
+All ordinary characters are copied directly into the array.
 A conversion specification consists of a percent sign
 .Ql %
 and one other character.
 .PP
 No more than
-.I maxsize\^
-characters are be placed into the array.
-If the total number of resulting characters, including the terminating
-null character, is not more than
-.IR maxsize\^ ,
-.I strftime\^
-returns the number of characters in the array, not counting the
-terminating null.
-Otherwise, zero is returned.
+.I maxsize
+bytes are placed into the array.
 .PP
 Each conversion specification is replaced by the characters as
-follows which are then copied into the buffer.
+follows which are then copied into the array.
 .TP
 %A
 is replaced by the locale's full weekday name.
 .TP
 %a
 is replaced by the locale's abbreviated weekday name.
 .TP
 %B
 is replaced by the locale's full month name.
 .TP
 %b or %h
 is replaced by the locale's abbreviated month name.
 .TP
 %C
 is replaced by the century (a year divided by 100 and truncated to an integer)
-as a decimal number (00-99).
+as a decimal number [00,99].
 .TP
 %c
 is replaced by the locale's appropriate date and time representation.
 .TP
 %D
-is replaced by the date in the format %m/%d/%y.
+is equivalent to
+.c %m/%d/%y .
 .TP
 %d
-is replaced by the day of the month as a decimal number (01-31).
+is replaced by the day of the month as a decimal number [01,31].
 .TP
 %e
-is replaced by the day of month as a decimal number (1-31);
+is replaced by the day of month as a decimal number [1,31];
 single digits are preceded by a blank.
 .TP
 %F
-is replaced by the date in the format %Y-%m-%d.
+is equivalent to
+.c %Y-%m-%d
+(the ISO 8601 date format).
 .TP
 %G
 is replaced by the ISO 8601 year with century as a decimal number.
+See also the
+.c %V
+conversion specification.
 .TP
 %g
-is replaced by the ISO 8601 year without century as a decimal number (00-99).
+is replaced by the ISO 8601 year without century as a decimal number [00,99].
+This is the year that includes the greater part of the week.
+(Monday as the first day of a week).
+See also the
+.c %V
+conversion specification.
 .TP
 %H
-is replaced by the hour (24-hour clock) as a decimal number (00-23).
+is replaced by the hour (24-hour clock) as a decimal number [00,23].
 .TP
 %I
-is replaced by the hour (12-hour clock) as a decimal number (01-12).
+is replaced by the hour (12-hour clock) as a decimal number [01,12].
 .TP
 %j
-is replaced by the day of the year as a decimal number (001-366).
+is replaced by the day of the year as a decimal number [001,366].
 .TP
 %k
-is replaced by the hour (24-hour clock) as a decimal number (0-23);
+is replaced by the hour (24-hour clock) as a decimal number [0,23];
 single digits are preceded by a blank.
 .TP
 %l
-is replaced by the hour (12-hour clock) as a decimal number (1-12);
+is replaced by the hour (12-hour clock) as a decimal number [1,12];
 single digits are preceded by a blank.
 .TP
 %M
-is replaced by the minute as a decimal number (00-59).
+is replaced by the minute as a decimal number [00,59].
 .TP
 %m
-is replaced by the month as a decimal number (01-12).
+is replaced by the month as a decimal number [01,12].
 .TP
 %n
 is replaced by a newline.
 .TP
 %p
-is replaced by the locale's equivalent of either AM or PM.
+is replaced by the locale's equivalent of either
+.q AM
+or
+.q PM .
 .TP
 %R
-is replaced by the time in the format %H:%M.
+is replaced by the time in the format
+.c %H:%M .
 .TP
 %r
 is replaced by the locale's representation of 12-hour clock time
 using AM/PM notation.
 .TP
 %S
-is replaced by the second as a decimal number (00-60).
+is replaced by the second as a decimal number [00,60].
+The range of
+seconds is [00,60] instead of [00,59] to allow for the periodic occurrence
+of leap seconds.
 .TP
 %s
-is replaced by the number of seconds since the Epoch, UTC (see mktime(3)).
+is replaced by the number of seconds since the Epoch (see
+.BR ctime (3)).
 .TP
 %T
-is replaced by the time in the format %H:%M:%S.
+is replaced by the time in the format
+.c %H:%M:%S .
 .TP
 %t
 is replaced by a tab.
 .TP
 %U
 is replaced by the week number of the year (Sunday as the first day of
-the week) as a decimal number (00-53).
+the week) as a decimal number [00,53].
 .TP
 %u
 is replaced by the weekday (Monday as the first day of the week)
-as a decimal number (1-7).
+as a decimal number [1,7].
 .TP
 %V
 is replaced by the week number of the year (Monday as the first day of
-the week) as a decimal number (01-53).  If the week containing January
+the week) as a decimal number [01,53].  If the week containing January
 1 has four or more days in the new year, then it is week 1; otherwise
 it is week 53 of the previous year, and the next week is week 1.
+The year is given by the
+.c %G
+conversion specification.
 .TP
 %W
 is replaced by the week number of the year (Monday as the first day of
-the week) as a decimal number (00-53).
+the week) as a decimal number [00,53].
 .TP
 %w
 is replaced by the weekday (Sunday as the first day of the week)
-as a decimal number (0-6).
+as a decimal number [0,6].
 .TP
 %X
 is replaced by the locale's appropriate time representation.
 .TP
 %x
 is replaced by the locale's appropriate date representation.
 .TP
 %Y
 is replaced by the year with century as a decimal number.
 .TP
 %y
-is replaced by the year without century as a decimal number (00-99).
+is replaced by the year without century as a decimal number [00,99].
 .TP
 %Z
-is replaced by the time zone name,
+is replaced by the time zone abbreviation,
 or by the empty string if this is not determinable.
 .TP
 %z
-is replaced by the offset from UTC in the format +HHMM or -HHMM as appropriate,
+is replaced by the offset from the Prime Meridian
+in the format +HHMM or \*-HHMM (ISO 8601) as appropriate,
 with positive values representing locations east of Greenwich,
 or by the empty string if this is not determinable.
+The numeric time zone abbreviation \*-0000 is used when the time is
+Universal Time
+but local time is indeterminate; by convention this is used for
+locations while uninhabited, and corresponds to a zero offset when the
+time zone abbreviation begins with
+.q "\*-" .
 .TP
 %%
 is replaced by a single %.
 .TP
 %+
-is replaced by the date and time in date(1) format.
+is replaced by the locale's date and time in
+.BR date (1)
+format.
+.SH "RETURN VALUE"
+If the conversion is successful,
+.B strftime
+returns the number of bytes placed into the array, not counting the
+terminating NUL;
+.B errno
+is unchanged if the returned value is zero.
+Otherwise,
+.B errno
+is set to indicate the error, zero is returned,
+and the array contents are unspecified.
+.SH ERRORS
+This function fails if:
+.TP
+[ERANGE]
+The total number of resulting bytes, including the terminating
+NUL character, is more than
+.IR maxsize .
+.PP
+This function may fail if:
+.TP
+[EOVERFLOW]
+The format includes an
+.c %s
+conversion and the number of seconds since the Epoch cannot be represented
+in a
+.c time_t .
 .SH SEE ALSO
 date(1),
 getenv(3),
 newctime(3),
 newtzset(3),
 time(2),
 tzfile(5)
-.\" @(#)newstrftime.3	8.2
-.\" This file is in the public domain, so clarified as of
-.\" 2009-05-17 by Arthur David Olson.
+.SH BUGS
+There is no conversion specification for the phase of the moon.
diff --git a/newstrftime.3.txt b/newstrftime.3.txt
index ea210a869f4a..37329d91dbc6 100644
--- a/newstrftime.3.txt
+++ b/newstrftime.3.txt
@@ -1,149 +1,169 @@
-NAME
+NEWSTRFTIME(3)             Library Functions Manual             NEWSTRFTIME(3)
 
-     strftime - format date and time
+NAME
+       strftime - format date and time
 
 SYNOPSIS
-     #include 
-     #include 
+       #include 
 
-     size_t strftime(buf, maxsize, format, timeptr)
-     char *buf;
-     size_t maxsize;
-     const char *format;
-     const struct tm *timeptr
+       size_t strftime(char *restrict buf, size_t maxsize,
+           char const *restrict format, struct tm const *restrict timeptr);
 
-     cc ... -ltz
+       cc ... -ltz
 
 DESCRIPTION
-     The strftime function formats the information from timeptr
-     into the buffer buf according to the string pointed to by
-     format.
+       The strftime function formats the information from timeptr into the
+       array pointed to by buf according to the string pointed to by format.
+
+       The format string consists of zero or more conversion specifications
+       and ordinary characters.  All ordinary characters are copied directly
+       into the array.  A conversion specification consists of a percent sign
+       and one other character.
+
+       No more than maxsize bytes are placed into the array.
+
+       Each conversion specification is replaced by the characters as follows
+       which are then copied into the array.
+
+       %A     is replaced by the locale's full weekday name.
 
-     The format string consists of zero or more conversion
-     specifications and ordinary characters.  All ordinary
-     characters are copied directly into the buffer.  A
-     conversion specification consists of a percent sign and one
-     other character.
+       %a     is replaced by the locale's abbreviated weekday name.
 
-     No more than maxsize characters are be placed into the
-     array.  If the total number of resulting characters,
-     including the terminating null character, is not more than
-     maxsize, strftime returns the number of characters in the
-     array, not counting the terminating null.  Otherwise, zero
-     is returned.
+       %B     is replaced by the locale's full month name.
 
-     Each conversion specification is replaced by the characters
-     as follows which are then copied into the buffer.
+       %b or %h
+              is replaced by the locale's abbreviated month name.
 
-     %A   is replaced by the locale's full weekday name.
+       %C     is replaced by the century (a year divided by 100 and truncated
+              to an integer) as a decimal number [00,99].
 
-     %a   is replaced by the locale's abbreviated weekday name.
+       %c     is replaced by the locale's appropriate date and time
+              representation.
 
-     %B   is replaced by the locale's full month name.
+       %D     is equivalent to %m/%d/%y.
 
-     %b or %h
-          is replaced by the locale's abbreviated month name.
+       %d     is replaced by the day of the month as a decimal number [01,31].
 
-     %C   is replaced by the century (a year divided by 100 and
-          truncated to an integer) as a decimal number (00-99).
+       %e     is replaced by the day of month as a decimal number [1,31];
+              single digits are preceded by a blank.
 
-     %c   is replaced by the locale's appropriate date and time
-          representation.
+       %F     is equivalent to %Y-%m-%d (the ISO 8601 date format).
 
-     %D   is replaced by the date in the format %m/%d/%y.
+       %G     is replaced by the ISO 8601 year with century as a decimal
+              number.  See also the %V conversion specification.
 
-     %d   is replaced by the day of the month as a decimal number
-          (01-31).
+       %g     is replaced by the ISO 8601 year without century as a decimal
+              number [00,99].  This is the year that includes the greater part
+              of the week.  (Monday as the first day of a week).  See also the
+              %V conversion specification.
 
-     %e   is replaced by the day of month as a decimal number
-          (1-31); single digits are preceded by a blank.
-     %F   is replaced by the date in the format %Y-%m-%d.
+       %H     is replaced by the hour (24-hour clock) as a decimal number
+              [00,23].
 
-     %G   is replaced by the ISO 8601 year with century as a
-          decimal number.
+       %I     is replaced by the hour (12-hour clock) as a decimal number
+              [01,12].
 
-     %g   is replaced by the ISO 8601 year without century as a
-          decimal number (00-99).
-     %H   is replaced by the hour (24-hour clock) as a decimal
-          number (00-23).
+       %j     is replaced by the day of the year as a decimal number
+              [001,366].
 
-     %I   is replaced by the hour (12-hour clock) as a decimal
-          number (01-12).
+       %k     is replaced by the hour (24-hour clock) as a decimal number
+              [0,23]; single digits are preceded by a blank.
 
-     %j   is replaced by the day of the year as a decimal number
-          (001-366).
+       %l     is replaced by the hour (12-hour clock) as a decimal number
+              [1,12]; single digits are preceded by a blank.
 
-     %k   is replaced by the hour (24-hour clock) as a decimal
-          number (0-23); single digits are preceded by a blank.
+       %M     is replaced by the minute as a decimal number [00,59].
 
-     %l   is replaced by the hour (12-hour clock) as a decimal
-          number (1-12); single digits are preceded by a blank.
+       %m     is replaced by the month as a decimal number [01,12].
 
-     %M   is replaced by the minute as a decimal number (00-59).
+       %n     is replaced by a newline.
 
-     %m   is replaced by the month as a decimal number (01-12).
+       %p     is replaced by the locale's equivalent of either "AM" or "PM".
 
-     %n   is replaced by a newline.
+       %R     is replaced by the time in the format %H:%M.
 
-     %p   is replaced by the locale's equivalent of either AM or
-          PM.
+       %r     is replaced by the locale's representation of 12-hour clock time
+              using AM/PM notation.
 
-     %R   is replaced by the time in the format %H:%M.
+       %S     is replaced by the second as a decimal number [00,60].  The
+              range of seconds is [00,60] instead of [00,59] to allow for the
+              periodic occurrence of leap seconds.
 
-     %r   is replaced by the locale's representation of 12-hour
-          clock time using AM/PM notation.
+       %s     is replaced by the number of seconds since the Epoch (see
+              ctime(3)).
 
-     %S   is replaced by the second as a decimal number (00-60).
+       %T     is replaced by the time in the format %H:%M:%S.
 
-     %s   is replaced by the number of seconds since the Epoch,
-          UTC (see mktime(3)).
+       %t     is replaced by a tab.
 
-     %T   is replaced by the time in the format %H:%M:%S.
+       %U     is replaced by the week number of the year (Sunday as the first
+              day of the week) as a decimal number [00,53].
 
-     %t   is replaced by a tab.
+       %u     is replaced by the weekday (Monday as the first day of the week)
+              as a decimal number [1,7].
 
-     %U   is replaced by the week number of the year (Sunday as
-          the first day of the week) as a decimal number (00-53).
+       %V     is replaced by the week number of the year (Monday as the first
+              day of the week) as a decimal number [01,53].  If the week
+              containing January 1 has four or more days in the new year, then
+              it is week 1; otherwise it is week 53 of the previous year, and
+              the next week is week 1.  The year is given by the %G conversion
+              specification.
 
-     %u   is replaced by the weekday (Monday as the first day of
-          the week) as a decimal number (1-7).
+       %W     is replaced by the week number of the year (Monday as the first
+              day of the week) as a decimal number [00,53].
 
-     %V   is replaced by the week number of the year (Monday as
-          the first day of the week) as a decimal number (01-53).
-          If the week containing January 1 has four or more days
-          in the new year, then it is week 1; otherwise it is
-          week 53 of the previous year, and the next week is week
-          1.
+       %w     is replaced by the weekday (Sunday as the first day of the week)
+              as a decimal number [0,6].
 
-     %W   is replaced by the week number of the year (Monday as
-          the first day of the week) as a decimal number (00-53).
+       %X     is replaced by the locale's appropriate time representation.
 
-     %w   is replaced by the weekday (Sunday as the first day of
-          the week) as a decimal number (0-6).
+       %x     is replaced by the locale's appropriate date representation.
 
-     %X   is replaced by the locale's appropriate time
-          representation.
-     %x   is replaced by the locale's appropriate date
-          representation.
+       %Y     is replaced by the year with century as a decimal number.
 
-     %Y   is replaced by the year with century as a decimal
-          number.
+       %y     is replaced by the year without century as a decimal number
+              [00,99].
 
-     %y   is replaced by the year without century as a decimal
-          number (00-99).
+       %Z     is replaced by the time zone abbreviation, or by the empty
+              string if this is not determinable.
 
-     %Z   is replaced by the time zone name, or by the empty
-          string if this is not determinable.
+       %z     is replaced by the offset from the Prime Meridian in the format
+              +HHMM or -HHMM (ISO 8601) as appropriate, with positive values
+              representing locations east of Greenwich, or by the empty string
+              if this is not determinable.  The numeric time zone abbreviation
+              -0000 is used when the time is Universal Time but local time is
+              indeterminate; by convention this is used for locations while
+              uninhabited, and corresponds to a zero offset when the time zone
+              abbreviation begins with "-".
 
-     %z   is replaced by the offset from UTC in the format +HHMM
-          or -HHMM as appropriate, with positive values
-          representing locations east of Greenwich, or by the
-          empty string if this is not determinable.
+       %%     is replaced by a single %.
 
-     %%   is replaced by a single %.
+       %+     is replaced by the locale's date and time in date(1) format.
 
-     %+   is replaced by the date and time in date(1) format.
+RETURN VALUE
+       If the conversion is successful, strftime returns the number of bytes
+       placed into the array, not counting the terminating NUL; errno is
+       unchanged if the returned value is zero.  Otherwise, errno is set to
+       indicate the error, zero is returned, and the array contents are
+       unspecified.
+
+ERRORS
+       This function fails if:
+
+       [ERANGE]
+              The total number of resulting bytes, including the terminating
+              NUL character, is more than maxsize.
+
+       This function may fail if:
+
+       [EOVERFLOW]
+              The format includes an %s conversion and the number of seconds
+              since the Epoch cannot be represented in a time_t.
 
 SEE ALSO
-     date(1), getenv(3), newctime(3), newtzset(3), time(2),
-     tzfile(5)
+       date(1), getenv(3), newctime(3), newtzset(3), time(2), tzfile(5)
+
+BUGS
+       There is no conversion specification for the phase of the moon.
+
+                                                                NEWSTRFTIME(3)
diff --git a/newtzset.3 b/newtzset.3
index 07c5e0c605a7..8aaa0ff41732 100644
--- a/newtzset.3
+++ b/newtzset.3
@@ -1,239 +1,350 @@
 .TH NEWTZSET 3
 .SH NAME
 tzset \- initialize time conversion information
 .SH SYNOPSIS
 .nf
-.B void tzset()
+.ie \n(.g .ds - \f(CW-\fP
+.el .ds - \-
+.B #include 
 .PP
-.B cc ... -ltz
+.B timezone_t tzalloc(char const *TZ);
+.PP
+.B void tzfree(timezone_t tz);
+.PP
+.B void tzset(void);
+.PP
+.B cc ... \*-ltz
 .fi
 .SH DESCRIPTION
-.I Tzset
-uses the value of the environment variable
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+The
+.B tzalloc
+function
+allocates and returns a timezone object described by
+.BR TZ .
+If
 .B TZ
-to set time conversion information used by
-.IR localtime .
+is not a valid timezone description, or if the object cannot be allocated,
+.B tzalloc
+returns a null pointer and sets
+.BR errno .
+.PP
+The
+.B tzfree
+function
+frees a timezone object
+.BR tz ,
+which should have been successfully allocated by
+.BR tzalloc .
+This invalidates any
+.B tm_zone
+pointers that
+.B tz
+was used to set.
+.PP
+The
+.B tzset
+function
+acts like
+.BR tzalloc(getenv("TZ")) ,
+except it saves any resulting timezone object into internal
+storage that is accessed by
+.BR localtime ,
+.BR localtime_r ,
+and
+.BR mktime .
+The anonymous shared timezone object is freed by the next call to
+.BR tzset .
+If the implied call to
+.B tzalloc
+fails,
+.B tzset
+falls back on Universal Time (UT).
+.PP
 If
 .B TZ
-does not appear in the environment,
-the best available approximation to local wall clock time, as specified
-by the
-.IR tzfile (5)-format
+is null, the best available approximation to local (wall
+clock) time, as specified by the
+.BR tzfile (5)-format
 file
 .B localtime
-in the system time conversion information directory, is used by
-.IR localtime .
+in the system time conversion information directory, is used.
 If
 .B TZ
-appears in the environment but its value is a null string,
-Coordinated Universal Time (UTC) is used (without leap second
-correction).  If
+is the empty string,
+UT is used, with the abbreviation "UTC"
+and without leap second correction; please see
+.BR newctime (3)
+for more about UT, UTC, and leap seconds.  If
 .B TZ
-appears in the environment and its value is not a null string:
+is nonnull and nonempty:
 .IP
 if the value begins with a colon, it is used as a pathname of a file
 from which to read the time conversion information;
 .IP
 if the value does not begin with a colon, it is first used as the
 pathname of a file from which to read the time conversion information,
 and, if that file cannot be read, is used directly as a specification of
 the time conversion information.
 .PP
 When
 .B TZ
 is used as a pathname, if it begins with a slash,
 it is used as an absolute pathname; otherwise,
 it is used as a pathname relative to a system time conversion information
 directory.
 The file must be in the format specified in
-.IR tzfile (5).
+.BR tzfile (5).
 .PP
 When
 .B TZ
 is used directly as a specification of the time conversion information,
 it must have the following syntax (spaces inserted for clarity):
 .IP
 \fIstd\|offset\fR[\fIdst\fR[\fIoffset\fR][\fB,\fIrule\fR]]
 .PP
 Where:
 .RS
 .TP 15
 .IR std " and " dst
 Three or more bytes that are the designation for the standard
 .RI ( std )
-or summer
-.RI ( dst )
+or the alternative
+.RI ( dst ,
+such as daylight saving time)
 time zone.  Only
 .I std
 is required; if
 .I dst
-is missing, then summer time does not apply in this locale.
+is missing, then daylight saving time does not apply in this locale.
 Upper- and lowercase letters are explicitly allowed.  Any characters
 except a leading colon
 .RB ( : ),
 digits, comma
 .RB ( , ),
-minus
-.RB ( \(mi ),
-plus
-.RB ( \(pl ),
-and ASCII NUL are allowed.
+ASCII minus
+.RB ( \*- ),
+ASCII plus
+.RB ( + ),
+and NUL bytes are allowed.
+Alternatively, a designation can be surrounded by angle brackets
+.B <
+and
+.BR > ;
+in this case, the designation can contain any characters other than
+.B >
+and NUL.
 .TP
 .I offset
 Indicates the value one must add to the local time to arrive at
 Coordinated Universal Time.  The
 .I offset
 has the form:
 .RS
 .IP
 \fIhh\fR[\fB:\fImm\fR[\fB:\fIss\fR]]
 .RE
 .IP
 The minutes
 .RI ( mm )
 and seconds
 .RI ( ss )
 are optional.  The hour
 .RI ( hh )
 is required and may be a single digit.  The
 .I offset
 following
 .I std
 is required.  If no
 .I offset
 follows
 .IR dst ,
-summer time is assumed to be one hour ahead of standard time.  One or
+daylight saving time is assumed to be one hour ahead of standard time.  One or
 more digits may be used; the value is always interpreted as a decimal
 number.  The hour must be between zero and 24, and the minutes (and
-seconds) \(em if present \(em between zero and 59.  If preceded by a
-.RB `` \(mi '',
+seconds) \*(en if present \*(en between zero and 59.  If preceded by a
+.q "\*-" ,
 the time zone shall be east of the Prime Meridian; otherwise it shall be
 west (which may be indicated by an optional preceding
-.RB `` \(pl '').
+.q "+" .
 .TP
 .I rule
-Indicates when to change to and back from summer time.  The
+Indicates when to change to and back from daylight saving time.  The
 .I rule
 has the form:
 .RS
 .IP
 \fIdate\fB/\fItime\fB,\fIdate\fB/\fItime\fR
 .RE
 .IP
 where the first
 .I date
-describes when the change from standard to summer time occurs and the
+describes when the change from standard to daylight saving time occurs and the
 second
 .I date
 describes when the change back happens.  Each
 .I time
 field describes when, in current local time, the change to the other
 time is made.
+As an extension to POSIX, daylight saving is assumed to be in effect
+all year if it begins January 1 at 00:00 and ends December 31 at
+24:00 plus the difference between daylight saving and standard time,
+leaving no room for standard time in the calendar.
 .IP
 The format of
 .I date
 is one of the following:
 .RS
 .TP 10
 .BI J n
 The Julian day
 .I n
 .RI "(1\ \(<=" "\ n\ " "\(<=\ 365).
-Leap days are not counted; that is, in all years \(em including leap
-years \(em February 28 is day 59 and March 1 is day 60.  It is
+Leap days are not counted; that is, in all years \*(en including leap
+years \*(en February 28 is day 59 and March 1 is day 60.  It is
 impossible to explicitly refer to the occasional February 29.
 .TP
 .I n
 The zero-based Julian day
 .RI "(0\ \(<=" "\ n\ " "\(<=\ 365).
 Leap days are counted, and it is possible to refer to February 29.
 .TP
 .BI M m . n . d
 The
 .IR d' th
 day
 .RI "(0\ \(<=" "\ d\ " "\(<=\ 6)
 of week
 .I n
 of month
 .I m
 of the year
 .RI "(1\ \(<=" "\ n\ " "\(<=\ 5,
 .RI "1\ \(<=" "\ m\ " "\(<=\ 12,
-where week 5 means ``the last
-.I d
-day in month
-.IR m ''
+where week 5 means
+.q "the last \fId\fP day in month \fIm\fP"
 which may occur in either the fourth or the fifth week).  Week 1 is the
 first week in which the
 .IR d' th
 day occurs.  Day zero is Sunday.
 .RE
 .IP "" 15
 The
 .I time
 has the same format as
 .I offset
-except that no leading sign
-.RB (`` \(mi ''
+except that POSIX does not allow a leading sign (\c
+.q "\*-"
 or
-.RB `` \(pl '')
-is allowed.  The default, if
+.q "+" ).
+As an extension to POSIX, the hours part of
+.I time
+can range from \-167 through 167; this allows for unusual rules such
+as
+.q "the Saturday before the first Sunday of March" .
+The default, if
 .I time
 is not given, is
 .BR 02:00:00 .
 .RE
 .LP
+Here are some examples of
+.B TZ
+values that directly specify the timezone; they use some of the
+extensions to POSIX.
+.TP
+.B EST5
+stands for US Eastern Standard
+Time (EST), 5 hours behind UT, without daylight saving.
+.TP
+.B <+12>\*-12<+13>,M11.1.0,M1.2.1/147
+stands for Fiji time, 12 hours ahead
+of UT, springing forward on November's first Sunday at 02:00, and
+falling back on January's second Monday at 147:00 (i.e., 03:00 on the
+first Sunday on or after January 14).  The abbreviations for standard
+and daylight saving time are
+.q "+12"
+and
+.q "+13".
+.TP
+.B IST\*-2IDT,M3.4.4/26,M10.5.0
+stands for Israel Standard Time (IST) and Israel Daylight Time (IDT),
+2 hours ahead of UT, springing forward on March's fourth
+Thursday at 26:00 (i.e., 02:00 on the first Friday on or after March
+23), and falling back on October's last Sunday at 02:00.
+.TP
+.B <\*-04>4<\*-03>,J1/0,J365/25
+stands for permanent daylight saving time, 3 hours behind UT with
+abbreviation
+.q "\*-03".
+There is a dummy fall-back transition on December 31 at 25:00 daylight
+saving time (i.e., 24:00 standard time, equivalent to January 1 at
+00:00 standard time), and a simultaneous spring-forward transition on
+January 1 at 00:00 standard time, so daylight saving time is in effect
+all year and the initial
+.B <\*-04>
+is a placeholder.
+.TP
+.B <\*-03>3<\*-02>,M3.5.0/\*-2,M10.5.0/\*-1
+stands for time in western Greenland, 3 hours behind UT, where clocks
+follow the EU rules of
+springing forward on March's last Sunday at 01:00 UT (\-02:00 local
+time, i.e., 22:00 the previous day) and falling back on October's last
+Sunday at 01:00 UT (\-01:00 local time, i.e., 23:00 the previous day).
+The abbreviations for standard and daylight saving time are
+.q "\*-03"
+and
+.q "\*-02".
+.PP
 If no
 .I rule
 is present in
 .BR TZ ,
 the rules specified
 by the
-.IR tzfile (5)-format
+.BR tzfile (5)-format
 file
 .B posixrules
 in the system time conversion information directory are used, with the
-standard and summer time offsets from UTC replaced by those specified by
+standard and daylight saving time offsets from UT replaced by those specified by
 the
 .I offset
 values in
 .BR TZ .
 .PP
 For compatibility with System V Release 3.1, a semicolon
 .RB ( ; )
 may be used to separate the
 .I rule
 from the rest of the specification.
-.PP
-If the
-.B TZ
-environment variable does not specify a
-.IR tzfile (5)-format
-and cannot be interpreted as a direct specification,
-UTC is used.
 .SH FILES
-.ta \w'/usr/local/etc/zoneinfo/posixrules\0\0'u
-/usr/local/etc/zoneinfo	time zone information directory
+.ta \w'/usr/share/zoneinfo/posixrules\0\0'u
+/usr/share/zoneinfo	timezone information directory
 .br
-/usr/local/etc/zoneinfo/localtime	local time zone file
+/usr/share/zoneinfo/localtime	local timezone file
 .br
-/usr/local/etc/zoneinfo/posixrules	used with POSIX-style TZ's
+/usr/share/zoneinfo/posixrules	used with POSIX-style TZ's
 .br
-/usr/local/etc/zoneinfo/GMT	for UTC leap seconds
+/usr/share/zoneinfo/GMT	for UTC leap seconds
 .sp
 If
-.B /usr/local/etc/zoneinfo/GMT
+.B /usr/share/zoneinfo/GMT
 is absent,
 UTC leap seconds are loaded from
-.BR /usr/local/etc/zoneinfo/posixrules .
+.BR /usr/share/zoneinfo/posixrules .
 .SH SEE ALSO
 getenv(3),
 newctime(3),
 newstrftime(3),
 time(2),
 tzfile(5)
-.\" @(#)newtzset.3	8.2
 .\" This file is in the public domain, so clarified as of
 .\" 2009-05-17 by Arthur David Olson.
diff --git a/newtzset.3.txt b/newtzset.3.txt
index 9d7d02233ee0..171e8291f8ce 100644
--- a/newtzset.3.txt
+++ b/newtzset.3.txt
@@ -1,153 +1,199 @@
-NAME
+NEWTZSET(3)                Library Functions Manual                NEWTZSET(3)
 
-     tzset - initialize time conversion information
+NAME
+       tzset - initialize time conversion information
 
 SYNOPSIS
-     void tzset()
+       #include 
+
+       timezone_t tzalloc(char const *TZ);
 
-     cc ... -ltz
+       void tzfree(timezone_t tz);
+
+       void tzset(void);
+
+       cc ... -ltz
 
 DESCRIPTION
-     Tzset uses the value of the environment variable TZ to set
-     time conversion information used by localtime.  If TZ does
-     not appear in the environment, the best available
-     approximation to local wall clock time, as specified by the
-     tzfile(5)-format file localtime in the system time
-     conversion information directory, is used by localtime.  If
-     TZ appears in the environment but its value is a null
-     string, Coordinated Universal Time (UTC) is used (without
-     leap second correction).  If TZ appears in the environment
-     and its value is not a null string:
-
-          if the value begins with a colon, it is used as a
-          pathname of a file from which to read the time
-          conversion information;
-
-          if the value does not begin with a colon, it is first
-          used as the pathname of a file from which to read the
-          time conversion information, and, if that file cannot
-          be read, is used directly as a specification of the
-          time conversion information.
-
-     When TZ is used as a pathname, if it begins with a slash, it
-     is used as an absolute pathname; otherwise, it is used as a
-     pathname relative to a system time conversion information
-     directory.  The file must be in the format specified in
-     tzfile(5).
-
-     When TZ is used directly as a specification of the time
-     conversion information, it must have the following syntax
-     (spaces inserted for clarity):
-
-          stdoffset[dst[offset][,rule]]
-
-     Where:
-
-          std and dst    Three or more bytes that are the
-                         designation for the standard (std) or
-                         summer (dst) time zone.  Only std is
-                         required; if dst is missing, then summer
-                         time does not apply in this locale.
-                         Upper- and lowercase letters are
-                         explicitly allowed.  Any characters
-                         except a leading colon (:), digits,
-                         comma (,), minus (-), plus (+), and
-                         ASCII NUL are allowed.
-
-          offset         Indicates the value one must add to the
-                         local time to arrive at Coordinated
-                         Universal Time.  The offset has the
-                         form:
-
-                              hh[:mm[:ss]]
-
-                         The minutes (mm) and seconds (ss) are
-                         optional.  The hour (hh) is required and
-                         may be a single digit.  The offset
-                         following std is required.  If no offset
-                         follows dst, summer time is assumed to
-                         be one hour ahead of standard time.  One
-                         or more digits may be used; the value is
-                         always interpreted as a decimal number.
-                         The hour must be between zero and 24,
-                         and the minutes (and seconds) -- if
-                         present -- between zero and 59.  If
-                         preceded by a ``-'', the time zone shall
-                         be east of the Prime Meridian; otherwise
-                         it shall be west (which may be indicated
-                         by an optional preceding ``+'').
-
-          rule           Indicates when to change to and back
-                         from summer time.  The rule has the
-                         form:
-
-                              date/time,date/time
-
-                         where the first date describes when the
-                         change from standard to summer time
-                         occurs and the second date describes
-                         when the change back happens.  Each time
-                         field describes when, in current local
-                         time, the change to the other time is
-                         made.
-
-                         The format of date is one of the
-                         following:
-
-                         Jn        The Julian day n
-                                   (1 <= n <= 365).  Leap days
-                                   are not counted; that is, in
-                                   all years -- including leap
-                                   years -- February 28 is day 59
-                                   and March 1 is day 60.  It is
-                                   impossible to explicitly refer
-                                   to the occasional February 29.
-
-                         n         The zero-based Julian day
-                                   (0 <= n <= 365).  Leap days
-                                   are counted, and it is
-                                   possible to refer to February
-                                   29.
-
-                         Mm.n.d    The d'th day (0 <= d <= 6) of
-                                   week n of month m of the year
-                                   (1 <= n <= 5, 1 <= m <= 12,
-                                   where week 5 means ``the last
-                                   d day in month m'' which may
-                                   occur in either the fourth or
-                                   the fifth week).  Week 1 is
-                                   the first week in which the
-                                   d'th day occurs.  Day zero is
-                                   Sunday.
-
-                         The time has the same format as offset
-                         except that no leading sign (``-'' or
-                         ``+'') is allowed.  The default, if time
-                         is not given, is 02:00:00.
-
-     If no rule is present in TZ, the rules specified by the
-     tzfile(5)-format file posixrules in the system time
-     conversion information directory are used, with the standard
-     and summer time offsets from UTC replaced by those specified
-     by the offset values in TZ.
-     For compatibility with System V Release 3.1, a semicolon (;)
-     may be used to separate the rule from the rest of the
-     specification.
-
-     If the TZ environment variable does not specify a
-     tzfile(5)-format and cannot be interpreted as a direct
-     specification, UTC is used.
+       The tzalloc function allocates and returns a timezone object described
+       by TZ.  If TZ is not a valid timezone description, or if the object
+       cannot be allocated, tzalloc returns a null pointer and sets errno.
+
+       The tzfree function frees a timezone object tz, which should have been
+       successfully allocated by tzalloc.  This invalidates any tm_zone
+       pointers that tz was used to set.
+
+       The tzset function acts like tzalloc(getenv("TZ")), except it saves any
+       resulting timezone object into internal storage that is accessed by
+       localtime, localtime_r, and mktime.  The anonymous shared timezone
+       object is freed by the next call to tzset.  If the implied call to
+       tzalloc fails, tzset falls back on Universal Time (UT).
+
+       If TZ is null, the best available approximation to local (wall clock)
+       time, as specified by the tzfile(5)-format file localtime in the system
+       time conversion information directory, is used.  If TZ is the empty
+       string, UT is used, with the abbreviation "UTC" and without leap second
+       correction; please see newctime(3) for more about UT, UTC, and leap
+       seconds.  If TZ is nonnull and nonempty:
+
+              if the value begins with a colon, it is used as a pathname of a
+              file from which to read the time conversion information;
+
+              if the value does not begin with a colon, it is first used as
+              the pathname of a file from which to read the time conversion
+              information, and, if that file cannot be read, is used directly
+              as a specification of the time conversion information.
+
+       When TZ is used as a pathname, if it begins with a slash, it is used as
+       an absolute pathname; otherwise, it is used as a pathname relative to a
+       system time conversion information directory.  The file must be in the
+       format specified in tzfile(5).
+
+       When TZ is used directly as a specification of the time conversion
+       information, it must have the following syntax (spaces inserted for
+       clarity):
+
+              stdoffset[dst[offset][,rule]]
+
+       Where:
+
+              std and dst    Three or more bytes that are the designation for
+                             the standard (std) or the alternative (dst, such
+                             as daylight saving time) time zone.  Only std is
+                             required; if dst is missing, then daylight saving
+                             time does not apply in this locale.  Upper- and
+                             lowercase letters are explicitly allowed.  Any
+                             characters except a leading colon (:), digits,
+                             comma (,), ASCII minus (-), ASCII plus (+), and
+                             NUL bytes are allowed.  Alternatively, a
+                             designation can be surrounded by angle brackets <
+                             and >; in this case, the designation can contain
+                             any characters other than > and NUL.
+
+              offset         Indicates the value one must add to the local
+                             time to arrive at Coordinated Universal Time.
+                             The offset has the form:
+
+                                    hh[:mm[:ss]]
+
+                             The minutes (mm) and seconds (ss) are optional.
+                             The hour (hh) is required and may be a single
+                             digit.  The offset following std is required.  If
+                             no offset follows dst, daylight saving time is
+                             assumed to be one hour ahead of standard time.
+                             One or more digits may be used; the value is
+                             always interpreted as a decimal number.  The hour
+                             must be between zero and 24, and the minutes (and
+                             seconds) - if present - between zero and 59.  If
+                             preceded by a "-", the time zone shall be east of
+                             the Prime Meridian; otherwise it shall be west
+                             (which may be indicated by an optional preceding
+                             "+".
+
+              rule           Indicates when to change to and back from
+                             daylight saving time.  The rule has the form:
+
+                                    date/time,date/time
+
+                             where the first date describes when the change
+                             from standard to daylight saving time occurs and
+                             the second date describes when the change back
+                             happens.  Each time field describes when, in
+                             current local time, the change to the other time
+                             is made.  As an extension to POSIX, daylight
+                             saving is assumed to be in effect all year if it
+                             begins January 1 at 00:00 and ends December 31 at
+                             24:00 plus the difference between daylight saving
+                             and standard time, leaving no room for standard
+                             time in the calendar.
+
+                             The format of date is one of the following:
+
+                             Jn        The Julian day n (1 <= n <= 365).  Leap
+                                       days are not counted; that is, in all
+                                       years - including leap years - February
+                                       28 is day 59 and March 1 is day 60.  It
+                                       is impossible to explicitly refer to
+                                       the occasional February 29.
+
+                             n         The zero-based Julian day
+                                       (0 <= n <= 365).  Leap days are
+                                       counted, and it is possible to refer to
+                                       February 29.
+
+                             Mm.n.d    The d'th day (0 <= d <= 6) of week n of
+                                       month m of the year (1 <= n <= 5,
+                                       1 <= m <= 12, where week 5 means "the
+                                       last d day in month m" which may occur
+                                       in either the fourth or the fifth
+                                       week).  Week 1 is the first week in
+                                       which the d'th day occurs.  Day zero is
+                                       Sunday.
+
+                             The time has the same format as offset except
+                             that POSIX does not allow a leading sign ("-" or
+                             "+").  As an extension to POSIX, the hours part
+                             of time can range from -167 through 167; this
+                             allows for unusual rules such as "the Saturday
+                             before the first Sunday of March".  The default,
+                             if time is not given, is 02:00:00.
+
+       Here are some examples of TZ values that directly specify the timezone;
+       they use some of the extensions to POSIX.
+
+       EST5   stands for US Eastern Standard Time (EST), 5 hours behind UT,
+              without daylight saving.
+
+       <+12>-12<+13>,M11.1.0,M1.2.1/147
+              stands for Fiji time, 12 hours ahead of UT, springing forward on
+              November's first Sunday at 02:00, and falling back on January's
+              second Monday at 147:00 (i.e., 03:00 on the first Sunday on or
+              after January 14).  The abbreviations for standard and daylight
+              saving time are "+12" and "+13".
+
+       IST-2IDT,M3.4.4/26,M10.5.0
+              stands for Israel Standard Time (IST) and Israel Daylight Time
+              (IDT), 2 hours ahead of UT, springing forward on March's fourth
+              Thursday at 26:00 (i.e., 02:00 on the first Friday on or after
+              March 23), and falling back on October's last Sunday at 02:00.
+
+       <-04>4<-03>,J1/0,J365/25
+              stands for permanent daylight saving time, 3 hours behind UT
+              with abbreviation "-03".  There is a dummy fall-back transition
+              on December 31 at 25:00 daylight saving time (i.e., 24:00
+              standard time, equivalent to January 1 at 00:00 standard time),
+              and a simultaneous spring-forward transition on January 1 at
+              00:00 standard time, so daylight saving time is in effect all
+              year and the initial <-04> is a placeholder.
+
+       <-03>3<-02>,M3.5.0/-2,M10.5.0/-1
+              stands for time in western Greenland, 3 hours behind UT, where
+              clocks follow the EU rules of springing forward on March's last
+              Sunday at 01:00 UT (-02:00 local time, i.e., 22:00 the previous
+              day) and falling back on October's last Sunday at 01:00 UT
+              (-01:00 local time, i.e., 23:00 the previous day).  The
+              abbreviations for standard and daylight saving time are "-03"
+              and "-02".
+
+       If no rule is present in TZ, the rules specified by the
+       tzfile(5)-format file posixrules in the system time conversion
+       information directory are used, with the standard and daylight saving
+       time offsets from UT replaced by those specified by the offset values
+       in TZ.
+
+       For compatibility with System V Release 3.1, a semicolon (;) may be
+       used to separate the rule from the rest of the specification.
 
 FILES
-     /usr/local/etc/zoneinfo             time zone information
-     directory
-     /usr/local/etc/zoneinfo/localtime   local time zone file
-     /usr/local/etc/zoneinfo/posixrules  used with POSIX-style
-     TZ's
-     /usr/local/etc/zoneinfo/GMT         for UTC leap seconds
+       /usr/share/zoneinfo             timezone information directory
+       /usr/share/zoneinfo/localtime   local timezone file
+       /usr/share/zoneinfo/posixrules  used with POSIX-style TZ's
+       /usr/share/zoneinfo/GMT         for UTC leap seconds
 
-     If /usr/local/etc/zoneinfo/GMT is absent, UTC leap seconds
-     are loaded from /usr/local/etc/zoneinfo/posixrules.
+       If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from
+       /usr/share/zoneinfo/posixrules.
 
 SEE ALSO
-     getenv(3), newctime(3), newstrftime(3), time(2), tzfile(5)
+       getenv(3), newctime(3), newstrftime(3), time(2), tzfile(5)
+
+                                                                   NEWTZSET(3)
diff --git a/private.h b/private.h
index 008d468ac787..9c31ec5434f2 100644
--- a/private.h
+++ b/private.h
@@ -1,298 +1,814 @@
+/* Private header for tzdb code.  */
+
 #ifndef PRIVATE_H
 
 #define PRIVATE_H
 
 /*
 ** This file is in the public domain, so clarified as of
 ** 1996-06-05 by Arthur David Olson.
 */
 
 /*
 ** This header is for use ONLY with the time conversion code.
 ** There is no guarantee that it will remain unchanged,
 ** or that it will remain at all.
 ** Do NOT copy it to any system include directory.
 ** Thank you!
 */
 
 /*
-** ID
+** zdump has been made independent of the rest of the time
+** conversion package to increase confidence in the verification it provides.
+** You can use zdump to help in verifying other implementations.
+** To do this, compile with -DUSE_LTZ=0 and link without the tz library.
 */
+#ifndef USE_LTZ
+# define USE_LTZ 1
+#endif
 
-#ifndef lint
-#ifndef NOID
-static char	privatehid[] = "@(#)private.h	8.6";
-#endif /* !defined NOID */
-#endif /* !defined lint */
-
+/* This string was in the Factory zone through version 2016f.  */
 #define GRANDPARENTED	"Local time zone must be set--see zic manual page"
 
 /*
 ** Defaults for preprocessor symbols.
-** You can override these in your C compiler options, e.g. `-DHAVE_ADJTIME=0'.
+** You can override these in your C compiler options, e.g. '-DHAVE_GETTEXT=1'.
 */
 
-#ifndef HAVE_ADJTIME
-#define HAVE_ADJTIME		1
-#endif /* !defined HAVE_ADJTIME */
+#ifndef HAVE_DECL_ASCTIME_R
+# define HAVE_DECL_ASCTIME_R 1
+#endif
+
+#if !defined HAVE_GENERIC && defined __has_extension
+# if __has_extension(c_generic_selections)
+#  define HAVE_GENERIC 1
+# else
+#  define HAVE_GENERIC 0
+# endif
+#endif
+/* _Generic is buggy in pre-4.9 GCC.  */
+#if !defined HAVE_GENERIC && defined __GNUC__
+# define HAVE_GENERIC (4 < __GNUC__ + (9 <= __GNUC_MINOR__))
+#endif
+#ifndef HAVE_GENERIC
+# define HAVE_GENERIC (201112 <= __STDC_VERSION__)
+#endif
 
 #ifndef HAVE_GETTEXT
-#define HAVE_GETTEXT		0
+# define HAVE_GETTEXT 0
 #endif /* !defined HAVE_GETTEXT */
 
 #ifndef HAVE_INCOMPATIBLE_CTIME_R
-#define HAVE_INCOMPATIBLE_CTIME_R	0
-#endif /* !defined INCOMPATIBLE_CTIME_R */
+# define HAVE_INCOMPATIBLE_CTIME_R 0
+#endif
+
+#ifndef HAVE_LINK
+# define HAVE_LINK 1
+#endif /* !defined HAVE_LINK */
+
+#ifndef HAVE_MALLOC_ERRNO
+# define HAVE_MALLOC_ERRNO 1
+#endif
+
+#ifndef HAVE_POSIX_DECLS
+# define HAVE_POSIX_DECLS 1
+#endif
+
+#ifndef HAVE_STDBOOL_H
+# define HAVE_STDBOOL_H (199901 <= __STDC_VERSION__)
+#endif
 
-#ifndef HAVE_SETTIMEOFDAY
-#define HAVE_SETTIMEOFDAY	3
-#endif /* !defined HAVE_SETTIMEOFDAY */
+#ifndef HAVE_STRDUP
+# define HAVE_STRDUP 1
+#endif
+
+#ifndef HAVE_STRTOLL
+# define HAVE_STRTOLL 1
+#endif
 
 #ifndef HAVE_SYMLINK
-#define HAVE_SYMLINK		1
+# define HAVE_SYMLINK 1
 #endif /* !defined HAVE_SYMLINK */
 
 #ifndef HAVE_SYS_STAT_H
-#define HAVE_SYS_STAT_H		1
+# define HAVE_SYS_STAT_H 1
 #endif /* !defined HAVE_SYS_STAT_H */
 
-#ifndef HAVE_SYS_WAIT_H
-#define HAVE_SYS_WAIT_H		1
-#endif /* !defined HAVE_SYS_WAIT_H */
-
 #ifndef HAVE_UNISTD_H
-#define HAVE_UNISTD_H		1
+# define HAVE_UNISTD_H 1
 #endif /* !defined HAVE_UNISTD_H */
 
 #ifndef HAVE_UTMPX_H
-#define HAVE_UTMPX_H		0
+# define HAVE_UTMPX_H 1
 #endif /* !defined HAVE_UTMPX_H */
 
-#ifndef LOCALE_HOME
-#define LOCALE_HOME		"/usr/lib/locale"
-#endif /* !defined LOCALE_HOME */
+#ifndef NETBSD_INSPIRED
+# define NETBSD_INSPIRED 1
+#endif
 
 #if HAVE_INCOMPATIBLE_CTIME_R
-#define asctime_r _incompatible_asctime_r
-#define ctime_r _incompatible_ctime_r
+# define asctime_r _incompatible_asctime_r
+# define ctime_r _incompatible_ctime_r
 #endif /* HAVE_INCOMPATIBLE_CTIME_R */
 
+/* Enable tm_gmtoff, tm_zone, and environ on GNUish systems.  */
+#define _GNU_SOURCE 1
+/* Fix asctime_r on Solaris 11.  */
+#define _POSIX_PTHREAD_SEMANTICS 1
+/* Enable strtoimax on pre-C99 Solaris 11.  */
+#define __EXTENSIONS__ 1
+
+/* To avoid having 'stat' fail unnecessarily with errno == EOVERFLOW,
+   enable large files on GNUish systems ...  */
+#ifndef _FILE_OFFSET_BITS
+# define _FILE_OFFSET_BITS 64
+#endif
+/* ... and on AIX ...  */
+#define _LARGE_FILES 1
+/* ... and enable large inode numbers on Mac OS X 10.5 and later.  */
+#define _DARWIN_USE_64_BIT_INODE 1
+
 /*
 ** Nested includes
 */
 
-#include "sys/types.h"	/* for time_t */
-#include "stdio.h"
-#include "errno.h"
-#include "string.h"
-#include "limits.h"	/* for CHAR_BIT et al. */
-#include "time.h"
-#include "stdlib.h"
+/* Avoid clashes with NetBSD by renaming NetBSD's declarations.
+   If defining the 'timezone' variable, avoid a clash with FreeBSD's
+   'timezone' function by renaming its declaration.  */
+#define localtime_rz sys_localtime_rz
+#define mktime_z sys_mktime_z
+#define posix2time_z sys_posix2time_z
+#define time2posix_z sys_time2posix_z
+#if defined USG_COMPAT && USG_COMPAT == 2
+# define timezone sys_timezone
+#endif
+#define timezone_t sys_timezone_t
+#define tzalloc sys_tzalloc
+#define tzfree sys_tzfree
+#include 
+#undef localtime_rz
+#undef mktime_z
+#undef posix2time_z
+#undef time2posix_z
+#if defined USG_COMPAT && USG_COMPAT == 2
+# undef timezone
+#endif
+#undef timezone_t
+#undef tzalloc
+#undef tzfree
+
+#include 	/* for time_t */
+#include 
+#include 	/* for CHAR_BIT et al. */
+#include 
 
-#if HAVE_GETTEXT
-#include "libintl.h"
-#endif /* HAVE_GETTEXT */
+#include 
 
-#if HAVE_SYS_WAIT_H
-#include 	/* for WIFEXITED and WEXITSTATUS */
-#endif /* HAVE_SYS_WAIT_H */
+#ifndef EINVAL
+# define EINVAL ERANGE
+#endif
+
+#ifndef ELOOP
+# define ELOOP EINVAL
+#endif
+#ifndef ENAMETOOLONG
+# define ENAMETOOLONG EINVAL
+#endif
+#ifndef ENOMEM
+# define ENOMEM EINVAL
+#endif
+#ifndef ENOTSUP
+# define ENOTSUP EINVAL
+#endif
+#ifndef EOVERFLOW
+# define EOVERFLOW EINVAL
+#endif
 
-#ifndef WIFEXITED
-#define WIFEXITED(status)	(((status) & 0xff) == 0)
-#endif /* !defined WIFEXITED */
-#ifndef WEXITSTATUS
-#define WEXITSTATUS(status)	(((status) >> 8) & 0xff)
-#endif /* !defined WEXITSTATUS */
+#if HAVE_GETTEXT
+# include 
+#endif /* HAVE_GETTEXT */
 
 #if HAVE_UNISTD_H
-#include "unistd.h"	/* for F_OK, R_OK, and other POSIX goodness */
+# include  /* for R_OK, and other POSIX goodness */
 #endif /* HAVE_UNISTD_H */
 
-#ifndef F_OK
-#define F_OK	0
-#endif /* !defined F_OK */
+#ifndef HAVE_STRFTIME_L
+# if _POSIX_VERSION < 200809
+#  define HAVE_STRFTIME_L 0
+# else
+#  define HAVE_STRFTIME_L 1
+# endif
+#endif
+
+#ifndef USG_COMPAT
+# ifndef _XOPEN_VERSION
+#  define USG_COMPAT 0
+# else
+#  define USG_COMPAT 1
+# endif
+#endif
+
+#ifndef HAVE_TZNAME
+# if _POSIX_VERSION < 198808 && !USG_COMPAT
+#  define HAVE_TZNAME 0
+# else
+#  define HAVE_TZNAME 1
+# endif
+#endif
+
+#ifndef ALTZONE
+# if defined __sun || defined _M_XENIX
+#  define ALTZONE 1
+# else
+#  define ALTZONE 0
+# endif
+#endif
+
 #ifndef R_OK
-#define R_OK	4
+# define R_OK 4
 #endif /* !defined R_OK */
 
-/* Unlike 's isdigit, this also works if c < 0 | c > UCHAR_MAX. */
-#define is_digit(c) ((unsigned)(c) - '0' <= 9)
-
 /*
 ** Define HAVE_STDINT_H's default value here, rather than at the
-** start, since __GLIBC__'s value depends on previously-included
-** files.
-** (glibc 2.1 and later have stdint.h, even with pre-C99 compilers.)
+** start, since __GLIBC__ and INTMAX_MAX's values depend on
+** previously-included files.  glibc 2.1 and Solaris 10 and later have
+** stdint.h, even with pre-C99 compilers.
 */
 #ifndef HAVE_STDINT_H
-#define HAVE_STDINT_H \
-	(199901 <= __STDC_VERSION__ || \
-	2 < (__GLIBC__ + (0 < __GLIBC_MINOR__)))
+# define HAVE_STDINT_H \
+   (199901 <= __STDC_VERSION__ \
+    || 2 < __GLIBC__ + (1 <= __GLIBC_MINOR__) \
+    || __CYGWIN__ || INTMAX_MAX)
 #endif /* !defined HAVE_STDINT_H */
 
 #if HAVE_STDINT_H
-#include "stdint.h"
+# include 
 #endif /* !HAVE_STDINT_H */
 
-#ifndef INT_FAST64_MAX
+#ifndef HAVE_INTTYPES_H
+# define HAVE_INTTYPES_H HAVE_STDINT_H
+#endif
+#if HAVE_INTTYPES_H
+# include 
+#endif
+
 /* Pre-C99 GCC compilers define __LONG_LONG_MAX__ instead of LLONG_MAX.  */
-#if defined LLONG_MAX || defined __LONG_LONG_MAX__
+#ifdef __LONG_LONG_MAX__
+# ifndef LLONG_MAX
+#  define LLONG_MAX __LONG_LONG_MAX__
+# endif
+# ifndef LLONG_MIN
+#  define LLONG_MIN (-1 - LLONG_MAX)
+# endif
+#endif
+
+#ifndef INT_FAST64_MAX
+# ifdef LLONG_MAX
 typedef long long	int_fast64_t;
-#else /* ! (defined LLONG_MAX || defined __LONG_LONG_MAX__) */
-#if (LONG_MAX >> 31) < 0xffffffff
+#  define INT_FAST64_MIN LLONG_MIN
+#  define INT_FAST64_MAX LLONG_MAX
+# else
+#  if LONG_MAX >> 31 < 0xffffffff
 Please use a compiler that supports a 64-bit integer type (or wider);
 you may need to compile with "-DHAVE_STDINT_H".
-#endif /* (LONG_MAX >> 31) < 0xffffffff */
+#  endif
 typedef long		int_fast64_t;
-#endif /* ! (defined LLONG_MAX || defined __LONG_LONG_MAX__) */
-#endif /* !defined INT_FAST64_MAX */
+#  define INT_FAST64_MIN LONG_MIN
+#  define INT_FAST64_MAX LONG_MAX
+# endif
+#endif
+
+#ifndef PRIdFAST64
+# if INT_FAST64_MAX == LLONG_MAX
+#  define PRIdFAST64 "lld"
+# else
+#  define PRIdFAST64 "ld"
+# endif
+#endif
+
+#ifndef SCNdFAST64
+# define SCNdFAST64 PRIdFAST64
+#endif
+
+#ifndef INT_FAST32_MAX
+# if INT_MAX >> 31 == 0
+typedef long int_fast32_t;
+#  define INT_FAST32_MAX LONG_MAX
+#  define INT_FAST32_MIN LONG_MIN
+# else
+typedef int int_fast32_t;
+#  define INT_FAST32_MAX INT_MAX
+#  define INT_FAST32_MIN INT_MIN
+# endif
+#endif
+
+#ifndef INTMAX_MAX
+# ifdef LLONG_MAX
+typedef long long intmax_t;
+#  if HAVE_STRTOLL
+#   define strtoimax strtoll
+#  endif
+#  define INTMAX_MAX LLONG_MAX
+#  define INTMAX_MIN LLONG_MIN
+# else
+typedef long intmax_t;
+#  define INTMAX_MAX LONG_MAX
+#  define INTMAX_MIN LONG_MIN
+# endif
+# ifndef strtoimax
+#  define strtoimax strtol
+# endif
+#endif
+
+#ifndef PRIdMAX
+# if INTMAX_MAX == LLONG_MAX
+#  define PRIdMAX "lld"
+# else
+#  define PRIdMAX "ld"
+# endif
+#endif
+
+#ifndef UINT_FAST32_MAX
+typedef unsigned long uint_fast32_t;
+#endif
+
+#ifndef UINT_FAST64_MAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+typedef unsigned long long uint_fast64_t;
+# else
+#  if ULONG_MAX >> 31 >> 1 < 0xffffffff
+Please use a compiler that supports a 64-bit integer type (or wider);
+you may need to compile with "-DHAVE_STDINT_H".
+#  endif
+typedef unsigned long	uint_fast64_t;
+# endif
+#endif
+
+#ifndef UINTMAX_MAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+typedef unsigned long long uintmax_t;
+# else
+typedef unsigned long uintmax_t;
+# endif
+#endif
+
+#ifndef PRIuMAX
+# if defined ULLONG_MAX || defined __LONG_LONG_MAX__
+#  define PRIuMAX "llu"
+# else
+#  define PRIuMAX "lu"
+# endif
+#endif
 
 #ifndef INT32_MAX
-#define INT32_MAX 0x7fffffff
+# define INT32_MAX 0x7fffffff
 #endif /* !defined INT32_MAX */
 #ifndef INT32_MIN
-#define INT32_MIN (-1 - INT32_MAX)
+# define INT32_MIN (-1 - INT32_MAX)
 #endif /* !defined INT32_MIN */
 
+#ifndef SIZE_MAX
+# define SIZE_MAX ((size_t) -1)
+#endif
+
+#if 3 <= __GNUC__
+# define ATTRIBUTE_CONST __attribute__((const))
+# define ATTRIBUTE_MALLOC __attribute__((__malloc__))
+# define ATTRIBUTE_PURE __attribute__((__pure__))
+# define ATTRIBUTE_FORMAT(spec) __attribute__((__format__ spec))
+#else
+# define ATTRIBUTE_CONST /* empty */
+# define ATTRIBUTE_MALLOC /* empty */
+# define ATTRIBUTE_PURE /* empty */
+# define ATTRIBUTE_FORMAT(spec) /* empty */
+#endif
+
+#if !defined _Noreturn && __STDC_VERSION__ < 201112
+# if 2 < __GNUC__ + (8 <= __GNUC_MINOR__)
+#  define _Noreturn __attribute__((__noreturn__))
+# else
+#  define _Noreturn
+# endif
+#endif
+
+#if __STDC_VERSION__ < 199901 && !defined restrict
+# define restrict /* empty */
+#endif
+
 /*
 ** Workarounds for compilers/systems.
 */
 
-/*
-** Some time.h implementations don't declare asctime_r.
-** Others might define it as a macro.
-** Fix the former without affecting the latter.
-*/
+#ifndef EPOCH_LOCAL
+# define EPOCH_LOCAL 0
+#endif
+#ifndef EPOCH_OFFSET
+# define EPOCH_OFFSET 0
+#endif
+#ifndef RESERVE_STD_EXT_IDS
+# define RESERVE_STD_EXT_IDS 0
+#endif
 
-#ifndef asctime_r
-extern char *	asctime_r(struct tm const *, char *);
+/* If standard C identifiers with external linkage (e.g., localtime)
+   are reserved and are not already being renamed anyway, rename them
+   as if compiling with '-Dtime_tz=time_t'.  */
+#if !defined time_tz && RESERVE_STD_EXT_IDS && USE_LTZ
+# define time_tz time_t
 #endif
 
 /*
-** Private function declarations.
+** Compile with -Dtime_tz=T to build the tz package with a private
+** time_t type equivalent to T rather than the system-supplied time_t.
+** This debugging feature can test unusual design decisions
+** (e.g., time_t wider than 'long', or unsigned time_t) even on
+** typical platforms.
 */
+#if defined time_tz || EPOCH_LOCAL || EPOCH_OFFSET != 0
+# define TZ_TIME_T 1
+#else
+# define TZ_TIME_T 0
+#endif
 
-char *		icalloc(int nelem, int elsize);
-char *		icatalloc(char * old, const char * new);
-char *		icpyalloc(const char * string);
-char *		imalloc(int n);
-void *		irealloc(void * pointer, int size);
-void		icfree(char * pointer);
-void		ifree(char * pointer);
-const char *	scheck(const char * string, const char * format);
+#if defined LOCALTIME_IMPLEMENTATION && TZ_TIME_T
+static time_t sys_time(time_t *x) { return time(x); }
+#endif
+
+#if TZ_TIME_T
+
+typedef time_tz tz_time_t;
+
+# undef  asctime
+# define asctime tz_asctime
+# undef  asctime_r
+# define asctime_r tz_asctime_r
+# undef  ctime
+# define ctime tz_ctime
+# undef  ctime_r
+# define ctime_r tz_ctime_r
+# undef  difftime
+# define difftime tz_difftime
+# undef  gmtime
+# define gmtime tz_gmtime
+# undef  gmtime_r
+# define gmtime_r tz_gmtime_r
+# undef  localtime
+# define localtime tz_localtime
+# undef  localtime_r
+# define localtime_r tz_localtime_r
+# undef  localtime_rz
+# define localtime_rz tz_localtime_rz
+# undef  mktime
+# define mktime tz_mktime
+# undef  mktime_z
+# define mktime_z tz_mktime_z
+# undef  offtime
+# define offtime tz_offtime
+# undef  posix2time
+# define posix2time tz_posix2time
+# undef  posix2time_z
+# define posix2time_z tz_posix2time_z
+# undef  strftime
+# define strftime tz_strftime
+# undef  time
+# define time tz_time
+# undef  time2posix
+# define time2posix tz_time2posix
+# undef  time2posix_z
+# define time2posix_z tz_time2posix_z
+# undef  time_t
+# define time_t tz_time_t
+# undef  timegm
+# define timegm tz_timegm
+# undef  timelocal
+# define timelocal tz_timelocal
+# undef  timeoff
+# define timeoff tz_timeoff
+# undef  tzalloc
+# define tzalloc tz_tzalloc
+# undef  tzfree
+# define tzfree tz_tzfree
+# undef  tzset
+# define tzset tz_tzset
+# if HAVE_STRFTIME_L
+#  undef  strftime_l
+#  define strftime_l tz_strftime_l
+# endif
+# if HAVE_TZNAME
+#  undef  tzname
+#  define tzname tz_tzname
+# endif
+# if USG_COMPAT
+#  undef  daylight
+#  define daylight tz_daylight
+#  undef  timezone
+#  define timezone tz_timezone
+# endif
+# if ALTZONE
+#  undef  altzone
+#  define altzone tz_altzone
+# endif
+
+char *asctime(struct tm const *);
+char *asctime_r(struct tm const *restrict, char *restrict);
+char *ctime(time_t const *);
+char *ctime_r(time_t const *, char *);
+double difftime(time_t, time_t) ATTRIBUTE_CONST;
+size_t strftime(char *restrict, size_t, char const *restrict,
+		struct tm const *restrict);
+# if HAVE_STRFTIME_L
+size_t strftime_l(char *restrict, size_t, char const *restrict,
+		  struct tm const *restrict, locale_t);
+# endif
+struct tm *gmtime(time_t const *);
+struct tm *gmtime_r(time_t const *restrict, struct tm *restrict);
+struct tm *localtime(time_t const *);
+struct tm *localtime_r(time_t const *restrict, struct tm *restrict);
+time_t mktime(struct tm *);
+time_t time(time_t *);
+void tzset(void);
+#endif
+
+#if !HAVE_DECL_ASCTIME_R && !defined asctime_r
+extern char *asctime_r(struct tm const *restrict, char *restrict);
+#endif
+
+#ifndef HAVE_DECL_ENVIRON
+# if defined environ || defined __USE_GNU
+#  define HAVE_DECL_ENVIRON 1
+# else
+#  define HAVE_DECL_ENVIRON 0
+# endif
+#endif
+
+#if !HAVE_DECL_ENVIRON
+extern char **environ;
+#endif
+
+#if 2 <= HAVE_TZNAME + (TZ_TIME_T || !HAVE_POSIX_DECLS)
+extern char *tzname[];
+#endif
+#if 2 <= USG_COMPAT + (TZ_TIME_T || !HAVE_POSIX_DECLS)
+extern long timezone;
+extern int daylight;
+#endif
+#if 2 <= ALTZONE + (TZ_TIME_T || !HAVE_POSIX_DECLS)
+extern long altzone;
+#endif
 
 /*
-** Finally, some convenience items.
+** The STD_INSPIRED functions are similar, but most also need
+** declarations if time_tz is defined.
 */
 
-#ifndef TRUE
-#define TRUE	1
-#endif /* !defined TRUE */
-
-#ifndef FALSE
-#define FALSE	0
-#endif /* !defined FALSE */
+#ifdef STD_INSPIRED
+# if TZ_TIME_T || !defined offtime
+struct tm *offtime(time_t const *, long);
+# endif
+# if TZ_TIME_T || !defined timegm
+time_t timegm(struct tm *);
+# endif
+# if TZ_TIME_T || !defined timelocal
+time_t timelocal(struct tm *);
+# endif
+# if TZ_TIME_T || !defined timeoff
+time_t timeoff(struct tm *, long);
+# endif
+# if TZ_TIME_T || !defined time2posix
+time_t time2posix(time_t);
+# endif
+# if TZ_TIME_T || !defined posix2time
+time_t posix2time(time_t);
+# endif
+#endif
 
-#ifndef TYPE_BIT
-#define TYPE_BIT(type)	(sizeof (type) * CHAR_BIT)
-#endif /* !defined TYPE_BIT */
+/* Infer TM_ZONE on systems where this information is known, but suppress
+   guessing if NO_TM_ZONE is defined.  Similarly for TM_GMTOFF.  */
+#if (defined __GLIBC__ \
+     || defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ \
+     || (defined __APPLE__ && defined __MACH__))
+# if !defined TM_GMTOFF && !defined NO_TM_GMTOFF
+#  define TM_GMTOFF tm_gmtoff
+# endif
+# if !defined TM_ZONE && !defined NO_TM_ZONE
+#  define TM_ZONE tm_zone
+# endif
+#endif
 
-#ifndef TYPE_SIGNED
-#define TYPE_SIGNED(type) (((type) -1) < 0)
-#endif /* !defined TYPE_SIGNED */
+/*
+** Define functions that are ABI compatible with NetBSD but have
+** better prototypes.  NetBSD 6.1.4 defines a pointer type timezone_t
+** and labors under the misconception that 'const timezone_t' is a
+** pointer to a constant.  This use of 'const' is ineffective, so it
+** is not done here.  What we call 'struct state' NetBSD calls
+** 'struct __state', but this is a private name so it doesn't matter.
+*/
+#if NETBSD_INSPIRED
+typedef struct state *timezone_t;
+struct tm *localtime_rz(timezone_t restrict, time_t const *restrict,
+			struct tm *restrict);
+time_t mktime_z(timezone_t restrict, struct tm *restrict);
+timezone_t tzalloc(char const *);
+void tzfree(timezone_t);
+# ifdef STD_INSPIRED
+#  if TZ_TIME_T || !defined posix2time_z
+time_t posix2time_z(timezone_t, time_t) ATTRIBUTE_PURE;
+#  endif
+#  if TZ_TIME_T || !defined time2posix_z
+time_t time2posix_z(timezone_t, time_t) ATTRIBUTE_PURE;
+#  endif
+# endif
+#endif
 
 /*
-** Since the definition of TYPE_INTEGRAL contains floating point numbers,
-** it cannot be used in preprocessor directives.
+** Finally, some convenience items.
 */
 
-#ifndef TYPE_INTEGRAL
-#define TYPE_INTEGRAL(type) (((type) 0.5) != 0.5)
-#endif /* !defined TYPE_INTEGRAL */
+#if HAVE_STDBOOL_H
+# include 
+#else
+# define true 1
+# define false 0
+# define bool int
+#endif
+
+#define TYPE_BIT(type)	(sizeof(type) * CHAR_BIT)
+#define TYPE_SIGNED(type) (((type) -1) < 0)
+#define TWOS_COMPLEMENT(t) ((t) ~ (t) 0 < 0)
+
+/* Minimum and maximum of two values.  Use lower case to avoid
+   naming clashes with standard include files.  */
+#define max(a, b) ((a) > (b) ? (a) : (b))
+#define min(a, b) ((a) < (b) ? (a) : (b))
+
+/* Max and min values of the integer type T, of which only the bottom
+   B bits are used, and where the highest-order used bit is considered
+   to be a sign bit if T is signed.  */
+#define MAXVAL(t, b)						\
+  ((t) (((t) 1 << ((b) - 1 - TYPE_SIGNED(t)))			\
+	- 1 + ((t) 1 << ((b) - 1 - TYPE_SIGNED(t)))))
+#define MINVAL(t, b)						\
+  ((t) (TYPE_SIGNED(t) ? - TWOS_COMPLEMENT(t) - MAXVAL(t, b) : 0))
+
+/* The extreme time values, assuming no padding.  */
+#define TIME_T_MIN_NO_PADDING MINVAL(time_t, TYPE_BIT(time_t))
+#define TIME_T_MAX_NO_PADDING MAXVAL(time_t, TYPE_BIT(time_t))
+
+/* The extreme time values.  These are macros, not constants, so that
+   any portability problems occur only when compiling .c files that use
+   the macros, which is safer for applications that need only zdump and zic.
+   This implementation assumes no padding if time_t is signed and
+   either the compiler lacks support for _Generic or time_t is not one
+   of the standard signed integer types.  */
+#if HAVE_GENERIC
+# define TIME_T_MIN \
+    _Generic((time_t) 0, \
+	     signed char: SCHAR_MIN, short: SHRT_MIN, \
+	     int: INT_MIN, long: LONG_MIN, long long: LLONG_MIN, \
+	     default: TIME_T_MIN_NO_PADDING)
+# define TIME_T_MAX \
+    (TYPE_SIGNED(time_t) \
+     ? _Generic((time_t) 0, \
+		signed char: SCHAR_MAX, short: SHRT_MAX, \
+		int: INT_MAX, long: LONG_MAX, long long: LLONG_MAX, \
+		default: TIME_T_MAX_NO_PADDING)			    \
+     : (time_t) -1)
+#else
+# define TIME_T_MIN TIME_T_MIN_NO_PADDING
+# define TIME_T_MAX TIME_T_MAX_NO_PADDING
+#endif
 
-#ifndef INT_STRLEN_MAXIMUM
 /*
 ** 302 / 1000 is log10(2.0) rounded up.
 ** Subtract one for the sign bit if the type is signed;
 ** add one for integer division truncation;
 ** add one more for a minus sign if the type is signed.
 */
 #define INT_STRLEN_MAXIMUM(type) \
 	((TYPE_BIT(type) - TYPE_SIGNED(type)) * 302 / 1000 + \
 	1 + TYPE_SIGNED(type))
-#endif /* !defined INT_STRLEN_MAXIMUM */
 
 /*
 ** INITIALIZE(x)
 */
 
-#ifndef GNUC_or_lint
-#ifdef lint
-#define GNUC_or_lint
-#endif /* defined lint */
-#ifndef lint
-#ifdef __GNUC__
-#define GNUC_or_lint
-#endif /* defined __GNUC__ */
-#endif /* !defined lint */
-#endif /* !defined GNUC_or_lint */
-
-#ifndef INITIALIZE
-#ifdef GNUC_or_lint
-#define INITIALIZE(x)	((x) = 0)
-#endif /* defined GNUC_or_lint */
-#ifndef GNUC_or_lint
-#define INITIALIZE(x)
-#endif /* !defined GNUC_or_lint */
-#endif /* !defined INITIALIZE */
+#ifdef GCC_LINT
+# define INITIALIZE(x)	((x) = 0)
+#else
+# define INITIALIZE(x)
+#endif
+
+/* Whether memory access must strictly follow the C standard.
+   If 0, it's OK to read uninitialized storage so long as the value is
+   not relied upon.  Defining it to 0 lets mktime access parts of
+   struct tm that might be uninitialized, as a heuristic when the
+   standard doesn't say what to return and when tm_gmtoff can help
+   mktime likely infer a better value.  */
+#ifndef UNINIT_TRAP
+# define UNINIT_TRAP 0
+#endif
+
+#ifdef DEBUG
+# define UNREACHABLE() abort()
+#elif 4 < __GNUC__ + (5 <= __GNUC_MINOR__)
+# define UNREACHABLE() __builtin_unreachable()
+#elif defined __has_builtin
+# if __has_builtin(__builtin_unreachable)
+#  define UNREACHABLE() __builtin_unreachable()
+# endif
+#endif
+#ifndef UNREACHABLE
+# define UNREACHABLE() ((void) 0)
+#endif
 
 /*
 ** For the benefit of GNU folk...
-** `_(MSGID)' uses the current locale's message library string for MSGID.
+** '_(MSGID)' uses the current locale's message library string for MSGID.
 ** The default is to use gettext if available, and use MSGID otherwise.
 */
 
-#ifndef _
 #if HAVE_GETTEXT
 #define _(msgid) gettext(msgid)
 #else /* !HAVE_GETTEXT */
 #define _(msgid) msgid
 #endif /* !HAVE_GETTEXT */
-#endif /* !defined _ */
 
-#ifndef TZ_DOMAIN
-#define TZ_DOMAIN "tz"
-#endif /* !defined TZ_DOMAIN */
+#if !defined TZ_DOMAIN && defined HAVE_GETTEXT
+# define TZ_DOMAIN "tz"
+#endif
 
 #if HAVE_INCOMPATIBLE_CTIME_R
 #undef asctime_r
 #undef ctime_r
 char *asctime_r(struct tm const *, char *);
 char *ctime_r(time_t const *, char *);
 #endif /* HAVE_INCOMPATIBLE_CTIME_R */
 
-#ifndef YEARSPERREPEAT
-#define YEARSPERREPEAT		400	/* years before a Gregorian repeat */
-#endif /* !defined YEARSPERREPEAT */
+/* Handy macros that are independent of tzfile implementation.  */
+
+enum {
+  SECSPERMIN = 60,
+  MINSPERHOUR = 60,
+  SECSPERHOUR = SECSPERMIN * MINSPERHOUR,
+  HOURSPERDAY = 24,
+  DAYSPERWEEK = 7,
+  DAYSPERNYEAR = 365,
+  DAYSPERLYEAR = DAYSPERNYEAR + 1,
+  MONSPERYEAR = 12,
+  YEARSPERREPEAT = 400	/* years before a Gregorian repeat */
+};
+
+#define SECSPERDAY	((int_fast32_t) SECSPERHOUR * HOURSPERDAY)
+
+#define DAYSPERREPEAT		((int_fast32_t) 400 * 365 + 100 - 4 + 1)
+#define SECSPERREPEAT		((int_fast64_t) DAYSPERREPEAT * SECSPERDAY)
+#define AVGSECSPERYEAR		(SECSPERREPEAT / YEARSPERREPEAT)
+
+enum {
+  TM_SUNDAY,
+  TM_MONDAY,
+  TM_TUESDAY,
+  TM_WEDNESDAY,
+  TM_THURSDAY,
+  TM_FRIDAY,
+  TM_SATURDAY
+};
+
+enum {
+  TM_JANUARY,
+  TM_FEBRUARY,
+  TM_MARCH,
+  TM_APRIL,
+  TM_MAY,
+  TM_JUNE,
+  TM_JULY,
+  TM_AUGUST,
+  TM_SEPTEMBER,
+  TM_OCTOBER,
+  TM_NOVEMBER,
+  TM_DECEMBER
+};
+
+enum {
+  TM_YEAR_BASE = 1900,
+  TM_WDAY_BASE = TM_MONDAY,
+  EPOCH_YEAR = 1970,
+  EPOCH_WDAY = TM_THURSDAY
+};
+
+#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
 
 /*
-** The Gregorian year averages 365.2425 days, which is 31556952 seconds.
+** Since everything in isleap is modulo 400 (or a factor of 400), we know that
+**	isleap(y) == isleap(y % 400)
+** and so
+**	isleap(a + b) == isleap((a + b) % 400)
+** or
+**	isleap(a + b) == isleap(a % 400 + b % 400)
+** This is true even if % means modulo rather than Fortran remainder
+** (which is allowed by C89 but not by C99 or later).
+** We use this to avoid addition overflow problems.
 */
 
-#ifndef AVGSECSPERYEAR
-#define AVGSECSPERYEAR		31556952L
-#endif /* !defined AVGSECSPERYEAR */
-
-#ifndef SECSPERREPEAT
-#define SECSPERREPEAT		((int_fast64_t) YEARSPERREPEAT * (int_fast64_t) AVGSECSPERYEAR)
-#endif /* !defined SECSPERREPEAT */
-
-#ifndef SECSPERREPEAT_BITS
-#define SECSPERREPEAT_BITS	34	/* ceil(log2(SECSPERREPEAT)) */
-#endif /* !defined SECSPERREPEAT_BITS */
-
-/*
-** UNIX was a registered trademark of The Open Group in 2003.
-*/
+#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
 
 #endif /* !defined PRIVATE_H */
diff --git a/scheck.c b/scheck.c
deleted file mode 100644
index 74d9b07c149b..000000000000
--- a/scheck.c
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
-** This file is in the public domain, so clarified as of
-** 2006-07-17 by Arthur David Olson.
-*/
-
-#ifndef lint
-#ifndef NOID
-static char	elsieid[] = "@(#)scheck.c	8.19";
-#endif /* !defined lint */
-#endif /* !defined NOID */
-
-/*LINTLIBRARY*/
-
-#include "private.h"
-
-const char *
-scheck(string, format)
-const char * const	string;
-const char * const	format;
-{
-	register char *		fbuf;
-	register const char *	fp;
-	register char *		tp;
-	register int		c;
-	register const char *	result;
-	char			dummy;
-
-	result = "";
-	if (string == NULL || format == NULL)
-		return result;
-	fbuf = imalloc((int) (2 * strlen(format) + 4));
-	if (fbuf == NULL)
-		return result;
-	fp = format;
-	tp = fbuf;
-	while ((*tp++ = c = *fp++) != '\0') {
-		if (c != '%')
-			continue;
-		if (*fp == '%') {
-			*tp++ = *fp++;
-			continue;
-		}
-		*tp++ = '*';
-		if (*fp == '*')
-			++fp;
-		while (is_digit(*fp))
-			*tp++ = *fp++;
-		if (*fp == 'l' || *fp == 'h')
-			*tp++ = *fp++;
-		else if (*fp == '[')
-			do *tp++ = *fp++;
-				while (*fp != '\0' && *fp != ']');
-		if ((*tp++ = *fp++) == '\0')
-			break;
-	}
-	*(tp - 1) = '%';
-	*tp++ = 'c';
-	*tp = '\0';
-	if (sscanf(string, fbuf, &dummy) != 1)
-		result = (char *) format;
-	ifree(fbuf);
-	return result;
-}
diff --git a/strftime.c b/strftime.c
index d036d07690f6..deba2b5e7a48 100644
--- a/strftime.c
+++ b/strftime.c
@@ -1,761 +1,648 @@
-#ifndef lint
-#ifndef NOID
-static char	elsieid[] = "@(#)strftime.c	8.3";
+/* Convert a broken-down timestamp to a string.  */
+
+/* Copyright 1989 The Regents of the University of California.
+   All rights reserved.
+
+   Redistribution and use in source and binary forms, with or without
+   modification, are permitted provided that the following conditions
+   are met:
+   1. Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+   2. Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+   3. Neither the name of the University nor the names of its contributors
+      may be used to endorse or promote products derived from this software
+      without specific prior written permission.
+
+   THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
+   ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+   IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+   ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+   FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+   OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+   LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+   OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+   SUCH DAMAGE.  */
+
 /*
-** Based on the UCB version with the ID appearing below.
+** Based on the UCB version with the copyright notice appearing above.
+**
 ** This is ANSIish only when "multibyte character == plain character".
 */
-#endif /* !defined NOID */
-#endif /* !defined lint */
 
 #include "private.h"
 
-/*
-** Copyright (c) 1989 The Regents of the University of California.
-** All rights reserved.
-**
-** Redistribution and use in source and binary forms are permitted
-** provided that the above copyright notice and this paragraph are
-** duplicated in all such forms and that any documentation,
-** advertising materials, and other materials related to such
-** distribution and use acknowledge that the software was developed
-** by the University of California, Berkeley. The name of the
-** University may not be used to endorse or promote products derived
-** from this software without specific prior written permission.
-** THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
-** IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
-** WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
-*/
-
-#ifndef LIBC_SCCS
-#ifndef lint
-static const char	sccsid[] = "@(#)strftime.c	5.4 (Berkeley) 3/14/89";
-#endif /* !defined lint */
-#endif /* !defined LIBC_SCCS */
+#include 
+#include 
+#include 
 
-#include "tzfile.h"
-#include "fcntl.h"
-#include "locale.h"
+#ifndef DEPRECATE_TWO_DIGIT_YEARS
+# define DEPRECATE_TWO_DIGIT_YEARS false
+#endif
 
 struct lc_time_T {
 	const char *	mon[MONSPERYEAR];
 	const char *	month[MONSPERYEAR];
 	const char *	wday[DAYSPERWEEK];
 	const char *	weekday[DAYSPERWEEK];
 	const char *	X_fmt;
 	const char *	x_fmt;
 	const char *	c_fmt;
 	const char *	am;
 	const char *	pm;
 	const char *	date_fmt;
 };
 
-#ifdef LOCALE_HOME
-#include "sys/stat.h"
-static struct lc_time_T		localebuf;
-static struct lc_time_T *	_loc(void);
-#define Locale	_loc()
-#endif /* defined LOCALE_HOME */
-#ifndef LOCALE_HOME
-#define Locale	(&C_time_locale)
-#endif /* !defined LOCALE_HOME */
-
 static const struct lc_time_T	C_time_locale = {
 	{
 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 	}, {
 		"January", "February", "March", "April", "May", "June",
 		"July", "August", "September", "October", "November", "December"
 	}, {
 		"Sun", "Mon", "Tue", "Wed",
 		"Thu", "Fri", "Sat"
 	}, {
 		"Sunday", "Monday", "Tuesday", "Wednesday",
 		"Thursday", "Friday", "Saturday"
 	},
 
 	/* X_fmt */
 	"%H:%M:%S",
 
 	/*
 	** x_fmt
-	** C99 requires this format.
+	** C99 and later require this format.
 	** Using just numbers (as here) makes Quakers happier;
 	** it's also compatible with SVR4.
 	*/
 	"%m/%d/%y",
 
 	/*
 	** c_fmt
-	** C99 requires this format.
+	** C99 and later require this format.
 	** Previously this code used "%D %X", but we now conform to C99.
 	** Note that
 	**	"%a %b %d %H:%M:%S %Y"
 	** is used by Solaris 2.3.
 	*/
 	"%a %b %e %T %Y",
 
 	/* am */
 	"AM",
 
 	/* pm */
 	"PM",
 
 	/* date_fmt */
 	"%a %b %e %H:%M:%S %Z %Y"
 };
 
+enum warn { IN_NONE, IN_SOME, IN_THIS, IN_ALL };
+
 static char *	_add(const char *, char *, const char *);
 static char *	_conv(int, const char *, char *, const char *);
 static char *	_fmt(const char *, const struct tm *, char *, const char *,
-			int *);
-static char *	_yconv(int, int, int, int, char *, const char *);
-
-extern char *	tzname[];
+		     enum warn *);
+static char *	_yconv(int, int, bool, bool, char *, char const *);
 
 #ifndef YEAR_2000_NAME
-#define YEAR_2000_NAME	"CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
+# define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
 #endif /* !defined YEAR_2000_NAME */
 
-#define IN_NONE	0
-#define IN_SOME	1
-#define IN_THIS	2
-#define IN_ALL	3
+#if HAVE_STRFTIME_L
+size_t
+strftime_l(char *s, size_t maxsize, char const *format, struct tm const *t,
+	   locale_t locale)
+{
+  /* Just call strftime, as only the C locale is supported.  */
+  return strftime(s, maxsize, format, t);
+}
+#endif
 
 size_t
-strftime(s, maxsize, format, t)
-char * const		s;
-const size_t		maxsize;
-const char * const	format;
-const struct tm * const	t;
+strftime(char *s, size_t maxsize, const char *format, const struct tm *t)
 {
 	char *	p;
-	int	warn;
+	int saved_errno = errno;
+	enum warn warn = IN_NONE;
 
 	tzset();
-#ifdef LOCALE_HOME
-	localebuf.mon[0] = 0;
-#endif /* defined LOCALE_HOME */
-	warn = IN_NONE;
-	p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
-#ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
-	if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
-		(void) fprintf(stderr, "\n");
-		if (format == NULL)
-			(void) fprintf(stderr, "NULL strftime format ");
-		else	(void) fprintf(stderr, "strftime format \"%s\" ",
-				format);
-		(void) fprintf(stderr, "yields only two digits of years in ");
+	p = _fmt(format, t, s, s + maxsize, &warn);
+	if (!p) {
+	  errno = EOVERFLOW;
+	  return 0;
+	}
+	if (DEPRECATE_TWO_DIGIT_YEARS
+	    && warn != IN_NONE && getenv(YEAR_2000_NAME)) {
+		fprintf(stderr, "\n");
+		fprintf(stderr, "strftime format \"%s\" ", format);
+		fprintf(stderr, "yields only two digits of years in ");
 		if (warn == IN_SOME)
-			(void) fprintf(stderr, "some locales");
+			fprintf(stderr, "some locales");
 		else if (warn == IN_THIS)
-			(void) fprintf(stderr, "the current locale");
-		else	(void) fprintf(stderr, "all locales");
-		(void) fprintf(stderr, "\n");
+			fprintf(stderr, "the current locale");
+		else	fprintf(stderr, "all locales");
+		fprintf(stderr, "\n");
 	}
-#endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
-	if (p == s + maxsize)
+	if (p == s + maxsize) {
+		errno = ERANGE;
 		return 0;
+	}
 	*p = '\0';
+	errno = saved_errno;
 	return p - s;
 }
 
 static char *
-_fmt(format, t, pt, ptlim, warnp)
-const char *		format;
-const struct tm * const	t;
-char *			pt;
-const char * const	ptlim;
-int *			warnp;
+_fmt(const char *format, const struct tm *t, char *pt,
+     const char *ptlim, enum warn *warnp)
 {
+	struct lc_time_T const *Locale = &C_time_locale;
+
 	for ( ; *format; ++format) {
 		if (*format == '%') {
 label:
 			switch (*++format) {
 			case '\0':
 				--format;
 				break;
 			case 'A':
 				pt = _add((t->tm_wday < 0 ||
 					t->tm_wday >= DAYSPERWEEK) ?
 					"?" : Locale->weekday[t->tm_wday],
 					pt, ptlim);
 				continue;
 			case 'a':
 				pt = _add((t->tm_wday < 0 ||
 					t->tm_wday >= DAYSPERWEEK) ?
 					"?" : Locale->wday[t->tm_wday],
 					pt, ptlim);
 				continue;
 			case 'B':
 				pt = _add((t->tm_mon < 0 ||
 					t->tm_mon >= MONSPERYEAR) ?
 					"?" : Locale->month[t->tm_mon],
 					pt, ptlim);
 				continue;
 			case 'b':
 			case 'h':
 				pt = _add((t->tm_mon < 0 ||
 					t->tm_mon >= MONSPERYEAR) ?
 					"?" : Locale->mon[t->tm_mon],
 					pt, ptlim);
 				continue;
 			case 'C':
 				/*
 				** %C used to do a...
 				**	_fmt("%a %b %e %X %Y", t);
 				** ...whereas now POSIX 1003.2 calls for
 				** something completely different.
 				** (ado, 1993-05-24)
 				*/
-				pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
-					pt, ptlim);
+				pt = _yconv(t->tm_year, TM_YEAR_BASE,
+					    true, false, pt, ptlim);
 				continue;
 			case 'c':
 				{
-				int warn2 = IN_SOME;
+				enum warn warn2 = IN_SOME;
 
 				pt = _fmt(Locale->c_fmt, t, pt, ptlim, &warn2);
 				if (warn2 == IN_ALL)
 					warn2 = IN_THIS;
 				if (warn2 > *warnp)
 					*warnp = warn2;
 				}
 				continue;
 			case 'D':
 				pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
 				continue;
 			case 'd':
 				pt = _conv(t->tm_mday, "%02d", pt, ptlim);
 				continue;
 			case 'E':
 			case 'O':
 				/*
-				** C99 locale modifiers.
+				** Locale modifiers of C99 and later.
 				** The sequences
 				**	%Ec %EC %Ex %EX %Ey %EY
 				**	%Od %oe %OH %OI %Om %OM
 				**	%OS %Ou %OU %OV %Ow %OW %Oy
-				** are supposed to provide alternate
+				** are supposed to provide alternative
 				** representations.
 				*/
 				goto label;
 			case 'e':
 				pt = _conv(t->tm_mday, "%2d", pt, ptlim);
 				continue;
 			case 'F':
 				pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
 				continue;
 			case 'H':
 				pt = _conv(t->tm_hour, "%02d", pt, ptlim);
 				continue;
 			case 'I':
 				pt = _conv((t->tm_hour % 12) ?
 					(t->tm_hour % 12) : 12,
 					"%02d", pt, ptlim);
 				continue;
 			case 'j':
 				pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
 				continue;
 			case 'k':
 				/*
 				** This used to be...
 				**	_conv(t->tm_hour % 12 ?
 				**		t->tm_hour % 12 : 12, 2, ' ');
 				** ...and has been changed to the below to
 				** match SunOS 4.1.1 and Arnold Robbins'
 				** strftime version 3.0. That is, "%k" and
 				** "%l" have been swapped.
 				** (ado, 1993-05-24)
 				*/
 				pt = _conv(t->tm_hour, "%2d", pt, ptlim);
 				continue;
 #ifdef KITCHEN_SINK
 			case 'K':
 				/*
 				** After all this time, still unclaimed!
 				*/
 				pt = _add("kitchen sink", pt, ptlim);
 				continue;
 #endif /* defined KITCHEN_SINK */
 			case 'l':
 				/*
 				** This used to be...
 				**	_conv(t->tm_hour, 2, ' ');
 				** ...and has been changed to the below to
 				** match SunOS 4.1.1 and Arnold Robbin's
 				** strftime version 3.0. That is, "%k" and
 				** "%l" have been swapped.
 				** (ado, 1993-05-24)
 				*/
 				pt = _conv((t->tm_hour % 12) ?
 					(t->tm_hour % 12) : 12,
 					"%2d", pt, ptlim);
 				continue;
 			case 'M':
 				pt = _conv(t->tm_min, "%02d", pt, ptlim);
 				continue;
 			case 'm':
 				pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
 				continue;
 			case 'n':
 				pt = _add("\n", pt, ptlim);
 				continue;
 			case 'p':
 				pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
 					Locale->pm :
 					Locale->am,
 					pt, ptlim);
 				continue;
 			case 'R':
 				pt = _fmt("%H:%M", t, pt, ptlim, warnp);
 				continue;
 			case 'r':
 				pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp);
 				continue;
 			case 'S':
 				pt = _conv(t->tm_sec, "%02d", pt, ptlim);
 				continue;
 			case 's':
 				{
 					struct tm	tm;
 					char		buf[INT_STRLEN_MAXIMUM(
 								time_t) + 1];
 					time_t		mkt;
 
 					tm = *t;
 					mkt = mktime(&tm);
-					if (TYPE_SIGNED(time_t))
-						(void) sprintf(buf, "%ld",
-							(long) mkt);
-					else	(void) sprintf(buf, "%lu",
-							(unsigned long) mkt);
+					/* There is no portable, definitive
+					   test for whether whether mktime
+					   succeeded, so treat (time_t) -1 as
+					   the success that it might be.  */
+					if (TYPE_SIGNED(time_t)) {
+					  intmax_t n = mkt;
+					  sprintf(buf, "%"PRIdMAX, n);
+					} else {
+					  uintmax_t n = mkt;
+					  sprintf(buf, "%"PRIuMAX, n);
+					}
 					pt = _add(buf, pt, ptlim);
 				}
 				continue;
 			case 'T':
 				pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
 				continue;
 			case 't':
 				pt = _add("\t", pt, ptlim);
 				continue;
 			case 'U':
 				pt = _conv((t->tm_yday + DAYSPERWEEK -
 					t->tm_wday) / DAYSPERWEEK,
 					"%02d", pt, ptlim);
 				continue;
 			case 'u':
 				/*
 				** From Arnold Robbins' strftime version 3.0:
 				** "ISO 8601: Weekday as a decimal number
 				** [1 (Monday) - 7]"
 				** (ado, 1993-05-24)
 				*/
 				pt = _conv((t->tm_wday == 0) ?
 					DAYSPERWEEK : t->tm_wday,
 					"%d", pt, ptlim);
 				continue;
 			case 'V':	/* ISO 8601 week number */
 			case 'G':	/* ISO 8601 year (four digits) */
 			case 'g':	/* ISO 8601 year (two digits) */
 /*
 ** From Arnold Robbins' strftime version 3.0: "the week number of the
 ** year (the first Monday as the first day of week 1) as a decimal number
 ** (01-53)."
 ** (ado, 1993-05-24)
 **
-** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
+** From  by Markus Kuhn:
 ** "Week 01 of a year is per definition the first week which has the
 ** Thursday in this year, which is equivalent to the week which contains
 ** the fourth day of January. In other words, the first week of a new year
 ** is the week which has the majority of its days in the new year. Week 01
 ** might also contain days from the previous year and the week before week
 ** 01 of a year is the last week (52 or 53) of the previous year even if
 ** it contains days from the new year. A week starts with Monday (day 1)
 ** and ends with Sunday (day 7). For example, the first week of the year
 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
 ** (ado, 1996-01-02)
 */
 				{
 					int	year;
 					int	base;
 					int	yday;
 					int	wday;
 					int	w;
 
 					year = t->tm_year;
 					base = TM_YEAR_BASE;
 					yday = t->tm_yday;
 					wday = t->tm_wday;
 					for ( ; ; ) {
 						int	len;
 						int	bot;
 						int	top;
 
 						len = isleap_sum(year, base) ?
 							DAYSPERLYEAR :
 							DAYSPERNYEAR;
 						/*
 						** What yday (-3 ... 3) does
 						** the ISO year begin on?
 						*/
 						bot = ((yday + 11 - wday) %
 							DAYSPERWEEK) - 3;
 						/*
 						** What yday does the NEXT
 						** ISO year begin on?
 						*/
 						top = bot -
 							(len % DAYSPERWEEK);
 						if (top < -3)
 							top += DAYSPERWEEK;
 						top += len;
 						if (yday >= top) {
 							++base;
 							w = 1;
 							break;
 						}
 						if (yday >= bot) {
 							w = 1 + ((yday - bot) /
 								DAYSPERWEEK);
 							break;
 						}
 						--base;
 						yday += isleap_sum(year, base) ?
 							DAYSPERLYEAR :
 							DAYSPERNYEAR;
 					}
 #ifdef XPG4_1994_04_09
 					if ((w == 52 &&
 						t->tm_mon == TM_JANUARY) ||
 						(w == 1 &&
 						t->tm_mon == TM_DECEMBER))
 							w = 53;
 #endif /* defined XPG4_1994_04_09 */
 					if (*format == 'V')
 						pt = _conv(w, "%02d",
 							pt, ptlim);
 					else if (*format == 'g') {
 						*warnp = IN_ALL;
-						pt = _yconv(year, base, 0, 1,
+						pt = _yconv(year, base,
+							false, true,
 							pt, ptlim);
-					} else	pt = _yconv(year, base, 1, 1,
+					} else	pt = _yconv(year, base,
+							true, true,
 							pt, ptlim);
 				}
 				continue;
 			case 'v':
 				/*
 				** From Arnold Robbins' strftime version 3.0:
 				** "date as dd-bbb-YYYY"
 				** (ado, 1993-05-24)
 				*/
 				pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
 				continue;
 			case 'W':
 				pt = _conv((t->tm_yday + DAYSPERWEEK -
 					(t->tm_wday ?
 					(t->tm_wday - 1) :
 					(DAYSPERWEEK - 1))) / DAYSPERWEEK,
 					"%02d", pt, ptlim);
 				continue;
 			case 'w':
 				pt = _conv(t->tm_wday, "%d", pt, ptlim);
 				continue;
 			case 'X':
 				pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp);
 				continue;
 			case 'x':
 				{
-				int	warn2 = IN_SOME;
+				enum warn warn2 = IN_SOME;
 
 				pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2);
 				if (warn2 == IN_ALL)
 					warn2 = IN_THIS;
 				if (warn2 > *warnp)
 					*warnp = warn2;
 				}
 				continue;
 			case 'y':
 				*warnp = IN_ALL;
-				pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
+				pt = _yconv(t->tm_year, TM_YEAR_BASE,
+					false, true,
 					pt, ptlim);
 				continue;
 			case 'Y':
-				pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
+				pt = _yconv(t->tm_year, TM_YEAR_BASE,
+					true, true,
 					pt, ptlim);
 				continue;
 			case 'Z':
 #ifdef TM_ZONE
-				if (t->TM_ZONE != NULL)
-					pt = _add(t->TM_ZONE, pt, ptlim);
-				else
-#endif /* defined TM_ZONE */
+				pt = _add(t->TM_ZONE, pt, ptlim);
+#elif HAVE_TZNAME
 				if (t->tm_isdst >= 0)
 					pt = _add(tzname[t->tm_isdst != 0],
 						pt, ptlim);
+#endif
 				/*
-				** C99 says that %Z must be replaced by the
-				** empty string if the time zone is not
+				** C99 and later say that %Z must be
+				** replaced by the empty string if the
+				** time zone abbreviation is not
 				** determinable.
 				*/
 				continue;
 			case 'z':
+#if defined TM_GMTOFF || USG_COMPAT || ALTZONE
 				{
-				int		diff;
+				long		diff;
 				char const *	sign;
+				bool negative;
 
-				if (t->tm_isdst < 0)
-					continue;
-#ifdef TM_GMTOFF
+# ifdef TM_GMTOFF
 				diff = t->TM_GMTOFF;
-#else /* !defined TM_GMTOFF */
+# else
 				/*
-				** C99 says that the UTC offset must
+				** C99 and later say that the UT offset must
 				** be computed by looking only at
 				** tm_isdst. This requirement is
 				** incorrect, since it means the code
 				** must rely on magic (in this case
 				** altzone and timezone), and the
 				** magic might not have the correct
 				** offset. Doing things correctly is
-				** tricky and requires disobeying C99;
+				** tricky and requires disobeying the standard;
 				** see GNU C strftime for details.
 				** For now, punt and conform to the
 				** standard, even though it's incorrect.
 				**
-				** C99 says that %z must be replaced by the
-				** empty string if the time zone is not
+				** C99 and later say that %z must be replaced by
+				** the empty string if the time zone is not
 				** determinable, so output nothing if the
 				** appropriate variables are not available.
 				*/
+				if (t->tm_isdst < 0)
+					continue;
 				if (t->tm_isdst == 0)
-#ifdef USG_COMPAT
+#  if USG_COMPAT
 					diff = -timezone;
-#else /* !defined USG_COMPAT */
+#  else
 					continue;
-#endif /* !defined USG_COMPAT */
+#  endif
 				else
-#ifdef ALTZONE
+#  if ALTZONE
 					diff = -altzone;
-#else /* !defined ALTZONE */
+#  else
 					continue;
-#endif /* !defined ALTZONE */
-#endif /* !defined TM_GMTOFF */
-				if (diff < 0) {
+#  endif
+# endif
+				negative = diff < 0;
+				if (diff == 0) {
+# ifdef TM_ZONE
+				  negative = t->TM_ZONE[0] == '-';
+# else
+				  negative = t->tm_isdst < 0;
+#  if HAVE_TZNAME
+				  if (tzname[t->tm_isdst != 0][0] == '-')
+				    negative = true;
+#  endif
+# endif
+				}
+				if (negative) {
 					sign = "-";
 					diff = -diff;
 				} else	sign = "+";
 				pt = _add(sign, pt, ptlim);
 				diff /= SECSPERMIN;
 				diff = (diff / MINSPERHOUR) * 100 +
 					(diff % MINSPERHOUR);
 				pt = _conv(diff, "%04d", pt, ptlim);
 				}
+#endif
 				continue;
 			case '+':
 				pt = _fmt(Locale->date_fmt, t, pt, ptlim,
 					warnp);
 				continue;
 			case '%':
 			/*
 			** X311J/88-090 (4.12.3.5): if conversion char is
 			** undefined, behavior is undefined. Print out the
 			** character itself as printf(3) also does.
 			*/
 			default:
 				break;
 			}
 		}
 		if (pt == ptlim)
 			break;
 		*pt++ = *format;
 	}
 	return pt;
 }
 
 static char *
-_conv(n, format, pt, ptlim)
-const int		n;
-const char * const	format;
-char * const		pt;
-const char * const	ptlim;
+_conv(int n, const char *format, char *pt, const char *ptlim)
 {
 	char	buf[INT_STRLEN_MAXIMUM(int) + 1];
 
-	(void) sprintf(buf, format, n);
+	sprintf(buf, format, n);
 	return _add(buf, pt, ptlim);
 }
 
 static char *
-_add(str, pt, ptlim)
-const char *		str;
-char *			pt;
-const char * const	ptlim;
+_add(const char *str, char *pt, const char *ptlim)
 {
 	while (pt < ptlim && (*pt = *str++) != '\0')
 		++pt;
 	return pt;
 }
 
 /*
 ** POSIX and the C Standard are unclear or inconsistent about
 ** what %C and %y do if the year is negative or exceeds 9999.
 ** Use the convention that %C concatenated with %y yields the
 ** same output as %Y, and that %Y contains at least 4 bytes,
 ** with more only if necessary.
 */
 
 static char *
-_yconv(a, b, convert_top, convert_yy, pt, ptlim)
-const int		a;
-const int		b;
-const int		convert_top;
-const int		convert_yy;
-char *			pt;
-const char * const	ptlim;
+_yconv(int a, int b, bool convert_top, bool convert_yy,
+       char *pt, const char *ptlim)
 {
 	register int	lead;
 	register int	trail;
 
-#define DIVISOR	100
+	int DIVISOR = 100;
 	trail = a % DIVISOR + b % DIVISOR;
 	lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
 	trail %= DIVISOR;
 	if (trail < 0 && lead > 0) {
 		trail += DIVISOR;
 		--lead;
 	} else if (lead < 0 && trail > 0) {
 		trail -= DIVISOR;
 		++lead;
 	}
 	if (convert_top) {
 		if (lead == 0 && trail < 0)
 			pt = _add("-0", pt, ptlim);
 		else	pt = _conv(lead, "%02d", pt, ptlim);
 	}
 	if (convert_yy)
 		pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
 	return pt;
 }
-
-#ifdef LOCALE_HOME
-static struct lc_time_T *
-_loc(void)
-{
-	static const char	locale_home[] = LOCALE_HOME;
-	static const char	lc_time[] = "LC_TIME";
-	static char *		locale_buf;
-
-	int			fd;
-	int			oldsun;	/* "...ain't got nothin' to do..." */
-	char *			lbuf;
-	char *			name;
-	char *			p;
-	const char **		ap;
-	const char *		plim;
-	char			filename[FILENAME_MAX];
-	struct stat		st;
-	size_t			namesize;
-	size_t			bufsize;
-
-	/*
-	** Use localebuf.mon[0] to signal whether locale is already set up.
-	*/
-	if (localebuf.mon[0])
-		return &localebuf;
-	name = setlocale(LC_TIME, (char *) NULL);
-	if (name == NULL || *name == '\0')
-		goto no_locale;
-	/*
-	** If the locale name is the same as our cache, use the cache.
-	*/
-	lbuf = locale_buf;
-	if (lbuf != NULL && strcmp(name, lbuf) == 0) {
-		p = lbuf;
-		for (ap = (const char **) &localebuf;
-			ap < (const char **) (&localebuf + 1);
-				++ap)
-					*ap = p += strlen(p) + 1;
-		return &localebuf;
-	}
-	/*
-	** Slurp the locale file into the cache.
-	*/
-	namesize = strlen(name) + 1;
-	if (sizeof filename <
-		((sizeof locale_home) + namesize + (sizeof lc_time)))
-			goto no_locale;
-	oldsun = 0;
-	(void) sprintf(filename, "%s/%s/%s", locale_home, name, lc_time);
-	fd = open(filename, O_RDONLY);
-	if (fd < 0) {
-		/*
-		** Old Sun systems have a different naming and data convention.
-		*/
-		oldsun = 1;
-		(void) sprintf(filename, "%s/%s/%s", locale_home,
-			lc_time, name);
-		fd = open(filename, O_RDONLY);
-		if (fd < 0)
-			goto no_locale;
-	}
-	if (fstat(fd, &st) != 0)
-		goto bad_locale;
-	if (st.st_size <= 0)
-		goto bad_locale;
-	bufsize = namesize + st.st_size;
-	locale_buf = NULL;
-	lbuf = (lbuf == NULL) ? malloc(bufsize) : realloc(lbuf, bufsize);
-	if (lbuf == NULL)
-		goto bad_locale;
-	(void) strcpy(lbuf, name);
-	p = lbuf + namesize;
-	plim = p + st.st_size;
-	if (read(fd, p, (size_t) st.st_size) != st.st_size)
-		goto bad_lbuf;
-	if (close(fd) != 0)
-		goto bad_lbuf;
-	/*
-	** Parse the locale file into localebuf.
-	*/
-	if (plim[-1] != '\n')
-		goto bad_lbuf;
-	for (ap = (const char **) &localebuf;
-		ap < (const char **) (&localebuf + 1);
-			++ap) {
-				if (p == plim)
-					goto bad_lbuf;
-				*ap = p;
-				while (*p != '\n')
-					++p;
-				*p++ = '\0';
-	}
-	if (oldsun) {
-		/*
-		** SunOS 4 used an obsolescent format; see localdtconv(3).
-		** c_fmt had the ``short format for dates and times together''
-		** (SunOS 4 date, "%a %b %e %T %Z %Y" in the C locale);
-		** date_fmt had the ``long format for dates''
-		** (SunOS 4 strftime %C, "%A, %B %e, %Y" in the C locale).
-		** Discard the latter in favor of the former.
-		*/
-		localebuf.date_fmt = localebuf.c_fmt;
-	}
-	/*
-	** Record the successful parse in the cache.
-	*/
-	locale_buf = lbuf;
-
-	return &localebuf;
-
-bad_lbuf:
-	free(lbuf);
-bad_locale:
-	(void) close(fd);
-no_locale:
-	localebuf = C_time_locale;
-	locale_buf = NULL;
-	return &localebuf;
-}
-#endif /* defined LOCALE_HOME */
diff --git a/theory.html b/theory.html
new file mode 100644
index 000000000000..56390ae44a8d
--- /dev/null
+++ b/theory.html
@@ -0,0 +1,1479 @@
+
+
+
+  Theory and pragmatics of the tz code and data
+  
+  
+
+
+
+Theory and pragmatics of the tz code and data
+  Outline
+  
+    
+      Scope of the tz
+	  database
+      Timezone identifiers
+      Time zone abbreviations
+      Accuracy of the tz
+	  database
+      Time and date functions
+      Interface stability
+      Leap seconds
+      Calendrical issues
+      Time and time zones on other planets
+    
+  
+
+
+  Scope of the tz database
+
+The tz
+database attempts to record the history and predicted future of
+civil time scales.
+It organizes time zone and daylight saving time
+data by partitioning the world into timezones
+whose clocks all agree about timestamps that occur after the POSIX Epoch
+(1970-01-01 00:00:00 UTC).
+Although 1970 is a somewhat-arbitrary cutoff, there are significant
+challenges to moving the cutoff earlier even by a decade or two, due
+to the wide variety of local practices before computer timekeeping
+became prevalent.
+Most timezones correspond to a notable location and the database
+records all known clock transitions for that location;
+some timezones correspond instead to a fixed UTC offset.
+
+
+
+Each timezone typically corresponds to a geographical region that is
+smaller than a traditional time zone, because clocks in a timezone
+all agree after 1970 whereas a traditional time zone merely
+specifies current standard time. For example, applications that deal
+with current and future timestamps in the traditional North
+American mountain time zone can choose from the timezones
+America/Denver which observes US-style daylight saving
+time (DST),
+America/Mazatlan which observes Mexican-style DST,
+and America/Phoenix which does not observe DST.
+Applications that also deal with past timestamps in the mountain time
+zone can choose from over a dozen timezones, such as
+America/Boise, America/Edmonton, and
+America/Hermosillo, each of which currently uses mountain
+time but differs from other timezones for some timestamps after 1970.
+
+
+
+Clock transitions before 1970 are recorded for location-based timezones,
+because most systems support timestamps before 1970 and could
+misbehave if data entries were omitted for pre-1970 transitions.
+However, the database is not designed for and does not suffice for
+applications requiring accurate handling of all past times everywhere,
+as it would take far too much effort and guesswork to record all
+details of pre-1970 civil timekeeping.
+Although some information outside the scope of the database is
+collected in a file backzone that is distributed along
+with the database proper, this file is less reliable and does not
+necessarily follow database guidelines.
+
+
+
+As described below, reference source code for using the
+tz database is also available.
+The tz code is upwards compatible with POSIX, an international
+standard for UNIX-like systems.
+As of this writing, the current edition of POSIX is:  The Open
+Group Base Specifications Issue 7, IEEE Std 1003.1-2017, 2018
+Edition.
+Because the database's scope encompasses real-world changes to civil
+timekeeping, its model for describing time is more complex than the
+standard and daylight saving times supported by POSIX.
+A tz timezone corresponds to a ruleset that can
+have more than two changes per year, these changes need not merely
+flip back and forth between two alternatives, and the rules themselves
+can change at times.
+Whether and when a timezone changes its clock,
+and even the timezone's notional base offset from UTC,
+are variable.
+It does not always make sense to talk about a timezone's
+"base offset", which is not necessarily a single number.
+
+
+
+
+
+  Timezone identifiers
+
+Each timezone has a name that uniquely identifies the timezone.
+Inexperienced users are not expected to select these names unaided.
+Distributors should provide documentation and/or a simple selection
+interface that explains each name via a map or via descriptive text like
+"Czech Republic" instead of the timezone name "Europe/Prague".
+If geolocation information is available, a selection interface can
+locate the user on a timezone map or prioritize names that are
+geographically close. For an example selection interface, see the
+tzselect program in the tz code.
+The Unicode Common Locale Data
+Repository contains data that may be useful for other selection
+interfaces; it maps timezone names like Europe/Prague to
+locale-dependent strings like "Prague", "Praha", "Прага", and "布拉格".
+
+
+
+The naming conventions attempt to strike a balance
+among the following goals:
+
+
+
+  
+    Uniquely identify every timezone where clocks have agreed since 1970.
+    This is essential for the intended use: static clocks keeping local
+    civil time.
+  
+  
+    Indicate to experts where the timezone's clocks typically are.
+  
+  
+    Be robust in the presence of political changes.
+    For example, names are typically not tied to countries, to avoid
+    incompatibilities when countries change their name (e.g.,
+    Swaziland→Eswatini) or when locations change countries (e.g., Hong
+    Kong from UK colony to China).
+    There is no requirement that every country or national
+    capital must have a timezone name.
+  
+  
+    Be portable to a wide variety of implementations.
+  
+  
+    Use a consistent naming conventions over the entire world.
+  
+
+
+
+Names normally have the form
+AREA/LOCATION, where
+AREA is a continent or ocean, and
+LOCATION is a specific location within the area.
+North and South America share the same area, 'America'.
+Typical names are 'Africa/Cairo',
+'America/New_York', and 'Pacific/Honolulu'.
+Some names are further qualified to help avoid confusion; for example,
+'America/Indiana/Petersburg' distinguishes Petersburg,
+Indiana from other Petersburgs in America.
+
+
+
+Here are the general guidelines used for
+choosing timezone names,
+in decreasing order of importance:
+
+
+
+  
+    Use only valid POSIX file name components (i.e., the parts of
+    names other than '/').
+    Do not use the file name components '.' and
+    '..'.
+    Within a file name component, use only ASCII letters,
+    '.', '-' and '_'.
+    Do not use digits, as that might create an ambiguity with POSIX
+    TZ strings.
+    A file name component must not exceed 14 characters or start with
+    '-'.
+    E.g., prefer America/Noronha to
+    America/Fernando_de_Noronha.
+    Exceptions: see the discussion of legacy names below.
+  
+  
+    A name must not be empty, or contain '//', or
+    start or end with '/'.
+  
+  
+    Do not use names that differ only in case.
+    Although the reference implementation is case-sensitive, some
+    other implementations are not, and they would mishandle names
+    differing only in case.
+  
+  
+    If one name A is an initial prefix of another
+    name AB (ignoring case), then B must not
+    start with '/', as a regular file cannot have the
+    same name as a directory in POSIX.
+    For example, America/New_York precludes
+    America/New_York/Bronx.
+  
+  
+    Uninhabited regions like the North Pole and Bouvet Island
+    do not need locations, since local time is not defined there.
+  
+  
+    If all the clocks in a timezone have agreed since 1970,
+    do not bother to include more than one timezone
+    even if some of the clocks disagreed before 1970.
+    Otherwise these tables would become annoyingly large.
+  
+  
+    If boundaries between regions are fluid, such as during a war or
+    insurrection, do not bother to create a new timezone merely
+    because of yet another boundary change. This helps prevent table
+    bloat and simplifies maintenance.
+  
+  
+    If a name is ambiguous, use a less ambiguous alternative;
+    e.g., many cities are named San José and Georgetown, so
+    prefer America/Costa_Rica to
+    America/San_Jose and America/Guyana
+    to America/Georgetown.
+  
+  
+    Keep locations compact.
+    Use cities or small islands, not countries or regions, so that any
+    future changes do not split individual locations into different
+    timezones.
+    E.g., prefer Europe/Paris to Europe/France,
+    since
+    France
+    has had multiple time zones.
+  
+  
+    Use mainstream English spelling, e.g., prefer
+    Europe/Rome to Europa/Roma, and
+    prefer Europe/Athens to the Greek
+    Ευρώπη/Αθήνα or the Romanized
+    Evrópi/Athína.
+    The POSIX file name restrictions encourage this guideline.
+  
+  
+    Use the most populous among locations in a region,
+    e.g., prefer Asia/Shanghai to
+    Asia/Beijing.
+    Among locations with similar populations, pick the best-known
+    location, e.g., prefer Europe/Rome to
+    Europe/Milan.
+  
+  
+    Use the singular form, e.g., prefer Atlantic/Canary to
+    Atlantic/Canaries.
+  
+  
+    Omit common suffixes like '_Islands' and
+    '_City', unless that would lead to ambiguity.
+    E.g., prefer America/Cayman to
+    America/Cayman_Islands and
+    America/Guatemala to
+    America/Guatemala_City, but prefer
+    America/Mexico_City to
+    America/Mexico
+    because the
+    country of Mexico has several time zones.
+  
+  
+    Use '_' to represent a space.
+  
+  
+    Omit '.' from abbreviations in names.
+    E.g., prefer Atlantic/St_Helena to
+    Atlantic/St._Helena.
+  
+  
+    Do not change established names if they only marginally violate
+    the above guidelines.
+    For example, do not change the existing name Europe/Rome to
+    Europe/Milan merely because Milan's population has grown
+    to be somewhat greater than Rome's.
+  
+  
+    If a name is changed, put its old spelling in the
+    'backward' file as a link to the new spelling.
+    This means old spellings will continue to work.
+    Ordinarily a name change should occur only in the rare case when
+    a location's consensus English-language spelling changes; for example,
+    in 2008 Asia/Calcutta was renamed to Asia/Kolkata
+    due to long-time widespread use of the new city name instead of the old.
+  
+
+
+
+Guidelines have evolved with time, and names following old versions of
+these guidelines might not follow the current version. When guidelines
+have changed, old names continue to be supported. Guideline changes
+have included the following:
+
+
+
+
+Older versions of this package used a different naming scheme.
+See the file 'backward' for most of these older names
+(e.g., 'US/Eastern' instead of 'America/New_York').
+The other old-fashioned names still supported are
+'WET', 'CET', 'MET', and
+'EET' (see the file 'europe').
+
+
+
+Older versions of this package defined legacy names that are
+incompatible with the first guideline of location names, but which are
+still supported.
+These legacy names are mostly defined in the file
+'etcetera'.
+Also, the file 'backward' defines the legacy names
+'GMT0', 'GMT-0' and 'GMT+0',
+and the file 'northamerica' defines the legacy names
+'EST5EDT', 'CST6CDT',
+'MST7MDT', and 'PST8PDT'.
+
+
+
+Older versions of these guidelines said that
+there should typically be at least one name for each ISO
+3166-1 officially assigned two-letter code for an inhabited
+country or territory.
+This old guideline has been dropped, as it was not needed to handle
+timestamps correctly and it increased maintenance burden.
+
+
+
+
+The file zone1970.tab lists geographical locations used
+to name timezones.
+It is intended to be an exhaustive list of names for geographic
+regions as described above; this is a subset of the timezones in the data.
+Although a zone1970.tab location's
+longitude
+corresponds to
+its local mean
+time (LMT) offset with one hour for every 15°
+east longitude, this relationship is not exact.
+The backward-compatibility file zone.tab is similar
+but conforms to the older-version guidelines related to ISO 3166-1;
+it lists only one country code per entry and unlike zone1970.tab
+it can list names defined in backward.
+
+
+
+The database defines each timezone name to be a zone, or a link to a zone.
+The source file backward defines links for backward
+compatibility; it does not define zones.
+Although backward was originally designed to be optional,
+nowadays distributions typically use it
+and no great weight should be attached to whether a link
+is defined in backward or in some other file.
+The source file etcetera defines names that may be useful
+on platforms that do not support POSIX-style TZ strings;
+no other source file other than backward
+contains links to its zones.
+One of etcetera's names is Etc/UTC,
+used by functions like gmtime to obtain leap
+second information on platforms that support leap seconds.
+Another etcetera name, GMT,
+is used by older code releases.
+
+
+
+
+  Time zone abbreviations
+
+When this package is installed, it generates time zone abbreviations
+like 'EST' to be compatible with human tradition and POSIX.
+Here are the general guidelines used for choosing time zone abbreviations,
+in decreasing order of importance:
+
+
+
+  
+    Use three to six characters that are ASCII alphanumerics or
+    '+' or '-'.
+    Previous editions of this database also used characters like
+    space and '?', but these characters have a
+    special meaning to the
+    UNIX shell
+    and cause commands like
+    'set
+    `date`'
+    to have unexpected effects.
+    Previous editions of this guideline required upper-case letters, but the
+    Congressman who introduced
+    Chamorro
+    Standard Time preferred "ChST", so lower-case letters are now
+    allowed.
+    Also, POSIX from 2001 on relaxed the rule to allow '-',
+    '+', and alphanumeric characters from the portable
+    character set in the current locale.
+    In practice ASCII alphanumerics and '+' and
+    '-' are safe in all locales.
+
+    
+    In other words, in the C locale the POSIX extended regular
+    expression [-+[:alnum:]]{3,6} should match the
+    abbreviation.
+    This guarantees that all abbreviations could have been specified by a
+    POSIX TZ string.
+    
+  
+  
+    Use abbreviations that are in common use among English-speakers,
+    e.g., 'EST' for Eastern Standard Time in North America.
+    We assume that applications translate them to other languages
+    as part of the normal localization process; for example,
+    a French application might translate 'EST' to 'HNE'.
+
+    
+    These abbreviations (for standard/daylight/etc. time) are:
+      ACST/ACDT Australian Central,
+      AST/ADT/APT/AWT/ADDT Atlantic,
+      AEST/AEDT Australian Eastern,
+      AHST/AHDT Alaska-Hawaii,
+      AKST/AKDT Alaska,
+      AWST/AWDT Australian Western,
+      BST/BDT Bering,
+      CAT/CAST Central Africa,
+      CET/CEST/CEMT Central European,
+      ChST Chamorro,
+      CST/CDT/CWT/CPT/CDDT Central [North America],
+      CST/CDT China,
+      GMT/BST/IST/BDST Greenwich,
+      EAT East Africa,
+      EST/EDT/EWT/EPT/EDDT Eastern [North America],
+      EET/EEST Eastern European,
+      GST/GDT Guam,
+      HST/HDT/HWT/HPT Hawaii,
+      HKT/HKST/HKWT Hong Kong,
+      IST India,
+      IST/GMT Irish,
+      IST/IDT/IDDT Israel,
+      JST/JDT Japan,
+      KST/KDT Korea,
+      MET/MEST Middle European (a backward-compatibility alias for
+	Central European),
+      MSK/MSD Moscow,
+      MST/MDT/MWT/MPT/MDDT Mountain,
+      NST/NDT/NWT/NPT/NDDT Newfoundland,
+      NST/NDT/NWT/NPT Nome,
+      NZMT/NZST New Zealand through 1945,
+      NZST/NZDT New Zealand 1946–present,
+      PKT/PKST Pakistan,
+      PST/PDT/PWT/PPT/PDDT Pacific,
+      PST/PDT Philippine,
+      SAST South Africa,
+      SST Samoa,
+      UTC Universal,
+      WAT/WAST West Africa,
+      WET/WEST/WEMT Western European,
+      WIB Waktu Indonesia Barat,
+      WIT Waktu Indonesia Timur,
+      WITA Waktu Indonesia Tengah,
+      YST/YDT/YWT/YPT/YDDT Yukon.
+    
+  
+  
+    
+    For times taken from a city's longitude, use the
+    traditional xMT notation.
+    The only abbreviation like this in current use is 'GMT'.
+    The others are for timestamps before 1960,
+    except that Monrovia Mean Time persisted until 1972.
+    Typically, numeric abbreviations (e.g., '-004430' for
+    MMT) would cause trouble here, as the numeric strings would exceed
+    the POSIX length limit.
+    
+
+    
+    These abbreviations are:
+      AMT Asunción, Athens;
+      BMT Baghdad, Bangkok, Batavia, Bermuda, Bern, Bogotá, Bridgetown,
+        Brussels, Bucharest;
+      CMT Calamarca, Caracas, Chisinau, Colón, Córdoba;
+      DMT Dublin/Dunsink;
+      EMT Easter;
+      FFMT Fort-de-France;
+      FMT Funchal;
+      GMT Greenwich;
+      HMT Havana, Helsinki, Horta, Howrah;
+      IMT Irkutsk, Istanbul;
+      JMT Jerusalem;
+      KMT Kaunas, Kyiv, Kingston;
+      LMT Lima, Lisbon, local, Luanda;
+      MMT Macassar, Madras, Malé, Managua, Minsk, Monrovia, Montevideo,
+	Moratuwa, Moscow;
+      PLMT Phù Liễn;
+      PMT Paramaribo, Paris, Perm, Pontianak, Prague;
+      PMMT Port Moresby;
+      QMT Quito;
+      RMT Rangoon, Riga, Rome;
+      SDMT Santo Domingo;
+      SJMT San José;
+      SMT Santiago, Simferopol, Singapore, Stanley;
+      TBMT Tbilisi;
+      TMT Tallinn, Tehran;
+      WMT Warsaw;
+      ZMT Zomba.
+    
+
+    
+    A few abbreviations also follow the pattern that
+    GMT/BST established for time in the UK.
+    They are:
+      BMT/BST for Bermuda 1890–1930,
+      CMT/BST for Calamarca Mean Time and Bolivian Summer Time
+	1890–1932,
+      DMT/IST for Dublin/Dunsink Mean Time and Irish Summer Time
+	1880–1916,
+      MMT/MST/MDST for Moscow 1880–1919, and
+      RMT/LST for Riga Mean Time and Latvian Summer time 1880–1926.
+    
+    
+  
+  
+    Use 'LMT' for local mean time of locations before the
+    introduction of standard time; see "Scope of the
+    tz database".
+  
+  
+    If there is no common English abbreviation, use numeric offsets like
+    -05 and +0530 that are generated
+    by zic's %z notation.
+  
+  
+    Use current abbreviations for older timestamps to avoid confusion.
+    For example, in 1910 a common English abbreviation for time
+    in central Europe was 'MEZ' (short for both "Middle European
+    Zone" and for "Mitteleuropäische Zeit" in German).
+    Nowadays 'CET' ("Central European Time") is more common in
+    English, and the database uses 'CET' even for circa-1910
+    timestamps as this is less confusing for modern users and avoids
+    the need for determining when 'CET' supplanted 'MEZ' in common
+    usage.
+  
+  
+    Use a consistent style in a timezone's history.
+    For example, if a history tends to use numeric
+    abbreviations and a particular entry could go either way, use a
+    numeric abbreviation.
+  
+  
+    Use
+    Universal Time
+    (UT) (with time zone abbreviation '-00') for
+    locations while uninhabited.
+    The leading '-' is a flag that the UT offset is in
+    some sense undefined; this notation is derived
+    from Internet
+    RFC 3339.
+  
+
+
+
+Application writers should note that these abbreviations are ambiguous
+in practice: e.g., 'CST' means one thing in China and something else
+in North America, and 'IST' can refer to time in India, Ireland or
+Israel.
+To avoid ambiguity, use numeric UT offsets like
+'-0600' instead of time zone abbreviations like 'CST'.
+
+
+
+
+  Accuracy of the tz database
+
+The tz database is not authoritative, and it
+surely has errors.
+Corrections are welcome and encouraged; see the file CONTRIBUTING.
+Users requiring authoritative data should consult national standards
+bodies and the references cited in the database's comments.
+
+
+
+Errors in the tz database arise from many sources:
+
+
+
+  
+    The tz database predicts future
+    timestamps, and current predictions
+    will be incorrect after future governments change the rules.
+    For example, if today someone schedules a meeting for 13:00 next
+    October 1, Casablanca time, and tomorrow Morocco changes its
+    daylight saving rules, software can mess up after the rule change
+    if it blithely relies on conversions made before the change.
+  
+  
+    The pre-1970 entries in this database cover only a tiny sliver of how
+    clocks actually behaved; the vast majority of the necessary
+    information was lost or never recorded.
+    Thousands more timezones would be needed if
+    the tz database's scope were extended to
+    cover even just the known or guessed history of standard time; for
+    example, the current single entry for France would need to split
+    into dozens of entries, perhaps hundreds.
+    And in most of the world even this approach would be misleading
+    due to widespread disagreement or indifference about what times
+    should be observed.
+    In her 2015 book
+    The
+    Global Transformation of Time, 1870–1950,
+    Vanessa Ogle writes
+    "Outside of Europe and North America there was no system of time
+    zones at all, often not even a stable landscape of mean times,
+    prior to the middle decades of the twentieth century".
+    See: Timothy Shenk, Booked:
+      A Global History of Time. Dissent 2015-12-17.
+  
+  
+    Most of the pre-1970 data entries come from unreliable sources, often
+    astrology books that lack citations and whose compilers evidently
+    invented entries when the true facts were unknown, without
+    reporting which entries were known and which were invented.
+    These books often contradict each other or give implausible entries,
+    and on the rare occasions when they are checked they are
+    typically found to be incorrect.
+  
+  
+    For the UK the tz database relies on
+    years of first-class work done by
+    Joseph Myers and others; see
+    "History of
+    legal time in Britain".
+    Other countries are not done nearly as well.
+  
+  
+    Sometimes, different people in the same city maintain clocks
+    that differ significantly.
+    Historically, railway time was used by railroad companies (which
+    did not always
+    agree with each other), church-clock time was used for birth
+    certificates, etc.
+    More recently, competing political groups might disagree about
+    clock settings. Often this is merely common practice, but
+    sometimes it is set by law.
+    For example, from 1891 to 1911 the UT offset in France
+    was legally UT +00:09:21 outside train stations and
+    UT +00:04:21 inside. Other examples include
+    Chillicothe in 1920, Palm Springs in 1946/7, and Jerusalem and
+    Ürümqi to this day.
+  
+  
+    Although a named location in the tz
+    database stands for the containing region, its pre-1970 data
+    entries are often accurate for only a small subset of that region.
+    For example, Europe/London stands for the United
+    Kingdom, but its pre-1847 times are valid only for locations that
+    have London's exact meridian, and its 1847 transition
+    to GMT is known to be valid only for the L&NW and
+    the Caledonian railways.
+  
+  
+    The tz database does not record the
+    earliest time for which a timezone's
+    data entries are thereafter valid for every location in the region.
+    For example, Europe/London is valid for all locations
+    in its region after GMT was made the standard time,
+    but the date of standardization (1880-08-02) is not in the
+    tz database, other than in commentary.
+    For many timezones the earliest time of
+    validity is unknown.
+  
+  
+    The tz database does not record a
+    region's boundaries, and in many cases the boundaries are not known.
+    For example, the timezone
+    America/Kentucky/Louisville represents a region
+    around the city of Louisville, the boundaries of which are
+    unclear.
+  
+  
+    Changes that are modeled as instantaneous transitions in the
+    tz
+    database were often spread out over hours, days, or even decades.
+  
+  
+    Even if the time is specified by law, locations sometimes
+    deliberately flout the law.
+  
+  
+    Early timekeeping practices, even assuming perfect clocks, were
+    often not specified to the accuracy that the
+    tz database requires.
+  
+  
+    The tz database cannot represent stopped clocks.
+    However, on 1911-03-11 at 00:00, some public-facing French clocks
+    were changed by stopping them for a few minutes to effect a transition.
+    The tz database models this via a
+    backward transition; the relevant French legislation does not
+    specify exactly how the transition was to occur.
+  
+  
+    Sometimes historical timekeeping was specified more precisely
+    than what the tz code can handle.
+    For example, from 1880 to 1916 clocks in Ireland observed Dublin Mean
+    Time (estimated to be UT
+    −00:25:21.1); although the tz
+    source data can represent the .1 second, TZif files and the code cannot.
+    In practice these old specifications were rarely if ever
+    implemented to subsecond precision.
+  
+  
+    Even when all the timestamp transitions recorded by the
+    tz database are correct, the
+    tz rules that generate them may not
+    faithfully reflect the historical rules.
+    For example, from 1922 until World War II the UK moved clocks
+    forward the day following the third Saturday in April unless that
+    was Easter, in which case it moved clocks forward the previous
+    Sunday.
+    Because the tz database has no
+    way to specify Easter, these exceptional years are entered as
+    separate tz Rule lines, even though the
+    legal rules did not change.
+    When transitions are known but the historical rules behind them are not,
+    the database contains Zone and Rule
+    entries that are intended to represent only the generated
+    transitions, not any underlying historical rules; however, this
+    intent is recorded at best only in commentary.
+  
+  
+    The tz database models time
+    using the proleptic
+    Gregorian calendar with days containing 24 equal-length hours
+    numbered 00 through 23, except when clock transitions occur.
+    Pre-standard time is modeled as local mean time.
+    However, historically many people used other calendars and other timescales.
+    For example, the Roman Empire used
+    the Julian
+    calendar,
+    and Roman
+    timekeeping had twelve varying-length daytime hours with a
+    non-hour-based system at night.
+    And even today, some local practices diverge from the Gregorian
+    calendar with 24-hour days. These divergences range from
+    relatively minor, such as Japanese bars giving times like "24:30" for the
+    wee hours of the morning, to more-significant differences such as the
+    east African practice of starting the day at dawn, renumbering
+    the Western 06:00 to be 12:00. These practices are largely outside
+    the scope of the tz code and data, which
+    provide only limited support for date and time localization
+    such as that required by POSIX.
+    If DST is not used a different time zone
+    can often do the trick; for example, in Kenya a TZ setting
+    like <-03>3 or America/Cayenne starts
+    the day six hours later than Africa/Nairobi does.
+  
+  
+    Early clocks were less reliable, and data entries do not represent
+    clock error.
+  
+  
+    The tz database assumes Universal Time
+    (UT) as an origin, even though UT is not
+    standardized for older timestamps.
+    In the tz database commentary,
+    UT denotes a family of time standards that includes
+    Coordinated Universal Time (UTC) along with other
+    variants such as UT1 and GMT,
+    with days starting at midnight.
+    Although UT equals UTC for modern
+    timestamps, UTC was not defined until 1960, so
+    commentary uses the more-general abbreviation UT for
+    timestamps that might predate 1960.
+    Since UT, UT1, etc. disagree slightly,
+    and since pre-1972 UTC seconds varied in length,
+    interpretation of older timestamps can be problematic when
+    subsecond accuracy is needed.
+  
+  
+    Civil time was not based on atomic time before 1972, and we do not
+    know the history of
+    earth's
+    rotation accurately enough to map SI seconds to
+    historical solar time
+    to more than about one-hour accuracy.
+    See: Stephenson FR, Morrison LV, Hohenkerk CY.
+    Measurement of
+    the Earth's rotation: 720 BC to AD 2015.
+    Proc Royal Soc A. 2016;472:20160404.
+    Also see: Espenak F. Uncertainty
+    in Delta T (ΔT).
+  
+  
+    The relationship between POSIX time (that is, UTC but
+    ignoring leap
+    seconds) and UTC is not agreed upon after 1972.
+    Although the POSIX
+    clock officially stops during an inserted leap second, at least one
+    proposed standard has it jumping back a second instead; and in
+    practice POSIX clocks more typically either progress glacially during
+    a leap second, or are slightly slowed while near a leap second.
+  
+  
+    The tz database does not represent how
+    uncertain its information is.
+    Ideally it would contain information about when data entries are
+    incomplete or dicey.
+    Partial temporal knowledge is a field of active research, though,
+    and it is not clear how to apply it here.
+  
+
+
+
+In short, many, perhaps most, of the tz
+database's pre-1970 and future timestamps are either wrong or
+misleading.
+Any attempt to pass the
+tz database off as the definition of time
+should be unacceptable to anybody who cares about the facts.
+In particular, the tz database's
+LMT offsets should not be considered meaningful, and
+should not prompt creation of timezones
+merely because two locations
+differ in LMT or transitioned to standard time at
+different dates.
+
+
+
+
+  Time and date functions
+
+The tz code contains time and date functions
+that are upwards compatible with those of POSIX.
+Code compatible with this package is already
+part of many platforms, where the
+primary use of this package is to update obsolete time-related files.
+To do this, you may need to compile the time zone compiler
+'zic' supplied with this package instead of using the
+system 'zic', since the format of zic's
+input is occasionally extended, and a platform may still be shipping
+an older zic.
+
+
+POSIX properties and limitations
+
+  
+    
+    In POSIX, time display in a process is controlled by the
+    environment variable TZ.
+    Unfortunately, the POSIX
+    TZ string takes a form that is hard to describe and
+    is error-prone in practice.
+    Also, POSIX TZ strings cannot deal with daylight
+    saving time rules not based on the Gregorian calendar (as in
+    Iran), or with situations where more than two time zone
+    abbreviations or UT offsets are used in an area.
+    
+
+    
+    The POSIX TZ string takes the following form:
+    
+
+    
+    stdoffset[dst[offset][,date[/time],date[/time]]]
+    
+
+    
+    where:
+    
+
+    
+      std and dst

+	are 3 or more characters specifying the standard
+	and daylight saving time (DST) zone abbreviations.
+	Starting with POSIX.1-2001, std and dst
+	may also be in a quoted form like '<+09>';
+	this allows "+" and "-" in the names.
+      
+      offset

+	is of the form
+	'[±]hh:[mm[:ss]]'
+	and specifies the offset west of UT.
+	'hh' may be a single digit;
+	0≤hh≤24.
+	The default DST offset is one hour ahead of
+	standard time.
+      
+      date[/time],date[/time]

+	specifies the beginning and end of DST.
+	If this is absent, the system supplies its own ruleset
+	for DST, and its rules can differ from year to year;
+	typically US DST rules are used.
+      
+      time

+	takes the form
+	'hh:[mm[:ss]]'
+	and defaults to 02:00.
+	This is the same format as the offset, except that a
+	leading '+' or '-' is not allowed.
+      
+      date

+	takes one of the following forms:
+	
+	  Jn (1≤n≤365)

+	    origin-1 day number not counting February 29
+	  
+	  n (0≤n≤365)

+	    origin-0 day number counting February 29 if present
+	  
+	  Mm.n.d
+	    (0[Sunday]≤d≤6[Saturday], 1≤n≤5,
+	    1≤m≤12)

+	    for the dth day of week n of
+	    month m of the year, where week 1 is the first
+	    week in which day d appears, and
+	    '5' stands for the last week in which
+	    day d appears (which may be either the 4th or
+	    5th week).
+	    Typically, this is the only useful form; the n
+	    and Jn forms are rarely used.
+	  
+	
+      
+    
+
+    
+    Here is an example POSIX TZ string for New
+    Zealand after 2007.
+    It says that standard time (NZST) is 12 hours ahead
+    of UT, and that daylight saving time
+    (NZDT) is observed from September's last Sunday at
+    02:00 until April's first Sunday at 03:00:
+    
+
+    TZ='NZST-12NZDT,M9.5.0,M4.1.0/3'
+
+    
+    This POSIX TZ string is hard to remember, and
+    mishandles some timestamps before 2008.
+    With this package you can use this instead:
+    
+
+    TZ='Pacific/Auckland'
+  
+  
+    POSIX does not define the DST transitions
+    for TZ values like
+    "EST5EDT".
+    Traditionally the current US DST rules
+    were used to interpret such values, but this meant that the
+    US DST rules were compiled into each
+    program that did time conversion. This meant that when
+    US time conversion rules changed (as in the United
+    States in 1987), all programs that did time conversion had to be
+    recompiled to ensure proper results.
+  
+  
+    The TZ environment variable is process-global, which
+    makes it hard to write efficient, thread-safe applications that
+    need access to multiple timezones.
+  
+  
+    In POSIX, there is no tamper-proof way for a process to learn the
+    system's best idea of local (wall clock) time.
+    This is important for applications that an administrator wants
+    used only at certain times – without regard to whether the
+    user has fiddled the
+    TZ environment variable.
+    While an administrator can "do everything in UT" to
+    get around the problem, doing so is inconvenient and precludes
+    handling daylight saving time shifts – as might be required to
+    limit phone calls to off-peak hours.
+  
+  
+    POSIX provides no convenient and efficient way to determine
+    the UT offset and time zone abbreviation of arbitrary
+    timestamps, particularly for timezones
+    that do not fit into the POSIX model.
+  
+  
+    POSIX requires that time_t clock counts exclude leap
+    seconds.
+  
+  
+    The tz code attempts to support all the
+    time_t implementations allowed by POSIX.
+    The time_t type represents a nonnegative count of seconds
+    since 1970-01-01 00:00:00 UTC, ignoring leap seconds.
+    In practice, time_t is usually a signed 64- or 32-bit
+    integer; 32-bit signed time_t values stop working after
+    2038-01-19 03:14:07 UTC, so new implementations these
+    days typically use a signed 64-bit integer.
+    Unsigned 32-bit integers are used on one or two platforms, and 36-bit
+    and 40-bit integers are also used occasionally.
+    Although earlier POSIX versions allowed time_t to be a
+    floating-point type, this was not supported by any practical system,
+    and POSIX.1-2013 and the tz code both
+    require time_t to be an integer type.
+  
+
+
+Extensions to POSIX in the
+tz code
+
+  
+    
+    The TZ environment variable is used in generating
+    the name of a file from which time-related information is read
+    (or is interpreted à la POSIX); TZ is no longer
+    constrained to be a string containing abbreviations
+    and numeric data as described above.
+    The file's format is TZif,
+    a timezone information format that contains binary data; see
+    Internet
+    RFC 8536.
+    The daylight saving time rules to be used for a
+    particular timezone are encoded in the
+    TZif file; the format of the file allows US,
+    Australian, and other rules to be encoded, and
+    allows for situations where more than two time zone
+    abbreviations are used.
+    
+    
+    It was recognized that allowing the TZ environment
+    variable to take on values such as 'America/New_York'
+    might cause "old" programs (that expect TZ to have a
+    certain form) to operate incorrectly; consideration was given to using
+    some other environment variable (for example, TIMEZONE)
+    to hold the string used to generate the TZif file's name.
+    In the end, however, it was decided to continue using
+    TZ: it is widely used for time zone purposes;
+    separately maintaining both TZ
+    and TIMEZONE seemed a nuisance; and systems where
+    "new" forms of TZ might cause problems can simply
+    use legacy TZ values such as "EST5EDT" which
+    can be used by "new" programs as well as by "old" programs that
+    assume pre-POSIX TZ values.
+    
+  
+  
+    The code supports platforms with a UT offset member
+    in struct tm, e.g., tm_gmtoff,
+    or with a time zone abbreviation member in
+    struct tm, e.g., tm_zone. As noted
+    in Austin
+    Group defect 1533, a future version of POSIX is planned to
+    require tm_gmtoff and tm_zone.
+  
+  
+    Functions tzalloc, tzfree,
+    localtime_rz, and mktime_z for
+    more-efficient thread-safe applications that need to use multiple
+    timezones.
+    The tzalloc and tzfree functions
+    allocate and free objects of type timezone_t,
+    and localtime_rz and mktime_z are
+    like localtime_r and mktime with an
+    extra timezone_t argument.
+    The functions were inspired by NetBSD.
+  
+  
+    Negative time_t values are supported, on systems
+    where time_t is signed.
+  
+  
+    These functions can account for leap seconds;
+    see Leap seconds below.
+  
+
+
+POSIX features no longer needed
+
+POSIX and ISO C
+define some APIs that are vestigial:
+they are not needed, and are relics of a too-simple model that does
+not suffice to handle many real-world timestamps.
+Although the tz code supports these
+vestigial APIs for backwards compatibility, they should
+be avoided in portable applications.
+The vestigial APIs are:
+
+
+  
+    The POSIX tzname variable does not suffice and is no
+    longer needed.
+    To get a timestamp's time zone abbreviation, consult
+    the tm_zone member if available; otherwise,
+    use strftime's "%Z" conversion
+    specification.
+  
+  
+    The POSIX daylight and timezone
+    variables do not suffice and are no longer needed.
+    To get a timestamp's UT offset, consult
+    the tm_gmtoff member if available; otherwise,
+    subtract values returned by localtime
+    and gmtime using the rules of the Gregorian calendar,
+    or use strftime's "%z" conversion
+    specification if a string like "+0900" suffices.
+  
+  
+    The tm_isdst member is almost never needed and most of
+    its uses should be discouraged in favor of the abovementioned
+    APIs.
+    Although it can still be used in arguments to
+    mktime to disambiguate timestamps near
+    a DST transition when the clock jumps back on
+    platforms lacking tm_gmtoff, this
+    disambiguation does not work when standard time itself jumps back,
+    which can occur when a location changes to a time zone with a
+    lesser UT offset.
+  
+
+
+Other portability notes
+
+  
+    The 7th Edition
+    UNIX timezone function is not present in this
+    package; it is impossible to reliably map timezone's
+    arguments (a "minutes west of GMT" value and a
+    "daylight saving time in effect" flag) to a time zone
+    abbreviation, and we refuse to guess.
+    Programs that in the past used the timezone function
+    may now examine localtime(&clock)->tm_zone
+    (if TM_ZONE is defined) or
+    tzname[localtime(&clock)->tm_isdst]
+    (if HAVE_TZNAME is nonzero) to learn the correct time
+    zone abbreviation to use.
+  
+  
+    The 4.2BSD
+    gettimeofday function is not
+    used in this package.
+    This formerly let users obtain the current UTC offset
+    and DST flag, but this functionality was removed in
+    later versions of BSD.
+  
+  
+    In SVR2, time conversion fails for near-minimum or
+    near-maximum time_t values when doing conversions
+    for places that do not use UT.
+    This package takes care to do these conversions correctly.
+    A comment in the source code tells how to get compatibly wrong
+    results.
+  
+  
+    The functions that are conditionally compiled
+    if STD_INSPIRED is defined should, at this point, be
+    looked on primarily as food for thought.
+    They are not in any sense "standard compatible" – some are
+    not, in fact, specified in any standard.
+    They do, however, represent responses of various authors to
+    standardization proposals.
+  
+  
+    Other time conversion proposals, in particular those supported by the
+    Time Zone
+    Database Parser, offer a wider selection of functions
+    that provide capabilities beyond those provided here.
+    The absence of such functions from this package is not meant to
+    discourage the development, standardization, or use of such
+    functions.
+    Rather, their absence reflects the decision to make this package
+    contain valid extensions to POSIX, to ensure its broad
+    acceptability.
+    If more powerful time conversion functions can be standardized, so
+    much the better.
+  
+
+
+
+
+  Interface stability
+
+The tz code and data supply the following interfaces:
+
+
+
+  
+    A set of timezone names as per
+      "Timezone identifiers" above.
+  
+  
+    Library functions described in "Time and date
+      functions" above.
+  
+  
+    The programs tzselect, zdump,
+    and zic, documented in their man pages.
+  
+  
+    The format of zic input files, documented in
+    the zic man page.
+  
+  
+    The format of zic output files, documented in
+    the tzfile man page.
+  
+  
+    The format of zone table files, documented in zone1970.tab.
+  
+  
+    The format of the country code file, documented in iso3166.tab.
+  
+  
+    The version number of the code and data, as the first line of
+    the text file 'version' in each release.
+  
+
+
+
+Interface changes in a release attempt to preserve compatibility with
+recent releases.
+For example, tz data files typically do not
+rely on recently-added zic features, so that users can
+run older zic versions to process newer data files.
+Downloading
+the tz database describes how releases
+are tagged and distributed.
+
+
+
+Interfaces not listed above are less stable.
+For example, users should not rely on particular UT
+offsets or abbreviations for timestamps, as data entries are often
+based on guesswork and these guesses may be corrected or improved.
+
+
+
+Timezone boundaries are not part of the stable interface.
+For example, even though the Asia/Bangkok timezone
+currently includes Chang Mai, Hanoi, and Phnom Penh, this is not part
+of the stable interface and the timezone can split at any time.
+If a calendar application records a future event in some location other
+than Bangkok by putting "Asia/Bangkok" in the event's record,
+the application should be robust in the presence of timezone splits
+between now and the future time.
+
+
+
+
+  Leap seconds
+
+The tz code and data can account for leap seconds,
+thanks to code contributed by Bradley White.
+However, the leap second support of this package is rarely used directly
+because POSIX requires leap seconds to be excluded and many
+software packages would mishandle leap seconds if they were present.
+Instead, leap seconds are more commonly handled by occasionally adjusting
+the operating system kernel clock as described in
+Precision timekeeping,
+and this package by default installs a leapseconds file
+commonly used by
+NTP
+software that adjusts the kernel clock.
+However, kernel-clock twiddling approximates UTC only roughly,
+and systems needing more-precise UTC can use this package's leap
+second support directly.
+
+
+
+The directly-supported mechanism assumes that time_t
+counts of seconds since the POSIX epoch normally include leap seconds,
+as opposed to POSIX time_t counts which exclude leap seconds.
+This modified timescale is converted to UTC
+at the same point that time zone and DST
+adjustments are applied –
+namely, at calls to localtime and analogous functions –
+and the process is driven by leap second information
+stored in alternate versions of the TZif files.
+Because a leap second adjustment may be needed even
+if no time zone correction is desired,
+calls to gmtime-like functions
+also need to consult a TZif file,
+conventionally named Etc/UTC
+(GMT in previous versions),
+to see whether leap second corrections are needed.
+To convert an application's time_t timestamps to or from
+POSIX time_t timestamps (for use when, say,
+embedding or interpreting timestamps in portable
+tar
+files),
+the application can call the utility functions
+time2posix and posix2time
+included with this package.
+
+
+
+If the POSIX-compatible TZif file set is installed
+in a directory whose basename is zoneinfo, the
+leap-second-aware file set is by default installed in a separate
+directory zoneinfo-leaps.
+Although each process can have its own time zone by setting
+its TZ environment variable, there is no support for some
+processes being leap-second aware while other processes are
+POSIX-compatible; the leap-second choice is system-wide.
+So if you configure your kernel to count leap seconds, you should also
+discard zoneinfo and rename zoneinfo-leaps
+to zoneinfo.
+Alternatively, you can install just one set of TZif files
+in the first place; see the REDO variable in this package's
+makefile.
+
+
+
+
+  Calendrical issues
+
+Calendrical issues are a bit out of scope for a time zone database,
+but they indicate the sort of problems that we would run into if we
+extended the time zone database further into the past.
+An excellent resource in this area is Edward M. Reingold
+and Nachum Dershowitz, Calendrical
+Calculations: The Ultimate Edition, Cambridge University Press (2018).
+Other information and sources are given in the file 'calendars'
+in the tz distribution.
+They sometimes disagree.
+
+
+
+
+  Time and time zones on other planets
+
+Some people's work schedules have used
+Mars time.
+Jet Propulsion Laboratory (JPL) coordinators kept Mars time on
+and off during the
+Mars
+Pathfinder mission (1997).
+Some of their family members also adapted to Mars time.
+Dozens of special Mars watches were built for JPL workers who kept
+Mars time during the
+Mars
+Exploration Rovers (MER) mission (2004–2018).
+These timepieces looked like normal Seikos and Citizens but were adjusted
+to use Mars seconds rather than terrestrial seconds, although
+unfortunately the adjusted watches were unreliable and appear to have
+had only limited use.
+
+
+
+A Mars solar day is called a "sol" and has a mean period equal to
+about 24 hours 39 minutes 35.244 seconds in terrestrial time.
+It is divided into a conventional 24-hour clock, so each Mars second
+equals about 1.02749125 terrestrial seconds.
+(One MER worker noted, "If I am working Mars hours, and Mars hours are
+2.5% more than Earth hours, shouldn't I get an extra 2.5% pay raise?")
+
+
+
+The prime
+meridian of Mars goes through the center of the crater
+Airy-0, named in
+honor of the British astronomer who built the Greenwich telescope that
+defines Earth's prime meridian.
+Mean solar time on the Mars prime meridian is
+called Mars Coordinated Time (MTC).
+
+
+
+Each landed mission on Mars has adopted a different reference for
+solar timekeeping, so there is no real standard for Mars time zones.
+For example, the MER mission defined two time zones "Local
+Solar Time A" and "Local Solar Time B" for its two missions, each zone
+designed so that its time equals local true solar time at
+approximately the middle of the nominal mission.
+The A and B zones differ enough so that an MER worker assigned to
+the A zone might suffer "Mars lag" when switching to work in the B zone.
+Such a "time zone" is not particularly suited for any application
+other than the mission itself.
+
+
+
+Many calendars have been proposed for Mars, but none have achieved
+wide acceptance.
+Astronomers often use Mars Sol Date (MSD) which is a
+sequential count of Mars solar days elapsed since about 1873-12-29
+12:00 GMT.
+
+
+
+In our solar system, Mars is the planet with time and calendar most
+like Earth's.
+On other planets, Sun-based time and calendars would work quite
+differently.
+For example, although Mercury's
+sidereal
+rotation period is 58.646 Earth days, Mercury revolves around the
+Sun so rapidly that an observer on Mercury's equator would see a
+sunrise only every 175.97 Earth days, i.e., a Mercury year is 0.5 of a
+Mercury day.
+Venus is more complicated, partly because its rotation is slightly
+retrograde:
+its year is 1.92 of its days.
+Gas giants like Jupiter are trickier still, as their polar and
+equatorial regions rotate at different rates, so that the length of a
+day depends on latitude.
+This effect is most pronounced on Neptune, where the day is about 12
+hours at the poles and 18 hours at the equator.
+
+
+
+Although the tz database does not support
+time on other planets, it is documented here in the hopes that support
+will be added eventually.
+
+
+
+Sources for time on other planets:
+
+
+
+  
+    Michael Allison and Robert Schmunk,
+    "Technical
+      Notes on Mars Solar Time as Adopted by the Mars24 Sunclock"
+    (2020-03-08).
+  
+  
+    Zara Mirmalek,
+    Making
+	Time on Mars, MIT Press (March 2020), ISBN 978-0262043854.
+  
+  
+    Jia-Rui Chong,
+    "Workdays
+    Fit for a Martian", Los Angeles Times
+    (2004-01-14), pp A1, A20–A21.
+  
+  
+    Tom Chmielewski,
+    "Jet
+    Lag Is Worse on Mars", The Atlantic (2015-02-26)
+  
+  
+    Matt Williams,
+    "How
+    long is a day on the other planets of the solar system?"
+    (2016-01-20).
+  
+
+
+
+
+  
+  This file is in the public domain, so clarified as of 2009-05-17 by
+  Arthur David Olson.
+
+
+
diff --git a/time2posix.3 b/time2posix.3
index 64ea048f8182..1fcdf9e55733 100644
--- a/time2posix.3
+++ b/time2posix.3
@@ -1,121 +1,133 @@
 .TH TIME2POSIX 3
 .SH NAME
 time2posix, posix2time \- convert seconds since the Epoch
 .SH SYNOPSIS
 .nf
-.B #include 
+.ie \n(.g .ds - \f(CW-\fP
+.el .ds - \-
 .B #include 
 .PP
-.B time_t time2posix(t)
-.B time_t t
+.B time_t time2posix(time_t t);
 .PP
-.B time_t posix2time(t)
-.B time_t t
+.B time_t posix2time(time_t t);
 .PP
-.B cc ... -ltz
+.B cc ... \*-ltz
 .fi
 .SH DESCRIPTION
+.ie '\(en'' .ds en \-
+.el .ds en \(en
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
 IEEE Standard 1003.1
 (POSIX)
-legislates that a time_t value of
-536457599 shall correspond to "Wed Dec 31 23:59:59 UTC 1986."
-This effectively implies that POSIX time_t's cannot include leap
+requires the time_t value 536457599 to stand for 1986-12-31 23:59:59 UTC.
+This effectively implies that POSIX time_t values cannot include leap
 seconds and,
 therefore,
 that the system time must be adjusted as each leap occurs.
 .PP
 If the time package is configured with leap-second support
 enabled,
 however,
 no such adjustment is needed and
 time_t values continue to increase over leap events
-(as a true `seconds since...' value).
+(as a true
+.q "seconds since...\&"
+value).
 This means that these values will differ from those required by POSIX
 by the net number of leap seconds inserted since the Epoch.
 .PP
 Typically this is not a problem as the type time_t is intended
 to be
 (mostly)
-opaque\(emtime_t values should only be obtained-from and
+opaque \*(en time_t values should only be obtained-from and
 passed-to functions such as
-.IR time(2) ,
-.IR localtime(3) ,
-.IR mktime(3) ,
+.BR time(2) ,
+.BR localtime(3) ,
+.BR mktime(3) ,
 and
-.IR difftime(3) .
+.BR difftime(3) .
 However,
 POSIX gives an arithmetic
 expression for directly computing a time_t value from a given date/time,
 and the same relationship is assumed by some
 (usually older)
 applications.
 Any programs creating/dissecting time_t's
 using such a relationship will typically not handle intervals
 over leap seconds correctly.
 .PP
 The
-.I time2posix
+.B time2posix
 and
-.I posix2time
+.B posix2time
 functions are provided to address this time_t mismatch by converting
 between local time_t values and their POSIX equivalents.
 This is done by accounting for the number of time-base changes that
 would have taken place on a POSIX system as leap seconds were inserted
 or deleted.
 These converted values can then be used in lieu of correcting the older
 applications,
 or when communicating with POSIX-compliant systems.
 .PP
-.I Time2posix
+The
+.B time2posix
+function
 is single-valued.
 That is,
 every local time_t
 corresponds to a single POSIX time_t.
-.I Posix2time
+The
+.B posix2time
+function
 is less well-behaved:
 for a positive leap second hit the result is not unique,
 and for a negative leap second hit the corresponding
 POSIX time_t doesn't exist so an adjacent value is returned.
 Both of these are good indicators of the inferiority of the
 POSIX representation.
 .PP
 The following table summarizes the relationship between a time
 T and it's conversion to,
 and back from,
 the POSIX representation over the leap second inserted at the end of June,
 1993.
 .nf
 .ta \w'93/06/30 'u +\w'23:59:59 'u +\w'A+0 'u +\w'X=time2posix(T) 'u
 DATE	TIME	T	X=time2posix(T)	posix2time(X)
 93/06/30	23:59:59	A+0	B+0	A+0
 93/06/30	23:59:60	A+1	B+1	A+1 or A+2
 93/07/01	00:00:00	A+2	B+1	A+1 or A+2
 93/07/01	00:00:01	A+3	B+2	A+3
 
 A leap second deletion would look like...
 
 DATE	TIME	T	X=time2posix(T)	posix2time(X)
 ??/06/30	23:59:58	A+0	B+0	A+0
 ??/07/01	00:00:00	A+1	B+2	A+1
 ??/07/01	00:00:01	A+2	B+3	A+2
 .sp
 .ce
 	[Note: posix2time(B+1) => A+0 or A+1]
 .fi
 .PP
 If leap-second support is not enabled,
 local time_t's and
 POSIX time_t's are equivalent,
 and both
-.I time2posix
+.B time2posix
 and
-.I posix2time
+.B posix2time
 degenerate to the identity function.
 .SH SEE ALSO
 difftime(3),
 localtime(3),
 mktime(3),
 time(2)
-.\" @(#)time2posix.3	8.2
 .\" This file is in the public domain, so clarified as of
 .\" 1996-06-05 by Arthur David Olson.
diff --git a/time2posix.3.txt b/time2posix.3.txt
index 1bcf168e2e6c..aae7e1190584 100644
--- a/time2posix.3.txt
+++ b/time2posix.3.txt
@@ -1,83 +1,76 @@
-NAME
+TIME2POSIX(3)              Library Functions Manual              TIME2POSIX(3)
 
-     time2posix, posix2time - convert seconds since the Epoch
+NAME
+       time2posix, posix2time - convert seconds since the Epoch
 
 SYNOPSIS
-     #include 
-     #include 
+       #include 
 
-     time_t time2posix(t)
-     time_t t
+       time_t time2posix(time_t t);
 
-     time_t posix2time(t)
-     time_t t
+       time_t posix2time(time_t t);
 
-     cc ... -ltz
+       cc ... -ltz
 
 DESCRIPTION
-     IEEE Standard 1003.1 (POSIX) legislates that a time_t value
-     of 536457599 shall correspond to "Wed Dec 31 23:59:59 UTC
-     1986."  This effectively implies that POSIX time_t's cannot
-     include leap seconds and, therefore, that the system time
-     must be adjusted as each leap occurs.
-
-     If the time package is configured with leap-second support
-     enabled, however, no such adjustment is needed and time_t
-     values continue to increase over leap events (as a true
-     `seconds since...' value).  This means that these values
-     will differ from those required by POSIX by the net number
-     of leap seconds inserted since the Epoch.
-
-     Typically this is not a problem as the type time_t is
-     intended to be (mostly) opaque--time_t values should only be
-     obtained-from and passed-to functions such as time(2),
-     localtime(3), mktime(3), and difftime(3).  However, POSIX
-     gives an arithmetic expression for directly computing a
-     time_t value from a given date/time, and the same
-     relationship is assumed by some (usually older)
-     applications.  Any programs creating/dissecting time_t's
-     using such a relationship will typically not handle
-     intervals over leap seconds correctly.
-
-     The time2posix and posix2time functions are provided to
-     address this time_t mismatch by converting between local
-     time_t values and their POSIX equivalents.  This is done by
-     accounting for the number of time-base changes that would
-     have taken place on a POSIX system as leap seconds were
-     inserted or deleted.  These converted values can then be
-     used in lieu of correcting the older applications, or when
-     communicating with POSIX-compliant systems.
-
-     Time2posix is single-valued.  That is, every local time_t
-     corresponds to a single POSIX time_t.  Posix2time is less
-     well-behaved: for a positive leap second hit the result is
-     not unique, and for a negative leap second hit the
-     corresponding POSIX time_t doesn't exist so an adjacent
-     value is returned.  Both of these are good indicators of the
-     inferiority of the POSIX representation.
-
-     The following table summarizes the relationship between a
-     time T and it's conversion to, and back from, the POSIX
-     representation over the leap second inserted at the end of
-     June, 1993.
-     DATE     TIME     T   X=time2posix(T) posix2time(X)
-     93/06/30 23:59:59 A+0 B+0             A+0
-     93/06/30 23:59:60 A+1 B+1             A+1 or A+2
-     93/07/01 00:00:00 A+2 B+1             A+1 or A+2
-     93/07/01 00:00:01 A+3 B+2             A+3
-
-     A leap second deletion would look like...
-
-     DATE     TIME     T   X=time2posix(T) posix2time(X)
-     ??/06/30 23:59:58 A+0 B+0             A+0
-     ??/07/01 00:00:00 A+1 B+2             A+1
-     ??/07/01 00:00:01 A+2 B+3             A+2
-
-                     [Note: posix2time(B+1) => A+0 or A+1]
-
-     If leap-second support is not enabled, local time_t's and
-     POSIX time_t's are equivalent, and both time2posix and
-     posix2time degenerate to the identity function.
+       IEEE Standard 1003.1 (POSIX) requires the time_t value 536457599 to
+       stand for 1986-12-31 23:59:59 UTC.  This effectively implies that POSIX
+       time_t values cannot include leap seconds and, therefore, that the
+       system time must be adjusted as each leap occurs.
+
+       If the time package is configured with leap-second support enabled,
+       however, no such adjustment is needed and time_t values continue to
+       increase over leap events (as a true "seconds since..." value).  This
+       means that these values will differ from those required by POSIX by the
+       net number of leap seconds inserted since the Epoch.
+
+       Typically this is not a problem as the type time_t is intended to be
+       (mostly) opaque - time_t values should only be obtained-from and
+       passed-to functions such as time(2), localtime(3), mktime(3), and
+       difftime(3).  However, POSIX gives an arithmetic expression for
+       directly computing a time_t value from a given date/time, and the same
+       relationship is assumed by some (usually older) applications.  Any
+       programs creating/dissecting time_t's using such a relationship will
+       typically not handle intervals over leap seconds correctly.
+
+       The time2posix and posix2time functions are provided to address this
+       time_t mismatch by converting between local time_t values and their
+       POSIX equivalents.  This is done by accounting for the number of time-
+       base changes that would have taken place on a POSIX system as leap
+       seconds were inserted or deleted.  These converted values can then be
+       used in lieu of correcting the older applications, or when
+       communicating with POSIX-compliant systems.
+
+       The time2posix function is single-valued.  That is, every local time_t
+       corresponds to a single POSIX time_t.  The posix2time function is less
+       well-behaved: for a positive leap second hit the result is not unique,
+       and for a negative leap second hit the corresponding POSIX time_t
+       doesn't exist so an adjacent value is returned.  Both of these are good
+       indicators of the inferiority of the POSIX representation.
+
+       The following table summarizes the relationship between a time T and
+       it's conversion to, and back from, the POSIX representation over the
+       leap second inserted at the end of June, 1993.
+       DATE     TIME     T   X=time2posix(T) posix2time(X)
+       93/06/30 23:59:59 A+0 B+0             A+0
+       93/06/30 23:59:60 A+1 B+1             A+1 or A+2
+       93/07/01 00:00:00 A+2 B+1             A+1 or A+2
+       93/07/01 00:00:01 A+3 B+2             A+3
+
+       A leap second deletion would look like...
+
+       DATE     TIME     T   X=time2posix(T) posix2time(X)
+       ??/06/30 23:59:58 A+0 B+0             A+0
+       ??/07/01 00:00:00 A+1 B+2             A+1
+       ??/07/01 00:00:01 A+2 B+3             A+2
+
+                            [Note: posix2time(B+1) => A+0 or A+1]
+
+       If leap-second support is not enabled, local time_t's and POSIX
+       time_t's are equivalent, and both time2posix and posix2time degenerate
+       to the identity function.
 
 SEE ALSO
-     difftime(3), localtime(3), mktime(3), time(2)
+       difftime(3), localtime(3), mktime(3), time(2)
+
+                                                                 TIME2POSIX(3)
diff --git a/tz-art.htm b/tz-art.htm
deleted file mode 100644
index ff2afa906244..000000000000
--- a/tz-art.htm
+++ /dev/null
@@ -1,472 +0,0 @@
-
-
-
-
-Time and the Arts
-
-
-Time and the Arts
-
-@(#)tz-art.htm	8.17
-
-
-This file is in the public domain, so clarified as of
-2009-05-17 by Arthur David Olson.
-
-
-Please send corrections to this web page to the
-time zone mailing list.
-
-See also Sources for Time Zone and Daylight Saving Time Data.
-
-
-Data on recordings of "Save That Time," Russ Long, Serrob Publishing, BMI:
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
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-
-
-
-
-
-
-Artist Karrin Allyson
CD I Didn't Know About You
Copyright Date 1993
Label Concord Jazz, Inc.
ID CCD-4543
Track Time 3:44
Personnel Karrin Allyson, vocal;
-Russ Long, piano;
-Gerald Spaits, bass;
-Todd Strait, drums
Notes CD notes "additional lyric by Karrin Allyson;
-arranged by Russ Long and Karrin Allyson"
ADO Rating 1 star
AMG Rating 4 stars
Penguin Rating 3.5 stars
 
Artist Kevin Mahogany
CD Double Rainbow
Copyright Date 1993
Label Enja Records
ID ENJ-7097 2
Track Time 6:27
Personnel Kevin Mahogany, vocal;
-Kenny Barron, piano;
-Ray Drummond, bass;
-Ralph Moore, tenor saxophone;
-Lewis Nash, drums
ADO Rating 1.5 stars
AMG Rating 3 stars
Penguin Rating 3 stars
 
Artist Joe Williams
CD Here's to Life
Copyright Date 1994
Label Telarc International Corporation
ID CD-83357
Track Time 3:58
Personnel Joe Williams, vocal
-The Robert Farnon [39 piece] Orchestra
Notes This CD is also available as part of a 3-CD package from
-Telarc, "Triple Play" (CD-83461)
ADO Rating black dot
AMG Rating 2 stars
Penguin Rating 3 stars
 
Artist Charles Fambrough
CD Keeper of the Spirit
Copyright Date 1995
Label AudioQuest Music
ID AQ-CD1033
Track Time 7:07
Personnel Charles Fambrough, bass;
-Joel Levine, tenor recorder;
-Edward Simon, piano;
-Lenny White, drums;
-Marion Simon, percussion
Notes On-line information and samples available at
-http://wwmusic.com/~music/audioq/rel/1033.html
ADO Rating 2 stars
AMG Rating unrated
Penguin Rating 3 stars
-
-Also of note:
-
-
-
-
-
-
-
-
-
-
-
-
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-
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-
-
-Artist Holly Cole Trio
CD Blame It On My Youth
Copyright Date 1992
Label Manhattan
ID CDP 7 97349 2
Total Time 37:45
Personnel Holly Cole, voice;
-Aaron Davis, piano;
-David Piltch, string bass
Notes Lyrical reference to "Eastern Standard Time" in
-Tom Waits' "Purple Avenue"
ADO Rating 2.5 stars
AMG Rating 3 stars
Penguin Rating unrated
 
Artist Milt Hinton
CD Old Man Time
Copyright Date 1990
Label Chiaroscuro
ID CR(D) 310
Total Time 149:38 (two CDs)
Personnel Milt Hinton, bass;
-Doc Cheatham, Dizzy Gillespie, Clark Terry, trumpet;
-Al Grey, trombone;
-Eddie Barefield, Joe Camel (Flip Phillips), Buddy Tate,
-clarinet and saxophone;
-John Bunch, Red Richards, Norman Simmons, Derek Smith,
-Ralph Sutton, piano;
-Danny Barker, Al Casey, guitar;
-Gus Johnson, Gerryck King, Bob Rosengarden, Jackie Williams,
-drums;
-Lionel Hampton, vibraphone;
-Cab Calloway, Joe Williams, vocal;
-Buck Clayton, arrangements
Notes tunes include Old Man Time, Time After Time,
-Sometimes I'm Happy,
-A Hot Time in the Old Town Tonight,
-Four or Five Times, Now's the Time,
-Time on My Hands, This Time It's Us,
-and Good Time Charlie
-On-line samples available at
-http://www.chiaroscurojazz.com/albuminfo.php3?albumid=49
ADO Rating 3 stars
AMG Rating 4.5 stars
Penguin Rating 3 stars
 
Artist Alan Broadbent
CD Pacific Standard Time
Copyright Date 1995
Label Concord Jazz, Inc.
ID CCD-4664
Total Time 62:42
Personnel Alan Broadbent, piano;
-Putter Smith, Bass;
-Frank Gibson, Jr., drums
Notes The CD cover features an analemma for equation-of-time fans
ADO Rating 1 star
AMG Rating 4 stars
Penguin Rating 3.5 stars
 
Artist Anthony Braxton/Richard Teitelbaum
CD Silence/Time Zones
Copyright Date 1996
Label Black Lion
ID BLCD 760221
Total Time 72:58
Personnel Anthony Braxton, sopranino and alto saxophones,
-contrebasse clarinet, miscellaneous instruments;
-Leo Smith, trumpet and miscellaneous instruments;
-Leroy Jenkins, violin and miscellaneous instruments;
-Richard Teitelbaum, modular moog and micromoog synthesizer
ADO Rating black dot
AMG Rating unrated
 
Artist Charles Gayle
CD Time Zones
Copyright Date 2006
Label Tompkins Square
ID TSQ2839
Total Time 49:06
Personnel Charles Gayle, piano
ADO Rating 1 star
AMG Rating 4.5 stars
 
Artist The Get Up Kids
CD Eudora
Copyright Date 2001
Label Vagrant
ID 357
Total Time 65:12
Notes Includes the song "Central Standard Time." Thanks to Colin Bowern for this information.
AMG Rating 2.5 stars
 
Artist Coldplay
Song Clocks
Copyright Date 2003
Label Capitol Records
ID 52608
Total Time 4:13
Notes Won the 2004 Record of the Year honor at the
-Grammy Awards. Co-written and performed by Chris Martin,
-great-great-grandson of DST inventor William Willett. The song's first
-line is "Lights go out and I can't be saved".
 
Artist Irving Kahal and Harry Richman
Song There Ought to be a Moonlight Saving Time
Copyright Date 1931
Notes This musical standard was a #1 hit for Guy Lombardo
-in 1931, and was also performed by Maurice Chevalier, Blossom Dearie
-and many others. The phrase "Moonlight saving time" also appears in
-the 1995 country song "Not Enough Hours in the Night" written by Aaron
-Barker, Kim Williams and Rob Harbin and performed by Doug
-Supernaw.
 
Artist The Microscopic Septet
CD Lobster Leaps In
Copyright Date 2008
Label Cuneiform
ID 272
Total Time 73:05
Notes Includes the song "Twilight Time Zone."
AMG Rating 3.5 stars
ADO Rating 2 stars
 
Artist Bob Dylan
CD The Time They Are A-Changin'
Copyright Date 1964
Label Columbia
ID CK-8905
Total Time 45:36
AMG Rating 4.5 stars
ADO Rating 1.5 stars
Notes The title song is also available on "Bob Dylan's Greatest Hits" and "The Essential Bob Dylan."
 
Artist Luciana Souza
CD Tide
Copyright Date 2009
Label Universal Jazz France
ID B0012688-02
Total Time 42:31
AMG Rating 3.5 stars
ADO Rating 2.5 stars
Notes Includes the song "Fire and Wood" with the lyric
-"The clocks were turned back you remeber/Think it's still November."
-
 
TV episode title The Lost Hour
TV series Eerie, Indiana
TV episode number 10
Network NBC
Air date 1991-12-01
Notes Despite Indiana's then-lack of DST, Marshall changes his clock with unusual consequences.
 
TV episode title Time Tunnel
TV series The Adventures of Pete & Pete
TV episode number 5, season 2
Network Nickelodeon
Air date 1994-10-23
Notes The two Petes travel back in time an hour on the day that DST ends.
 
TV episode title King-Size Homer
TV series The Simpsons
TV episode number 135
Network Fox
Air date 1995-11-05
Notes Homer, working from home, remarks "8:58, first
-time I've ever been early for work. Except for all those daylight
-savings days. Lousy farmers."
 
Artist Jules Verne
Book Le Tour du Monde en Quatre-Vingts Jours
-(Around the World in Eighty Days)
Notes Wall-clock time plays a central role in the plot.
-European readers of the 1870s clearly held the U.S. press in
-deep contempt; the protagonists cross the U.S. without once
-reading a paper.
-An on-line French-language version of the book
-"with illustrations from the original 1873 French-language edition"
-is available at
-http://fourmilab.ch/etexts/www/tdm80j
-An on-line English-language translation of the book is available at
-http://www.literature.org/Works/Jules-Verne/eighty
 
Artist Umberto Eco
Book The Island of the Day Before
-(L'isola del giorno prima)
Copyright Date 1994
Notes 
-"...the story of a 17th century Italian nobleman trapped near an island
-on the International Date Line.  Time and time zones play an integral
-part in the novel." (Paul Eggert, 2006-04-22)
-
 
Artist David Jebb
Book 
-The Thirteenth Time Zone
Notes 
-"It's fiction, but it's based on his experiences and travels." (Paul Eggert, 2006-04-22)
-
 
Artist John Dunning
Book Two
-O'Clock, Eastern Wartime
Copyright Date 2001
Notes 
-Mystery, history, daylight saving time, and old-time radio.
-
 
Film Bell Science - About Time
Notes The Frank Baxter/Richard Deacon extravaganza.
-Information is available at
-http://www.videoflicks.com/titles/1035/1035893.htm
-
-
-
-An episode of "The Adventures of Superman" entitled "The Mysterious
-Cube," first aired 1958-02-24, had Superman convincing the controllers
-of WWV to broadcast time signals five minutes ahead of actual time;
-doing so got a crook trying to beat the statute of limitations to
-emerge a bit too early from the titular enclosure.
-
-
-The 1960s ITC television series "The Prisoner" included an episode
-entitled "The Chimes of Big Ben" in which our protagonist tumbled to
-the fraudulent nature of a Poland-to-England escape upon hearing "Big
-Ben" chiming on Polish local time.
-
-
-The series "Seinfeld" included an episode entitled "The Susie," first
-broadcast 1997-02-13, in which Kramer decides that daylight saving time
-isn't coming fast enough, so he sets his watch ahead an hour.
-
-
-The syndicated comic strip "Dilbert" featured an all-too-rare example of
-time zone humor on 1998-03-14.
-
-
-Surrealist artist Guy Billout's work "Date Line" appeared on page 103
-of the 1999-11 Atlantic Monthly.
-
-
-"Gloom, Gloom, Go Away" by Walter Kirn appeared on page 106 of Time
-Magazine's 2002-11-11 issue; among other things, it proposed
-year-round DST as a way of lessening wintertime despair.
-
-
-The "20 Hours in America" episode of "The West Wing," first aired 2002-09-25,
-saw White House staffers stranded in Indiana; they thought they had time to
-catch Air Force One but were done in by intra-Indiana local time changes.
-
-
-"In what time zone would you find New York City?" was a $200 question on
-the 1999-11-13 United States airing of "Who Wants to Be a Millionaire?"
-"In 1883, what industry led the movement to divide the U.S. into four time
-zones?" was a $32,000 question on the 2001-05-23 United States airing of
-"Who Wants to Be a Millionaire?" At this rate, the million-dollar time-zone
-question should have been asked 2002-06-04.
-
-
-A private jet's mid-flight change of time zones distorts Alison Dubois'
-premonition in the "We Had a Dream" episode of "Medium"
-(originally aired 2007-02-28).
-
-
-In the "30 Rock" episode "Anna Howard Shaw Day" (first broadcast 2010-02-11),
-Jack Donaghy's date realizes that a Geneva-to-New-York business phone call
-received in the evening must be fake given the difference in local times.
-
-
-In the 1946 movie "A Matter of Life and Death"
-(U.S. title "Stairway to Heaven")
-there is a reference to British Double Summer Time.
-The time does not play a large part in the plot;
-it's just a passing reference to the time when one of the
-characters was supposed to have died (but didn't).
-The IMDb page is at
-
-http://us.imdb.com/title/tt0038733/
-. (Dave Cantor)
-

-The 1953 railway comedy movie "The Titfield Thunderbolt" includes a
-play on words on British Double Summer Time. Valentine's wife wants
-him to leave the pub and asks him, "Do you know what time it is?"
-And he, happy where he is, replies: "Yes, my love. Summer double time."
-IMDB page:
-
-http://us.imdb.com/title/tt0046436/
-. (Mark Brader, 2009-10-02)
-
-
-The premise of the 1999 caper movie "Entrapment" involves computers
-in an international banking network being shut down briefly at
-midnight in each time zone to avoid any problems at the transition
-from the year 1999 to 2000 in that zone. (Hmmmm.) If this shutdown
-is extended by 10 seconds, it will create a one-time opportunity for
-a gigantic computerized theft. To achieve this, at one location the
-crooks interfere with the microwave system supplying time signals to
-the computer, advancing the time by 0.1 second each minute over the
-last hour of 1999. (So this movie teaches us that 0.1 x 60 = 10.)
-IMDB page:
-
-http://us.imdb.com/title/tt0137494/
-. (Mark Brader, 2009-10-02)
-
-
-
-
-
-
-"We're been using the five-cent nickle in this country since 1492.
-Now that's pretty near 100 years, daylight savings [sic]."
-(Groucho Marx as Captain Spaulding in "Animal Crackers", 1930,
-as noted by Will Fitzerald)
-
-
-Brady: "...[Bishop Usher] determined that the Lord began the Creation
-on the 23rd of October in the Year 4004 B.C. at -- uh, at 9 A.M.!"
-

-Drummond: "That Eastern Standard Time? (Laughter)  Or Rocky Mountain
-Time? (More laughter)  It wasn't daylight-saving time, was it?  Because
-the Lord didn't make the sun until the fourth day!"
-

-(From the play "Inherit the Wind" by Jerome Lawrence and Robert E. Lee,
-filmed in 1960 with Spencer Tracy as Drummond and Fredric March as
-Brady, and several other times. Thanks to Mark Brader.)
-
-
-"Good news."
-"What did they do? Extend Daylight Saving Time year round?"
-(Professional tanner George Hamilton, in dialog from a
-May, 1999 episode of the syndicated television series "Baywatch")
-
-
-"A fundamental belief held by Americans is that if you are on land, you
-cannot be killed by a fish...So most Americans remain on land, believing
-they're safe. Unfortunately, this belief—like so many myths, such as that
-there's a reason for 'Daylight Saving Time'—is false."
-(Dave Barry column, 2000-07-02)
-
-
-"I once had sex for an hour and five minutes, but that was on the day
-when you turn the clocks ahead."
-(Garry Shandling, 52nd Annual Emmys, 2000-09-10)
-
-
-"Would it impress you if I told you I invented Daylight Savings Time?"
-("Sahjhan" to "Lilah" in dialog from the "Loyalty" episode of "Angel,"
-originally aired 2002-02-25)
-
-
-"I thought you said Tulsa was a three hour flight."
-"Well, you're forgetting about the time difference."
-("Chandler" and "Joey" in dialog from the episode of "Friends" first
-aired 2002-12-05)
-
-
-"Is that a pertinent fact,
-or are you trying to dazzle me with your command of time zones?"
-(Kelsey Grammer as "Frasier Crane")
-
-
-"Don't worry about the world coming to an end today.
-It is already tomorrow in Australia."
-(Charles M. Schulz, provided by Steve Summit)
-
-
-
-
diff --git a/tz-art.html b/tz-art.html
new file mode 100644
index 000000000000..567953415f63
--- /dev/null
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@@ -0,0 +1,636 @@
+
+
+
+
+Time and the Arts
+
+
+Time and the Arts
+Documentaries
+
+
+"Daylight
+Saving Time Explained" (2011; 6:39) lightly covers daylight saving
+time's theory, history, pros and cons. Among other things, it explains
+Arizona's daylight-saving enclaves quite well.
+
+"The Problem
+with Time & Timezones – Computerphile" (2013; 10:12) delves
+into problems that programmers have with timekeeping.
+
+"All The Time In The World:
+Explaining The Mysteries Of Time Zones" (2017; 2:15)
+briefly says why France has more time zones than Russia.
+

+"Why Denmark is
+.17 Seconds Behind The World" (2019; 6:29) explains why Denmark and
+the United Kingdom don't exactly follow their own law about civil time.
+

+"About Time" (1962; 59 minutes) is part of the
+Bell Science extravaganza, with Frank Baxter, Richard Deacon, and Les Tremayne.
+Its advisor was Richard Feynman, and it was voiced by Mel Blanc.
+(IMDb entry.)
+
+Movies
+
+
+In the 1946 movie A Matter of Life and Death
+(U.S. title Stairway to Heaven)
+there is a reference to British Double Summer Time.
+The time does not play a large part in the plot;
+it's just a passing reference to the time when one of the
+characters was supposed to have died (but didn't).
+(IMDb entry.)
+(Dave Cantor)
+

+The 1953 railway comedy movie The Titfield Thunderbolt includes a
+play on words on British Double Summer Time. Valentine's wife wants
+him to leave the pub and asks him, "Do you know what time it is?"
+And he, happy where he is, replies: "Yes, my love. Summer double time."
+(IMDb entry.)
+(Mark Brader, 2009-10-02)
+
+
+The premise of the 1999 caper movie Entrapment involves computers
+in an international banking network being shut down briefly at
+midnight in each time zone to avoid any problems at the transition
+from the year 1999 to 2000 in that zone. (Hmmmm.) If this shutdown
+is extended by 10 seconds, it will create a one-time opportunity for
+a gigantic computerized theft. To achieve this, at one location the
+crooks interfere with the microwave system supplying time signals to
+the computer, advancing the time by 0.1 second each minute over the
+last hour of 1999. (So this movie teaches us that 0.1 × 60 = 10.)
+(IMDb entry.)
+(Mark Brader, 2009-10-02)
+
+
+One mustn't forget the
+trailer
+(2014; 2:23) for the movie Daylight Saving.
+
+
+TV episodes
+
+
+An episode of The Adventures of Superman entitled "The Mysterious
+Cube," first aired 1958-02-24, had Superman convincing the controllers
+of the Arlington Time Signal to broadcast ahead of actual time;
+doing so got a crook trying to be declared dead to
+emerge a bit too early from the titular enclosure.
+(IMDb entry.)
+
+
+"The Chimes
+of Big Ben", The Prisoner, episode 2, ITC, 1967-10-06.
+Our protagonist tumbles to
+the fraudulent nature of a Poland-to-England escape upon hearing "Big
+Ben" chiming on Polish local time.
+(IMDb entry.)
+
+
+"The Susie", Seinfeld, season 8, episode 15, NBC, 1997-02-13.
+Kramer decides that daylight saving time
+isn't coming fast enough, so he sets his watch ahead an hour.
+
+
+"20 Hours in America", The West Wing, season 4, episodes 1–2,
+2002-09-25, contained a scene that
+saw White House staffers stranded in Indiana; they thought they had time to
+catch Air Force One but were done in by intra-Indiana local time changes.
+
+
+"In what time zone would you find New York City?" was a $200 question on
+the 1999-11-13 United States airing of Who Wants to Be a Millionaire?,
+and "In 1883, what industry led the movement to divide the U.S. into four time
+zones?" was a $32,000 question on the 2001-05-23 United States airing of
+the same show. At this rate, the million-dollar time-zone
+question should have been asked 2002-06-04.
+
+
+A private jet's mid-flight change of time zones distorts Alison Dubois'
+premonition in the "We Had a Dream" episode of Medium
+(originally aired 2007-02-28).
+
+
+A criminal's failure to account for the start of daylight saving is pivotal
+in "Mr. Monk
+and the Rapper" (first aired 2007-07-20).
+
+
+In the 30 Rock episode "Anna Howard Shaw Day"
+(first broadcast 2010-02-11),
+Jack Donaghy's date realizes that a Geneva-to-New-York business phone call
+received in the evening must be fake given the difference in local times.
+
+
+In the "Run by the Monkeys" episode of Da Vinci's Inquest
+(first broadcast 2002-11-17),
+a witness in a five-year-old fire case realizes they may not have set
+their clock back when daylight saving ended on the day of the fire,
+introducing the possibility of an hour when arson might have occurred.
+
+
+In "The Todd Couple" episode of Outsourced (first aired 2011-02-10),
+Manmeet sets up Valentine's Day teledates for 6:00 and 9:00pm;
+since one is with a New Yorker and the other with a San Franciscan,
+hilarity ensues.
+(Never mind that this should be 7:30am in Mumbai, yet for some reason the show
+proceeds as though it's also mid-evening there.)
+
+
+In the "14 Days to Go"/"T Minus..." episode of
+You, Me and the Apocalypse
+(first aired 2015-11-11 in the UK, 2016-03-10 in the US),
+the success of a mission to deal with a comet
+hinges on whether or not Russia observes daylight saving time.
+(In the US,
+the episode first aired in the week before the switch to DST.)
+
+
+"The Lost Hour", Eerie, Indiana, episode 10, NBC, 1991-12-01.
+Despite Indiana's then-lack of DST,
+Marshall changes his clock with unusual consequences.
+See "Eerie,
+Indiana was a few dimensions ahead of its time".
+
+
+"Time Tunnel", The Adventures of Pete & Pete, season 2, episode 5,
+Nickelodeon, 1994-10-23.
+The two Petes travel back in time an hour
+on the day that DST ends.
+
+
+"King-Size Homer", The Simpsons, episode 135, Fox, 1995-11-05.
+Homer, working from home, remarks "8:58, first
+time I've ever been early for work. Except for all those daylight
+savings days. Lousy farmers."
+
+
+Last Week Tonight with John Oliver, season 2, episode 5, 2015-03-08,
+asked, "Daylight Saving
+Time – How Is This Still A Thing?"
+
+
+"Tracks", The Good Wife, season 7, episode 12,
+CBS, 2016-01-17.
+The applicability of a contract hinges on the
+time zone associated with a video timestamp.
+
+
+"Justice", Veep, season 6, episode 4, HBO, 2017-05-07.
+Jonah's inability to understand DST ends up impressing a wealthy
+backer who sets him up for a 2020 presidential run.
+
+
+Books, plays, and magazines
+
+
+Jules Verne, Around the World in Eighty Days
+(Le tour du monde en quatre-vingts jours), 1873.
+Wall-clock time plays a central role in the plot.
+European readers of the 1870s clearly held the U.S. press in
+deep contempt; the protagonists cross the U.S. without once
+reading a paper.
+Available versions include
+an English
+translation, and
+the original French
+"with illustrations from the original 1873 French-language edition".
+
+
+Nick Enright, Daylight Saving, 1989.
+A fast-paced comedy about love and loneliness as the clocks turn back.
+
+
+Umberto Eco,
+The
+Island of the Day Before
+(L'isola del giorno prima), 1994.
+"...the story of a 17th century Italian nobleman trapped near an island
+on the International Date Line.  Time and time zones play an integral
+part in the novel." (Paul Eggert, 2006-04-22)
+
+
+John Dunning, Two
+O'Clock, Eastern Wartime, 2001.
+Mystery, history, daylight saving time, and old-time radio.
+
+
+Surrealist artist Guy Billout's work "Date Line" appeared on page 103
+of the 1999-11 Atlantic Monthly.
+
+
+"Gloom, Gloom, Go Away" by Walter Kirn appeared on page 106 of Time
+magazine's 2002-11-11 issue; among other things, it proposed
+year-round DST as a way of lessening wintertime despair.
+
+
+Music
+
+Data on recordings of "Save That Time," Russ Long, Serrob Publishing, BMI:
+
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+
+
+Artist Karrin Allyson
CD I Didn't Know About You
Copyright Date 1993
Label Concord Jazz, Inc.
ID CCD-4543
Track Time 3:44
Personnel Karrin Allyson, vocal;
+Russ Long, piano;
+Gerald Spaits, bass;
+Todd Strait, drums
Notes CD notes "additional lyric by Karrin Allyson;
+arranged by Russ Long and Karrin Allyson"
ADO Rating 1 star
AMG Rating 4 stars
Penguin Rating 3.5 stars
  
Artist Kevin Mahogany
CD Double Rainbow
Copyright Date 1993
Label Enja Records
ID ENJ-7097 2
Track Time 6:27
Personnel Kevin Mahogany, vocal;
+Kenny Barron, piano;
+Ray Drummond, bass;
+Ralph Moore, tenor saxophone;
+Lewis Nash, drums
ADO Rating 1.5 stars
AMG Rating 3 stars
Penguin Rating 3 stars
  
Artist Joe Williams
CD Here's to Life
Copyright Date 1994
Label Telarc International Corporation
ID CD-83357
Track Time 3:58
Personnel Joe Williams, vocal
+The Robert Farnon [39 piece] Orchestra
Notes This CD is also available as part of a 3-CD package from
+Telarc, "Triple Play" (CD-83461)
ADO Rating black dot
AMG Rating 2 stars
Penguin Rating 3 stars
  
Artist Charles Fambrough
CD Keeper of the Spirit
Copyright Date 1995
Label AudioQuest Music
ID AQ-CD1033
Track Time 7:07
Personnel Charles Fambrough, bass;
+Joel Levine, tenor recorder;
+Edward Simon, piano;
+Lenny White, drums;
+Marion Simon, percussion
ADO Rating 2 stars
AMG Rating unrated
Penguin Rating 3 stars
+
+Also of note:
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+Artist Holly Cole Trio
CD Blame It On My Youth
Copyright Date 1992
Label Manhattan
ID CDP 7 97349 2
Total Time 37:45
Personnel Holly Cole, voice;
+Aaron Davis, piano;
+David Piltch, string bass
Notes Lyrical reference to "Eastern Standard Time" in
+Tom Waits' "Purple Avenue"
ADO Rating 2.5 stars
AMG Rating 3 stars
Penguin Rating unrated
  
Artist Milt Hinton
CD Old Man Time
Copyright Date 1990
Label Chiaroscuro
ID CR(D) 310
Total Time 149:38 (two CDs)
Personnel Milt Hinton, bass;
+Doc Cheatham, Dizzy Gillespie, Clark Terry, trumpet;
+Al Grey, trombone;
+Eddie Barefield, Joe Camel (Flip Phillips), Buddy Tate,
+clarinet and saxophone;
+John Bunch, Red Richards, Norman Simmons, Derek Smith,
+Ralph Sutton, piano;
+Danny Barker, Al Casey, guitar;
+Gus Johnson, Gerryck King, Bob Rosengarden, Jackie Williams,
+drums;
+Lionel Hampton, vibraphone;
+Cab Calloway, Joe Williams, vocal;
+Buck Clayton, arrangements
Notes tunes include Old Man Time, Time After Time,
+Sometimes I'm Happy,
+A Hot Time in the Old Town Tonight,
+Four or Five Times, Now's the Time,
+Time on My Hands, This Time It's Us,
+and Good Time Charlie.
+Album info
+is available.
ADO Rating 3 stars
AMG Rating 4.5 stars
Penguin Rating 3 stars
  
Artist Alan Broadbent
CD Pacific Standard Time
Copyright Date 1995
Label Concord Jazz, Inc.
ID CCD-4664
Total Time 62:42
Personnel Alan Broadbent, piano;
+Putter Smith, Bass;
+Frank Gibson, Jr., drums
Notes The CD cover features an analemma for equation-of-time fans
ADO Rating 1 star
AMG Rating 4 stars
Penguin Rating 3.5 stars
  
Artist Anthony Braxton/Richard Teitelbaum
CD Silence/Time Zones
Copyright Date 1996
Label Black Lion
ID BLCD 760221
Total Time 72:58
Personnel Anthony Braxton, sopranino and alto saxophones,
+contrebasse clarinet, miscellaneous instruments;
+Leo Smith, trumpet and miscellaneous instruments;
+Leroy Jenkins, violin and miscellaneous instruments;
+Richard Teitelbaum, modular moog and micromoog synthesizer
ADO Rating black dot
AMG Rating 4 stars
  
Artist Charles Gayle
CD Time Zones
Copyright Date 2006
Label Tompkins Square
ID TSQ2839
Total Time 49:06
Personnel Charles Gayle, piano
ADO Rating 1 star
AMG Rating 4.5 stars
  
Artist The Get Up Kids
CD Eudora
Copyright Date 2001
Label Vagrant
ID 357
Total Time 65:12
Notes Includes the song "Central Standard Time." Thanks to Colin Bowern for this information.
AMG Rating 2.5 stars
  
Artist Coldplay
Song Clocks
Copyright Date 2003
Label Capitol Records
ID 52608
Total Time 4:13
Notes Won the 2004 Record of the Year honor at the
+Grammy Awards. Co-written and performed by Chris Martin,
+great-great-grandson of DST inventor William Willett.
+The song's first line is "Lights go out and I can't be saved".
  
Artist Jaime Guevara
Song Qué
+hora es
Date 1993
Total Time 3:04
Notes The song protested "Sixto Hour" in Ecuador
+(1992–3). Its lyrics include "Amanecía en mitad de la noche, los
+guaguas iban a clase sin sol" ("It was dawning in the middle of the
+night, the buses went to class without sun").
+
  
Artist Irving Kahal and Harry Richman
Song There Ought to be a Moonlight Saving Time
Copyright Date 1931
Notes This musical standard was a No. 1 hit for Guy Lombardo
+in 1931, and was also performed by Maurice Chevalier, Blossom Dearie
+and many others. The phrase "Moonlight saving time" also appears in
+the 1995 country song "Not Enough Hours in the Night" written by Aaron
+Barker, Kim Williams and Rob Harbin and performed by Doug
+Supernaw.
  
Artist The Microscopic Septet
CD Lobster Leaps In
Copyright Date 2008
Label Cuneiform
ID 272
Total Time 73:05
Notes Includes the song "Twilight Time Zone."
AMG Rating 3.5 stars
ADO Rating 2 stars
  
Artist Bob Dylan
CD The Times They Are a-Changin'
Copyright Date 1964
Label Columbia
ID CK-8905
Total Time 45:36
AMG Rating 4.5 stars
ADO Rating 1.5 stars
Notes The title song is also available on "Bob Dylan's Greatest Hits" and "The Essential Bob Dylan."
  
Artist Luciana Souza
CD Tide
Copyright Date 2009
Label Universal Jazz France
ID B0012688-02
Total Time 42:31
AMG Rating 3.5 stars
ADO Rating 2.5 stars
Notes Includes the song "Fire and Wood" with the lyric
+"The clocks were turned back you remember/Think it's still November."
+
  
Artist Ken Nordine
CD You're Getting Better: The Word Jazz Dot Masters
Copyright Date 2005
Label Geffen
ID B0005171-02
Total Time 156:22
ADO Rating 1 star
AMG Rating 4.5 stars
Notes Includes the piece "What Time Is It"
+("He knew what time it was everywhere...that counted").
  
Artist Chicago
CD Chicago Transit Authority
Copyright Date 1969
Label Columbia
ID 64409
Total Time 1:16:20
AMG Rating 4 stars
Notes Includes the song "Does Anybody Really Know What Time It Is?"
+Comics
+
+
+The webcomic xkcd has the strip
+"The Sun" (2009-12-09) and the panels
+"Backward in Time" (2012-02-14),
+"EST" (2012-05-28),
+"ISO 8601" (2013-02-27),
+"Now" (2014-02-26),
+"Doomsday Clock" (2016-03-14),
+"Bad Map Projection: Time Zones"
+(2017-02-15),
+"Supervillain Plan" (2017-08-30),
+"6/6 Time" (2018-09-24),
+and "Leap Smearing" (2020-02-10).
+The related book What If? has an entry
+"Leap Seconds" (2012-12-31).
+
+
+Pig kills time in Pearls
+Before Swine (2016-11-06).
+
+
+Stonehenge is abandoned in Non Sequitur
+(2017-03-12).
+

+The boss freaks out in Dilbert (1998-03-14).
+
+
+Peppermint Patty: "What if the world comes to an end tonight, Marcie?"
+

+Marcie: "I promise there'll be a tomorrow, sir ... in fact,
+it's already tomorrow in Australia!"
+

+(Charles M. Schulz, Peanuts, 1980-06-13)
+
+
+Jokes
+
+
+The idea behind daylight saving time was first proposed as a joke by
+Benjamin Franklin. To enforce it, he suggested, "Every
+morning, as soon as the sun rises, let all the bells in every church
+be set ringing; and if that is not sufficient, let cannon be fired in
+every street, to wake the sluggards effectually, and make them open
+their eyes to see their true interest. All the difficulty will be in
+the first two or three days: after which the reformation will be as
+natural and easy as the present irregularity; for, ce n'est que le
+premier pas qui coûte."
+Franklin's
+joke was first published on 1784-04-26 by the
+Journal de Paris as an
+anonymous letter translated into French.
+
+
+"We've been using the five-cent nickel in this country since 1492.
+Now that's pretty near 100 years, daylight saving."
+(Groucho Marx as Captain Spaulding in Animal Crackers, 1930,
+as noted by Will Fitzgerald)
+
+
+BRADY. ...[Bishop Usher] determined that the Lord began the Creation
+on the 23rd of October in the Year 4,004 B.C. at – uh, 9 A.M.!
+

+DRUMMOND. That Eastern Standard Time? (Laughter.) Or Rocky Mountain
+Time? (More laughter.) It wasn't daylight-saving time, was it? Because
+the Lord didn't make the sun until the fourth day!
+

+(From the play Inherit the Wind by Jerome Lawrence and Robert E. Lee,
+filmed in 1960 with Spencer Tracy as Drummond and Fredric March as
+Brady, and several other times. Thanks to Mark Brader.)
+
+
+"Good news."
+"What did they do? Extend Daylight Saving Time year round?"
+(Professional tanner George Hamilton, in dialog from a
+May, 1999 episode of the syndicated television series Baywatch)
+
+
+"A fundamental belief held by Americans is that if you are on land, you
+cannot be killed by a fish...So most Americans remain on land, believing
+they're safe. Unfortunately, this belief – like so many myths, such as that
+there's a reason for 'Daylight Saving Time' – is false."
+(Dave Barry column, 2000-07-02)
+
+
+"I once had sex for an hour and five minutes, but that was on the day
+when you turn the clocks ahead."
+(Garry Shandling, 52nd Annual Emmys, 2000-09-10)
+
+
+"Would it impress you if I told you I invented Daylight Savings Time?"
+("Sahjhan" to "Lilah" in dialog from the "Loyalty" episode of Angel,
+originally aired 2002-02-25)
+
+
+"I thought you said Tulsa was a three-hour flight."
+"Well, you're forgetting about the time difference."
+("Joey" and "Chandler" in dialog from the episode of Friends
+entitled "The One With Rachel's Phone Number," originally aired 2002-12-05)
+
+
+"Is that a pertinent fact,
+or are you just trying to dazzle me with your command of time zones?"
+(Kelsey Grammer as "Frasier Crane" to "Roz" from the episode of Frasier
+entitled "The Kid," originally aired 1997-11-04)
+
+
+"I put myself and my staff through this crazy, huge ordeal, all because
+I refused to go on at midnight, okay?  And so I work, you know, and
+then I get this job at eleven, supposed to be a big deal.  Then
+yesterday daylight [saving] time ended. Right now it's basically
+midnight." (Conan O'Brien on the 2010-11-08 premiere of Conan.)
+
+
+"The best method, I told folks, was to hang a large clock high on a
+barn wall where all the cows could see it. If you have Holsteins, you
+will need to use an analog clock." (Jerry Nelson, How
+to adjust dairy cows to daylight saving time", Successful Farming,
+2017-10-09.)
+
+
+"And now, driving to California, I find that I must enter a password
+in order to change the time zone on my laptop clock. Evidently,
+someone is out to mess up my schedule and my clock must be secured."
+(Garrison Keillor,
+"We've
+never been here before", 2017-08-22)
+
+
+"Well, in my time zone that's all the time I have,
+but maybe in your time zone I haven't finished yet. So stay tuned!"
+(Goldie Hawn, Rowan & Martin's Laugh-In No. 65, 1970-03-09)
+
+
+See also
+
+Time Zone and Daylight Saving
+Time Data
+
+
+
+This web page is in the public domain, so clarified as of
+2009-05-17 by Arthur David Olson.
+

+Please send corrections to this web page to the
+time zone mailing list.
+
+
+
diff --git a/tz-how-to.html b/tz-how-to.html
new file mode 100644
index 000000000000..e1e28f2e257d
--- /dev/null
+++ b/tz-how-to.html
@@ -0,0 +1,719 @@
+
+
+
+How to Read the tz Database
+
+
+
+
+How to Read the tz
+Database Source Files
+by Bill Seymour
+This guide uses the America/Chicago and
+Pacific/Honolulu zones as examples of how to infer
+times of day from the tz database
+source files. It might be helpful, but not absolutely necessary,
+for the reader to have already downloaded the
+latest release of the database and become familiar with the basic layout
+of the data files. The format is explained in the “man
+page” for the zic compiler, zic.8.txt, in
+the code subdirectory.
+Although this guide covers many of the common cases, it is not a
+complete summary of what zic accepts; the man page is the
+authoritative reference.
+
+We’ll begin by talking about the rules for changing between standard
+and daylight saving time since we’ll need that information when we talk
+about the zones.
+
+First, let’s consider the special daylight saving time rules
+for Chicago (from the northamerica file in
+the data subdirectory):
+
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+  
+
+From the Source File

+    
+      
++#Rule NAME    FROM TO    -   IN  ON      AT   SAVE LETTER
+Rule  Chicago 1920 only  -   Jun 13      2:00 1:00 D
+Rule  Chicago 1920 1921  -   Oct lastSun 2:00 0    S
+Rule  Chicago 1921 only  -   Mar lastSun 2:00 1:00 D
+Rule  Chicago 1922 1966  -   Apr lastSun 2:00 1:00 D
+Rule  Chicago 1922 1954  -   Sep lastSun 2:00 0    S
+Rule  Chicago 1955 1966  -   Oct lastSun 2:00 0    S
+
+  
Reformatted a Bit
From To On At Action
1920 only June 13^th 02:00 local go to daylight saving time
1920 1921 last Sunday in October return to standard time
1921 only in March go to daylight saving time
1922 1966 in April
1954 in September return to standard time
1955 1966 in October
+
+The FROM and TO columns, respectively, specify the
+first and last calendar years defining a contiguous range over which a specific
+Rule line is to apply.  The keyword only can be used in the
+TO field to repeat the value of the FROM field in the
+event that a rule should only apply to a single year.  Often, the keyword
+max is used to extend a rule’s application into the
+indefinite future; it is a platform-agnostic stand-in for the largest
+representable year.
+
+
The next column, -, is reserved; for compatibility with earlier
+releases, it always contains a hyphen, which acts as a kind of null value.
+Prior to the 2020b release, it was called the TYPE field, though
+it had not been used in the main data since the 2000e release.
+An obsolescent supplementary file used the
+field as a proof-of-concept to allow zic to apply a given Rule
+line only to certain “types” of years within the specified range as
+dictated by the output of a separate script, such as: only years which would
+have a US presidential election, or only years which wouldn’t.
+
+
The SAVE column contains the local (wall clock) offset from
+local standard time.
+This is usually either zero for standard time or one hour for daylight
+saving time; but there’s no reason, in principle, why it can’t
+take on other values.
+
+
The LETTER (sometimes called LETTER/S)
+column can contain a variable
+part of the usual abbreviation of the time zone’s name, or it can just
+be a hyphen if there’s no variable part. For example, the abbreviation
+used in the central time zone will be either “CST” or
+“CDT”. The variable part is ‘S’ or ‘D’;
+and, sure enough, that’s just what we find in
+the LETTER column
+in the Chicago rules. More about this when we talk about
+“Zone” lines.
+
+
One important thing to notice is that “Rule” lines
+want at once to be both transitions and steady states:
+

+On the one hand, they represent transitions between standard and
+daylight saving time; and any number of Rule lines can be in effect
+during a given period (which will always be a non-empty set of
+contiguous calendar years).
+On the other hand, the SAVE and LETTER
+columns contain state that exists between transitions. More about this
+when we talk about the US rules.
+
+
+In the example above, the transition to daylight saving time
+happened on the 13^th of June in 1920, and on
+the last Sunday in March in 1921; but the return to standard time
+happened on the last Sunday in October in both of those
+years. Similarly, the rule for changing to daylight saving time was
+the same from 1922 to 1966; but the rule for returning to standard
+time changed in 1955. Got it?
+
+OK, now for the somewhat more interesting “US” rules:
+
+
+
+  
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+From the Source File

+    
+      
++#Rule NAME FROM TO    -   IN  ON        AT   SAVE LETTER/S
+Rule  US   1918 1919  -   Mar lastSun  2:00  1:00 D
+Rule  US   1918 1919  -   Oct lastSun  2:00  0    S
+Rule  US   1942 only  -   Feb 9        2:00  1:00 W # War
+Rule  US   1945 only  -   Aug 14      23:00u 1:00 P # Peace
+Rule  US   1945 only  -   Sep 30       2:00  0    S
+Rule  US   1967 2006  -   Oct lastSun  2:00  0    S
+Rule  US   1967 1973  -   Apr lastSun  2:00  1:00 D
+Rule  US   1974 only  -   Jan 6        2:00  1:00 D
+Rule  US   1975 only  -   Feb 23       2:00  1:00 D
+Rule  US   1976 1986  -   Apr lastSun  2:00  1:00 D
+Rule  US   1987 2006  -   Apr Sun>=1   2:00  1:00 D
+Rule  US   2007 max   -   Mar Sun>=8   2:00  1:00 D
+Rule  US   2007 max   -   Nov Sun>=1   2:00  0    S
+
+  
Reformatted a Bit
From To On At Action
1918 1919 last Sunday in March 02:00 local go to daylight saving time
in October return to standard time
1942 only February 9^th go to “war time”
1945 only August 14^th 23:00 UT 
+    rename “war time” to “peace
time;”
+    clocks don’t change
+  
September 30^th 02:00 local return to standard time
1967 2006 last Sunday in October
1973 in April go to daylight saving time
1974 only January 6^th
1975 only February 23^rd
1976 1986 last Sunday in April
1987 2006 first Sunday
2007 present second Sunday in March
first Sunday in November return to standard time
+
+There are two interesting things to note here.
+
+First, the time that something happens (in the AT
+column) is not necessarily the local (wall clock) time. The time can be
+suffixed with ‘s’ (for “standard”) to mean
+local standard time, different from local (wall clock) time when observing
+daylight saving time; or it can be suffixed with ‘g’,
+‘u’, or ‘z’, all three of which mean the
+standard time at the
+prime meridian.
+‘g’ stands for “GMT”;
+‘u’ stands for “UT” or “UTC”
+(whichever was official at the time); ‘z’ stands for the
+nautical time zone
+Z (a.k.a. “Zulu” which, in turn, stands for ‘Z’).
+The time can also be suffixed with ‘w’ meaning local (wall
+clock) time; but it usually isn’t because that’s the
+default.
+
+Second, the day in the ON column, in addition to
+“lastSun” or a particular day of the month,
+can have the form, “Sun>=x” or
+“Sun<=x,” where x is a day
+of the month. For example, “Sun>=8” means
+“the first Sunday on or after the eighth of the month,” in
+other words, the second Sunday of the month. Furthermore, although
+there are no examples above, the weekday needn’t be
+“Sun” in either form, but can be the usual
+three-character English abbreviation for any day of the week.
+
+And the US rules give us more examples of a couple of things
+already mentioned:
+
+
+The rules for changing to and from daylight saving time are
+actually different sets of rules; and the two sets can change
+independently. Consider, for example, that the rule for the return to
+standard time stayed the same from 1967 to 2006; but the rule for the
+transition to daylight saving time changed several times in the same
+period.  There can also be periods, 1946 to 1966 for example, when no
+rule from this group is in effect, and so either no transition
+happened in those years, or some other rule is in effect (perhaps a
+state or other more local rule).
+
+The SAVE and LETTER columns
+contain steady state, not transitions. Consider, for example,
+the transition from “war time” to “peace time”
+that happened on August 14, 1945. The “1:00” in
+the SAVE column is not an instruction to advance
+the clock an hour. It means that clocks should be one hour
+ahead of standard time, which they already are because of the previous
+rule, so there should be no change.
+
+
+
+OK, now let’s look at a Zone record:
+
+
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+
+From the Source File

+    
+      
++#Zone       NAME      STDOFF   RULES FORMAT [UNTIL]
+Zone  America/Chicago -5:50:36 -       LMT  1883 Nov 18 12:09:24
+                      -6:00    US      C%sT 1920
+                      -6:00    Chicago C%sT 1936 Mar  1  2:00
+                      -5:00    -       EST  1936 Nov 15  2:00
+                      -6:00    Chicago C%sT 1942
+                      -6:00    US      C%sT 1946
+                      -6:00    Chicago C%sT 1967
+                      -6:00    US      C%sT
+
+  
Columns Renamed
Standard Offset

+    from Prime
+    Meridian Daylight
Saving Time Abbreviation(s) Ending at Local Time
Date Time
−5:50:36 not observed LMT 1883-11-18 12:09:24
−6:00:00 US rules CST or CDT 1920-01-01 00:00:00
Chicago rules 1936-03-01 02:00:00
−5:00:00 not observed EST 1936-11-15
−6:00:00 Chicago rules CST or CDT 1942-01-01 00:00:00
US rules CST, CWT or CPT 1946-01-01
Chicago rules CST or CDT 1967-01-01
US rules —
+
+There are a couple of interesting differences between Zones and Rules.
+
+First, and somewhat trivially, whereas Rules are considered to
+contain one or more records, a Zone is considered to be a single
+record with zero or more continuation lines. Thus, the keyword,
+“Zone,” and the zone name are not
+repeated. The last line is the one without anything in
+the [UNTIL] column.
+
+Second, and more fundamentally, each line of a Zone represents a
+steady state, not a transition between states. The state exists from
+the date and time in the previous line’s [UNTIL]
+column up to the date and time in the current
+line’s [UNTIL] column. In other words, the date and
+time in the [UNTIL] column is the instant that separates
+this state from the next. Where that would be ambiguous because
+we’re setting our clocks back, the [UNTIL] column
+specifies the first occurrence of the instant. The state specified by
+the last line, the one without anything in the [UNTIL]
+column, continues to the present.
+
+The first line typically specifies the mean solar time observed
+before the introduction of standard time. Since there’s no line before
+that, it has no beginning. 8-)  For some places near the International
+Date Line, the first two lines will show solar times
+differing by 24 hours; this corresponds to a movement of the Date
+Line.  For example:
+
++#Zone NAME          STDOFF   RULES FORMAT [UNTIL]
+Zone America/Juneau 15:02:19 -     LMT    1867 Oct 18
+                    -8:57:41 -     LMT    ...
+
+
+When Alaska was purchased from Russia in 1867, the Date Line moved
+from the Alaska/Canada border to the Bering Strait; and the time in
+Alaska was then 24 hours earlier than it had
+been. <aside>(6 October in the Julian calendar,
+which Russia was still using then for religious reasons, was followed
+by a second instance of the same day with a different name, 18
+October in the Gregorian calendar. Isn’t civil time
+wonderful? 8-))</aside>
+
+The abbreviation, “LMT” stands for “local mean
+time”, which is an invention of
+the tz
+database and was probably never actually used during the
+period. Furthermore, the value is almost certainly wrong except in the
+archetypal place after which the zone is named. (The tz database
+usually doesn’t provide a separate Zone record for places where
+nothing significant happened after 1970.)
+
+The RULES column tells us whether daylight saving time is being observed:
+

+A hyphen, a kind of null value, means that we have not set our
+clocks ahead of standard time.
+
+An amount of time (usually but not necessarily “1:00”
+meaning one hour) means that we have set our clocks ahead by that
+amount.
+
+Some alphabetic string means that we might have set our
+clocks ahead; and we need to check the rule the name of which is the
+given alphabetic string.
+
+
+An example of a specific amount of time is:
++#Zone NAME            STDOFF RULES FORMAT [UNTIL]
+Zone Pacific/Honolulu ...                 1933 Apr 30  2:00
+                      -10:30 1:00  HDT    1933 May 21 12:00
+                      ...
+
+
+Hawaii tried daylight saving time for three weeks in 1933 and
+decided they didn’t like it. 8-) Note that
+the STDOFF column always contains the standard time
+offset, so the local (wall clock) time during this period was GMT −
+10:30 + 1:00 = GMT − 9:30.
+
+The FORMAT column specifies the usual abbreviation of
+the time zone name. It should have one of four forms:
+
+
+a time zone abbreviation that is a string of three or more
+characters that are either ASCII alphanumerics,
+“+”, or “-”
+
+the string “%z”, in which case the
+“%z” will be replaced by a numeric time zone
+abbreviation
+
+a pair of time zone abbreviations separated by a slash
+(‘/’), in which case the first string is the
+abbreviation for the standard time name and the second string is the
+abbreviation for the daylight saving time name
+
+a string containing “%s”, in which case
+the “%s” will be replaced by the text in the
+appropriate Rule’s LETTER column, and the resulting
+string should be a time zone abbreviation
+
+
+The last two make sense only if there’s a named rule in effect.
+
+An example of a slash is:
++#Zone NAME          STDOFF RULES FORMAT  [UNTIL]
+Zone  Europe/London ...                  1996
+                    0:00   EU    GMT/BST
+
+
+The current time in the UK is called either Greenwich mean time or
+British summer time.
+
+One wrinkle, not fully explained in zic.8.txt, is what
+happens when switching to a named rule. To what values should
+the SAVE and LETTER data be initialized?
+
+
+If at least one transition has happened, use
+the SAVE and LETTER data from the most
+recent.
+
+If switching to a named rule before any transition has happened,
+assume standard time (SAVE zero), and use
+the LETTER data from the earliest transition with
+a SAVE of zero.
+
+
+
+And three last things about the FORMAT column:
+
+
+The tz
+database gives abbreviations for time zones in popular
+usage, which is not necessarily “correct” by law. For
+example, the last line in
+Zone Pacific/Honolulu (shown below) gives
+“HST” for “Hawaii standard time” even though the
+legal
+name for that time zone is “Hawaii-Aleutian standard time.”
+This author has read that there are also some places in Australia where
+popular time zone names differ from the legal ones.
+
+
No attempt is made to localize
+the abbreviations. They are intended to be the values returned through the
+"%Z" format specifier to
+C’s
+strftime
+function in the
+“C” locale.
+
+
If there is no generally-accepted abbreviation for a time zone,
+a numeric offset is used instead, e.g., +07 for 7 hours
+ahead of Greenwich. By convention, -00 is used in a
+zone while uninhabited, where the offset is zero but in some sense
+the true offset is undefined.
+
+
+As a final example, here’s the complete history for Hawaii:
+
+
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+
+Relevant Excerpts from the US Rules

+    
+      
++#Rule NAME FROM TO   -    IN  ON      AT     SAVE LETTER/S
+Rule  US   1918 1919 -    Oct lastSun  2:00  0    S
+Rule  US   1942 only -    Feb  9       2:00  1:00 W # War
+Rule  US   1945 only -    Aug 14      23:00u 1:00 P # Peace
+Rule  US   1945 only -    Sep lastSun  2:00  0    S
+
+  
The Zone Record

+    
+      
++#Zone NAME            STDOFF    RULES FORMAT [UNTIL]
+Zone Pacific/Honolulu -10:31:26 -     LMT    1896 Jan 13 12:00
+                      -10:30    -     HST    1933 Apr 30  2:00
+                      -10:30    1:00  HDT    1933 May 21  2:00
+                      -10:30    US    H%sT   1947 Jun  8  2:00
+                      -10:00    -     HST
+
+  
What We Infer
Wall-Clock
Offset from
Prime Meridian Adjust
Clocks Time Zone Ending at Local Time
Abbrv. Name Date Time
−10:31:26 — LMT local mean time 1896-01-13 12:00
−10:30 +0:01:26 HST Hawaii standard time 1933-04-30 02:00
−9:30 +1:00 HDT Hawaii daylight time 1933-05-21 12:00
−10:30¹ −1:00¹ HST¹ Hawaii standard time 1942-02-09 02:00
−9:30 +1:00 HWT Hawaii war time 1945-08-14 13:30²
0 HPT Hawaii peace time 1945-09-30 02:00
−10:30 −1:00 HST Hawaii standard time 1947-06-08
−10:00³ +0:30³ —

+    ¹Switching to US rules…most recent transition (in 1919) was to standard time
+  

+    ²23:00 UT
+    + (−9:30) = 13:30 local
+  

+    ³Since 1947–06–08T12:30Z,
+    the civil time in Hawaii has been
+    UT/UTC
+    − 10:00 year-round.
+  
+
+There will be a short quiz later. 8-)
+
+
+
+This web page is in the public domain, so clarified as of
+2015-10-20 by Bill Seymour.
+

+All suggestions and corrections will be welcome; all flames will be amusing.
+Mail to was at pobox dot com.
+
+
+
diff --git a/tz-link.htm b/tz-link.htm
deleted file mode 100644
index 26235100b98b..000000000000
--- a/tz-link.htm
+++ /dev/null
@@ -1,678 +0,0 @@
-
-
-
-Sources for Time Zone and Daylight Saving Time Data
-
-
-
-
-
-
-
-
-
-
-Sources for Time Zone and Daylight Saving Time Data
-
-@(#)tz-link.htm	8.30
-
-
-This file is in the public domain, so clarified as of
-2009-05-17 by Arthur David Olson.
-
-
-Please send corrections to this web page to the
-time zone mailing list.
-The tz database
-
-The public-domain
-time zone database contains code and data
-that represent the history of local time
-for many representative locations around the globe.
-It is updated periodically to reflect changes made by political bodies
-to time zone
-boundaries, UTC offsets, and
-daylight-saving
-rules.
-This database (often called zoneinfo or tz)
-is used by several implementations,
-including
-the
-GNU
-C Library used in
-GNU/Linux,
-FreeBSD,
-NetBSD,
-OpenBSD,
-Cygwin,
-DJGPP,
-AIX,
-Mac OS X,
-OpenVMS,
-Oracle Database,
-Solaris,
-Tru64, and
-UnixWare.
-
-Each location in the database represents a national region where all
-clocks keeping local time have agreed since 1970.
-Locations are identified by continent or ocean and then by the name of
-the location, which is typically the largest city within the region.
-For example, America/New_York
-represents most of the US eastern time zone;
-America/Phoenix represents most of Arizona, which
-uses mountain time without daylight saving time (DST);
-America/Detroit represents most of Michigan, which uses
-eastern time but with different DST rules in 1975;
-and other entries represent smaller regions like Starke County,
-Indiana, which switched from central to eastern time in 1991
-and switched back in 2006.
-To use the database on an extended POSIX
-implementation set the TZ environment variable to
-the location's full name, e.g., TZ="America/New_York".
-
-In the tz database's
-FTP distribution
-the code is in the file tzcodeC.tar.gz,
-where C is the code's version;
-similarly, the data are in tzdataD.tar.gz,
-where D is the data's version.
-Each version is a four-digit year followed by lower-case letters
-(a through z, then za through zz, then zza through zzz, and so on).
-The following shell commands download
-these files to a GNU/Linux or similar host;
-see the downloaded
-README file for what to do next.
-wget 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz'
-gzip -dc tzcode*.tar.gz | tar -xf -
-gzip -dc tzdata*.tar.gz | tar -xf -
-
-
-The code lets you compile the tz source files into
-machine-readable binary files, one for each location. It also lets
-you read a tz binary file and interpret time stamps for that
-location.
-
-The data are by no means authoritative. If you find errors, please
-send changes to the time zone
-mailing list. You can also browse recent
-messages sent to the mailing list, subscribe to it,
-retrieve the full archive of old
-messages (in gzip compressed format), or retrieve archived older versions of code
-and data.
-
-The Web has several other sources for time zone and daylight saving time data.
-Here are some recent links that may be of interest.
-
-Web pages using recent versions of the tz database
-
-These are listed roughly in ascending order of complexity and fanciness.
-
-
-
-
-Permatime
-is a service for generating and viewing links that refer to a
-particular point in time and can be displayed in multiple timezones.
-It uses the ruby tzinfo gem. 
-(From Tim Diggins, 2009-11-03.)
-
-Date and Time Gateway
-lets you see the TZ values directly.
-Current
-Time in 1000 Places uses descriptions of the values.
-Time Zone Converter
-uses a pulldown menu.
-Complete
-timezone information for all countries displays tables of DST rules.
-
The World Clock -
-Time Zones lets you sort zone names and convert times.
-Graphical Display of
-Time Zones and Daylight Saving Times shows a graph of time
-difference versus time for any pair of locations.
-The World Time Engine
-also contains data about time zone boundaries; it supports queries via place
-names and shows location maps.
-Simple Timer + Clocks
-is a Firefox add-on which uses a timezone data file generated from the
-tz data files.
-
-Other time zone database formats
-
-The 
-Internet Calendaring and Scheduling Core Object Specification
-(iCalendar), Internet RFC 2445, published by the (now-concluded) IETF
-Calendaring and Scheduling Working Group (calsch)
-covers time zone
-data; see its VTIMEZONE calendar component.
-The Calendaring and Scheduling
-Consortium is promoting further work in this area. iCalendar
-TIMEZONE Problems and Recommendations offers guidelines and
-recommendations for the use of VTIMEZONE and tz.
-Extended Daylight
-Saving Time Links, Advisories and Changes lists vendor material on recent
-daylight saving time changes.
-Timezone
-Registry and Service Recommendations discusses a
-strategy for defining and deploying a time zone
-registration process that would establish unique names for each
-version of each tz zone, along with a polygonal
-representation of the geographical area corresponding to the
-zone.
-The www-rdf-calendar
-list discusses RDF-based calendar
-and group scheduling systems, and has a workspace on time zone
-data converted from tz. An earlier schema was sketched out.
-
-Other tz compilers
-
-Vzic iCalendar
-Timezone Converter describes a C
-program that compiles
-tz source into iCalendar-compatible VTIMEZONE files.
-Vzic is freely
-available under the GNU
-General Public License (GPL).
-tziCal - tz
-database conversion utility is like Vzic, except for the .NET framework.
-DateTime::TimeZone
-contains a script parse_olson that compiles
-tz source into Perl
-modules. It is part of the Perl DateTime Project, which is freely
-available under both the GPL and the Perl Artistic
-License. DateTime::TimeZone also contains a script
-tests_from_zdump that generates test cases for each clock
-transition in the tz database.
-International Components for
-Unicode (ICU) contains C/C++ and Java
-libraries for internationalization that
-has a compiler from tz source
-into an ICU-specific format.
-ICU is freely available under a
-BSD-style license.
-Joda Time - Java date
-and time API
-contains a class
-org.joda.time.tz.ZoneInfoCompiler that compiles
-tz source into a Joda-specific binary format. Joda Time
-is freely available under a BSD-style license.
-PyTZ - Python Time
-Zone Library compiles tz source into
-Python.
-It is freely available under a BSD-style license.
-TZInfo - Ruby Timezone Library
-compiles tz source into
-Ruby.
-It is freely available under the MIT license.
-The Chronos Date/Time
-Library is a Smalltalk class
-library that compiles tz source into a time zone repository whose format
-is either proprietary or an XML-encoded
-representation.
-Starting with version 8.5, Tcl
-contains a developer-oriented parser that compiles tz
-source into text files, along with a runtime that can read those
-files. Tcl is freely available under a BSD-style
-license.
-
-Other tz binary file readers
-
-The GNU C
-Library
-has an independent, thread-safe implementation of
-a tz binary file reader.
-This library is freely available under the
-
-GNU Lesser General Public License
-(LGPL),
-and is widely used in GNU/Linux systems.
-ZoneInfo.java
-is a tz binary file reader written in Java.
-It is freely available under the LGPL.
-Tcl, mentioned above, also contains a
-tz binary file reader.
-
-Other tz-based time zone software
-
-FoxClocks
-is an extension for Mozilla
-Toolkit applications like Firefox, Thunderbird, and
-Sunbird.
-It displays multiple clocks in the application window, and has a mapping
-interface to Google Earth.
-It is freely available under the GPL.
-International
-clock (intclock) is a multi-timezone clock for
-GNU/Linux and similar systems. It is freely available
-under the GPL.
-PublicDomain
-has a copy of a recent tz database, accessed via a C# library. As its
-name suggests, it is in the public domain. Only current time stamps
-are well supported; historical data are compiled into the runtime but
-are not easily accessible.
-Sun Java releases since 1.4
-contain a copy of a subset of a recent tz database in a
-Java-specific format.
-Time Zone is
-a WordPress plugin. It is freely
-available under a BSD-style license.
-VelaTerra is
-a Mac OS X program. Its developers
-offer free
-licenses to tz contributors.
-World Time Explorer is a
-Microsoft Windows program.
-
-
-WorldClock for Windows and Windows Mobile
-lets users "see the time in up to 25 locations in the world at once."
-(From Hans Nieuwenhuis, 2009-11-02.)
-
-
-Other time zone databases
-
-Atlas Query
-is Astrodienst's Web version of Shanks's
-excellent time zone history atlases published in both computer
-and book form (one volume
-for the USA, and one for
-other locations) by Astro Communications Services.
-WORLDTIME: interactive atlas,
-time info, public holidays
-contains information on local time, sunrise and sunset,
-and public holidays in several hundred cities around the world.
-World Time Server
-is another time zone database.
-World Time Zones
-contains data from the Time Service Department of the
-US Naval Observatory, used as the source
-for the usno* files in the tz distribution.
-The Standard
-Schedules Information Manual of the
-International Air Transport
-Association
-gives current time zone rules for airports served by commercial aviation.
-Some Microsoft Windows versions contain time zone information in
-an undocumented format, with IDs that can be mapped to TZ
-values using the Windows
-→ Tzid table maintained by the CLDR data mentioned
-below.
-
-
-http://code.google.com/p/tzdata/
-
-provides programming-language-specific representations of timezone
-data. Currently this includes XML, PHP, Ruby, Javascript, JSON and CSV
-formatted data. The repository is updated as soon as the FTP
-distribution is updated. All data can be downloaded as a zip and/or it
-can be obtained/synced via anonymous SVN. Data is made available under
-the MIT license. (From Rich Tibbett.)
-
-
-Maps
-
-The United States Central
-Intelligence Agency (CIA) publishes a time
-zone map; the
-Perry-Castañeda
-Library Map Collection
-of the University of Texas at Austin has copies of
-recent editions.
-The pictorial quality is good,
-but the maps do not indicate summer time,
-and parts of the data are a few years out of date.
-Current time around the world
-and standard time zones map of the world
-has several fancy time zone maps; it covers Russia particularly well.
-The maps' pictorial quality is not quite as good as the
-CIA's
-but the maps are more up to date.
-
-Time zone boundaries
-
-TZ timezone maps contains a shapefile of the
-tz regions in the world.
-Administrative Divisions
-of Countries ("Statoids") contains detailed lists of
-tz-related zone subdivision data.
-Time
-zone boundaries for multizone countries summarizes legal
-boundaries between time zones within countries.
-Manifold.net's Free Maps and
-GIS
-Data includes a Manifold-format map of
-world time zone boundaries distributed under the
-GPL.
-The US Geological Survey's National Atlas of
-the United States
-publishes the Time
-Zones of the United States in the public domain.
-The GeoCommunity lists several commercial sources for International
-Time Zones and Time Zone Data.
-A ship within the territorial
-waters of any nation uses that nation's time. In international
-waters, time zone boundaries are meridians 15° apart, except that
-UTC−12 and UTC+12 are each 7.5° wide and are separated by
-the 180° meridian (not by the International Date Line, which is
-for land and territorial waters only). A captain can change ship's
-clocks any time after entering a new time zone; midnight changes are
-common.
-
-Civil time concepts and history
-
-A
-Walk through Time
-surveys the evolution of timekeeping.
-About Daylight
-Saving Time - History, rationale, laws & dates
-is an overall history of DST.
-Saving Time,
-Saving Energy discusses a primary justification for DST.
-Who Knew? A Brief
-History of Daylight Saving Time summarizes some of the contentious
-history of DST.
-The
-Time of Internet
-describes time zones and daylight saving time,
-with diagrams.
-The time zone map is out of date, however.
-A History of
-the International Date Line tells the story of the most important
-time zone boundary.
-Basic Time
-Zone Concepts discusses terminological issues behind time zones.
-
-National histories of legal time
-
-Australia
-The Parliamentary Library has commissioned research
-note on daylight saving time in Australia.
-The Bureau of Meteorology publishes a list of
-Implementation Dates of Daylight Savings Time within Australia.
-Belgium
-The Royal Observatory of Belgium maintains a table of time in Belgium (in Dutch).
-Brazil
-The Time Service Department of the National Observatory
-records Brazil's daylight saving time decrees (in
-Portuguese).
-Canada
-The Institute for National Measurement Standards publishes current
-and some older information about Time
-Zones & Daylight Saving Time.
-Chile
-The Chilean Hydrographic and Oceanographic Service publishes a  history of
-official time (in Spanish).
-Germany
-The National Institute for Science and Technology maintains the Realisation of
-Legal Time in Germany.
-Israel
-The Interior Ministry periodically issues announcements (in Hebrew).
-Mexico
-The Investigation and Analysis Service of the Mexican Library of
-Congress has published a history of Mexican local time (in Spanish).
-Malaysia
-See Singapore below.
-Netherlands
-Legal time in the Netherlands (in Dutch)
-covers the history of local time in the Netherlands from ancient times.
-New Zealand
-The Department of Internal Affairs maintains a brief history About
-Daylight Saving. The privately-maintained History of New Zealand
-time has more details.
-Norway
-The Norwegian Meteorological Institute lists
-Summer
-time in Norway (in Norwegian), citing the
-Institute of Theoretical Astrophysics, Oslo.
-Singapore
-Why
-is Singapore in the "Wrong" Time Zone? details the
-history of legal time in Singapore and Malaysia.
-United Kingdom
-History of
-legal time in Britain discusses in detail the country
-with perhaps the best-documented history of clock adjustments.
-The National Physical Laboratory also maintains an Archive
-of Summer time dates.
-
-Precision timekeeping
-
-The
-Science of Timekeeping is a thorough introduction
-to the theory and practice of precision timekeeping.
-NTP: The Network
-Time Protocol
-discusses how to synchronize clocks of
-Internet hosts.
-Timezone
-Options for DHCP
-(Internet RFC 4833)
-specifies a DHCP option for a server to configure
-a client's time zone and daylight saving settings automatically.
-A Few
-Facts Concerning GMT, UT, and
-the RGO
-answers questions like "What is the
-difference between GMT and UTC?"
-Astronomical
-Times explains more abstruse astronomical time scales like
-TDT,
-TCG, and
-TDB.
-Time
-Scales goes into more detail, particularly for historical variants.
-The IAU's SOFA
-initiative publishes Fortran
-code for converting among time scales like
-TAI,
-TDB, TDT and
-UTC.
-Basics of
-Space Flight - Reference Systems - Time Conventions
-briefly explains interplanetary space flight timekeeping.
-Technical
-Notes on Mars Solar Time as Adopted by the Mars24 Sunclock briefly
-describes Mars Coordinated Time (MTC) and the
-diverse local time
-scales used by each landed mission on Mars.
-LeapSecond.com is
-dedicated not only to leap seconds but to precise time and frequency
-in general. It covers the state of the art in amateur timekeeping, and
-how the art has progressed over the past few decades.
-Bulletins
-maintained by the
-IERS
-EOP
-(PC) contains official publications of
-the Earth Orientation Parameters Product Center of the
-International Earth Rotation Service, the committee that decides
-when leap seconds occur.
-The Leap
-Second Discussion List covers McCarthy
-and Klepczynski's proposal to discontinue leap seconds,
-discussed further in
-The
-leap second: its history and possible future.
-The (now disbanded) AAS Leap Second
-Committee has solicited input on this proposal.
-The
-Future of Leap Seconds covers this
-contentious issue.
-
-Time notation
-
-
-A Summary of
-the International Standard Date and Time Notation is a good
-summary of
-ISO
-8601:2004 -- Data elements and interchange formats -- Information
-interchange -- Representation of dates and times.
-
-XML
-Schema: Datatypes - dateTime specifies a format inspired by
-ISO 8601 that is in common use in XML data.
-
-Internet
-Message Format (Internet RFC 2822) §3.3
-specifies the time notation used in email and HTTP
-headers.
-
-Date and Time
-on the Internet: Timestamps (Internet RFC 3339)
-specifies an ISO 8601
-profile for use in new Internet
-protocols.
-
-Date & Time
-Formats on the Web surveys web- and Internet-oriented date and time
-formats.
-
-The
-Best of Dates, the Worst of Dates covers many problems encountered
-by software developers when handling dates and time stamps.
-The Unicode Common Locale Data Repository
-(CLDR) Project has localizations for time zone names,
-abbreviations, identifiers, and formats. For example, it contains
-French translations for "Eastern European Summer Time", "EEST", and
-"Bucharest". By-Type
-Chart: names.metazone shows these values for many locales.
-ICU contains a mechanism for using this data.
-Alphabetic time zone abbreviations should not be used as unique
-identifiers for UTC offsets as they are ambiguous in
-practice. For example, "EST" denotes 5 hours behind
-UTC in English-speaking North America, but it denotes 10
-or 11 hours ahead of UTC in Australia; and
-French-speaking North Americans prefer
-"HNE" to
-"EST". For POSIX the tz
-database contains English abbreviations for all time stamps but in
-many cases these are merely inventions of the database
-maintainers.
-Numeric time zone abbreviations typically count hours east of
-UTC, e.g., +09 for Japan and
--10 for Hawaii. However, the POSIX
-TZ environment variable uses the opposite convention. For
-example, one might use TZ="JST-9" and
-TZ="HST10" for Japan and Hawaii, respectively. If the
-tz database is available, it is usually better to use
-settings like TZ="Asia/Tokyo" and
-TZ="Pacific/Honolulu" instead, as this should avoid
-confusion, handle old time stamps better, and insulate you better from
-any future changes to the rules. One should never set
-POSIX TZ to a value like
-"GMT-9", though, since this would falsely claim that
-local time is nine hours ahead of UTC and the time zone
-is called "GMT".
-
-Related indexes
-
-Time and the Arts
-Open Directory -
-Reference: Time
-Google Directory
-- Reference > Time
-Yahoo!
-Directory > Science > Measurements and Units > Time
-
-
-
diff --git a/tz-link.html b/tz-link.html
new file mode 100644
index 000000000000..d3b37664c71c
--- /dev/null
+++ b/tz-link.html
@@ -0,0 +1,1175 @@
+
+
+
+Time zone and daylight saving time data
+
+
+
+
+Time zone and daylight saving time data
+
+Time zone and
+daylight-saving
+rules are controlled by individual
+governments. They are sometimes changed with little notice, and their
+histories and planned futures are often recorded only fitfully. Here
+is a summary of attempts to organize and record relevant data in this
+area.
+
+  Outline
+  
+    
+      The tz database product and process
+	
+	  The tz database
+	  Downloading the tz database
+	  Changes to the tz database
+	  Commentary on the tz database
+	
+      
+      Uses of the tz database
+	
+	  Web sites using recent versions of the tz database
+	  Network protocols for tz data
+	  Other tz compilers
+	  Other TZif readers
+	  Other tz-based time zone software
+	
+      
+      Related data
+	
+	  Other time zone databases
+	  Maps
+	  Time zone boundaries
+	
+      
+      Timekeeping concepts
+	
+	  Civil time concepts and history
+	  National histories of legal time
+	  Costs and benefits of time shifts
+	  Precision timekeeping
+	  Time notation
+	
+      
+      See also
+    
+  
+
+
+The tz database
+
+The public-domain
+time zone database contains code and data
+that represent the history of local time
+for many representative locations around the globe.
+It is updated periodically to reflect changes made by political bodies
+to time zone boundaries and daylight saving rules.
+This database (known as tz,
+tzdb, or zoneinfo)
+is used by several implementations,
+including
+the
+GNU
+C Library (used in
+GNU/Linux),
+Android,
+FreeBSD,
+NetBSD,
+OpenBSD,
+Chromium OS,
+Cygwin,
+MariaDB,
+MINIX,
+MySQL,
+webOS,
+AIX,
+iOS,
+macOS,
+Microsoft Windows,
+OpenVMS,
+Oracle Database, and
+Oracle Solaris.
+
+Each main entry in the database represents a timezone
+for a set of civil-time clocks that have all agreed since 1970.
+Timezones are typically identified by continent or ocean and then by the
+name of the largest city within the region containing the clocks.
+For example, America/New_York
+represents most of the US eastern time zone;
+America/Phoenix represents most of Arizona, which
+uses mountain time without daylight saving time (DST);
+America/Detroit represents most of Michigan, which uses
+eastern time but with different DST rules in 1975;
+and other entries represent smaller regions like Starke County,
+Indiana, which switched from central to eastern time in 1991
+and switched back in 2006.
+To use the database on an extended POSIX
+implementation set the TZ
+environment variable to the location's full name,
+e.g., TZ="America/New_York".
+
+Associated with each timezone is a history of offsets from
+Universal
+Time (UT), which is Greenwich Mean
+Time (GMT) with days beginning at midnight;
+for timestamps after 1960 this is more precisely Coordinated
+Universal Time (UTC).
+The database also records when daylight saving time was in use,
+along with some time zone abbreviations such as EST
+for Eastern Standard Time in the US.
+
+
+
+Downloading the tz database
+
+The following shell commands download
+the latest release's two
+tarballs
+to a GNU/Linux or similar host.
+mkdir tzdb
+cd tzdb
+wget https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz
+wget https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz
+gzip -dc tzcode-latest.tar.gz | tar -xf -
+gzip -dc tzdata-latest.tar.gz | tar -xf -
+
+Alternatively, the following shell commands download the same
+release in a single-tarball format containing extra data
+useful for regression testing:
+wget https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz
+lzip -dc tzdb-latest.tar.lz | tar -xf -
+
+These commands use convenience links to the latest release
+of the tz database hosted by the
+Time Zone Database website
+of the Internet Assigned Numbers
+Authority (IANA).
+Older releases are in files named
+tzcodeV.tar.gz,
+tzdataV.tar.gz, and
+tzdb-V.tar.lz,
+where V is the version.
+Since 1996, each version has been a four-digit year followed by
+lower-case letter (a through z,
+then za through zz, then zza
+through zzz, and so on).
+Since version 2022a, each release has been distributed in
+POSIX
+ustar interchange format, compressed as described above;
+older releases use a nearly-compatible format.
+Since version 2016h, each release has contained a text file named
+"version" whose first (and currently only) line is the version.
+Older releases are archived,
+and are also available in an
+FTP directory via a
+less-secure protocol.
+Alternatively, a development repository of code and data can be
+retrieved from GitHub via the shell
+command:
+git clone https://github.com/eggert/tz
+
+
+Since version 2012e, each release has been tagged in development repositories.
+Untagged commits are less well tested and probably contain
+more errors.
+
+After obtaining the code and data files, see the
+README file for what to do next.
+The code lets you compile the tz source files into
+machine-readable binary files, one for each location. The binary files
+are in a special timezone information format (TZif)
+specified by Internet
+RFC 8536.
+The code also lets
+you read a TZif file and interpret timestamps for that
+location.
+
+
+
+Changes to the tz database
+
+The tz code and data
+are by no means authoritative. If you find errors, please
+send changes to tz@iana.org,
+the time zone mailing list. You can also subscribe to it
+and browse the archive of old
+messages.
+Metadata for mailing list
+discussions and corresponding data changes can be
+generated automatically.
+
+
+If your government plans to change its time zone boundaries or
+daylight saving rules, inform tz@iana.org well in
+advance, as this will coordinate updates to many cell phones,
+computers, and other devices around the world.
+The change should be officially announced at least a year before it affects
+how clocks operate; otherwise, there is a good chance that some
+clocks will operate incorrectly after the change, due
+to delays in propagating updates to software and data. The shorter
+the notice, the more likely clock problems will arise; see "On
+the Timing of Time Zone Changes" for examples.
+The tz data can represent planned changes
+far into the future, and a long-planned change can easily be reverted
+or otherwise altered with a year's notice before the change would have
+affected clocks.
+
+
+Changes to the tz code and data are often
+propagated to clients via operating system updates, so
+client tz data can often be corrected by
+applying these updates. With GNU/Linux and similar systems, if your
+maintenance provider has not yet adopted the
+latest tz data, you can often short-circuit
+the process by tailoring the generic instructions in
+the tz README file and installing the latest
+data yourself. System-specific instructions for installing the
+latest tz data have also been published
+for AIX,
+Android,
+ICU,
+IBM
+JDK,
+Joda-Time, MySQL,
+Noda Time, and OpenJDK/Oracle JDK.
+
+Since version 2013a,
+sources for the tz database have been
+UTF-8
+text files
+with lines terminated by LF,
+which can be modified by common text editors such
+as GNU Emacs,
+gedit, and
+vim.
+Specialized source-file editing can be done via the
+Sublime
+zoneinfo package for Sublime Text and the VSCode
+zoneinfo extension for Visual
+Studio Code.
+
+
+For further information about updates, please see
+Procedures for
+Maintaining the Time Zone Database (Internet RFC 6557). More detail can be
+found in Theory and pragmatics of the
+tz code and data.
+A0 TimeZone Migration
+displays changes between recent tzdb versions.
+
+
+
+
+Commentary on the tz database
+
+The article
+tz database is
+an encyclopedic summary.
+How to Read the
+tz Database Source Files explains the tz
+database format.
+A
+literary appreciation of the Olson/Zoneinfo/tz database comments on the
+database's style.
+What time is it:
+managing time in the internet analyzes the database longitudinally.
+
+
+
+
+Web sites using recent versions of the
+tz database
+
+These are listed roughly in ascending order of complexity and fanciness.
+
+
+Time.is shows locations'
+time and zones.
+TimeJones.com,
+Time Zone Converter and
+The World Clock
+are time zone converters.
+TimeZoneDB Database
+publishes tzdb-derived data in
+CSV and
+in SQL form.
+Date and Time Gateway
+lets you see the TZ values directly.
+Current
+Time in 1000 Places uses descriptions of the values.
+Complete
+timezone information for all countries
+displays tables of DST rules.
+
The World Clock –
+Worldwide lets you sort zone names and convert times.
+24TimeZones has a world
+time map and a time converter.
+Time Difference
+calculates the current time difference between locations.
+Weather Now and
+The Time Now list the weather too.
+
+
+
+
+Network protocols for tz data
+
+The Internet Engineering Task Force's
+Time Zone Data
+Distribution Service (tzdist) working group defined TZDIST
+(Internet RFC 7808), a time zone data distribution service,
+along with CalDAV
+(Internet RFC 7809), a calendar access protocol for
+transferring time zone data by reference.
+TZDIST
+implementations are available.
+The tzdist-bis
+mailing list discusses possible extensions.
+The 
+Internet Calendaring and Scheduling Core Object Specification
+(iCalendar) (Internet RFC 5445)
+covers time zone
+data; see its VTIMEZONE calendar component.
+The iCalendar format requires specialized parsers and generators; a
+variant xCal
+(Internet RFC 6321) uses
+XML format, and a variant
+jCal
+(Internet RFC 7265)
+uses JSON format.
+
+
+
+
+Other tz compilers
+Although some of these do not fully support
+tz data, in recent tzdb
+distributions you can generally work around compatibility problems by
+running the command make rearguard_tarballs and compiling
+from the resulting tarballs instead.
+
+Vzic is a C
+program that compiles
+tz source into iCalendar-compatible VTIMEZONE files.
+Vzic is freely
+available under the GNU
+General Public License (GPL).
+tziCal – tz
+database conversion utility is like Vzic, except for the .NET framework
+and with a BSD-style license.
+DateTime::TimeZone
+contains a script parse_olson that compiles
+tz source into Perl
+modules. It is part of the Perl DateTime Project,
+which is freely
+available under both the GPL and the Perl Artistic
+License. DateTime::TimeZone also contains a script
+tests_from_zdump that generates test cases for each clock
+transition in the tz database.
+The Time Zone
+Database Parser is a
+C++ parser and
+runtime library with API
+adopted by
+C++20,
+the current iteration of the C++ standard.
+It is freely available under the
+MIT license.
+International Components for
+Unicode (ICU) contains C/C++ and Java
+libraries for internationalization that
+has a compiler from tz source
+and from CLDR data
+(mentioned below)
+into an ICU-specific format.
+ICU is freely available under a
+BSD-style license.
+The Tzdata package for
+the Elixir language downloads
+and compiles tz source and exposes APIs for use. It is
+freely available under the MIT license.
+Java-based compilers and libraries include:
+
+The TZUpdater
+tool compiles tz source into the format used by
+OpenJDK and
+Oracle JDK.
+Although its source code is proprietary, its executable is available under the
+Java SE
+Timezone Updater License Agreement.
+The Java
+SE 8 Date and Time API can be supplemented by ThreeTen-Extra,
+which is freely available under a BSD-style license.
+Joda-Time – Java date
+and time API contains a class
+org.joda.time.tz.ZoneInfoCompiler that compiles
+tz source into a binary format. It inspired
+Java 8 java.time, which its users should migrate to once
+they can assume Java 8 or later. It is available under the Apache License.
+IANA Updater and ZIUpdater
+are alternatives to TZUpdater. IANA Updater's license is unclear;
+ZIUpdater is licensed under the GPL.
+Time4A: Advanced date and
+time library for Android and
+Time4J: Advanced date,
+time and interval library for Java compile
+tz source into a binary format.
+Time4A is available under the Apache License and Time4J is
+available under the GNU Lesser
+General Public License (LGPL).
+ICU (mentioned above) contains compilers and
+Java-based libraries.
+
+
Noda Time – Date and
+time API for .NET
+is like Joda-Time and Time4J, but for the .NET framework instead of Java.
+It is freely available under the Apache License.
+Many modern
+JavaScript
+runtimes support tz natively via the
+timeZone option of Intl.DateTimeFormat.
+This can be used as-is or with most of the following libraries,
+many of which also support runtimes lacking the timeZone option.
+
+The Intl.DateTimeFormat
+timezone polyfill
+is freely available under a BSD-style license.
+The date-fns
+library manipulates timezone-aware timestamps in browsers and
+in Node.js.
+It is freely available under the MIT license.
+Day.js is a
+minimalist replacement for the date and time API of
+the now-legacy Moment.js date
+manipulation library.
+It is freely available under the MIT license.
+Luxon improves
+timezone support for the Intl API.
+It is freely available under the MIT license.
+Moment Timezone is a
+Moment.js plugin.
+It is freely available under the MIT license.
+Timezone is a
+JavaScript library that supports date arithmetic that is time zone
+aware. It is freely available under the MIT license.
+@tubular/time
+supports live tzdb updates,
+astronomical and atomic time, a command-line interface,
+and full TypeScript.
+Its companion @tubular/time-tzdb
+can generate TZif and other files, and a companion website
+Timezone Database Explorer lets you
+convert timestamps, view transition histories, and download code and data.
+It is freely available under the MIT license.
+
+The proposed Temporal
+objects let programs access an abstract view of
+tzdb data, and are designed to replace JavaScript's
+problematic Date objects when working with dates and times.
+
JuliaTime contains a
+compiler from tz source into
+Julia. It is freely available
+under the MIT license.
+TZDB –
+IANA Time Zone Database for Delphi/FPC
+compiles from tz source into
+Object Pascal
+as compiled by Delphi
+and FPC.
+It is freely available under a BSD-style license.
+pytz – World Timezone
+Definitions for Python compiles tz source into
+Python.
+It is freely available under a BSD-style license.
+In code that can assume Python 3.6 or later it is largely superseded; see pytz:
+The Fastest Footgun in the West.
+TZInfo –
+Ruby Timezone Library
+compiles tz source into
+Ruby.
+It is freely available under the MIT license.
+The Chronos Date/Time
+Library is
+a Smalltalk class
+library that compiles tz source into a time
+zone repository whose format
+is either proprietary or an XML-encoded
+representation.
+Tcl
+contains a developer-oriented parser that compiles tz
+source into text files, along with a runtime that can read those
+files. Tcl is freely available under a BSD-style
+license.
+
+
+
+
+Other TZif readers
+
+The GNU C
+Library
+has an independent, thread-safe implementation of
+a TZif file reader.
+This library is freely available under the LGPL
+and is widely used in GNU/Linux systems.
+GNOME's
+GLib has
+a TZif file reader written in C that
+creates a GTimeZone object representing sets
+of UT offsets.
+It is freely available under the LGPL.
+The
+BDE Standard Library's
+baltzo::TimeZoneUtil component contains a C++
+implementation of a TZif file reader. It is freely available under
+the Apache License.
+CCTZ is a simple C++
+library that translates between UT and civil time and
+can read TZif files. It is freely available under the Apache
+License.
+Timelib is a C
+library that reads TZif files and converts
+timestamps from one time zone or format to another.
+It is used by PHP,
+HHVM,
+and MongoDB.
+It is freely available under the MIT license.
+Tcl, mentioned above, also contains a
+TZif file reader.
+
+DateTime::TimeZone::Tzfile
+is a TZif file reader written in Perl.
+It is freely available under the same terms as Perl
+(dual GPL and Artistic license).
+Python has a zoneinfo.ZoneInfo
+class that reads TZif data and creates objects
+that represent tzdb timezones.
+Python is freely available under the
+Python Software Foundation
+License.
+A companion PyPI module
+tzdata
+supplies TZif data if the underlying system data cannot be found;
+it is freely available under the Apache License.
+The
+public-domain tz.js
+library contains a Python tool that
+converts TZif data into
+JSON-format data suitable for use
+in its JavaScript library for time zone conversion. Dates before 1970
+are not supported.
+The timezone-olson
+package contains Haskell code that
+parses and uses TZif data. It is freely
+available under a BSD-style license.
+
+
+
+
+Other tz-based time zone software
+
+FoxClocks
+is an extension for Google
+Chrome and for Mozilla
+Toolkit applications like Firefox and Thunderbird.
+It displays multiple clocks in the application window, and has a mapping
+interface to Google Earth.
+It is freely available under the GPL.
+Go programming language
+implementations contain a copy of a 32-bit subset of a recent
+tz database in a
+Go-specific format.
+Microsoft Windows 8.1
+and later has tz data and CLDR
+data (mentioned below) used by the
+Windows Runtime /
+Universal Windows Platform classes
+DateTimeFormatter and
+Calendar.
+Exploring
+Windows Time Zones with System.TimeZoneInfo describes
+the older, proprietary method of Microsoft Windows 2000 and later,
+which stores time zone data in the
+Windows Registry. The
+Zone →
+Tzid table or XML
+file of the CLDR data maps proprietary zone IDs
+to tz names.
+These mappings can be performed programmatically via the TimeZoneConverter .NET library,
+or the ICU Java and C++ libraries mentioned above.
+
Oracle
+Java contains a copy of a subset of a recent
+tz database in a
+Java-specific format.
+
+
+
+
+Other time zone databases
+
+Time-zone Atlas
+is Astrodienst's Web version of Shanks and Pottenger's out-of-print
+time zone history atlases
+for the US and
+for the world.
+Although these extensive atlases
+were
+sources for much of the older tz data,
+they are unreliable as Shanks appears to have
+guessed many UT offsets and transitions. The atlases cite no
+sources and do not indicate which entries are guesswork.
+HP-UX has a database in
+its own tztab(4) format.
+Microsoft Windows has proprietary data mentioned
+above.
+World Time Server
+is another time zone database.
+The Standard
+Schedules Information Manual of the
+International Air Transport Association
+gives current time zone rules for airports served by commercial aviation.
+
+
+
+
+Maps
+
+The World
+and Regional Maps section of The World Factbook, published by the
+US Central Intelligence
+Agency (CIA), contains a time
+zone map; the
+Perry–Castañeda
+Library Map Collection
+of the University of Texas at Austin has copies of
+recent editions.
+The pictorial quality is good,
+but the maps do not indicate daylight saving time,
+and parts of the data are a few years out of date.
+World Time Zone Map
+with current time
+has several fancy time zone maps; it covers Russia particularly well.
+The maps' pictorial quality is not quite as good as the
+CIA's
+but the maps are more up to date.
+How
+much is time wrong around the world? maps the difference between
+mean solar and standard time, highlighting areas such as western China
+where the two differ greatly. It's a bit out of date, unfortunately.
+
+
+
+
+Time zone boundaries
+Geographical boundaries between timezones are available
+from several Internet
+geolocation
+services and other sources.
+
+Timezone
+Boundary Builder extracts
+Open Street Map data to build
+boundaries of tzdb timezones.
+Its code is freely available under the MIT license, and
+its data entries are freely available under the
+Open Data Commons
+Open Database License. The maps' borders appear to be quite accurate.
+Programmatic interfaces that map geographical coordinates via tz_world to
+tzdb timezones include:
+
+GeoTimeZone is
+written in C#
+and is freely available under the MIT license.
+The latlong package
+is written in Go and is freely available under the Apache License.
+LatLongToTimezone,
+in both Java and
+Swift
+form, is freely available under the MIT license.
+For Node.js,
+the geo-tz module
+is freely available under the MIT license, and
+the tz-lookup module
+is in the public domain.
+The timezonefinder
+library for Python is freely available under the MIT license.
+
The timezone_finder
+library for Ruby is freely available under the MIT license.
+
+Free access via a network API, if you register a key, is provided by
+the GeoNames
+Timezone web service, the Google
+Maps Time Zone API, and
+the TimeZoneDB API.
+Commercial network API access is provided
+by AskGeo
+and GeoGarage.
+
+"How
+to get a time zone from a location using latitude and longitude
+coordinates?" discusses other geolocation possibilities.
+Administrative
+Divisions of Countries ("Statoids") lists
+political subdivision data related to time zones.
+Time
+zone boundaries for multizone countries summarizes legal
+boundaries between time zones within countries.
+Manifold Software
+– GIS and Database Tools includes a Manifold-format map of
+world time zone boundaries distributed under the
+GPL.
+A ship within the territorial
+waters of any nation uses that nation's time. In international
+waters, time zone boundaries are meridians 15° apart, except that
+UT−12 and UT+12 are each 7.5°
+wide and are separated by
+the 180° meridian (not by the International Date Line, which is
+for land and territorial waters only). A captain can change ship's
+clocks any time after entering a new time zone; midnight changes are
+common.
+
+
+
+
+Civil time concepts and history
+
+A
+Walk through Time
+surveys the evolution of timekeeping.
+The history of daylight saving time is surveyed in About Daylight
+Saving Time – History, rationale, laws & dates and summarized in
+A Brief
+History of Daylight Saving Time.
+Time
+Lords discusses how authoritarians manipulate civil time.
+Working with Time Zones
+contains guidelines and best practices for software applications that
+deal with civil time.
+A History of
+the International Date Line tells the story of the most important
+time zone boundary.
+Basic Time
+Zone Concepts discusses terminological issues behind time zones.
+
+
+
+
+National histories of legal time
+
+Australia
+The Parliamentary Library commissioned a research
+paper on daylight saving time in Australia.
+The Bureau of Meteorology publishes a list of Implementation
+Dates of Daylight Savings Time within Australia.
+Belgium
+The Royal Observatory of Belgium maintains a table of time in
+Belgium (in
+Dutch and French).
+Brazil
+The Time Service Department of the National Observatory
+records Brazil's daylight saving time decrees (in
+Portuguese).
+Canada
+National Research Council Canada publishes current
+and some older information about time
+zones and daylight saving time.
+Chile
+The Hydrographic and Oceanographic Service of the Chilean Navy publishes a
+history of
+Chile's official time (in Spanish).
+China
+The Hong Kong Observatory maintains a
+history of
+ summer time in Hong Kong,
+and Macau's Meteorological and Geophysical Bureau maintains a similar
+history for Macau.
+Unfortunately the latter is incomplete and has errors.
+Czech Republic
+When daylight saving time starts and ends (in Czech)
+summarizes and cites historical DST regulations.
+Germany
+The National Institute for Science and Technology maintains the Realisation
+of Legal Time in Germany.
+Israel
+The Interior Ministry periodically issues announcements (in Hebrew).
+Malaysia
+See Singapore below.
+Mexico
+The Investigation and Analysis Service of the Mexican Library of
+Congress has published a history of Mexican local time (in Spanish).
+Netherlands
+Legal time in the Netherlands (in Dutch)
+covers the history of local time in the Netherlands from ancient times.
+New Zealand
+The Department of Internal Affairs maintains a brief History of
+Daylight Saving.
+Portugal
+The Lisbon Astronomical Observatory publishes a
+history of
+legal time (in Portuguese).
+Singapore
+Why
+is Singapore in the "Wrong" Time Zone? details the
+history of legal time in Singapore and Malaysia.
+United Kingdom
+History of
+legal time in Britain discusses in detail the country
+with perhaps the best-documented history of clock adjustments.
+United States
+The Department of Transportation's Recent
+Time Zone Proceedings lists changes to time zone boundaries.
+Uruguay
+The Oceanography, Hydrography, and Meteorology Service of the Uruguayan
+Navy (SOHMA) publishes an annual almanac
+(in Spanish).
+
+
+
+
+Costs and benefits of time shifts
+Various sources argue for and against daylight saving time and time
+zone shifts, and many scientific studies have been conducted. This
+section summarizes reviews and position statements based on
+scientific literature in the area.
+
+Carey RN, Sarma KM.
+Impact of
+daylight saving time on road traffic collision risk: a systematic
+review.
+BMJ Open. 2017;7(6):e014319. doi:10.1136/bmjopen-2016-014319.
+This reviews research literature and concludes that the evidence
+neither supports nor refutes road safety benefits from
+shifts in time zones.
+Havranek T, Herman D, Irsova D.
+Does
+daylight saving save electricity? A meta-analysis.
+Energy J. 2018;39(2):35–61.
+doi:10.5547/01956574.39.2.thav.
+This analyzes research literature and concludes, "Electricity savings
+are larger for countries farther away from the equator, while
+subtropical regions consume more electricity because of DST."
+Rishi MA, Ahmed O, Barrantes Perez JH et al.
+Daylight saving time:
+an American Academy of Sleep Medicine position statement.
+J Clin Sleep Med.
+2020;10.5664/jcsm.8780.
+This argues for permanent standard time due to health risks of both
+DST transitions and permanent DST.
+Roenneberg T, Wirz-Justice A, Skene DJ et al.
+Why
+should we abolish Daylight Saving Time?
+J Biol Rhythms. 2019;34(3):227–230.
+doi:10.1177/0748730419854197.
+This position paper of the Society for Research on Biological Rhythms
+opposes DST changes and permanent DST, and advocates that governments adopt
+"permanent Standard Time for the health and safety of their citizens".
+
+
+
+
+Precision timekeeping
+
+The
+Science of Timekeeping is a thorough introduction
+to the theory and practice of precision timekeeping.
+The Science of
+Time 2016 contains several freely-readable papers.
+NTP: The Network
+Time Protocol (Internet RFC 5905)
+discusses how to synchronize clocks of
+Internet hosts.
+The Huygens
+family of software algorithms can achieve accuracy to a few tens of
+nanoseconds in scalable server farms without special hardware.
+The Precision
+Time Protocol (IEEE 1588)
+can achieve submicrosecond clock accuracy on a local area network
+with special-purpose hardware.
+Timezone
+Options for DHCP
+(Internet RFC 4833)
+specifies a DHCP
+option for a server to configure
+a client's time zone and daylight saving settings automatically.
+Time
+Scales describes astronomical time scales like
+TDT,
+TCG, and
+TDB.
+
The IAU's SOFA
+collection contains C and Fortran
+code for converting among time scales like
+TAI,
+TDB, TDT and
+UTC. It is freely available under the
+SOFA license.
+Mars24 Sunclock
+– Time on Mars describes Airy Mean Time (AMT) and the
+diverse local time
+scales used by each landed mission on Mars.
+LeapSecond.com is
+dedicated not only to leap seconds but to precise time and frequency
+in general. It covers the state of the art in amateur timekeeping, and
+how the art has progressed over the past few decades.
+The rules for leap seconds are specified in Annex 1 (Time scales) of Standard-frequency
+and time-signal emissions, International Telecommunication Union –
+Radiocommunication Sector (ITU-R) Recommendation TF.460-6 (02/2002).
+IERS
+Bulletins contains official publications of the International
+Earth Rotation and Reference Systems Service, which decides when leap
+seconds occur. The tz code and data support leap seconds
+via an optional "right" configuration where a computer's internal
+time_t integer clock counts every TAI second,
+as opposed to the default "posix" configuration
+where the internal clock ignores leap seconds.
+The two configurations agree for timestamps starting with 1972-01-01 00:00:00
+UTC (time_t 63 072 000) and diverge for
+timestamps starting with time_t 78 796 800,
+which corresponds to the first leap second
+1972-06-30 23:59:60 UTC in the "right" configuration,
+and to
+1972-07-01 00:00:00 UTC in the "posix" configuration.
+In practice the two configurations also agree for timestamps before
+1972 even though the historical situation is messy, partly because
+neither UTC nor TAI
+is well-defined for sufficiently-old timestamps.
+Leap Smear
+discusses how to gradually adjust POSIX clocks near a
+leap second so that they disagree with UTC by at most a
+half second, even though every POSIX minute has exactly
+sixty seconds. This approach works with the default tz
+"posix" configuration, is supported by
+the NTP reference implementation, supports conversion between
+UTC and smeared POSIX timestamps, and is used by major
+cloud service providers. However, according to
+§3.7.1 of
+Network Time Protocol Best Current Practices
+(Internet RFC 8633), leap smearing is not suitable for
+applications requiring accurate UTC or civil time,
+and is intended for use only in single, well-controlled environments.
+The Leap
+Second Discussion List covers McCarthy
+and Klepczynski's 1999 proposal to discontinue leap seconds,
+discussed further in
+The
+leap second: its history and possible future.
+UTC
+might be redefined
+without Leap Seconds gives pointers on this
+contentious issue, which was active until 2015 and could become active
+again.
+
+
+
+
+Time notation
+
+The Unicode Common Locale Data
+Repository (CLDR) Project has localizations for time
+zone names, abbreviations, identifiers, and formats. For example, it
+contains French translations for "Eastern European Summer Time",
+"EEST", and
+"Bucharest". Its
+by-type
+charts show these values for many locales. Data values are available in
+both LDML
+(an XML format) and JSON.
+

+A summary of
+the international standard date and time notation covers
+ISO
+8601-1:2019 – Date and time – Representations for information
+interchange – Part 1: Basic rules.
+
+XML
+Schema: Datatypes – dateTime specifies a format inspired by
+ISO 8601 that is in common use in XML data.
+§3.3 of
+Internet Message Format (Internet RFC 5322)
+specifies the time notation used in email and HTTP
+headers.
+
+Date and Time
+on the Internet: Timestamps (Internet RFC 3339)
+specifies an ISO 8601
+profile for use in new Internet
+protocols.
+
+Date & Time
+Formats on the Web surveys web- and Internet-oriented date and time
+formats.
+Alphabetic time zone abbreviations should not be used as unique
+identifiers for UT offsets as they are ambiguous in
+practice. For example, in English-speaking North America
+"CST" denotes 6 hours behind UT,
+but in China it denotes 8 hours ahead of UT,
+and French-speaking North Americans prefer
+"HNC" to
+"CST". The tz
+database contains English abbreviations for many timestamps;
+unfortunately some of these abbreviations were merely the database maintainers'
+inventions, and these have been removed when possible.
+Numeric time zone abbreviations typically count hours east of
+UT, e.g., +09 for Japan and
+−10 for Hawaii. However, the POSIX
+TZ environment variable uses the opposite convention.
+For example, one might use TZ="JST-9" and
+TZ="HST10"
+for Japan and Hawaii, respectively. If the
+tz database is available, it is usually better to use
+settings like TZ="Asia/Tokyo" and
+TZ="Pacific/Honolulu" instead, as this should avoid
+confusion, handle old timestamps better, and insulate you better from
+any future changes to the rules. One should never set
+POSIX TZ to a value like
+"GMT-9", though, since this would incorrectly imply that
+local time is nine hours ahead of UT and the time zone
+is called "GMT".
+
+
+
+
+See also
+
+Theory and pragmatics of the
+tz code and data
+Time and the Arts
+
+
+
+
+
+This web page is in the public domain, so clarified as of
+2009-05-17 by Arthur David Olson.
+

+Please send corrections to this web page to the
+time zone mailing list.
+
+
+
diff --git a/tzfile.5 b/tzfile.5
index 9383ebf3618c..280e8d8a40ff 100644
--- a/tzfile.5
+++ b/tzfile.5
@@ -1,152 +1,496 @@
 .TH TZFILE 5
 .SH NAME
-tzfile \- time zone information
-.SH SYNOPSIS
-.B
-#include 
+tzfile \- timezone information
 .SH DESCRIPTION
-The time zone information files used by
-.IR tzset (3)
-begin with the magic characters "TZif" to identify them as
-time zone information files,
-followed by a character identifying the version of the file's format
-(as of 2005, either an ASCII NUL or a '2')
-followed by fifteen bytes containing zeroes reserved for future use,
-followed by six four-byte values of type
-.BR long ,
-written in a ``standard'' byte order
-(the high-order byte of the value is written first).
-These values are,
-in order:
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.ie \n(.g .ds - \f(CW-\fP
+.el .ds - \-
+The timezone information files used by
+.BR tzset (3)
+are typically found under a directory with a name like
+.IR /usr/share/zoneinfo .
+These files use the format described in Internet RFC 8536.
+Each file is a sequence of 8-bit bytes.
+In a file, a binary integer is represented by a sequence of one or
+more bytes in network order (bigendian, or high-order byte first),
+with all bits significant,
+a signed binary integer is represented using two's complement,
+and a boolean is represented by a one-byte binary integer that is
+either 0 (false) or 1 (true).
+The format begins with a 44-byte header containing the following fields:
+.IP * 2
+The magic four-byte ASCII sequence
+.q "TZif"
+identifies the file as a timezone information file.
+.IP *
+A byte identifying the version of the file's format
+(as of 2021, either an ASCII NUL,
+.q "2",
+.q "3",
+or
+.q "4" ).
+.IP *
+Fifteen bytes containing zeros reserved for future use.
+.IP *
+Six four-byte integer values, in the following order:
+.RS
 .TP
-.I tzh_ttisgmtcnt
-The number of UTC/local indicators stored in the file.
+.B tzh_ttisutcnt
+The number of UT/local indicators stored in the file.
+(UT is Universal Time.)
 .TP
-.I tzh_ttisstdcnt
+.B tzh_ttisstdcnt
 The number of standard/wall indicators stored in the file.
 .TP
-.I tzh_leapcnt
-The number of leap seconds for which data is stored in the file.
+.B tzh_leapcnt
+The number of leap seconds for which data entries are stored in the file.
 .TP
-.I tzh_timecnt
-The number of "transition times" for which data is stored
+.B tzh_timecnt
+The number of transition times for which data entries are stored
 in the file.
 .TP
-.I tzh_typecnt
-The number of "local time types" for which data is stored
+.B tzh_typecnt
+The number of local time types for which data entries are stored
 in the file (must not be zero).
 .TP
-.I tzh_charcnt
-The number of characters of "time zone abbreviation strings"
+.B tzh_charcnt
+The number of bytes of time zone abbreviation strings
 stored in the file.
+.RE
 .PP
-The above header is followed by
-.I tzh_timecnt
-four-byte values of type
-.BR long ,
-sorted in ascending order.
-These values are written in ``standard'' byte order.
+The above header is followed by the following fields, whose lengths
+depend on the contents of the header:
+.IP * 2
+.B tzh_timecnt
+four-byte signed integer values sorted in ascending order.
+These values are written in network byte order.
 Each is used as a transition time (as returned by
-.IR time (2))
+.BR time (2))
 at which the rules for computing local time change.
-Next come
-.I tzh_timecnt
-one-byte values of type
-.BR "unsigned char" ;
-each one tells which of the different types of ``local time'' types
-described in the file is associated with the same-indexed transition time.
-These values serve as indices into an array of
-.I ttinfo
-structures (with
-.I tzh_typecnt
-entries) that appears next in the file;
-these structures are defined as follows:
+.IP *
+.B tzh_timecnt
+one-byte unsigned integer values;
+each one but the last tells which of the different types of local time types
+described in the file is associated with the time period
+starting with the same-indexed transition time
+and continuing up to but not including the next transition time.
+(The last time type is present only for consistency checking with the
+POSIX-style TZ string described below.)
+These values serve as indices into the next field.
+.IP *
+.B tzh_typecnt
+.B ttinfo
+entries, each defined as follows:
 .in +.5i
 .sp
 .nf
-.ta .5i +\w'unsigned int\0\0'u
+.ta .5i +\w'unsigned char\0\0'u
 struct ttinfo {
-	long	tt_gmtoff;
-	int	tt_isdst;
-	unsigned int	tt_abbrind;
+	int32_t	tt_utoff;
+	unsigned char	tt_isdst;
+	unsigned char	tt_desigidx;
 };
 .in -.5i
 .fi
 .sp
-Each structure is written as a four-byte value for
-.I tt_gmtoff
-of type
-.BR long ,
-in a standard byte order, followed by a one-byte value for
-.I tt_isdst
+Each structure is written as a four-byte signed integer value for
+.BR tt_utoff ,
+in network byte order, followed by a one-byte boolean for
+.B tt_isdst
 and a one-byte value for
-.IR tt_abbrind .
+.BR tt_desigidx .
 In each structure,
-.I tt_gmtoff
-gives the number of seconds to be added to UTC,
-.I tt_isdst
+.B tt_utoff
+gives the number of seconds to be added to UT,
+.B tt_isdst
 tells whether
-.I tm_isdst
+.B tm_isdst
 should be set by
-.I localtime (3)
+.BR localtime (3)
 and
-.I tt_abbrind
-serves as an index into the array of time zone abbreviation characters
+.B tt_desigidx
+serves as an index into the array of time zone abbreviation bytes
 that follow the
-.I ttinfo
-structure(s) in the file.
-.PP
-Then there are
-.I tzh_leapcnt
-pairs of four-byte values, written in standard byte order;
-the first value of each pair gives the time
+.B ttinfo
+entries in the file; if the designated string is "\*-00", the
+.B ttinfo
+entry is a placeholder indicating that local time is unspecified.
+The
+.B tt_utoff
+value is never equal to \-2**31, to let 32-bit clients negate it without
+overflow.
+Also, in realistic applications
+.B tt_utoff
+is in the range [\-89999, 93599] (i.e., more than \-25 hours and less
+than 26 hours); this allows easy support by implementations that
+already support the POSIX-required range [\-24:59:59, 25:59:59].
+.IP *
+.B tzh_charcnt
+bytes that represent time zone designations,
+which are null-terminated byte strings, each indexed by the
+.B tt_desigidx
+values mentioned above.
+The byte strings can overlap if one is a suffix of the other.
+The encoding of these strings is not specified.
+.IP *
+.B tzh_leapcnt
+pairs of four-byte values, written in network byte order;
+the first value of each pair gives the nonnegative time
 (as returned by
-.IR time(2))
-at which a leap second occurs;
-the second gives the
+.BR time (2))
+at which a leap second occurs or at which the leap second table expires;
+the second is a signed integer specifying the correction, which is the
 .I total
-number of leap seconds to be applied after the given time.
-The pairs of values are sorted in ascending order by time.
-.PP
-Then there are
-.I tzh_ttisstdcnt
-standard/wall indicators, each stored as a one-byte value;
+number of leap seconds to be applied during the time period
+starting at the given time.
+The pairs of values are sorted in strictly ascending order by time.
+Each pair denotes one leap second, either positive or negative,
+except that if the last pair has the same correction as the previous one,
+the last pair denotes the leap second table's expiration time.
+Each leap second is at the end of a UTC calendar month.
+The first leap second has a nonnegative occurrence time,
+and is a positive leap second if and only if its correction is positive;
+the correction for each leap second after the first differs
+from the previous leap second by either 1 for a positive leap second,
+or \-1 for a negative leap second.
+If the leap second table is empty, the leap-second correction is zero
+for all timestamps;
+otherwise, for timestamps before the first occurrence time,
+the leap-second correction is zero if the first pair's correction is 1 or \-1,
+and is unspecified otherwise (which can happen only in files
+truncated at the start).
+.IP *
+.B tzh_ttisstdcnt
+standard/wall indicators, each stored as a one-byte boolean;
 they tell whether the transition times associated with local time types
-were specified as standard time or wall clock time,
-and are used when a time zone file is used in handling POSIX-style
-time zone environment variables.
-.PP
-Finally there are
-.I tzh_ttisgmtcnt
-UTC/local indicators, each stored as a one-byte value;
+were specified as standard time or local (wall clock) time.
+.IP *
+.B tzh_ttisutcnt
+UT/local indicators, each stored as a one-byte boolean;
 they tell whether the transition times associated with local time types
-were specified as UTC or local time,
-and are used when a time zone file is used in handling POSIX-style
-time zone environment variables.
+were specified as UT or local time.
+If a UT/local indicator is set, the corresponding standard/wall indicator
+must also be set.
 .PP
-.I Localtime
-uses the first standard-time
-.I ttinfo
+The standard/wall and UT/local indicators were designed for
+transforming a TZif file's transition times into transitions appropriate
+for another time zone specified via a POSIX-style TZ string that lacks rules.
+For example, when TZ="EET\*-2EEST" and there is no TZif file "EET\*-2EEST",
+the idea was to adapt the transition times from a TZif file with the
+well-known name "posixrules" that is present only for this purpose and
+is a copy of the file "Europe/Brussels", a file with a different UT offset.
+POSIX does not specify this obsolete transformational behavior,
+the default rules are installation-dependent, and no implementation
+is known to support this feature for timestamps past 2037,
+so users desiring (say) Greek time should instead specify
+TZ="Europe/Athens" for better historical coverage, falling back on
+TZ="EET\*-2EEST,M3.5.0/3,M10.5.0/4" if POSIX conformance is required
+and older timestamps need not be handled accurately.
+.PP
+The
+.BR localtime (3)
+function
+normally uses the first
+.B ttinfo
 structure in the file
-(or simply the first
-.I ttinfo
-structure in the absence of a standard-time structure)
 if either
-.I tzh_timecnt
+.B tzh_timecnt
 is zero or the time argument is less than the first transition time recorded
 in the file.
-.PP
-For version-2-format time zone files,
-the above header and data is followed by a second header and data,
+.SS Version 2 format
+For version-2-format timezone files,
+the above header and data are followed by a second header and data,
 identical in format except that
 eight bytes are used for each transition time or leap second time.
+(Leap second counts remain four bytes.)
 After the second header and data comes a newline-enclosed,
 POSIX-TZ-environment-variable-style string for use in handling instants
 after the last transition time stored in the file
-(with nothing between the newlines if there is no POSIX representation for
-such instants).
+or for all instants if the file has no transitions.
+The POSIX-style TZ string is empty (i.e., nothing between the newlines)
+if there is no POSIX-style representation for such instants.
+If nonempty, the POSIX-style TZ string must agree with the local time
+type after the last transition time if present in the eight-byte data;
+for example, given the string
+.q "WET0WEST,M3.5.0,M10.5.0/3"
+then if a last transition time is in July, the transition's local time
+type must specify a daylight-saving time abbreviated
+.q "WEST"
+that is one hour east of UT.
+Also, if there is at least one transition, time type 0 is associated
+with the time period from the indefinite past up to but not including
+the earliest transition time.
+.SS Version 3 format
+For version-3-format timezone files, the POSIX-TZ-style string may
+use two minor extensions to the POSIX TZ format, as described in
+.BR newtzset (3).
+First, the hours part of its transition times may be signed and range from
+\-167 through 167 instead of the POSIX-required unsigned values
+from 0 through 24.
+Second, DST is in effect all year if it starts
+January 1 at 00:00 and ends December 31 at 24:00 plus the difference
+between daylight saving and standard time.
+.SS Version 4 format
+For version-4-format TZif files,
+the first leap second record can have a correction that is neither
++1 nor \-1, to represent truncation of the TZif file at the start.
+Also, if two or more leap second transitions are present and the last
+entry's correction equals the previous one, the last entry
+denotes the expiration of the leap second table instead of a leap second;
+timestamps after this expiration are unreliable in that future
+releases will likely add leap second entries after the expiration, and
+the added leap seconds will change how post-expiration timestamps are treated.
+.SS Interoperability considerations
+Future changes to the format may append more data.
+.PP
+Version 1 files are considered a legacy format and
+should not be generated, as they do not support transition
+times after the year 2038.
+Readers that understand only Version 1 must ignore
+any data that extends beyond the calculated end of the version
+1 data block.
+.PP
+Other than version 1, writers should generate
+the lowest version number needed by a file's data.
+For example, a writer should generate a version 4 file
+only if its leap second table either expires or is truncated at the start.
+Likewise, a writer not generating a version 4 file
+should generate a version 3 file only if
+TZ string extensions are necessary to accurately
+model transition times.
+.PP
+The sequence of time changes defined by the version 1
+header and data block should be a contiguous sub-sequence
+of the time changes defined by the version 2+ header and data
+block, and by the footer.
+This guideline helps obsolescent version 1 readers
+agree with current readers about timestamps within the
+contiguous sub-sequence.  It also lets writers not
+supporting obsolescent readers use a
+.B tzh_timecnt
+of zero
+in the version 1 data block to save space.
+.PP
+When a TZif file contains a leap second table expiration
+time, TZif readers should either refuse to process
+post-expiration timestamps, or process them as if the expiration
+time did not exist (possibly with an error indication).
+.PP
+Time zone designations should consist of at least three (3)
+and no more than six (6) ASCII characters from the set of
+alphanumerics,
+.q "\*-",
+and
+.q "+".
+This is for compatibility with POSIX requirements for
+time zone abbreviations.
+.PP
+When reading a version 2 or higher file, readers
+should ignore the version 1 header and data block except for
+the purpose of skipping over them.
+.PP
+Readers should calculate the total lengths of the
+headers and data blocks and check that they all fit within
+the actual file size, as part of a validity check for the file.
+.PP
+When a positive leap second occurs, readers should append an extra
+second to the local minute containing the second just before the leap
+second.  If this occurs when the UTC offset is not a multiple of 60
+seconds, the leap second occurs earlier than the last second of the
+local minute and the minute's remaining local seconds are numbered
+through 60 instead of the usual 59; the UTC offset is unaffected.
+.SS Common interoperability issues
+This section documents common problems in reading or writing TZif files.
+Most of these are problems in generating TZif files for use by
+older readers.
+The goals of this section are:
+.IP * 2
+to help TZif writers output files that avoid common
+pitfalls in older or buggy TZif readers,
+.IP *
+to help TZif readers avoid common pitfalls when reading
+files generated by future TZif writers, and
+.IP *
+to help any future specification authors see what sort of
+problems arise when the TZif format is changed.
+.PP
+When new versions of the TZif format have been defined, a
+design goal has been that a reader can successfully use a TZif
+file even if the file is of a later TZif version than what the
+reader was designed for.
+When complete compatibility was not achieved, an attempt was
+made to limit glitches to rarely used timestamps and allow
+simple partial workarounds in writers designed to generate
+new-version data useful even for older-version readers.
+This section attempts to document these compatibility issues and
+workarounds, as well as to document other common bugs in
+readers.
+.PP
+Interoperability problems with TZif include the following:
+.IP * 2
+Some readers examine only version 1 data.
+As a partial workaround, a writer can output as much version 1
+data as possible.
+However, a reader should ignore version 1 data, and should use
+version 2+ data even if the reader's native timestamps have only
+32 bits.
+.IP *
+Some readers designed for version 2 might mishandle
+timestamps after a version 3 or higher file's last transition, because
+they cannot parse extensions to POSIX in the TZ-like string.
+As a partial workaround, a writer can output more transitions
+than necessary, so that only far-future timestamps are
+mishandled by version 2 readers.
+.IP *
+Some readers designed for version 2 do not support
+permanent daylight saving time with transitions after 24:00
+\(en e.g., a TZ string
+.q "EST5EDT,0/0,J365/25"
+denoting permanent Eastern Daylight Time
+(\-04).
+As a workaround, a writer can substitute standard time
+for two time zones east, e.g.,
+.q "XXX3EDT4,0/0,J365/23"
+for a time zone with a never-used standard time (XXX, \-03)
+and negative daylight saving time (EDT, \-04) all year.
+Alternatively,
+as a partial workaround a writer can substitute standard time
+for the next time zone east \(en e.g.,
+.q "AST4"
+for permanent
+Atlantic Standard Time (\-04).
+.IP *
+Some readers designed for version 2 or 3, and that require strict
+conformance to RFC 8536, reject version 4 files whose leap second
+tables are truncated at the start or that end in expiration times.
+.IP *
+Some readers ignore the footer, and instead predict future
+timestamps from the time type of the last transition.
+As a partial workaround, a writer can output more transitions
+than necessary.
+.IP *
+Some readers do not use time type 0 for timestamps before
+the first transition, in that they infer a time type using a
+heuristic that does not always select time type 0.
+As a partial workaround, a writer can output a dummy (no-op)
+first transition at an early time.
+.IP *
+Some readers mishandle timestamps before the first
+transition that has a timestamp not less than \-2**31.
+Readers that support only 32-bit timestamps are likely to be
+more prone to this problem, for example, when they process
+64-bit transitions only some of which are representable in 32
+bits.
+As a partial workaround, a writer can output a dummy
+transition at timestamp \-2**31.
+.IP *
+Some readers mishandle a transition if its timestamp has
+the minimum possible signed 64-bit value.
+Timestamps less than \-2**59 are not recommended.
+.IP *
+Some readers mishandle POSIX-style TZ strings that
+contain
+.q "<"
+or
+.q ">".
+As a partial workaround, a writer can avoid using
+.q "<"
+or
+.q ">"
+for time zone abbreviations containing only alphabetic
+characters.
+.IP *
+Many readers mishandle time zone abbreviations that contain
+non-ASCII characters.
+These characters are not recommended.
+.IP *
+Some readers may mishandle time zone abbreviations that
+contain fewer than 3 or more than 6 characters, or that
+contain ASCII characters other than alphanumerics,
+.q "\*-",
+and
+.q "+".
+These abbreviations are not recommended.
+.IP *
+Some readers mishandle TZif files that specify
+daylight-saving time UT offsets that are less than the UT
+offsets for the corresponding standard time.
+These readers do not support locations like Ireland, which
+uses the equivalent of the POSIX TZ string
+.q "IST\*-1GMT0,M10.5.0,M3.5.0/1",
+observing standard time
+(IST, +01) in summer and daylight saving time (GMT, +00) in winter.
+As a partial workaround, a writer can output data for the
+equivalent of the POSIX TZ string
+.q "GMT0IST,M3.5.0/1,M10.5.0",
+thus swapping standard and daylight saving time.
+Although this workaround misidentifies which part of the year
+uses daylight saving time, it records UT offsets and time zone
+abbreviations correctly.
+.IP *
+Some readers generate ambiguous timestamps for positive leap seconds
+that occur when the UTC offset is not a multiple of 60 seconds.
+For example, in a timezone with UTC offset +01:23:45 and with
+a positive leap second 78796801 (1972-06-30 23:59:60 UTC), some readers will
+map both 78796800 and 78796801 to 01:23:45 local time the next day
+instead of mapping the latter to 01:23:46, and they will map 78796815 to
+01:23:59 instead of to 01:23:60.
+This has not yet been a practical problem, since no civil authority
+has observed such UTC offsets since leap seconds were
+introduced in 1972.
+.PP
+Some interoperability problems are reader bugs that
+are listed here mostly as warnings to developers of readers.
+.IP * 2
+Some readers do not support negative timestamps.
+Developers of distributed applications should keep this
+in mind if they need to deal with pre-1970 data.
+.IP *
+Some readers mishandle timestamps before the first
+transition that has a nonnegative timestamp.
+Readers that do not support negative timestamps are likely to
+be more prone to this problem.
+.IP *
+Some readers mishandle time zone abbreviations like
+.q "\*-08"
+that contain
+.q "+",
+.q "\*-",
+or digits.
+.IP *
+Some readers mishandle UT offsets that are out of the
+traditional range of \-12 through +12 hours, and so do not
+support locations like Kiritimati that are outside this
+range.
+.IP *
+Some readers mishandle UT offsets in the range [\-3599, \-1]
+seconds from UT, because they integer-divide the offset by
+3600 to get 0 and then display the hour part as
+.q "+00".
+.IP *
+Some readers mishandle UT offsets that are not a multiple
+of one hour, or of 15 minutes, or of 1 minute.
 .SH SEE ALSO
-newctime(3)
-.\" @(#)tzfile.5	8.3
+.BR time (2),
+.BR localtime (3),
+.BR tzset (3),
+.BR tzselect (8),
+.BR zdump (8),
+.BR zic (8).
+.PP
+Olson A, Eggert P, Murchison K. The Time Zone Information Format (TZif).
+2019 Feb.
+.UR https://\:datatracker.ietf.org/\:doc/\:html/\:rfc8536
+Internet RFC 8536
+.UE
+.UR https://\:doi.org/\:10.17487/\:RFC8536
+doi:10.17487/RFC8536
+.UE .
 .\" This file is in the public domain, so clarified as of
 .\" 1996-06-05 by Arthur David Olson.
diff --git a/tzfile.5.txt b/tzfile.5.txt
index 6e563e6bc6f5..945b7793da42 100644
--- a/tzfile.5.txt
+++ b/tzfile.5.txt
@@ -1,106 +1,369 @@
+TZFILE(5)                     File Formats Manual                    TZFILE(5)
+
 NAME
+       tzfile - timezone information
+
+DESCRIPTION
+       The timezone information files used by tzset(3) are typically found
+       under a directory with a name like /usr/share/zoneinfo.  These files
+       use the format described in Internet RFC 8536.  Each file is a sequence
+       of 8-bit bytes.  In a file, a binary integer is represented by a
+       sequence of one or more bytes in network order (bigendian, or high-
+       order byte first), with all bits significant, a signed binary integer
+       is represented using two's complement, and a boolean is represented by
+       a one-byte binary integer that is either 0 (false) or 1 (true).  The
+       format begins with a 44-byte header containing the following fields:
 
-     tzfile - time zone information
+       * The magic four-byte ASCII sequence "TZif" identifies the file as a
+         timezone information file.
 
-SYNOPSIS
-     #include 
+       * A byte identifying the version of the file's format (as of 2021,
+         either an ASCII NUL, "2", "3", or "4").
 
-DESCRIPTION
-     The time zone information files used by tzset(3) begin with
-     the magic characters "TZif" to identify them as time zone
-     information files, followed by a character identifying the
-     version of the file's format (as of 2005, either an ASCII
-     NUL or a '2') followed by fifteen bytes containing zeroes
-     reserved for future use, followed by six four-byte values of
-     type long, written in a ``standard'' byte order (the high-
-     order byte of the value is written first).  These values
-     are, in order:
-
-     tzh_ttisgmtcnt
-          The number of UTC/local indicators stored in the file.
-
-     tzh_ttisstdcnt
-          The number of standard/wall indicators stored in the
-          file.
-
-     tzh_leapcnt
-          The number of leap seconds for which data is stored in
-          the file.
-
-     tzh_timecnt
-          The number of "transition times" for which data is
-          stored in the file.
-
-     tzh_typecnt
-          The number of "local time types" for which data is
-          stored in the file (must not be zero).
-
-     tzh_charcnt
-          The number of characters of "time zone abbreviation
-          strings" stored in the file.
-
-     The above header is followed by tzh_timecnt four-byte values
-     of type long, sorted in ascending order.  These values are
-     written in ``standard'' byte order.  Each is used as a
-     transition time (as returned by time(2)) at which the rules
-     for computing local time change.  Next come tzh_timecnt one-
-     byte values of type unsigned char; each one tells which of
-     the different types of ``local time'' types described in the
-     file is associated with the same-indexed transition time.
-     These values serve as indices into an array of ttinfo
-     structures (with tzh_typecnt entries) that appears next in
-     the file; these structures are defined as follows:
-
-          struct ttinfo {
-               long          tt_gmtoff;
-               int           tt_isdst;
-               unsigned int  tt_abbrind;
-          };
-
-     Each structure is written as a four-byte value for tt_gmtoff
-     of type long, in a standard byte order, followed by a one-
-     byte value for tt_isdst and a one-byte value for tt_abbrind.
-     In each structure, tt_gmtoff gives the number of seconds to
-     be added to UTC, tt_isdst tells whether tm_isdst should be
-     set by localtime (3) and tt_abbrind serves as an index into
-     the array of time zone abbreviation characters that follow
-     the ttinfo structure(s) in the file.
-
-     Then there are tzh_leapcnt pairs of four-byte values,
-     written in standard byte order; the first value of each pair
-     gives the time (as returned by time(2)) at which a leap
-     second occurs; the second gives the total number of leap
-     seconds to be applied after the given time.  The pairs of
-     values are sorted in ascending order by time.
-
-     Then there are tzh_ttisstdcnt standard/wall indicators, each
-     stored as a one-byte value; they tell whether the transition
-     times associated with local time types were specified as
-     standard time or wall clock time, and are used when a time
-     zone file is used in handling POSIX-style time zone
-     environment variables.
-
-     Finally there are tzh_ttisgmtcnt UTC/local indicators, each
-     stored as a one-byte value; they tell whether the transition
-     times associated with local time types were specified as UTC
-     or local time, and are used when a time zone file is used in
-     handling POSIX-style time zone environment variables.
-
-     Localtime uses the first standard-time ttinfo structure in
-     the file (or simply the first ttinfo structure in the
-     absence of a standard-time structure) if either tzh_timecnt
-     is zero or the time argument is less than the first
-     transition time recorded in the file.
-
-     For version-2-format time zone files, the above header and
-     data is followed by a second header and data, identical in
-     format except that eight bytes are used for each transition
-     time or leap second time.  After the second header and data
-     comes a newline-enclosed, POSIX-TZ-environment-variable-
-     style string for use in handling instants after the last
-     transition time stored in the file (with nothing between the
-     newlines if there is no POSIX representation for such
-     instants).
+       * Fifteen bytes containing zeros reserved for future use.
+
+       * Six four-byte integer values, in the following order:
+
+         tzh_ttisutcnt
+                The number of UT/local indicators stored in the file.  (UT is
+                Universal Time.)
+
+         tzh_ttisstdcnt
+                The number of standard/wall indicators stored in the file.
+
+         tzh_leapcnt
+                The number of leap seconds for which data entries are stored
+                in the file.
+
+         tzh_timecnt
+                The number of transition times for which data entries are
+                stored in the file.
+
+         tzh_typecnt
+                The number of local time types for which data entries are
+                stored in the file (must not be zero).
+
+         tzh_charcnt
+                The number of bytes of time zone abbreviation strings stored
+                in the file.
+
+       The above header is followed by the following fields, whose lengths
+       depend on the contents of the header:
+
+       * tzh_timecnt four-byte signed integer values sorted in ascending
+         order.  These values are written in network byte order.  Each is used
+         as a transition time (as returned by time(2)) at which the rules for
+         computing local time change.
+
+       * tzh_timecnt one-byte unsigned integer values; each one but the last
+         tells which of the different types of local time types described in
+         the file is associated with the time period starting with the same-
+         indexed transition time and continuing up to but not including the
+         next transition time.  (The last time type is present only for
+         consistency checking with the POSIX-style TZ string described below.)
+         These values serve as indices into the next field.
+
+       * tzh_typecnt ttinfo entries, each defined as follows:
+
+              struct ttinfo {
+                   int32_t        tt_utoff;
+                   unsigned char  tt_isdst;
+                   unsigned char  tt_desigidx;
+              };
+
+         Each structure is written as a four-byte signed integer value for
+         tt_utoff, in network byte order, followed by a one-byte boolean for
+         tt_isdst and a one-byte value for tt_desigidx.  In each structure,
+         tt_utoff gives the number of seconds to be added to UT, tt_isdst
+         tells whether tm_isdst should be set by localtime(3) and tt_desigidx
+         serves as an index into the array of time zone abbreviation bytes
+         that follow the ttinfo entries in the file; if the designated string
+         is "-00", the ttinfo entry is a placeholder indicating that local
+         time is unspecified.  The tt_utoff value is never equal to -2**31, to
+         let 32-bit clients negate it without overflow.  Also, in realistic
+         applications tt_utoff is in the range [-89999, 93599] (i.e., more
+         than -25 hours and less than 26 hours); this allows easy support by
+         implementations that already support the POSIX-required range
+         [-24:59:59, 25:59:59].
+
+       * tzh_charcnt bytes that represent time zone designations, which are
+         null-terminated byte strings, each indexed by the tt_desigidx values
+         mentioned above.  The byte strings can overlap if one is a suffix of
+         the other.  The encoding of these strings is not specified.
+
+       * tzh_leapcnt pairs of four-byte values, written in network byte order;
+         the first value of each pair gives the nonnegative time (as returned
+         by time(2)) at which a leap second occurs or at which the leap second
+         table expires; the second is a signed integer specifying the
+         correction, which is the total number of leap seconds to be applied
+         during the time period starting at the given time.  The pairs of
+         values are sorted in strictly ascending order by time.  Each pair
+         denotes one leap second, either positive or negative, except that if
+         the last pair has the same correction as the previous one, the last
+         pair denotes the leap second table's expiration time.  Each leap
+         second is at the end of a UTC calendar month.  The first leap second
+         has a nonnegative occurrence time, and is a positive leap second if
+         and only if its correction is positive; the correction for each leap
+         second after the first differs from the previous leap second by
+         either 1 for a positive leap second, or -1 for a negative leap
+         second.  If the leap second table is empty, the leap-second
+         correction is zero for all timestamps; otherwise, for timestamps
+         before the first occurrence time, the leap-second correction is zero
+         if the first pair's correction is 1 or -1, and is unspecified
+         otherwise (which can happen only in files truncated at the start).
+
+       * tzh_ttisstdcnt standard/wall indicators, each stored as a one-byte
+         boolean; they tell whether the transition times associated with local
+         time types were specified as standard time or local (wall clock)
+         time.
+
+       * tzh_ttisutcnt UT/local indicators, each stored as a one-byte boolean;
+         they tell whether the transition times associated with local time
+         types were specified as UT or local time.  If a UT/local indicator is
+         set, the corresponding standard/wall indicator must also be set.
+
+       The standard/wall and UT/local indicators were designed for
+       transforming a TZif file's transition times into transitions
+       appropriate for another time zone specified via a POSIX-style TZ string
+       that lacks rules.  For example, when TZ="EET-2EEST" and there is no
+       TZif file "EET-2EEST", the idea was to adapt the transition times from
+       a TZif file with the well-known name "posixrules" that is present only
+       for this purpose and is a copy of the file "Europe/Brussels", a file
+       with a different UT offset.  POSIX does not specify this obsolete
+       transformational behavior, the default rules are installation-
+       dependent, and no implementation is known to support this feature for
+       timestamps past 2037, so users desiring (say) Greek time should instead
+       specify TZ="Europe/Athens" for better historical coverage, falling back
+       on TZ="EET-2EEST,M3.5.0/3,M10.5.0/4" if POSIX conformance is required
+       and older timestamps need not be handled accurately.
+
+       The localtime(3) function normally uses the first ttinfo structure in
+       the file if either tzh_timecnt is zero or the time argument is less
+       than the first transition time recorded in the file.
+
+   Version 2 format
+       For version-2-format timezone files, the above header and data are
+       followed by a second header and data, identical in format except that
+       eight bytes are used for each transition time or leap second time.
+       (Leap second counts remain four bytes.)  After the second header and
+       data comes a newline-enclosed, POSIX-TZ-environment-variable-style
+       string for use in handling instants after the last transition time
+       stored in the file or for all instants if the file has no transitions.
+       The POSIX-style TZ string is empty (i.e., nothing between the newlines)
+       if there is no POSIX-style representation for such instants.  If
+       nonempty, the POSIX-style TZ string must agree with the local time type
+       after the last transition time if present in the eight-byte data; for
+       example, given the string "WET0WEST,M3.5.0,M10.5.0/3" then if a last
+       transition time is in July, the transition's local time type must
+       specify a daylight-saving time abbreviated "WEST" that is one hour east
+       of UT.  Also, if there is at least one transition, time type 0 is
+       associated with the time period from the indefinite past up to but not
+       including the earliest transition time.
+
+   Version 3 format
+       For version-3-format timezone files, the POSIX-TZ-style string may use
+       two minor extensions to the POSIX TZ format, as described in
+       newtzset(3).  First, the hours part of its transition times may be
+       signed and range from -167 through 167 instead of the POSIX-required
+       unsigned values from 0 through 24.  Second, DST is in effect all year
+       if it starts January 1 at 00:00 and ends December 31 at 24:00 plus the
+       difference between daylight saving and standard time.
+
+   Version 4 format
+       For version-4-format TZif files, the first leap second record can have
+       a correction that is neither +1 nor -1, to represent truncation of the
+       TZif file at the start.  Also, if two or more leap second transitions
+       are present and the last entry's correction equals the previous one,
+       the last entry denotes the expiration of the leap second table instead
+       of a leap second; timestamps after this expiration are unreliable in
+       that future releases will likely add leap second entries after the
+       expiration, and the added leap seconds will change how post-expiration
+       timestamps are treated.
+
+   Interoperability considerations
+       Future changes to the format may append more data.
+
+       Version 1 files are considered a legacy format and should not be
+       generated, as they do not support transition times after the year 2038.
+       Readers that understand only Version 1 must ignore any data that
+       extends beyond the calculated end of the version 1 data block.
+
+       Other than version 1, writers should generate the lowest version number
+       needed by a file's data.  For example, a writer should generate a
+       version 4 file only if its leap second table either expires or is
+       truncated at the start.  Likewise, a writer not generating a version 4
+       file should generate a version 3 file only if TZ string extensions are
+       necessary to accurately model transition times.
+
+       The sequence of time changes defined by the version 1 header and data
+       block should be a contiguous sub-sequence of the time changes defined
+       by the version 2+ header and data block, and by the footer.  This
+       guideline helps obsolescent version 1 readers agree with current
+       readers about timestamps within the contiguous sub-sequence.  It also
+       lets writers not supporting obsolescent readers use a tzh_timecnt of
+       zero in the version 1 data block to save space.
+
+       When a TZif file contains a leap second table expiration time, TZif
+       readers should either refuse to process post-expiration timestamps, or
+       process them as if the expiration time did not exist (possibly with an
+       error indication).
+
+       Time zone designations should consist of at least three (3) and no more
+       than six (6) ASCII characters from the set of alphanumerics, "-", and
+       "+".  This is for compatibility with POSIX requirements for time zone
+       abbreviations.
+
+       When reading a version 2 or higher file, readers should ignore the
+       version 1 header and data block except for the purpose of skipping over
+       them.
+
+       Readers should calculate the total lengths of the headers and data
+       blocks and check that they all fit within the actual file size, as part
+       of a validity check for the file.
+
+       When a positive leap second occurs, readers should append an extra
+       second to the local minute containing the second just before the leap
+       second.  If this occurs when the UTC offset is not a multiple of 60
+       seconds, the leap second occurs earlier than the last second of the
+       local minute and the minute's remaining local seconds are numbered
+       through 60 instead of the usual 59; the UTC offset is unaffected.
+
+   Common interoperability issues
+       This section documents common problems in reading or writing TZif
+       files.  Most of these are problems in generating TZif files for use by
+       older readers.  The goals of this section are:
+
+       * to help TZif writers output files that avoid common pitfalls in older
+         or buggy TZif readers,
+
+       * to help TZif readers avoid common pitfalls when reading files
+         generated by future TZif writers, and
+
+       * to help any future specification authors see what sort of problems
+         arise when the TZif format is changed.
+
+       When new versions of the TZif format have been defined, a design goal
+       has been that a reader can successfully use a TZif file even if the
+       file is of a later TZif version than what the reader was designed for.
+       When complete compatibility was not achieved, an attempt was made to
+       limit glitches to rarely used timestamps and allow simple partial
+       workarounds in writers designed to generate new-version data useful
+       even for older-version readers.  This section attempts to document
+       these compatibility issues and workarounds, as well as to document
+       other common bugs in readers.
+
+       Interoperability problems with TZif include the following:
+
+       * Some readers examine only version 1 data.  As a partial workaround, a
+         writer can output as much version 1 data as possible.  However, a
+         reader should ignore version 1 data, and should use version 2+ data
+         even if the reader's native timestamps have only 32 bits.
+
+       * Some readers designed for version 2 might mishandle timestamps after
+         a version 3 or higher file's last transition, because they cannot
+         parse extensions to POSIX in the TZ-like string.  As a partial
+         workaround, a writer can output more transitions than necessary, so
+         that only far-future timestamps are mishandled by version 2 readers.
+
+       * Some readers designed for version 2 do not support permanent daylight
+         saving time with transitions after 24:00 - e.g., a TZ string
+         "EST5EDT,0/0,J365/25" denoting permanent Eastern Daylight Time (-04).
+         As a workaround, a writer can substitute standard time for two time
+         zones east, e.g., "XXX3EDT4,0/0,J365/23" for a time zone with a
+         never-used standard time (XXX, -03) and negative daylight saving time
+         (EDT, -04) all year.  Alternatively, as a partial workaround a writer
+         can substitute standard time for the next time zone east - e.g.,
+         "AST4" for permanent Atlantic Standard Time (-04).
+
+       * Some readers designed for version 2 or 3, and that require strict
+         conformance to RFC 8536, reject version 4 files whose leap second
+         tables are truncated at the start or that end in expiration times.
+
+       * Some readers ignore the footer, and instead predict future timestamps
+         from the time type of the last transition.  As a partial workaround,
+         a writer can output more transitions than necessary.
+
+       * Some readers do not use time type 0 for timestamps before the first
+         transition, in that they infer a time type using a heuristic that
+         does not always select time type 0.  As a partial workaround, a
+         writer can output a dummy (no-op) first transition at an early time.
+
+       * Some readers mishandle timestamps before the first transition that
+         has a timestamp not less than -2**31.  Readers that support only
+         32-bit timestamps are likely to be more prone to this problem, for
+         example, when they process 64-bit transitions only some of which are
+         representable in 32 bits.  As a partial workaround, a writer can
+         output a dummy transition at timestamp -2**31.
+
+       * Some readers mishandle a transition if its timestamp has the minimum
+         possible signed 64-bit value.  Timestamps less than -2**59 are not
+         recommended.
+
+       * Some readers mishandle POSIX-style TZ strings that contain "<" or
+         ">".  As a partial workaround, a writer can avoid using "<" or ">"
+         for time zone abbreviations containing only alphabetic characters.
+
+       * Many readers mishandle time zone abbreviations that contain non-ASCII
+         characters.  These characters are not recommended.
+
+       * Some readers may mishandle time zone abbreviations that contain fewer
+         than 3 or more than 6 characters, or that contain ASCII characters
+         other than alphanumerics, "-", and "+".  These abbreviations are not
+         recommended.
+
+       * Some readers mishandle TZif files that specify daylight-saving time
+         UT offsets that are less than the UT offsets for the corresponding
+         standard time.  These readers do not support locations like Ireland,
+         which uses the equivalent of the POSIX TZ string
+         "IST-1GMT0,M10.5.0,M3.5.0/1", observing standard time (IST, +01) in
+         summer and daylight saving time (GMT, +00) in winter.  As a partial
+         workaround, a writer can output data for the equivalent of the POSIX
+         TZ string "GMT0IST,M3.5.0/1,M10.5.0", thus swapping standard and
+         daylight saving time.  Although this workaround misidentifies which
+         part of the year uses daylight saving time, it records UT offsets and
+         time zone abbreviations correctly.
+
+       * Some readers generate ambiguous timestamps for positive leap seconds
+         that occur when the UTC offset is not a multiple of 60 seconds.  For
+         example, in a timezone with UTC offset +01:23:45 and with a positive
+         leap second 78796801 (1972-06-30 23:59:60 UTC), some readers will map
+         both 78796800 and 78796801 to 01:23:45 local time the next day
+         instead of mapping the latter to 01:23:46, and they will map 78796815
+         to 01:23:59 instead of to 01:23:60.  This has not yet been a
+         practical problem, since no civil authority has observed such UTC
+         offsets since leap seconds were introduced in 1972.
+
+       Some interoperability problems are reader bugs that are listed here
+       mostly as warnings to developers of readers.
+
+       * Some readers do not support negative timestamps.  Developers of
+         distributed applications should keep this in mind if they need to
+         deal with pre-1970 data.
+
+       * Some readers mishandle timestamps before the first transition that
+         has a nonnegative timestamp.  Readers that do not support negative
+         timestamps are likely to be more prone to this problem.
+
+       * Some readers mishandle time zone abbreviations like "-08" that
+         contain "+", "-", or digits.
+
+       * Some readers mishandle UT offsets that are out of the traditional
+         range of -12 through +12 hours, and so do not support locations like
+         Kiritimati that are outside this range.
+
+       * Some readers mishandle UT offsets in the range [-3599, -1] seconds
+         from UT, because they integer-divide the offset by 3600 to get 0 and
+         then display the hour part as "+00".
+
+       * Some readers mishandle UT offsets that are not a multiple of one
+         hour, or of 15 minutes, or of 1 minute.
 
 SEE ALSO
-     newctime(3)
+       time(2), localtime(3), tzset(3), tzselect(8), zdump(8), zic(8).
+
+       Olson A, Eggert P, Murchison K. The Time Zone Information Format
+       (TZif).  2019 Feb.  Internet RFC 8536  doi:10.17487/RFC8536 .
+
+                                                                     TZFILE(5)
diff --git a/tzfile.h b/tzfile.h
index 3a9eee305a53..6b18d6b44c8e 100644
--- a/tzfile.h
+++ b/tzfile.h
@@ -1,180 +1,123 @@
+/* Layout and location of TZif files.  */
+
 #ifndef TZFILE_H
 
 #define TZFILE_H
 
 /*
 ** This file is in the public domain, so clarified as of
 ** 1996-06-05 by Arthur David Olson.
 */
 
 /*
 ** This header is for use ONLY with the time conversion code.
 ** There is no guarantee that it will remain unchanged,
 ** or that it will remain at all.
 ** Do NOT copy it to any system include directory.
 ** Thank you!
 */
 
-/*
-** ID
-*/
-
-#ifndef lint
-#ifndef NOID
-static char	tzfilehid[] = "@(#)tzfile.h	8.1";
-#endif /* !defined NOID */
-#endif /* !defined lint */
-
 /*
 ** Information about time zone files.
 */
 
 #ifndef TZDIR
-#define TZDIR	"/usr/local/etc/zoneinfo" /* Time zone object file directory */
+# define TZDIR "/usr/share/zoneinfo" /* Time zone object file directory */
 #endif /* !defined TZDIR */
 
 #ifndef TZDEFAULT
-#define TZDEFAULT	"localtime"
+# define TZDEFAULT "/etc/localtime"
 #endif /* !defined TZDEFAULT */
 
 #ifndef TZDEFRULES
-#define TZDEFRULES	"posixrules"
+# define TZDEFRULES "posixrules"
 #endif /* !defined TZDEFRULES */
 
+
+/* See Internet RFC 8536 for more details about the following format.  */
+
 /*
 ** Each file begins with. . .
 */
 
 #define	TZ_MAGIC	"TZif"
 
 struct tzhead {
 	char	tzh_magic[4];		/* TZ_MAGIC */
-	char	tzh_version[1];		/* '\0' or '2' as of 2005 */
-	char	tzh_reserved[15];	/* reserved--must be zero */
-	char	tzh_ttisgmtcnt[4];	/* coded number of trans. time flags */
+	char	tzh_version[1];		/* '\0' or '2'-'4' as of 2021 */
+	char	tzh_reserved[15];	/* reserved; must be zero */
+	char	tzh_ttisutcnt[4];	/* coded number of trans. time flags */
 	char	tzh_ttisstdcnt[4];	/* coded number of trans. time flags */
 	char	tzh_leapcnt[4];		/* coded number of leap seconds */
 	char	tzh_timecnt[4];		/* coded number of transition times */
 	char	tzh_typecnt[4];		/* coded number of local time types */
 	char	tzh_charcnt[4];		/* coded number of abbr. chars */
 };
 
 /*
 ** . . .followed by. . .
 **
 **	tzh_timecnt (char [4])s		coded transition times a la time(2)
 **	tzh_timecnt (unsigned char)s	types of local time starting at above
 **	tzh_typecnt repetitions of
-**		one (char [4])		coded UTC offset in seconds
+**		one (char [4])		coded UT offset in seconds
 **		one (unsigned char)	used to set tm_isdst
 **		one (unsigned char)	that's an abbreviation list index
 **	tzh_charcnt (char)s		'\0'-terminated zone abbreviations
 **	tzh_leapcnt repetitions of
 **		one (char [4])		coded leap second transition times
 **		one (char [4])		total correction after above
-**	tzh_ttisstdcnt (char)s		indexed by type; if TRUE, transition
-**					time is standard time, if FALSE,
-**					transition time is wall clock time
-**					if absent, transition times are
-**					assumed to be wall clock time
-**	tzh_ttisgmtcnt (char)s		indexed by type; if TRUE, transition
-**					time is UTC, if FALSE,
-**					transition time is local time
-**					if absent, transition times are
+**	tzh_ttisstdcnt (char)s		indexed by type; if 1, transition
+**					time is standard time, if 0,
+**					transition time is local (wall clock)
+**					time; if absent, transition times are
 **					assumed to be local time
+**	tzh_ttisutcnt (char)s		indexed by type; if 1, transition
+**					time is UT, if 0, transition time is
+**					local time; if absent, transition
+**					times are assumed to be local time.
+**					When this is 1, the corresponding
+**					std/wall indicator must also be 1.
 */
 
 /*
 ** If tzh_version is '2' or greater, the above is followed by a second instance
 ** of tzhead and a second instance of the data in which each coded transition
 ** time uses 8 rather than 4 chars,
 ** then a POSIX-TZ-environment-variable-style string for use in handling
 ** instants after the last transition time stored in the file
 ** (with nothing between the newlines if there is no POSIX representation for
 ** such instants).
+**
+** If tz_version is '3' or greater, the above is extended as follows.
+** First, the POSIX TZ string's hour offset may range from -167
+** through 167 as compared to the POSIX-required 0 through 24.
+** Second, its DST start time may be January 1 at 00:00 and its stop
+** time December 31 at 24:00 plus the difference between DST and
+** standard time, indicating DST all year.
 */
 
 /*
 ** In the current implementation, "tzset()" refuses to deal with files that
 ** exceed any of the limits below.
 */
 
 #ifndef TZ_MAX_TIMES
-#define TZ_MAX_TIMES	1200
+# define TZ_MAX_TIMES 2000
 #endif /* !defined TZ_MAX_TIMES */
 
 #ifndef TZ_MAX_TYPES
-#ifndef NOSOLAR
-#define TZ_MAX_TYPES	256 /* Limited by what (unsigned char)'s can hold */
-#endif /* !defined NOSOLAR */
-#ifdef NOSOLAR
-/*
-** Must be at least 14 for Europe/Riga as of Jan 12 1995,
-** as noted by Earl Chew.
-*/
-#define TZ_MAX_TYPES	20	/* Maximum number of local time types */
-#endif /* !defined NOSOLAR */
+/* This must be at least 17 for Europe/Samara and Europe/Vilnius.  */
+# define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
 #endif /* !defined TZ_MAX_TYPES */
 
 #ifndef TZ_MAX_CHARS
-#define TZ_MAX_CHARS	50	/* Maximum number of abbreviation characters */
+# define TZ_MAX_CHARS 50	/* Maximum number of abbreviation characters */
 				/* (limited by what unsigned chars can hold) */
 #endif /* !defined TZ_MAX_CHARS */
 
 #ifndef TZ_MAX_LEAPS
-#define TZ_MAX_LEAPS	50	/* Maximum number of leap second corrections */
+# define TZ_MAX_LEAPS 50	/* Maximum number of leap second corrections */
 #endif /* !defined TZ_MAX_LEAPS */
 
-#define SECSPERMIN	60
-#define MINSPERHOUR	60
-#define HOURSPERDAY	24
-#define DAYSPERWEEK	7
-#define DAYSPERNYEAR	365
-#define DAYSPERLYEAR	366
-#define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
-#define SECSPERDAY	((long) SECSPERHOUR * HOURSPERDAY)
-#define MONSPERYEAR	12
-
-#define TM_SUNDAY	0
-#define TM_MONDAY	1
-#define TM_TUESDAY	2
-#define TM_WEDNESDAY	3
-#define TM_THURSDAY	4
-#define TM_FRIDAY	5
-#define TM_SATURDAY	6
-
-#define TM_JANUARY	0
-#define TM_FEBRUARY	1
-#define TM_MARCH	2
-#define TM_APRIL	3
-#define TM_MAY		4
-#define TM_JUNE		5
-#define TM_JULY		6
-#define TM_AUGUST	7
-#define TM_SEPTEMBER	8
-#define TM_OCTOBER	9
-#define TM_NOVEMBER	10
-#define TM_DECEMBER	11
-
-#define TM_YEAR_BASE	1900
-
-#define EPOCH_YEAR	1970
-#define EPOCH_WDAY	TM_THURSDAY
-
-#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
-
-/*
-** Since everything in isleap is modulo 400 (or a factor of 400), we know that
-**	isleap(y) == isleap(y % 400)
-** and so
-**	isleap(a + b) == isleap((a + b) % 400)
-** or
-**	isleap(a + b) == isleap(a % 400 + b % 400)
-** This is true even if % means modulo rather than Fortran remainder
-** (which is allowed by C89 but not C99).
-** We use this to avoid addition overflow problems.
-*/
-
-#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
-
 #endif /* !defined TZFILE_H */
diff --git a/tzselect.8 b/tzselect.8
index 515b0ed51bfd..1a5ce110f47d 100644
--- a/tzselect.8
+++ b/tzselect.8
@@ -1,43 +1,125 @@
 .TH TZSELECT 8
 .SH NAME
-tzselect \- select a time zone
+tzselect \- select a timezone
 .SH SYNOPSIS
+.ie \n(.g .ds - \f(CW-\fP
+.el .ds - \-
+.ds d " degrees
+.ds m " minutes
+.ds s " seconds
+.ds _ " \&
+.if t \{\
+. if \n(.g .if c \(de .if c \(fm .if c \(sd \{\
+.  ds d \(de
+.  ds m \(fm
+.  ds s \(sd
+.  ds _ \|
+. \}
+.\}
 .B tzselect
+[
+.B \*-c
+.I coord
+] [
+.B \*-n
+.I limit
+] [
+.B \*-\*-help
+] [
+.B \*-\*-version
+]
 .SH DESCRIPTION
 The
 .B tzselect
 program asks the user for information about the current location,
-and outputs the resulting time zone description to standard output.
+and outputs the resulting timezone to standard output.
 The output is suitable as a value for the TZ environment variable.
 .PP
 All interaction with the user is done via standard input and standard error.
+.SH OPTIONS
+.TP
+.BI "\*-c " coord
+Instead of asking for continent and then country and then city,
+ask for selection from time zones whose largest cities
+are closest to the location with geographical coordinates
+.I coord.
+Use ISO 6709 notation for
+.I coord,
+that is, a latitude immediately followed by a longitude.  The latitude
+and longitude should be signed integers followed by an optional
+decimal point and fraction: positive numbers represent north and east,
+negative south and west.  Latitudes with two and longitudes with three
+integer digits are treated as degrees; latitudes with four or six and
+longitudes with five or seven integer digits are treated as
+.I "DDMM, DDDMM, DDMMSS,"
+or
+.I DDDMMSS
+representing
+.I DD
+or
+.I DDD
+degrees,
+.I MM
+minutes,
+and zero or
+.I SS
+seconds, with any trailing fractions represent fractional minutes or
+(if
+.I SS
+is present) seconds.  The decimal point is that of the current locale.
+For example, in the (default) C locale,
+.B "\*-c\ +40.689\*-074.045"
+specifies 40.689\*d\*_N, 74.045\*d\*_W,
+.B "\*-c\ +4041.4\*-07402.7"
+specifies 40\*d\*_41.4\*m\*_N, 74\*d\*_2.7\*m\*_W, and
+.B "\*-c\ +404121\*-0740240"
+specifies 40\*d\*_41\*m\*_21\*s\*_N, 74\*d\*_2\*m\*_40\*s\*_W.
+If
+.I coord
+is not one of the documented forms, the resulting behavior is unspecified.
+.TP
+.BI "\*-n " limit
+When
+.B \*-c
+is used, display the closest
+.I limit
+locations (default 10).
+.TP
+.B "\*-\*-help"
+Output help information and exit.
+.TP
+.B "\*-\*-version"
+Output version information and exit.
 .SH "ENVIRONMENT VARIABLES"
 .TP
 \f3AWK\fP
 Name of a Posix-compliant
-.I awk
+.B awk
 program (default:
 .BR awk ).
 .TP
 \f3TZDIR\fP
-Name of the directory containing time zone data files (default:
-.BR /usr/local/etc/zoneinfo ).
+Name of the directory containing timezone data files (default:
+.BR /usr/share/zoneinfo ).
 .SH FILES
 .TP
 \f2TZDIR\fP\f3/iso3166.tab\fP
 Table of ISO 3166 2-letter country codes and country names.
 .TP
-\f2TZDIR\fP\f3/zone.tab\fP
-Table of country codes, latitude and longitude, TZ values, and
+\f2TZDIR\fP\f3/zone1970.tab\fP
+Table of country codes, latitude and longitude, timezones, and
 descriptive comments.
 .TP
 \f2TZDIR\fP\f3/\fP\f2TZ\fP
-Time zone data file for time zone \f2TZ\fP.
+Timezone data file for timezone \f2TZ\fP.
 .SH "EXIT STATUS"
-The exit status is zero if a time zone was successfully obtained from the user,
+The exit status is zero if a timezone was successfully obtained from the user,
 nonzero otherwise.
 .SH "SEE ALSO"
 newctime(3), tzfile(5), zdump(8), zic(8)
-.\" @(#)tzselect.8	8.2
+.SH NOTES
+Applications should not assume that
+.BR tzselect 's
+output matches the user's political preferences.
 .\" This file is in the public domain, so clarified as of
 .\" 2009-05-17 by Arthur David Olson.
diff --git a/tzselect.8.txt b/tzselect.8.txt
index a492401b8219..9c6af9413bdb 100644
--- a/tzselect.8.txt
+++ b/tzselect.8.txt
@@ -1,41 +1,77 @@
-NAME
+TZSELECT(8)                 System Manager's Manual                TZSELECT(8)
 
-     tzselect - select a time zone
+NAME
+       tzselect - select a timezone
 
 SYNOPSIS
-     tzselect
+       tzselect [ -c coord ] [ -n limit ] [ --help ] [ --version ]
 
 DESCRIPTION
-     The tzselect program asks the user for information about the
-     current location, and outputs the resulting time zone
-     description to standard output.  The output is suitable as a
-     value for the TZ environment variable.
+       The tzselect program asks the user for information about the current
+       location, and outputs the resulting timezone to standard output.  The
+       output is suitable as a value for the TZ environment variable.
+
+       All interaction with the user is done via standard input and standard
+       error.
+
+OPTIONS
+       -c coord
+              Instead of asking for continent and then country and then city,
+              ask for selection from time zones whose largest cities are
+              closest to the location with geographical coordinates coord.
+              Use ISO 6709 notation for coord, that is, a latitude immediately
+              followed by a longitude.  The latitude and longitude should be
+              signed integers followed by an optional decimal point and
+              fraction: positive numbers represent north and east, negative
+              south and west.  Latitudes with two and longitudes with three
+              integer digits are treated as degrees; latitudes with four or
+              six and longitudes with five or seven integer digits are treated
+              as DDMM, DDDMM, DDMMSS, or DDDMMSS representing DD or DDD
+              degrees, MM minutes, and zero or SS seconds, with any trailing
+              fractions represent fractional minutes or (if SS is present)
+              seconds.  The decimal point is that of the current locale.  For
+              example, in the (default) C locale, -c +40.689-074.045 specifies
+              40.689 degrees N, 74.045 degrees W, -c +4041.4-07402.7 specifies
+              40 degrees 41.4 minutes N, 74 degrees 2.7 minutes W, and
+              -c +404121-0740240 specifies 40 degrees 41 minutes 21 seconds N,
+              74 degrees 2 minutes 40 seconds W.  If coord is not one of the
+              documented forms, the resulting behavior is unspecified.
 
-     All interaction with the user is done via standard input and
-     standard error.
+       -n limit
+              When -c is used, display the closest limit locations (default
+              10).
+
+       --help Output help information and exit.
+
+       --version
+              Output version information and exit.
 
 ENVIRONMENT VARIABLES
-     AWK  Name of a Posix-compliant awk program (default: awk).
+       AWK    Name of a Posix-compliant awk program (default: awk).
 
-     TZDIR
-          Name of the directory containing time zone data files
-          (default: /usr/local/etc/zoneinfo).
+       TZDIR  Name of the directory containing timezone data files (default:
+              /usr/share/zoneinfo).
 
 FILES
-     TZDIR/iso3166.tab
-          Table of ISO 3166 2-letter country codes and country
-          names.
+       TZDIR/iso3166.tab
+              Table of ISO 3166 2-letter country codes and country names.
 
-     TZDIR/zone.tab
-          Table of country codes, latitude and longitude, TZ
-          values, and descriptive comments.
+       TZDIR/zone1970.tab
+              Table of country codes, latitude and longitude, timezones, and
+              descriptive comments.
 
-     TZDIR/TZ
-          Time zone data file for time zone TZ.
+       TZDIR/TZ
+              Timezone data file for timezone TZ.
 
 EXIT STATUS
-     The exit status is zero if a time zone was successfully
-     obtained from the user, nonzero otherwise.
+       The exit status is zero if a timezone was successfully obtained from
+       the user, nonzero otherwise.
 
 SEE ALSO
-     newctime(3), tzfile(5), zdump(8), zic(8)
+       newctime(3), tzfile(5), zdump(8), zic(8)
+
+NOTES
+       Applications should not assume that tzselect's output matches the
+       user's political preferences.
+
+                                                                   TZSELECT(8)
diff --git a/tzselect.ksh b/tzselect.ksh
index 7b805336ab5d..5741b6ffe97f 100644
--- a/tzselect.ksh
+++ b/tzselect.ksh
@@ -1,323 +1,585 @@
-#! /bin/ksh
-
-VERSION='@(#)tzselect.ksh	8.2'
-
+#!/bin/bash
 # Ask the user about the time zone, and output the resulting TZ value to stdout.
 # Interact with the user via stderr and stdin.
 
-# Contributed by Paul Eggert.
+PKGVERSION='(tzcode) '
+TZVERSION=see_Makefile
+REPORT_BUGS_TO=tz@iana.org
+
+# Contributed by Paul Eggert.  This file is in the public domain.
 
 # Porting notes:
 #
-# This script requires several features of the Korn shell.
-# If your host lacks the Korn shell,
-# you can use either of the following free programs instead:
+# This script requires a Posix-like shell and prefers the extension of a
+# 'select' statement.  The 'select' statement was introduced in the
+# Korn shell and is available in Bash and other shell implementations.
+# If your host lacks both Bash and the Korn shell, you can get their
+# source from one of these locations:
 #
-#	
-#	Bourne-Again shell (bash)
-#	
+#	Bash 
+#	Korn Shell 
+#	MirBSD Korn Shell 
 #
-#	
-#	Public domain ksh
-#	
+# For portability to Solaris 10 /bin/sh (supported by Oracle through
+# January 2024) this script avoids some POSIX features and common
+# extensions, such as $(...) (which works sometimes but not others),
+# $((...)), ! CMD, ${#ID}, ${ID##PAT}, ${ID%%PAT}, and $10.
+
 #
 # This script also uses several features of modern awk programs.
-# If your host lacks awk, or has an old awk that does not conform to Posix.2,
+# If your host lacks awk, or has an old awk that does not conform to Posix,
 # you can use either of the following free programs instead:
 #
-#	
-#	GNU awk (gawk)
-#	
-#
-#	
-#	mawk
-#	
+#	Gawk (GNU awk) 
+#	mawk 
 
 
 # Specify default values for environment variables if they are unset.
 : ${AWK=awk}
-: ${TZDIR=$(pwd)}
+: ${TZDIR=`pwd`}
+
+# Output one argument as-is to standard output.
+# Safer than 'echo', which can mishandle '\' or leading '-'.
+say() {
+    printf '%s\n' "$1"
+}
 
 # Check for awk Posix compliance.
 ($AWK -v x=y 'BEGIN { exit 123 }') /dev/null 2>&1
 [ $? = 123 ] || {
-	echo >&2 "$0: Sorry, your \`$AWK' program is not Posix compatible."
+	say >&2 "$0: Sorry, your '$AWK' program is not Posix compatible."
 	exit 1
 }
 
-if [ "$1" = "--help" ]; then
-    cat </dev/null
+  esac
+then
+  # Do this inside 'eval', as otherwise the shell might exit when parsing it
+  # even though it is never executed.
+  eval '
+    doselect() {
+      select select_result
+      do
+	case $select_result in
+	"") echo >&2 "Please enter a number in range." ;;
+	?*) break
+	esac
+      done || exit
+    }
+  '
+else
+  doselect() {
+    # Field width of the prompt numbers.
+    select_width=`expr $# : '.*'`
+
+    select_i=
+
+    while :
+    do
+      case $select_i in
+      '')
+	select_i=0
+	for select_word
+	do
+	  select_i=`expr $select_i + 1`
+	  printf >&2 "%${select_width}d) %s\\n" $select_i "$select_word"
+	done ;;
+      *[!0-9]*)
+	echo >&2 'Please enter a number in range.' ;;
+      *)
+	if test 1 -le $select_i && test $select_i -le $#; then
+	  shift `expr $select_i - 1`
+	  select_result=$1
+	  break
+	fi
+	echo >&2 'Please enter a number in range.'
+      esac
+
+      # Prompt and read input.
+      printf >&2 %s "${PS3-#? }"
+      read select_i || exit
+    done
+  }
 fi
 
+while getopts c:n:t:-: opt
+do
+    case $opt$OPTARG in
+    c*)
+	coord=$OPTARG ;;
+    n*)
+	location_limit=$OPTARG ;;
+    t*) # Undocumented option, used for developer testing.
+	zonetabtype=$OPTARG ;;
+    -help)
+	exec echo "$usage" ;;
+    -version)
+	exec echo "tzselect $PKGVERSION$TZVERSION" ;;
+    -*)
+	say >&2 "$0: -$opt$OPTARG: unknown option; try '$0 --help'"; exit 1 ;;
+    *)
+	say >&2 "$0: try '$0 --help'"; exit 1 ;;
+    esac
+done
+
+shift `expr $OPTIND - 1`
+case $# in
+0) ;;
+*) say >&2 "$0: $1: unknown argument"; exit 1 ;;
+esac
+
 # Make sure the tables are readable.
 TZ_COUNTRY_TABLE=$TZDIR/iso3166.tab
-TZ_ZONE_TABLE=$TZDIR/zone.tab
+TZ_ZONE_TABLE=$TZDIR/$zonetabtype.tab
 for f in $TZ_COUNTRY_TABLE $TZ_ZONE_TABLE
 do
-	<$f || {
-		echo >&2 "$0: time zone files are not set up correctly"
+	<"$f" || {
+		say >&2 "$0: time zone files are not set up correctly"
 		exit 1
 	}
 done
 
+# If the current locale does not support UTF-8, convert data to current
+# locale's format if possible, as the shell aligns columns better that way.
+# Check the UTF-8 of U+12345 CUNEIFORM SIGN URU TIMES KI.
+$AWK 'BEGIN { u12345 = "\360\222\215\205"; exit length(u12345) != 1 }' || {
+    { tmp=`(mktemp -d) 2>/dev/null` || {
+	tmp=${TMPDIR-/tmp}/tzselect.$$ &&
+	(umask 77 && mkdir -- "$tmp")
+    };} &&
+    trap 'status=$?; rm -fr -- "$tmp"; exit $status' 0 HUP INT PIPE TERM &&
+    (iconv -f UTF-8 -t //TRANSLIT <"$TZ_COUNTRY_TABLE" >$tmp/iso3166.tab) \
+        2>/dev/null &&
+    TZ_COUNTRY_TABLE=$tmp/iso3166.tab &&
+    iconv -f UTF-8 -t //TRANSLIT <"$TZ_ZONE_TABLE" >$tmp/$zonetabtype.tab &&
+    TZ_ZONE_TABLE=$tmp/$zonetabtype.tab
+}
+
 newline='
 '
 IFS=$newline
 
 
-# Work around a bug in bash 1.14.7 and earlier, where $PS3 is sent to stdout.
-case $(echo 1 | (select x in x; do break; done) 2>/dev/null) in
-?*) PS3=
-esac
-
+# Awk script to read a time zone table and output the same table,
+# with each column preceded by its distance from 'here'.
+output_distances='
+  BEGIN {
+    FS = "\t"
+    while (getline &2 'Please identify a location' \
 		'so that time zone rules can be set correctly.'
 
 	continent=
 	country=
 	region=
 
+	case $coord in
+	?*)
+		continent=coord;;
+	'')
 
 	# Ask the user for continent or ocean.
 
-	echo >&2 'Please select a continent or ocean.'
-
-	select continent in \
-	    Africa \
-	    Americas \
-	    Antarctica \
-	    'Arctic Ocean' \
-	    Asia \
-	    'Atlantic Ocean' \
-	    Australia \
-	    Europe \
-	    'Indian Ocean' \
-	    'Pacific Ocean' \
-	    'none - I want to specify the time zone using the Posix TZ format.'
-	do
+	echo >&2 'Please select a continent, ocean, "coord", or "TZ".'
+
+        quoted_continents=`
+	  $AWK '
+	    function handle_entry(entry) {
+	      entry = substr(entry, 1, index(entry, "/") - 1)
+	      if (entry == "America")
+	       entry = entry "s"
+	      if (entry ~ /^(Arctic|Atlantic|Indian|Pacific)$/)
+	       entry = entry " Ocean"
+	      printf "'\''%s'\''\n", entry
+	    }
+	    BEGIN { FS = "\t" }
+	    /^[^#]/ {
+              handle_entry($3)
+            }
+	    /^#@/ {
+	      ncont = split($2, cont, /,/)
+	      for (ci = 1; ci <= ncont; ci++) {
+	        handle_entry(cont[ci])
+	      }
+	    }
+          ' <"$TZ_ZONE_TABLE" |
+	  sort -u |
+	  tr '\n' ' '
+	  echo ''
+	`
+
+	eval '
+	    doselect '"$quoted_continents"' \
+		"coord - I want to use geographical coordinates." \
+		"TZ - I want to specify the timezone using the Posix TZ format."
+	    continent=$select_result
 	    case $continent in
-	    '')
-		echo >&2 'Please enter a number in range.';;
-	    ?*)
-		case $continent in
-		Americas) continent=America;;
-		*' '*) continent=$(expr "$continent" : '\([^ ]*\)')
-		esac
-		break
+	    Americas) continent=America;;
+	    *" "*) continent=`expr "$continent" : '\''\([^ ]*\)'\''`
 	    esac
-	done
+	'
+	esac
+
 	case $continent in
-	'')
-		exit 1;;
-	none)
+	TZ)
 		# Ask the user for a Posix TZ string.  Check that it conforms.
 		while
 			echo >&2 'Please enter the desired value' \
 				'of the TZ environment variable.'
-			echo >&2 'For example, GST-10 is a zone named GST' \
-				'that is 10 hours ahead (east) of UTC.'
+			echo >&2 'For example, AEST-10 is abbreviated' \
+				'AEST and is 10 hours'
+			echo >&2 'ahead (east) of Greenwich,' \
+				'with no daylight saving time.'
 			read TZ
 			$AWK -v TZ="$TZ" 'BEGIN {
-				tzname = "[^-+,0-9][^-+,0-9][^-+,0-9]+"
-				time = "[0-2]?[0-9](:[0-5][0-9](:[0-5][0-9])?)?"
+				tzname = "(<[[:alnum:]+-]{3,}>|[[:alpha:]]{3,})"
+				time = "(2[0-4]|[0-1]?[0-9])" \
+				  "(:[0-5][0-9](:[0-5][0-9])?)?"
 				offset = "[-+]?" time
-				date = "(J?[0-9]+|M[0-9]+\.[0-9]+\.[0-9]+)"
-				datetime = "," date "(/" time ")?"
+				mdate = "M([1-9]|1[0-2])\\.[1-5]\\.[0-6]"
+				jdate = "((J[1-9]|[0-9]|J?[1-9][0-9]" \
+				  "|J?[1-2][0-9][0-9])|J?3[0-5][0-9]|J?36[0-5])"
+				datetime = ",(" mdate "|" jdate ")(/" time ")?"
 				tzpattern = "^(:.*|" tzname offset "(" tzname \
 				  "(" offset ")?(" datetime datetime ")?)?)$"
 				if (TZ ~ tzpattern) exit 1
 				exit 0
 			}'
 		do
-			echo >&2 "\`$TZ' is not a conforming" \
-				'Posix time zone string.'
+		    say >&2 "'$TZ' is not a conforming Posix timezone string."
 		done
 		TZ_for_date=$TZ;;
 	*)
+		case $continent in
+		coord)
+		    case $coord in
+		    '')
+			echo >&2 'Please enter coordinates' \
+				'in ISO 6709 notation.'
+			echo >&2 'For example, +4042-07403 stands for'
+			echo >&2 '40 degrees 42 minutes north,' \
+				'74 degrees 3 minutes west.'
+			read coord;;
+		    esac
+		    distance_table=`$AWK \
+			    -v coord="$coord" \
+			    -v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
+			    "$output_distances" <"$TZ_ZONE_TABLE" |
+		      sort -n |
+		      sed "${location_limit}q"
+		    `
+		    regions=`say "$distance_table" | $AWK '
+		      BEGIN { FS = "\t" }
+		      { print $NF }
+		    '`
+		    echo >&2 'Please select one of the following timezones,' \
+		    echo >&2 'listed roughly in increasing order' \
+			    "of distance from $coord".
+		    doselect $regions
+		    region=$select_result
+		    TZ=`say "$distance_table" | $AWK -v region="$region" '
+		      BEGIN { FS="\t" }
+		      $NF == region { print $4 }
+		    '`
+		    ;;
+		*)
 		# Get list of names of countries in the continent or ocean.
-		countries=$($AWK -F'\t' \
-			-v continent="$continent" \
+		countries=`$AWK \
+			-v continent_re="^$continent/" \
 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 		'
-			/^#/ { next }
-			$3 ~ ("^" continent "/") {
-				if (!cc_seen[$1]++) cc_list[++ccs] = $1
+			BEGIN { FS = "\t" }
+			/^#$/ { next }
+			/^#[^@]/ { next }
+			{
+			  commentary = $0 ~ /^#@/
+			  if (commentary) {
+			    col1ccs = substr($1, 3)
+			    conts = $2
+			  } else {
+			    col1ccs = $1
+			    conts = $3
+			  }
+			  ncc = split(col1ccs, cc, /,/)
+			  ncont = split(conts, cont, /,/)
+			  for (i = 1; i <= ncc; i++) {
+			    elsewhere = commentary
+			    for (ci = 1; ci <= ncont; ci++) {
+			      if (cont[ci] ~ continent_re) {
+				if (!cc_seen[cc[i]]++) cc_list[++ccs] = cc[i]
+				elsewhere = 0
+			      }
+			    }
+			    if (elsewhere) {
+			      for (i = 1; i <= ncc; i++) {
+			        cc_elsewhere[cc[i]] = 1
+			      }
+			    }
+			  }
 			}
 			END {
 				while (getline &2 'Please select a country.'
-			select country in $countries
-			do
-			    case $country in
-			    '') echo >&2 'Please enter a number in range.';;
-			    ?*) break
-			    esac
-			done
-
-			case $country in
-			'') exit 1
-			esac;;
+			echo >&2 'Please select a country' \
+				'whose clocks agree with yours.'
+			doselect $countries
+			country=$select_result;;
 		*)
 			country=$countries
 		esac
 
 
-		# Get list of names of time zone rule regions in the country.
-		regions=$($AWK -F'\t' \
+		# Get list of timezones in the country.
+		regions=`$AWK \
 			-v country="$country" \
 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 		'
 			BEGIN {
+				FS = "\t"
 				cc = country
 				while (getline &2 'Please select one of the following' \
-				'time zone regions.'
-			select region in $regions
-			do
-				case $region in
-				'') echo >&2 'Please enter a number in range.';;
-				?*) break
-				esac
-			done
-			case $region in
-			'') exit 1
-			esac;;
+			echo >&2 'Please select one of the following timezones.'
+			doselect $regions
+			region=$select_result;;
 		*)
 			region=$regions
 		esac
 
 		# Determine TZ from country and region.
-		TZ=$($AWK -F'\t' \
+		TZ=`$AWK \
 			-v country="$country" \
 			-v region="$region" \
 			-v TZ_COUNTRY_TABLE="$TZ_COUNTRY_TABLE" \
 		'
 			BEGIN {
+				FS = "\t"
 				cc = country
 				while (getline &2 "$0: time zone files are not set up correctly"
+		<"$TZ_for_date" || {
+			say >&2 "$0: time zone files are not set up correctly"
 			exit 1
 		}
 	esac
 
 
 	# Use the proposed TZ to output the current date relative to UTC.
 	# Loop until they agree in seconds.
 	# Give up after 8 unsuccessful tries.
 
 	extra_info=
 	for i in 1 2 3 4 5 6 7 8
 	do
-		TZdate=$(LANG=C TZ="$TZ_for_date" date)
-		UTdate=$(LANG=C TZ=UTC0 date)
-		TZsec=$(expr "$TZdate" : '.*:\([0-5][0-9]\)')
-		UTsec=$(expr "$UTdate" : '.*:\([0-5][0-9]\)')
+		TZdate=`LANG=C TZ="$TZ_for_date" date`
+		UTdate=`LANG=C TZ=UTC0 date`
+		TZsec=`expr "$TZdate" : '.*:\([0-5][0-9]\)'`
+		UTsec=`expr "$UTdate" : '.*:\([0-5][0-9]\)'`
 		case $TZsec in
 		$UTsec)
 			extra_info="
-Local time is now:	$TZdate.
+Selected time is now:	$TZdate.
 Universal Time is now:	$UTdate."
 			break
 		esac
 	done
 
 
 	# Output TZ info and ask the user to confirm.
 
 	echo >&2 ""
 	echo >&2 "The following information has been given:"
 	echo >&2 ""
-	case $country+$region in
-	?*+?*)	echo >&2 "	$country$newline	$region";;
-	?*+)	echo >&2 "	$country";;
-	+)	echo >&2 "	TZ='$TZ'"
+	case $country%$region%$coord in
+	?*%?*%)	say >&2 "	$country$newline	$region";;
+	?*%%)	say >&2 "	$country";;
+	%?*%?*) say >&2 "	coord $coord$newline	$region";;
+	%%?*)	say >&2 "	coord $coord";;
+	*)	say >&2 "	TZ='$TZ'"
 	esac
-	echo >&2 ""
-	echo >&2 "Therefore TZ='$TZ' will be used.$extra_info"
-	echo >&2 "Is the above information OK?"
+	say >&2 ""
+	say >&2 "Therefore TZ='$TZ' will be used.$extra_info"
+	say >&2 "Is the above information OK?"
 
-	ok=
-	select ok in Yes No
-	do
-	    case $ok in
-	    '') echo >&2 'Please enter 1 for Yes, or 2 for No.';;
-	    ?*) break
-	    esac
-	done
+	doselect Yes No
+	ok=$select_result
 	case $ok in
-	'') exit 1;;
 	Yes) break
 	esac
-do :
+do coord=
 done
 
 case $SHELL in
 *csh) file=.login line="setenv TZ '$TZ'";;
 *) file=.profile line="TZ='$TZ'; export TZ"
 esac
 
-echo >&2 "
+test -t 1 && say >&2 "
 You can make this change permanent for yourself by appending the line
 	$line
 to the file '$file' in your home directory; then log out and log in again.
 
 Here is that TZ value again, this time on standard output so that you
 can use the $0 command in shell scripts:"
 
-echo "$TZ"
+say "$TZ"
diff --git a/usno1988 b/usno1988
deleted file mode 100644
index 5766d9b057b9..000000000000
--- a/usno1988
+++ /dev/null
@@ -1,111 +0,0 @@
-# @(#)usno1988	8.1
-#
-# From Arthur David Olson (1989-01-19):
-#
-# Here's some United States Naval Observatory time zone data from
-# February 1988.  It's here mostly to convince you that the USNO has indeed
-# been updating its files (see its 1989 data elsewhere).
-#
-ANDORRA             1 H AHEAD OF UTC
-ARGENTINA           3 H BEHIND   UTC
-BRASIL   WEST       5 H BEHIND UTC        (CRUZEIRO DO SUL)
-BRASIL   CENTRAL    4 H BEHIND UTC              (MANAUS)
-BRASIL   EAST       3 H BEHIND UTC   COASTAL STATES, RIO, SP, BRASILIA
-BRASIL              2 H BEHIND UTC   ATLANTIC ISLANDS
-BRAZIL              5 H BEHIND UTC   WEST (CRUZEIRO DO SUL)
-BRAZIL              4 H BEHIND UTC   CENTRAL    (MANAUS)
-BRAZIL              3 H BEHIND UTC   COASTAL STATES, RIO, SP, BRASILIA
-BRAZIL              3 H BEHIND UTC   FOR MOST MAJOR AIRPORTS.
-BRAZIL              2 H BEHIND UTC   ATLANTIC ISLANDS
-BULGARIA            2 H AHEAD OF UTC WINTER
-BULGARIA            3 H AHEAD OF UTC SUMMER MAR31 - SEP 85, 0100 LOCAL
-CHINA               8 H AHEAD OF UTC; ALL OF CHINA, INCL TAIWAN
-CUBA                5 H BEHIND UTC IN WINTER
-CUBA                4 H BEHIND UTC MAY 8 - OCT 8
-CYPRUS              2 H AHEAD UTC IN WINTER
-CYPRUS              3 H AHEAD UTC MAR 25 - SEP 30
-DENMARK             1 H AHEAD UTC IN WINTER
-DENMARK             2 H AHEAD UTC MAR 31 - SEP 30  , 0200 LOCAL
-DENMK. FAEROE IS    1 H AHEAD UTC MAR 31 - SEP 30  , 0200 LOCAL
-EGYPT               2 H AHEAD UTC
-EGYPT               3 H AHEAD UTC SUMMER (AFTER RAMADAN)
-ENGLAND             ON UTC IN WINTER; WALES, SCOTLAND, N.I., CH.IS.
-ENGLAND             1 H AHEAD OF UTC; SUMMER TIL 28 OCT 0200 LOCAL
-FINLAND             2 H AHEAD OF UTC IN WINTER
-FINLAND             3 H AHEAD OF UTC MAR 25 - SEP 30
-FRANCE              1 H AHEAD OF UTC IN WINTER
-FRANCE              2 H AHEAD OF UTC MAR 31 - SEP 30 , 0100 LOCAL
-GREECE              2 H AHEAD OF UTC IN WINTER
-GREECE              3 H AHEAD OF UTC IN SUMMER EFF. 31MAR85 02/03 LOCAL
-GREECE              3 H AHEAD OF UTC MAR 25 - SEP 30
-GREENLAND           4 H BEHIND UTC  IN THULE AIRBASE YEAR ROUND
-GREENLAND           3 H BEHIND UTC  IN WINTER AT SONDRESTROM
-GREENLAND           2 H BEHIND UTC  30 MAR - 30 SEP 2200 LOCAL AT -"-
-GREENLAND           2 H BEHIND UTC  AROUND SCORESBY SUND
-ICELAND             ON UTC
-IRAN                3.5H AHEAD OF UTC
-IRELAND             ON UTC IN WINTER
-IRELAND             1 H AHEAD OF UTC MAR 31 - OCT 23  0200 LOCAL
-ITALY               1 H AHEAD OF UTC IN WINTER
-ITALY               2 H AHEAD OF UTC MAR 31 - SEP 30, 0030 LOCAL
-JAMAICA             5 H BEHIND UTC IN WINTER
-JAMAICA             4 H BEHIND UTC APR 29 - OCT 29
-LIBYA               2 H AHEAD OF UTC
-MEXICO BAJA CAL N   8 H BEHIND UTC IN WINTER; NORTH BAJA CAL, TIJUANA
-MEXICO BAJA CAL N   7 H BEHIND UTC APR 29 - OCT 29
-MEXICO BAJA CAL S   7 H BEHIND UTC ALL YEAR; MAZATLAN
-MEXICO CENTRAL      6 H BEHIND UTC ALL YEAR; MEXICO CITY
-MONACO              1 H AHEAD UTC IN WINTER
-MONACO              2 H AHEAD UTC MAR 25 - SEP30
-PARAGUAY            4 H BEHIND UTC IN WINTER
-PARAGUAY            3 H BEHIND UTC SEP 30 - MAR 30
-POLAND              1 H AHEAD OF UTC IN WINTER
-POLAND              2 H AHEAD OF UTC MAR 24 - SEP     0200 LOCAL
-PORTUGAL            ON UTC IN WINTER
-PORTUGAL            1 H AHEAD OF UTC IN SUMMER MAR 31 - SEP 29   0100 LOCAL
-PORTUGAL AZORES     1 H BEHIND UTC IN WINTER
-PORTUGAL AZORES     ON UTC IN SUMMER MAR 31 - SEP 29
-PORTUGAL MADEIRA    ON UTC ALL YEAR;
-ROMANIA             2 H AHEAD OF UTC IN WINTER
-ROMANIA             3 H AHEAD OF UTC APR 3 - SEP 24
-SCOTLAND            SEE ENGLAND
-SWITZERLAND         1 H AHEAD OF UTC IN WINTER
-SWITZERLAND         2 H AHEAD OF UTC MAR 31 - SEP 30  0200 LOCAL
-TURKEY              3 H AHEAD OF UTC
-USA   EASTERN       5 H BEHIND UTC IN WINTER; NEW YORK, WASHINGTON
-USA   EASTERN       4 H BEHIND UTC APR 29 - OCT 29
-USA   CENTRAL       6 H BEHIND UTC IN WINTER; CHICAGO, HOUSTON
-USA   CENTRAL       5 H BEHIND UTC APR 29 - OCT 29
-USA   MOUNTAIN      7 H BEHIND UTC IN WINTER; DENVER
-USA   MOUNTAIN      6 H BEHIND UTC APR 29 - OCT 29
-USA   PACIFIC       8 H BEHIND UTC IN WINTER; L.A., SAN FRANCISCO
-USA   PACIFIC       7 H BEHIND UTC APR 29 - OCT 29
-USA   ALASKA STD    9 H BEHIND UTC IN WINTER; MOST OF ALASKA     (AKST)
-USA   ALASKA STD    8 H BEHIND UTC APR 29 - OCT 29               (AKDT)
-USA   ALEUTIAN     10 H BEHIND UTC IN WINTER; ISLANDS WEST OF 170W
-USA   - " -         9 H BEHIND UTC APR 29 - OCT 29
-USA   HAWAII       10 H BEHIND UTC ALL YEAR;
-USA   BERING       11 H BEHIND UTC ALL YEAR; SAMOA, MIDWAY
-USSR WEST EUROP     3 H AHEAD OF UTC IN WINTER; LENINGRAD, MOSCOW
-USSR WEST EUROP     4 H AHEAD OF UTC APR 1 - SEP 30
-USSR CENTRAL EUR    4 H AHEAD OF UTC IN WINTER; ROSTOV, BAKU
-USSR CENTRAL EUR    5 H AHEAD OF UTC APR 1 - SEP 30
-USSR EAST EUROP     5 H AHEAD OF UTC IN WINTER; SVERDLOVSK
-USSR EAST EUROP     6 H AHEAD OF UTC APR 1 - SEP 30
-USSR WEST SIBERIAN  6 H AHEAD OF UTC IN WINTER; TASHKENT, ALMA ATA
-USSR WEST SIBERIAN  7 H AHEAD OF UTC APR 1 - SEP 30
-USSR WEST-CENTRAL   7 H AHEAD OF UTC IN WINTER; NOVOSIBIRSK
-USSR WEST-CENTRAL   8 H AHEAD OF UTC APR 1 - SEP 30
-USSR WEST-CENTRAL   8 H AHEAD OF UTC IN WINTER; IRKUTSK
-USSR WEST-CENTRAL   9 H AHEAD OF UTC APR 1 - SEP 30
-USSR CENTRAL SIB    9 H AHEAD OF UTC IN WINTER; YAKUTSK
-USSR CENTRAL SIB   10 H AHEAD OF UTC APR 1 - SEP 30
-USSR CENTRAL SIB   10 H AHEAD OF UTC IN WINTER; VLADIVOSTOK
-USSR CENTRAL SIB   11 H AHEAD OF UTC APR 1 - SEP 30
-USSR EAST SIBERIA  11 H AHEAD OF UTC IN WINTER; MAGADAN
-USSR EAST SIBERIA  12 H AHEAD OF UTC APR 1 - SEP 30
-USSR EAST SIBERIA  12 H AHEAD OF UTC IN WINTER; PETROPAVLOVSK
-USSR EAST SIBERIA  13 H AHEAD OF UTC APR 1 - SEP 30
-USSR EAST SIBERIA  13 H AHEAD OF UTC IN WINTER; UELEN
-USSR EAST SIBERIA  14 H AHEAD OF UTC APR 1 - SEP 30
-WALES               SEE ENGLAND
diff --git a/usno1989 b/usno1989
deleted file mode 100644
index e242cb90d374..000000000000
--- a/usno1989
+++ /dev/null
@@ -1,452 +0,0 @@
-# @(#)usno1989	8.1
-#
-# From Arthur David Olson (1989-01-19):
-#
-# Here's time zone information from the United States Naval Observatory;
-# no corrections have been made, and there are some obvious challenges.
-# The USNO warns:
-#	DUE TO FREQUENT CHANGES IN THE LOCAL LAWS GOVERNING DAYLIGHT
-#	SAVING TIME, WE CANNOT GUARANTEE THE ACCURACY OF THIS
-#	INFORMATION.  PLEASE ALERT US TO ANY DISCREPANCY YOU MAY
-#	DISCOVER.
-#
-AFGHANISTAN         4.5H AHEAD OF UTC
-ALBANIA             1 H  AHEAD OF UTC
-ALBANIA             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-ALBANIA                                (ESTIMATED)
-ALGERIA             1 H  AHEAD OF UTC
-AMERICAN SAMOA     11 H  BEHIND UTC
-ANDORRA             1 H  AHEAD OF UTC
-ANDORRA             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-ANDORRA                                (ESTIMATED)
-ANGOLA              1 H  AHEAD OF UTC
-ARGENTINA           3 H  BEHIND UTC
-ARUBA               4 H  BEHIND UTC    ALSO BONAIRE, CURACAO,
-ARUBA                                  ST.MAARTEN
-AUSTRALIA  WEST     8 H  AHEAD OF UTC  PERTH, EXMOUTH
-AUSTRALIA  N.T.     9.5H AHEAD OF UTC  DARWIN  NO ADVANCED TIME
-AUSTRALIA  N.T.                                IN SUMMER
-AUSTRALIA  SOUTH    9.5H AHEAD OF UTC  ADELAIDE
-AUSTRALIA                              INCLUDING BROKEN HILL, NSW
-AUSTRALIA  SOUTH   10.5H AHEAD OF UTC  ADELAIDE OCT 30, '88-MAR
-AUSTRALIA  SOUTH                       18, '89 INCLUDING BROKEN
-AUSTRIALIA SOUTH                       HILL, NSW
-AUSTRALIA  QUEENL  10 H  AHEAD OF UTC
-AUSTRALIA  NSW     10 H  AHEAD OF UTC  SYDNEY
-AUSTRALIA  NSW     11 H  AHEAD OF UTC  SYDNEY OCT 30, '88-MAR 18,
-AUSTRALIA  NSW                         '89
-AUSTRALIA  TASM.   10 H  AHEAD OF UTC  HOBART
-AUSTRALIA  TASM.   11 H  AHEAD OF UTC  HOBART OCT 30, '88-MAR 18,
-AUSTRALIA  TASM.                       '89
-AUSTRIA             1 H  AHEAD OF UTC
-AUSTRIA             2 H  AHEAD OF UTC  MAR 27 - SEPT 24
-AZORES                   SEE PORTUGAL
-BAHAMAS             5 H  BEHIND UTC    EXCLUDING TURKS AND CAICOS
-BAHAMAS                                ISLANDS)
-BAHAMAS             4 H  BEHIND UTC    APR 3 - OCT 29 (SAME
-BAHAMAS                                EXCLUSION)
-BAHRAIN             3 H  AHEAD OF UTC
-BANGLADESH          6 H  AHEAD OF UTC
-BARBADOS            4 H  BEHIND UTC
-BELGIUM             1 H  AHEAD OF UTC
-BELGIUM             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-BELIZE              6 H  BEHIND UTC
-BENIN PEOPLES REP   1 H  AHEAD OF UTC  DAHOMEY
-BERMUDA             4 H  BEHIND UTC
-BERMUDA             3 H  BEHIND UTC    APR 3 - OCT 29
-BHUTAN              6 H  AHEAD OF UTC
-BOLIVIA             4 H  BEHIND UTC
-BONAIRE             4 H  BEHIND UTC    ALSO ARUBA,CURACAO,
-BONAIRE                                ST.MAARTEN, SABA
-BOTSWANA            2 H  AHEAD OF UTC
-BRAZIL     WEST     5 H  BEHIND UTC    TERRITORY OF ACRE
-BRAZIL     WEST     4 H  BEHIND UTC    ACRE OCT 23, '88-FEB 11,
-BRAZIL                                 '89 (ESTIMATED)
-BRAZIL     CENTRAL  4 H  BEHIND UTC    MANAUS
-BRAZIL     CENTRAL  3 H  BEHIND UTC    MANAUS OCT 23, '88-FEB 11,
-BRAZIL     CENTRAL                     '89 (ESTIMATED)
-BRAZIL     EAST     3 H  BEHIND UTC    COASTAL STATES, RIO, SAO
-BRAZIL     EAST                        PAULO, BRASILIA
-BRAZIL     EAST     2 H  BEHIND UTC    COASTAL STATES, RIO, SAO
-BRAZIL                                 PAULO, BRASILIA OCT 23,
-BRAZIL                                 '88-FEB 11, '89
-BRAZIL                                 (ESTIMATED)
-BRAZIL              2 H  BEHIND UTC    ATLANTIC ISLANDS, FERNANDO
-BRAZIL                                 DE NORONHA
-BRAZIL              1 H  BEHIND UTC    OCT 23, '88-FEB 11, '89
-BRAZIL                                 (ESTIMATED)
-BRAZIL              3 H  BEHIND UTC    FOR MOST MAJOR AIRPORTS.
-BRITISH VIRGIN I.   4 H  BEHIND UTC
-BRUNEI              8 H  AHEAD OF UTC
-BULGARIA            2 H  AHEAD OF UTC
-BULGARIA            3 H  AHEAD OF UTC  MAR 27 - SEP 24
-BURKINA FASO        ON UTC
-BURMA               6.5H AHEAD OF UTC
-BURUNDI             2 H  AHEAD OF UTC
-CAMBODIA            SEE KAMPUCHEA
-CAMEROON            1 H  AHEAD OF UTC
-CANADA   NEW FDL    3.5H BEHIND UTC    ST.JOHN'S
-CANADA   NEW FDL    1.5H BEHIND UTC    APR 3 - OCT 29
-CANADA   ATLANTIC   4 H  BEHIND UTC    HALIFAX
-CANADA   ATLANTIC   3 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   EASTERN    5 H  BEHIND UTC    TORONTO, MONTREAL, OTTAWA
-CANADA   EASTERN    4 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   CENTRAL    6 H  BEHIND UTC    REGINA, WINNIPEG
-CANADA   CENTRAL    5 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   MOUNTAIN   7 H  BEHIND UTC    CALGARY, EDMONTON
-CANADA   MOUNTAIN   6 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   PACIFIC    8 H  BEHIND UTC    VANCOUVER
-CANADA   PACIFIC    7 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   YUKON      SAME AS PACIFIC    DAWSON
-CAPE VERDE          1 H  BEHIND UTC
-CAYMAN ISLANDS      5 H  BEHIND UTC
-CAROLINE ISLAND    10 H  AHEAD OF UTC  EXCLUDING PONAPE IS.,
-CAROLINE ISLAND                       KUSAIE, AND PINGELAP
-CENTRAL AFRICA      1 H  AHEAD OF UTC
-CEYLON              5.5H AHEAD OF UTC, SEE SRI LANKA
-CHAD                1 H  AHEAD OF UTC
-CHANNEL ISLANDS     SEE ENGLAND
-CHILE               4 H  BEHIND UTC    CONTINENTAL
-CHILE               3 H  BEHIND UTC    OCT 9, '88-MAR 11, '89
-CHILE               6 H  BEHIND UTC    EASTER ISLAND
-CHILE               5 H  BEHIND UTC    OCT 9, '88-MAR 11, '89
-CHINA               8 H  AHEAD OF UTC  ALL OF CHINA, INCL TAIWAN
-CHINA               9 H  AHEAD OF UTC  APR 17 - SEP 10
-COCOS (Keeling) I.  6.5H AHEAD OF UTC
-COLOMBIA            5 H  BEHIND UTC
-COMOROS             3 H  AHEAD OF UTC
-CONGO               1 H  AHEAD OF UTC
-COOK ISLANDS       10 H  BEHIND UTC
-COOK ISLANDS        9.5H  BEHIND UTC   OCT 30, '88-MAR 24, '89
-COOK ISLANDS                           (ESTIMATED)
-COSTA RICA          6 H  BEHIND UTC
-COTE D'IVOIRE       ON UTC
-CUBA                5 H  BEHIND UTC
-CUBA                4 H  BEHIND UTC    MAR 20 - OCT 8
-CURACAO             4 H  BEHIND UTC    ALSO BONAIRE, ARUBA,
-CURACAO                                ST.MAARTEN
-CYPRUS              2 H  AHEAD OF UTC
-CYPRUS              3 H  AHEAD OF UTC  MAR 27 - SEP 24
-CZECHOSLOVAKIA      1 H  AHEAD OF UTC
-CZECHOSLOVAKIA      2 H  AHEAD OF UTC  MAR 27 - SEP 24
-DENMARK             1 H  AHEAD OF UTC
-DENMARK             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-DENMK. FAEROE IS    1 H  AHEAD OF UTC  MAR 27 - SEP 24
-DJIBOUTI            3 H  AHEAD OF UTC
-DOMINICA            4 H  BEHIND UTC
-DOMINICAN REP       4 H  BEHIND UTC
-ECUADOR             5 H  BEHIND UTC    CONTINENTAL
-ECUADOR             6 H  BEHIND UTC    GALAPAGOS ISLANDS
-EGYPT               2 H  AHEAD OF UTC
-EGYPT               3 H  AHEAD OF UTC  MAY 17 - SEP 30 (AFTER
-EGYPT                                  RAMADAN)
-EL SALVADOR         6 H  BEHIND UTC
-ENGLAND             ON UTC             (WALES, SCOTLAND, N.I.,
-ENGLAND                                CH. IS.)
-ENGLAND             1 H  AHEAD OF UTC  MAR 27 - OCT 22
-ENEZUELA           4 H  BEHIND UTC
-EQUITORIAL GUINEA   1 H  AHEAD OF UTC
-ETHIOPIA            3 H  AHEAD OF UTC
-FALKLAND ISLANDS    4 H  BEHIND UTC
-FALKLAND ISLANDS    3 H  BEHIND UTC    SEP 11, '88-APR 15, '89
-FALKLAND ISLANDS                       (ESTIMATED)
-FAROE ISLAND        ON UTC
-FAROE ISLAND        1 H  AHEAD OF UTC  MAR 27 - SEP 24
-FIJI               12 H  AHEAD OF UTC
-FINLAND             2 H  AHEAD OF UTC
-FINLAND             3 H  AHEAD OF UTC  MAR 27 - SEP 24
-FRANCE              1 H  AHEAD OF UTC
-FRANCE              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-FRENCH GUIANA       3 H  BEHIND UTC
-FRENCH POLYNESIA    9 H  BEHIND UTC    GAMBIER ISLAND
-FRENCH POLYNESIA    9.5H BEHIND UTC    MARQUESAS ISLANDS
-FRENCH POLYNESIA   10 H  BEHIND UTC    SOCIETY ISLANDS, TUBUAI
-FRENCH POLYNESIA                       ISLANDS, TUAMOTU ISLAND,
-FRENCH POLYNESIA                       TAHITI
-GABON               1 H  AHEAD OF UTC
-GAMBIA              ON UTC
-GERMANY ALL         1 H  AHEAD OF UTC
-GERMANY ALL         2 H  AHEAD OF UTC  MAR 27 - SEP 24
-GHANA               ON UTC
-GIBRALTAR           1 H  AHEAD OF UTC
-GIBRALTAR           2 H  AHEAD OF UTC  MAR 27 - SEP 24
-GREECE              2 H  AHEAD OF UTC
-GREECE              3 H  AHEAD OF UTC  MAR 27 - SEP 24
-GREENLAND           4 H  BEHIND UTC    THULE AIRBASE YEAR ROUND
-GREENLAND           3 H  BEHIND UTC    ANGMAGSSALIK AND W. COAST
-GREENLAND           2 H  BEHIND UTC    MAR 27 - SEP 24
-GREENLAND           1 H  BEHIND UTC    SCORESBYSUND
-GREENLAND           ON UTC             MAR 27 - SEP 24
-GRENADA             4 H  BEHIND UTC
-GUADELOUPE          4 H  BEHIND UTC    ST. BARTHELEMY, NORTHERN
-GUADELOUPE                             ST. MARTIN MARTINIQUE
-GUAM               10 H  AHEAD OF UTC
-GUATEMALA           6 H  BEHIND UTC
-GUINEA              ON UTC
-GUINEA BISSAU       ON UTC
-GUINEA REPUBLIC     ON UTC
-GUINEA EQUATORIAL   1 H  AHEAD OF UTC
-GUYANA              3 H  BEHIND UTC
-HAITI               5 H  BEHIND UTC
-HAITI               4 H  BEHIND UTC    APR 3 - OCT 29
-HOLLAND             SEE NETHERLANDS
-HONDURAS            6 H  BEHIND UTC
-HONG KONG           8 H  AHEAD OF UTC
-HUNGARY             1 H  AHEAD OF UTC
-HUNGARY             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-ICELAND             ON UTC
-INDIA               5.5H AHEAD OF UTC  INCLUDING ANDAMAN ISLANDS
-INDONESIA WEST      7 H  AHEAD OF UTC  SUMATRA, JAVA, BALI,
-INDONESIA WEST                         JAKARTA
-INDONESIA CENTRAL   8 H  AHEAD OF UTC  KALIMANTAN, SULAWESI
-INDONESIA EAST      9 H  AHEAD OF UTC  IRIAN, BARAT
-IRAN                3.5H AHEAD OF UTC
-IRAQ                3 H  AHEAD OF UTC
-IRAQ                4 H  AHEAD OF UTC  APR 1 - SEP 30
-IRELAND             ON UTC
-IRELAND             1 H  AHEAD OF UTC  MAR 27 - OCT 22
-ISRAEL              2 H  AHEAD OF UTC
-ISRAEL              3 H  AHEAD OF UTC  APR 10 - SEP 3
-ITALY               1 H  AHEAD OF UTC
-ITALY               2 H  AHEAD OF UTC  MAR 27 - SEP 24
-IVORY COAST         ON UTC
-IWAN              8 H  AHEAD OF UTC
-JAMAICA             5 H  BEHIND UTC
-JAPAN               9 H  AHEAD OF UTC
-JOHNSTON ISLAND    10 H  BEHIND UTC
-JORDAN              2 H  AHEAD OF UTC
-JORDAN              3 H  AHEAD OF UTC  APR 1 - OCT 6
-KAMPUCHEA           7 H  AHEAD OF UTC
-KENYA               3 H  AHEAD OF UTC
-KIRIBATI, REP OF   12 H  AHEAD OF UTC  CANTON, ENDERBURY ISLANDS
-KIRIBATI, REP OF   11 H  AHEAD OF UTC  CHRISTMAS ISLAND
-KOREA               9 H  AHEAD OF UTC
-KOREA, REP OF       9 H  AHEAD OF UTC
-KOREA, REP OF      10 H  AHEAD OF UTC  MAY 8 - OCT 8
-KUWAIT              3 H  AHEAD OF UTC
-KUSAIE, PINGELAP  12 H  AHEAD OF UTC  INCLUDING MARSHALL IS.,
-KUSAIE, PINGELAP                      EXCLUDING KWAJALEIN)
-KWAJALEIN         12 H  BEHIND UTC
-LAOS                7 H  AHEAD OF UTC
-LEBANON             2 H  AHEAD OF UTC
-LEBANON             3 H  AHEAD OF UTC  JUN 1 - OCT 31
-LEEWARD ISLANDS     4 H BEHIND UTC     ANTIGUA, DOMINICA,
-LEEWARD ISLANDS                        MONTSERRAT, ST.
-LEEWARD ISLAANDS                       CHRISTOPHER, ST. KITTS,
-LEEWARD ISLANDS                        NEVIS, ANGUILLA
-LESOTHO             2 H  AHEAD OF UTC
-LIBERIA             ON UTC
-LIBYAN ARAB         1 H  AHEAD OF UTC  JAMAHIRIYA/LIBYA
-LIBYAN ARAB         2 H  AHEAD OF UTC  APR 1 - SEP 30 JAMAHIRIYA/LIBYA
-LIECHTENSTEIN       1 H  AHEAD OF UTC
-LIECHTENSTEIN       2 H  AHEAD OF UTC  MAR 27 - SEP 24
-LUXEMBOURG          1 H  AHEAD OF UTC
-LUXEMBOURG          2 H  AHEAD OF UTC  MAR 27 - SEP 24
-MACAO               8 H  AHEAD OF UTC
-MADAGASCAR          3 H  AHEAD OF UTC
-MADEIRA             SEE PORTUGAL
-MALAWI              2 H  AHEAD OF UTC
-MALAYSIA            8 H  AHEAD OF UTC
-MALDIVES            5 H  AHEAD OF UTC
-MALI                ON UTC
-MALTA               1 H  AHEAD OF UTC
-MALTA               2 H  AHEAD OF UTC  MAR 27 - SEP 24
-MARTINIQUE          4 H  BEHIND UTC
-MAURITANIA          ON UTC
-MAURITIUS           4 H  AHEAD OF UTC
-MARIANA ISLAND    10 H  AHEAD OF UTC  EXCLUDING GUAM
-MEXICO BAJA CAL N   7 H  BEHIND UTC    BAJA CALIFORNIA SUR AND
-MEXICO BAJA CAL N                      N. PACIFIC COAST (STATES
-MEXICO BAJA CAL N                      OF SINALOA AND SONORA)
-MEXICO BAJA CAL N   8 H  BEHIND UTC    ABOVE 28TH PARALLAL APR 3
-MEXICO BAJA CAL N                      - OCT 29
-MEXICO BAJA CAL N   7 H  BEHIND UTC    ABOVE 28TH PARALLAL APR 3
-MEXICO BAJA CAL N                      - 0CT 29
-MEXICO              6 H  BEHIND UTC    STATES OF DURANGO,
-MEXICO                                 COAHUILA, NUEVO LEON,
-MEXICO                                 TAMAULIPAS
-MEXICO              5 H  BEHIND UTC    STATES OF DURANGO,
-MEXICO                                 COAHUILA, NUEVO LEON,
-MEXICO                                 TAMAULIPAS  APR 3 - OCT 29
-MEXICO              6 H  BEHIND UTC    GENERAL MEXICO, STATES OF
-MEXICO                                 CAMPECHE, QUINTANA ROO AND
-MEXICO                                 YUCATAN
-MIDWAY ISLAND      11 H  BEHIND UTC
-MONACO              1 H  AHEAD OF UTC
-MONACO              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-MONGOLIA            8 H  AHEAD OF UTC
-MONGOLIA            9 H  AHEAD OF UTC  MAR 27 - SEP 24
-MONTSERRAT          4 H  BEHIND UTC
-MOROCCO             ON UTC
-MOZAMBIQUE          2 H  AHEAD OF UTC
-NAMIBIA             2 H  AHEAD OF UTC
-NAURU, REP OF      12 H  AHEAD OF UTC
-NEPAL              5H45M AHEAD OF UTC
-NETHERLANDS         1 H  AHEAD OF UTC
-NETHERLANDS         2 H  AHEAD OF UTC  MAR 27 - SEP 24
-NETHERLANDS         4 H  BEHIND UTC    ANTILLES AND SOUTHERN ST.
-NETHERLANDS                            MAARTEN
-NEW CALEDONIA      11 H  AHEAD OF UTC
-NEW HEBRIDES        SEE VANUATU
-NEW ZEALAND        12 H  AHEAD OF UTC  (EXCLUDING CHATHAM ISLAND)
-NEW ZEALAND        13 H  AHEAD OF UTC  OCT 30, '88-MAR 4, '89
-NEW ZEALAND       12H45M AHEAD OF UTC  CHATHAM ISLAND
-NICARAGUA           6 H  BEHIND UTC
-NIGER               1 H  AHEAD OF UTC
-NIGERIA             1 H  AHEAD OF UTC
-NIUE ISLAND        11 H  BEHIND UTC
-NORFOLK ISLAND    11H30M AHEAD OF UTC
-NORTHERN IRELAND    ON UTC             WALES, SCOTLAND, N.I.,
-NORTHERN IRELAND                       CH.IS.
-NORTHERN IRELAND    1 H  AHEAD OF UTC  MAR 27 - OCT 22
-NORWAY              1 H  AHEAD OF UTC
-NORWAY              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-OGO                ON UTC
-OMAN                4 H  AHEAD OF UTC
-PACIFIC ISLAND T.T.
-PALAU ISLAND       9 H  AHEAD OF UTC
-PAKISTAN            5 H  AHEAD OF UTC
-PANAMA              5 H  BEHIND UTC
-PAPUA NEW GUINEA   10 H  AHEAD OF UTC  INCLUDING BOUGAINVILLE
-PAPUA NEW GUINEA                       ISLAND
-PARAGUAY            4 H  BEHIND UTC
-PARAGUAY            3 H  BEHIND UTC    OCT 1, '88-MAR 31, '89
-PERU                5 H  BEHIND UTC
-PHILIPPINES         8 H  AHEAD OF UTC
-PONAPE ISLAND     11 H  AHEAD OF UTC
-POLAND              1 H  AHEAD OF UTC
-POLAND              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-PORTUGAL MAINLAND   ON UTC
-PORTUGAL MAINLAND   1 H  AHEAD OF UTC  MAR 27 - SEP 24
-PORTUGAL AZORES     1 H  BEHIND UTC
-PORTUGAL AZORES     ON UTC             MAR 27 - SEP 24
-PORTUGAL MADEIRA    ON UTC
-PORTUGAL MADEIRA    1 H  AHEAD OF UTC  MAR 27 - SEP 24
-PUERTO RICO         4 H  BEHIND UTC
-QATAR               3 H  AHEAD OF UTC
-ROMANIA             2 H  AHEAD OF UTC
-ROMANIA             3 H  AHEAD OF UTC  MAR 27 - SEP 24
-RUSSIA              SEE USSR
-RWANDA              2 H  AHEAD OF UTC
-SABA                4 H  BEHIND UTC    ALSO BONAIRE, CURACAO,
-SAMOA              11 H  BEHIND UTC
-SAN MARINO          1 H  AHEAD OF UTC
-SAN MARINO          2 H  AHEAD OF UTC  MAR 27 - SEP 24
-SAN SALVADOR        6  H  BEHIND UTC
-SAO TOME ISLAND     ON UTC             AND PRINCIPE ISLAND
-SAUDI ARABIA        3 H  AHEAD OF UTC
-SCOTLAND            SEE ENGLAND
-SENEGAL             ON UTC
-SEYCHELLES          4 H  AHEAD OF UTC
-SIERRA LEONE        ON UTC
-SINGAPORE           8 H  AHEAD OF UTC
-SOLOMON ISLANDS    11 H  AHEAD OF UTC  EXCLUDING BOUGAINVILLE
-SOLOMON ISLANDS                        ISLAND
-SOMALI              3 H  AHEAD OF UTC
-SOUTH AFRICA        2 H  AHEAD OF UTC
-SPAIN  CANARY IS    ON UTC
-SPAIN  CANARY IS    1 H  AHEAD OF UTC  MAR 27 - SEP 24
-SPAIN               1 H  AHEAD OF UTC  CONTINENTAL, BALEARIC AND
-SPAIN                                  MALLORCA ISLANDS
-SPAIN               2 H  AHEAD OF UTC  CONTINENTAL, BALEARIC AND
-SPAIN                                  MALLORCA ISLANDS  MAR 27 -
-SPAIN                                  SEP 24
-SPAIN  MAINLAND     1 H  AHEAD OF UTC  MELILLA
-SPAIN  MAINLAND     2 H  AHEAD OF UTC  MAR 27 - SEP 24
-SRI LANKA          5H30M AHEAD OF UTC
-ST.MAARTEN
-ST.KITTS-NEVIS     4 H  BEHIND UTC
-ST.LUCIA           4 H  BEHIND UTC
-ST.PIERRE          3 H  BEHIND UTC    INCLUDING MIQUELON
-ST.PIERRE          2 H  BEHIND UTC    INLCUDING MIQUELON  APR 3
-ST.PIERRE                             - OCT 29
-ST.VINCENT         4 H  BEHIND UTC    INCLUDING THE GRENADINES
-ST. HELENA          ON UTC
-SURINAME            3 H  BEHIND UTC
-SWAZILAND           2 H  AHEAD OF UTC
-SWEDEN              1 H  AHEAD OF UTC
-SWEDEN              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-SWITZERLAND         1 H  AHEAD OF UTC
-SWITZERLAND         2 H  AHEAD OF UTC  MAR 27 - SEP 24
-SYRIA               2 H  AHEAD OF UTC
-SYRIA               3 H  AHEAD OF UTC  MAR 15 - OCT 30
-TAHITI             10 H  BEHIND UTC
-TANZANIA            3 H  AHEAD OF UTC
-THAILAND            7 H  AHEAD OF UTC
-TRINIDAD / TOBAGO   4 H  BEHIND UTC
-TUNISIA             1 H  AHEAD OF UTC
-TUNISIA             2 H  AHEAD OF UTC  APR 10 - SEP 24
-TURKEY              2 H  AHEAD OF UTC
-TURKEY              3 H  AHEAD OF UTC  MAR 27 - SEP 24
-TURKS AND CAICOS    5 H  BEHIND UTC
-TURKS AND CAICOS    4 H  BEHIND UTC    APR 3 - OCT 29
-TUVALU             12 H  AHEAD OF UTC
-UDAN               2 H  AHEAD OF UTC
-UGANDA              3 H  AHEAD OF UTC
-UNITED ARAB EMIR.   4 H  AHEAD OF UTC  ABU DHABI, DUBAI, SHARJAH,
-UNITED ARAB EMIR                       RAS AL KHAIMAH
-UNITED KINGDOM      ON UTC             WALES, SCOTLAND, N.I., CH.
-UNITED KINGDOM                         IS.
-UNITED KINGDOM      1 H  AHEAD OF UTC  MAR 27 - OCT 22
-UNITED STATES       SEE USA
-UPPER VOLTA         ON UTC
-URUGUAY             3 H  BEHIND UTC
-URUGUAY             2 H  BEHIND UTC    DEC 11, '88-FEB 25, '89
-URAGUAY                                (ESTIMATED)
-USA  EASTERN       5 H  BEHIND UTC    NEW YORK, WASHINGTON
-USA  EASTERN       4 H  BEHIND UTC    APR 3 - OCT 30
-USA  CENTRAL       6 H  BEHIND UTC    CHICAGO, HOUSTON
-USA  CENTRAL       5 H  BEHIND UTC    APR 3 - OCT 30
-USA  MOUNTAIN      7 H  BEHIND UTC    DENVER
-USA  MOUNTAIN      6 H  BEHIND UTC    APR 3 - OCT 30
-USA  PACIFIC       8 H  BEHIND UTC    L.A., SAN FRANCISCO
-USA  PACIFIC       7 H  BEHIND UTC    APR 3 - OCT 30
-USA  ALASKA STD    9 H  BEHIND UTC    MOST OF ALASKA     (AKST)
-USA  ALASKA STD    8 H  BEHIND UTC    APR 3 - OCT 30 (AKDT)
-USA  ALEUTIAN     10 H  BEHIND UTC    ISLANDS WEST OF 170W
-USA  - " -         9 H  BEHIND UTC    APR 3 - OCT 30
-USA  HAWAII       10 H  BEHIND UTC
-USA  BERING       11 H  BEHIND UTC    SAMOA, MIDWAY
-USA  FOR SPECIFIC INFO ON USA ZONES/TIMES CALL DOT 202-426-4520
-USSR WEST EUROP     3 H  AHEAD OF UTC  LENINGRAD, MOSCOW
-USSR WEST EUROP     4 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR CENTRAL EUR    4 H  AHEAD OF UTC  ROSTOV, BAKU
-USSR CENTRAL EUR    5 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR EAST EUROP     5 H  AHEAD OF UTC  SVERDLOVSK
-USSR EAST EUROP     6 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR WEST SIBERIAN  6 H  AHEAD OF UTC  TASHKENT, ALMA ATA
-USSR WEST SIBERIAN  7 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR WEST-CENTRAL   7 H  AHEAD OF UTC  NOVOSIBIRSK
-USSR WEST-CENTRAL   8 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR WEST-CENTRAL   8 H  AHEAD OF UTC  IRKUTSK
-USSR WEST-CENTRAL   9 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR CENTRAL SIB    9 H  AHEAD OF UTC  YAKUTSK
-USSR CENTRAL SIB   10 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR CENTRAL SIB   10 H  AHEAD OF UTC  VLADIVOSTOK
-USSR CENTRAL SIB   11 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR EAST SIBERIA  11 H  AHEAD OF UTC  MAGADAN
-USSR EAST SIBERIA  12 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR EAST SIBERIA  12 H  AHEAD OF UTC  PETROPAVLOVSK
-USSR EAST SIBERIA  13 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR EAST SIBERIA  13 H  AHEAD OF UTC  UELEN
-USSR EAST SIBERIA  14 H  AHEAD OF UTC  APR 1 - SEP 30
-VANUATU            11 H  AHEAD OF UTC  (NEW HEBRIDES)
-VANUATU            12 H  AHEAD OF UTC  SEP 25, '88-MAR 25, '89
-VANUATU                                (ESTIMATED)
-VATICAN             1 H  AHEAD OF UTC
-VATICAN             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-VIETNAM             7 H  AHEAD OF UTC
-VIRGIN ISLANDS      4 H  BEHIND UTC    ST.CROIX, ST.THOMAS,
-VIRGIN ISLANDS                         ST.JOHN
-WAKE ISLAND        12 H  AHEAD OF UTC
-WALES               SEE ENGLAND
-WALLIS/FUTUNA IS.  12 H  AHEAD OF UTC
-WINDWARD ISLANDS    4 H  BEHIND UTC    GRENADA, ST. LUCIA
-YEMEN               3 H  AHEAD OF UTC  BOTH REPUBLICS
-YUGOSLAVIA          1 H  AHEAD OF UTC
-YUGOSLAVIA          2 H  AHEAD OF UTC  MAR 27 - SEP 24
-ZAIRE  EAST         1 H  AHEAD OF UTC  KINSHASA MBANDAKA
-ZAIRE  WEST         2 H  AHEAD OF UTC  LUBUMBASHI, KASAI, KIVU,
-ZAIRE  WEST                            HAUT-ZAIRE, SHABA
-ZAMBIA              2 H  AHEAD OF UTC
-ZIMBABWE            2 H  AHEAD OF UTC
diff --git a/usno1989a b/usno1989a
deleted file mode 100644
index b197b85bb1d1..000000000000
--- a/usno1989a
+++ /dev/null
@@ -1,452 +0,0 @@
-# @(#)usno1989a	8.1
-#
-# From Arthur David Olson (1994-02-07):
-#
-# Here's time zone information from the United States Naval Observatory,
-# with corrections from Paul Eggert.
-# The USNO warns:
-#	DUE TO FREQUENT CHANGES IN THE LOCAL LAWS GOVERNING DAYLIGHT
-#	SAVING TIME, WE CANNOT GUARANTEE THE ACCURACY OF THIS
-#	INFORMATION.  PLEASE ALERT US TO ANY DISCREPANCY YOU MAY
-#	DISCOVER.
-#
-AFGHANISTAN         4.5H AHEAD OF UTC
-ALBANIA             1 H  AHEAD OF UTC
-ALBANIA             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-ALBANIA                                (ESTIMATED)
-ALGERIA             1 H  AHEAD OF UTC
-AMERICAN SAMOA     11 H  BEHIND UTC
-ANDORRA             1 H  AHEAD OF UTC
-ANDORRA             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-ANDORRA                                (ESTIMATED)
-ANGOLA              1 H  AHEAD OF UTC
-ARGENTINA           3 H  BEHIND UTC
-ARUBA               4 H  BEHIND UTC    ALSO BONAIRE, CURACAO,
-ARUBA                                  ST.MAARTEN
-AUSTRALIA  WEST     8 H  AHEAD OF UTC  PERTH, EXMOUTH
-AUSTRALIA  N.T.     9.5H AHEAD OF UTC  DARWIN  NO ADVANCED TIME
-AUSTRALIA  N.T.                                IN SUMMER
-AUSTRALIA  SOUTH    9.5H AHEAD OF UTC  ADELAIDE
-AUSTRALIA                              INCLUDING BROKEN HILL, NSW
-AUSTRALIA  SOUTH   10.5H AHEAD OF UTC  ADELAIDE OCT 30, '88-MAR
-AUSTRALIA  SOUTH                       18, '89 INCLUDING BROKEN
-AUSTRIALIA SOUTH                       HILL, NSW
-AUSTRALIA  QUEENL  10 H  AHEAD OF UTC
-AUSTRALIA  NSW     10 H  AHEAD OF UTC  SYDNEY
-AUSTRALIA  NSW     11 H  AHEAD OF UTC  SYDNEY OCT 30, '88-MAR 18,
-AUSTRALIA  NSW                         '89
-AUSTRALIA  TASM.   10 H  AHEAD OF UTC  HOBART
-AUSTRALIA  TASM.   11 H  AHEAD OF UTC  HOBART OCT 30, '88-MAR 18,
-AUSTRALIA  TASM.                       '89
-AUSTRIA             1 H  AHEAD OF UTC
-AUSTRIA             2 H  AHEAD OF UTC  MAR 27 - SEPT 24
-AZORES                   SEE PORTUGAL
-BAHAMAS             5 H  BEHIND UTC    EXCLUDING TURKS AND CAICOS
-BAHAMAS                                ISLANDS)
-BAHAMAS             4 H  BEHIND UTC    APR 3 - OCT 29 (SAME
-BAHAMAS                                EXCLUSION)
-BAHRAIN             3 H  AHEAD OF UTC
-BANGLADESH          6 H  AHEAD OF UTC
-BARBADOS            4 H  BEHIND UTC
-BELGIUM             1 H  AHEAD OF UTC
-BELGIUM             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-BELIZE              6 H  BEHIND UTC
-BENIN PEOPLES REP   1 H  AHEAD OF UTC  DAHOMEY
-BERMUDA             4 H  BEHIND UTC
-BERMUDA             3 H  BEHIND UTC    APR 3 - OCT 29
-BHUTAN              6 H  AHEAD OF UTC
-BOLIVIA             4 H  BEHIND UTC
-BONAIRE             4 H  BEHIND UTC    ALSO ARUBA,CURACAO,
-BONAIRE                                ST.MAARTEN, SABA
-BOTSWANA            2 H  AHEAD OF UTC
-BRAZIL     WEST     5 H  BEHIND UTC    TERRITORY OF ACRE
-BRAZIL     WEST     4 H  BEHIND UTC    ACRE OCT 23, '88-FEB 11,
-BRAZIL                                 '89 (ESTIMATED)
-BRAZIL     CENTRAL  4 H  BEHIND UTC    MANAUS
-BRAZIL     CENTRAL  3 H  BEHIND UTC    MANAUS OCT 23, '88-FEB 11,
-BRAZIL     CENTRAL                     '89 (ESTIMATED)
-BRAZIL     EAST     3 H  BEHIND UTC    COASTAL STATES, RIO, SAO
-BRAZIL     EAST                        PAULO, BRASILIA
-BRAZIL     EAST     2 H  BEHIND UTC    COASTAL STATES, RIO, SAO
-BRAZIL                                 PAULO, BRASILIA OCT 23,
-BRAZIL                                 '88-FEB 11, '89
-BRAZIL                                 (ESTIMATED)
-BRAZIL              2 H  BEHIND UTC    ATLANTIC ISLANDS, FERNANDO
-BRAZIL                                 DE NORONHA
-BRAZIL              1 H  BEHIND UTC    OCT 23, '88-FEB 11, '89
-BRAZIL                                 (ESTIMATED)
-BRAZIL              3 H  BEHIND UTC    FOR MOST MAJOR AIRPORTS.
-BRITISH VIRGIN I.   4 H  BEHIND UTC
-BRUNEI              8 H  AHEAD OF UTC
-BULGARIA            2 H  AHEAD OF UTC
-BULGARIA            3 H  AHEAD OF UTC  MAR 27 - SEP 24
-BURKINA FASO        ON UTC
-BURMA               6.5H AHEAD OF UTC
-BURUNDI             2 H  AHEAD OF UTC
-CAMBODIA            SEE KAMPUCHEA
-CAMEROON            1 H  AHEAD OF UTC
-CANADA   NEW FDL    3.5H BEHIND UTC    ST.JOHN'S
-CANADA   NEW FDL    1.5H BEHIND UTC    APR 3 - OCT 29
-CANADA   ATLANTIC   4 H  BEHIND UTC    HALIFAX
-CANADA   ATLANTIC   3 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   EASTERN    5 H  BEHIND UTC    TORONTO, MONTREAL, OTTAWA
-CANADA   EASTERN    4 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   CENTRAL    6 H  BEHIND UTC    REGINA, WINNIPEG
-CANADA   CENTRAL    5 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   MOUNTAIN   7 H  BEHIND UTC    CALGARY, EDMONTON
-CANADA   MOUNTAIN   6 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   PACIFIC    8 H  BEHIND UTC    VANCOUVER
-CANADA   PACIFIC    7 H  BEHIND UTC    APR 3 - OCT 29
-CANADA   YUKON      SAME AS PACIFIC    DAWSON
-CAPE VERDE          1 H  BEHIND UTC
-CAYMAN ISLANDS      5 H  BEHIND UTC
-CAROLINE ISLAND    10 H  AHEAD OF UTC  EXCLUDING PONAPE IS.,
-CAROLINE ISLAND                        KUSAIE, AND PINGELAP
-CENTRAL AFRICA      1 H  AHEAD OF UTC
-CEYLON              5.5H AHEAD OF UTC, SEE SRI LANKA
-CHAD                1 H  AHEAD OF UTC
-CHANNEL ISLANDS     SEE ENGLAND
-CHILE               4 H  BEHIND UTC    CONTINENTAL
-CHILE               3 H  BEHIND UTC    OCT 9, '88-MAR 11, '89
-CHILE               6 H  BEHIND UTC    EASTER ISLAND
-CHILE               5 H  BEHIND UTC    OCT 9, '88-MAR 11, '89
-CHINA               8 H  AHEAD OF UTC  ALL OF CHINA, INCL TAIWAN
-CHINA               9 H  AHEAD OF UTC  APR 17 - SEP 10
-COCOS (Keeling) I.  6.5H AHEAD OF UTC
-COLOMBIA            5 H  BEHIND UTC
-COMOROS             3 H  AHEAD OF UTC
-CONGO               1 H  AHEAD OF UTC
-COOK ISLANDS       10 H  BEHIND UTC
-COOK ISLANDS        9.5H BEHIND UTC    OCT 30, '88-MAR 24, '89
-COOK ISLANDS                           (ESTIMATED)
-COSTA RICA          6 H  BEHIND UTC
-COTE D'IVOIRE       ON UTC
-CUBA                5 H  BEHIND UTC
-CUBA                4 H  BEHIND UTC    MAR 20 - OCT 8
-CURACAO             4 H  BEHIND UTC    ALSO BONAIRE, ARUBA,
-CURACAO                                ST.MAARTEN
-CYPRUS              2 H  AHEAD OF UTC
-CYPRUS              3 H  AHEAD OF UTC  MAR 27 - SEP 24
-CZECHOSLOVAKIA      1 H  AHEAD OF UTC
-CZECHOSLOVAKIA      2 H  AHEAD OF UTC  MAR 27 - SEP 24
-DENMARK             1 H  AHEAD OF UTC
-DENMARK             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-DENMK. FAEROE IS    1 H  AHEAD OF UTC  MAR 27 - SEP 24
-DJIBOUTI            3 H  AHEAD OF UTC
-DOMINICA            4 H  BEHIND UTC
-DOMINICAN REP       4 H  BEHIND UTC
-ECUADOR             5 H  BEHIND UTC    CONTINENTAL
-ECUADOR             6 H  BEHIND UTC    GALAPAGOS ISLANDS
-EGYPT               2 H  AHEAD OF UTC
-EGYPT               3 H  AHEAD OF UTC  MAY 17 - SEP 30 (AFTER
-EGYPT                                  RAMADAN)
-EL SALVADOR         6 H  BEHIND UTC
-ENGLAND             ON UTC             (WALES, SCOTLAND, N.I.,
-ENGLAND                                CH. IS.)
-ENGLAND             1 H  AHEAD OF UTC  MAR 27 - OCT 22
-EQUATORIAL GUINEA   1 H  AHEAD OF UTC
-ETHIOPIA            3 H  AHEAD OF UTC
-FALKLAND ISLANDS    4 H  BEHIND UTC
-FALKLAND ISLANDS    3 H  BEHIND UTC    SEP 11, '88-APR 15, '89
-FALKLAND ISLANDS                       (ESTIMATED)
-FAROE ISLAND        ON UTC
-FAROE ISLAND        1 H  AHEAD OF UTC  MAR 27 - SEP 24
-FIJI               12 H  AHEAD OF UTC
-FINLAND             2 H  AHEAD OF UTC
-FINLAND             3 H  AHEAD OF UTC  MAR 27 - SEP 24
-FRANCE              1 H  AHEAD OF UTC
-FRANCE              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-FRENCH GUIANA       3 H  BEHIND UTC
-FRENCH POLYNESIA    9 H  BEHIND UTC    GAMBIER ISLAND
-FRENCH POLYNESIA    9.5H BEHIND UTC    MARQUESAS ISLANDS
-FRENCH POLYNESIA   10 H  BEHIND UTC    SOCIETY ISLANDS, TUBUAI
-FRENCH POLYNESIA                       ISLANDS, TUAMOTU ISLAND,
-FRENCH POLYNESIA                       TAHITI
-GABON               1 H  AHEAD OF UTC
-GAMBIA              ON UTC
-GERMANY ALL         1 H  AHEAD OF UTC
-GERMANY ALL         2 H  AHEAD OF UTC  MAR 27 - SEP 24
-GHANA               ON UTC
-GIBRALTAR           1 H  AHEAD OF UTC
-GIBRALTAR           2 H  AHEAD OF UTC  MAR 27 - SEP 24
-GREECE              2 H  AHEAD OF UTC
-GREECE              3 H  AHEAD OF UTC  MAR 27 - SEP 24
-GREENLAND           4 H  BEHIND UTC    THULE AIRBASE YEAR ROUND
-GREENLAND           3 H  BEHIND UTC    ANGMAGSSALIK AND W. COAST
-GREENLAND           2 H  BEHIND UTC    MAR 27 - SEP 24
-GREENLAND           1 H  BEHIND UTC    SCORESBYSUND
-GREENLAND           ON UTC             MAR 27 - SEP 24
-GRENADA             4 H  BEHIND UTC
-GUADELOUPE          4 H  BEHIND UTC    ST. BARTHELEMY, NORTHERN
-GUADELOUPE                             ST. MARTIN MARTINIQUE
-GUAM               10 H  AHEAD OF UTC
-GUATEMALA           6 H  BEHIND UTC
-GUINEA              ON UTC
-GUINEA BISSAU       ON UTC
-GUINEA REPUBLIC     ON UTC
-GUINEA EQUATORIAL   1 H  AHEAD OF UTC
-GUYANA              3 H  BEHIND UTC
-HAITI               5 H  BEHIND UTC
-HAITI               4 H  BEHIND UTC    APR 3 - OCT 29
-HOLLAND             SEE NETHERLANDS
-HONDURAS            6 H  BEHIND UTC
-HONG KONG           8 H  AHEAD OF UTC
-HUNGARY             1 H  AHEAD OF UTC
-HUNGARY             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-ICELAND             ON UTC
-INDIA               5.5H AHEAD OF UTC  INCLUDING ANDAMAN ISLANDS
-INDONESIA WEST      7 H  AHEAD OF UTC  SUMATRA, JAVA, BALI,
-INDONESIA WEST                         JAKARTA
-INDONESIA CENTRAL   8 H  AHEAD OF UTC  KALIMANTAN, SULAWESI
-INDONESIA EAST      9 H  AHEAD OF UTC  IRIAN, BARAT
-IRAN                3.5H AHEAD OF UTC
-IRAQ                3 H  AHEAD OF UTC
-IRAQ                4 H  AHEAD OF UTC  APR 1 - SEP 30
-IRELAND             ON UTC
-IRELAND             1 H  AHEAD OF UTC  MAR 27 - OCT 22
-ISRAEL              2 H  AHEAD OF UTC
-ISRAEL              3 H  AHEAD OF UTC  APR 10 - SEP 3
-ITALY               1 H  AHEAD OF UTC
-ITALY               2 H  AHEAD OF UTC  MAR 27 - SEP 24
-IVORY COAST         ON UTC
-JAMAICA             5 H  BEHIND UTC
-JAPAN               9 H  AHEAD OF UTC
-JOHNSTON ISLAND    10 H  BEHIND UTC
-JORDAN              2 H  AHEAD OF UTC
-JORDAN              3 H  AHEAD OF UTC  APR 1 - OCT 6
-KAMPUCHEA           7 H  AHEAD OF UTC
-KENYA               3 H  AHEAD OF UTC
-KIRIBATI, REP OF   12 H  AHEAD OF UTC  CANTON, ENDERBURY ISLANDS
-KIRIBATI, REP OF   11 H  AHEAD OF UTC  CHRISTMAS ISLAND
-KOREA               9 H  AHEAD OF UTC
-KOREA, REP OF       9 H  AHEAD OF UTC
-KOREA, REP OF      10 H  AHEAD OF UTC  MAY 8 - OCT 8
-KUWAIT              3 H  AHEAD OF UTC
-KUSAIE, PINGELAP   12 H  AHEAD OF UTC  INCLUDING MARSHALL IS.,
-KUSAIE, PINGELAP                       EXCLUDING KWAJALEIN)
-KWAJALEIN          12 H  BEHIND UTC
-LAOS                7 H  AHEAD OF UTC
-LEBANON             2 H  AHEAD OF UTC
-LEBANON             3 H  AHEAD OF UTC  JUN 1 - OCT 31
-LEEWARD ISLANDS     4 H  BEHIND UTC    ANTIGUA, DOMINICA,
-LEEWARD ISLANDS                        MONTSERRAT, ST.
-LEEWARD ISLAANDS                       CHRISTOPHER, ST. KITTS,
-LEEWARD ISLANDS                        NEVIS, ANGUILLA
-LESOTHO             2 H  AHEAD OF UTC
-LIBERIA             ON UTC
-LIBYAN ARAB         1 H  AHEAD OF UTC  JAMAHIRIYA/LIBYA
-LIBYAN ARAB         2 H  AHEAD OF UTC  APR 1 - SEP 30 JAMAHIRIYA/LIBYA
-LIECHTENSTEIN       1 H  AHEAD OF UTC
-LIECHTENSTEIN       2 H  AHEAD OF UTC  MAR 27 - SEP 24
-LUXEMBOURG          1 H  AHEAD OF UTC
-LUXEMBOURG          2 H  AHEAD OF UTC  MAR 27 - SEP 24
-MACAO               8 H  AHEAD OF UTC
-MADAGASCAR          3 H  AHEAD OF UTC
-MADEIRA             SEE PORTUGAL
-MALAWI              2 H  AHEAD OF UTC
-MALAYSIA            8 H  AHEAD OF UTC
-MALDIVES            5 H  AHEAD OF UTC
-MALI                ON UTC
-MALTA               1 H  AHEAD OF UTC
-MALTA               2 H  AHEAD OF UTC  MAR 27 - SEP 24
-MARTINIQUE          4 H  BEHIND UTC
-MAURITANIA          ON UTC
-MAURITIUS           4 H  AHEAD OF UTC
-MARIANA ISLANDS    10 H  AHEAD OF UTC  EXCLUDING GUAM
-MEXICO BAJA CAL N   7 H  BEHIND UTC    BAJA CALIFORNIA SUR AND
-MEXICO BAJA CAL N                      N. PACIFIC COAST (STATES
-MEXICO BAJA CAL N                      OF SINALOA AND SONORA)
-MEXICO BAJA CAL N   8 H  BEHIND UTC    ABOVE 28TH PARALLAL APR 3
-MEXICO BAJA CAL N                      - OCT 29
-MEXICO BAJA CAL N   7 H  BEHIND UTC    ABOVE 28TH PARALLAL APR 3
-MEXICO BAJA CAL N                      - 0CT 29
-MEXICO              6 H  BEHIND UTC    STATES OF DURANGO,
-MEXICO                                 COAHUILA, NUEVO LEON,
-MEXICO                                 TAMAULIPAS
-MEXICO              5 H  BEHIND UTC    STATES OF DURANGO,
-MEXICO                                 COAHUILA, NUEVO LEON,
-MEXICO                                 TAMAULIPAS  APR 3 - OCT 29
-MEXICO              6 H  BEHIND UTC    GENERAL MEXICO, STATES OF
-MEXICO                                 CAMPECHE, QUINTANA ROO AND
-MEXICO                                 YUCATAN
-MIDWAY ISLAND      11 H  BEHIND UTC
-MONACO              1 H  AHEAD OF UTC
-MONACO              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-MONGOLIA            8 H  AHEAD OF UTC
-MONGOLIA            9 H  AHEAD OF UTC  MAR 27 - SEP 24
-MONTSERRAT          4 H  BEHIND UTC
-MOROCCO             ON UTC
-MOZAMBIQUE          2 H  AHEAD OF UTC
-NAMIBIA             2 H  AHEAD OF UTC
-NAURU, REP OF      12 H  AHEAD OF UTC
-NEPAL              5H45M AHEAD OF UTC
-NETHERLANDS         1 H  AHEAD OF UTC
-NETHERLANDS         2 H  AHEAD OF UTC  MAR 27 - SEP 24
-NETHERLANDS         4 H  BEHIND UTC    ANTILLES AND SOUTHERN ST.
-NETHERLANDS                            MAARTEN
-NEW CALEDONIA      11 H  AHEAD OF UTC
-NEW HEBRIDES        SEE VANUATU
-NEW ZEALAND        12 H  AHEAD OF UTC  (EXCLUDING CHATHAM ISLAND)
-NEW ZEALAND        13 H  AHEAD OF UTC  OCT 30, '88-MAR 4, '89
-NEW ZEALAND       12H45M AHEAD OF UTC  CHATHAM ISLAND
-NICARAGUA           6 H  BEHIND UTC
-NIGER               1 H  AHEAD OF UTC
-NIGERIA             1 H  AHEAD OF UTC
-NIUE ISLAND        11 H  BEHIND UTC
-NORFOLK ISLAND    11H30M AHEAD OF UTC
-NORTHERN IRELAND    ON UTC             WALES, SCOTLAND, N.I.,
-NORTHERN IRELAND                       CH.IS.
-NORTHERN IRELAND    1 H  AHEAD OF UTC  MAR 27 - OCT 22
-NORWAY              1 H  AHEAD OF UTC
-NORWAY              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-OMAN                4 H  AHEAD OF UTC
-PACIFIC ISLAND T.T.
-PALAU ISLANDS       9 H  AHEAD OF UTC
-PAKISTAN            5 H  AHEAD OF UTC
-PANAMA              5 H  BEHIND UTC
-PAPUA NEW GUINEA   10 H  AHEAD OF UTC  INCLUDING BOUGAINVILLE
-PAPUA NEW GUINEA                       ISLAND
-PARAGUAY            4 H  BEHIND UTC
-PARAGUAY            3 H  BEHIND UTC    OCT 1, '88-MAR 31, '89
-PERU                5 H  BEHIND UTC
-PHILIPPINES         8 H  AHEAD OF UTC
-PONAPE ISLAND      11 H  AHEAD OF UTC
-POLAND              1 H  AHEAD OF UTC
-POLAND              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-PORTUGAL MAINLAND   ON UTC
-PORTUGAL MAINLAND   1 H  AHEAD OF UTC  MAR 27 - SEP 24
-PORTUGAL AZORES     1 H  BEHIND UTC
-PORTUGAL AZORES     ON UTC             MAR 27 - SEP 24
-PORTUGAL MADEIRA    ON UTC
-PORTUGAL MADEIRA    1 H  AHEAD OF UTC  MAR 27 - SEP 24
-PUERTO RICO         4 H  BEHIND UTC
-QATAR               3 H  AHEAD OF UTC
-ROMANIA             2 H  AHEAD OF UTC
-ROMANIA             3 H  AHEAD OF UTC  MAR 27 - SEP 24
-RUSSIA              SEE USSR
-RWANDA              2 H  AHEAD OF UTC
-SABA                4 H  BEHIND UTC    ALSO BONAIRE, CURACAO,
-SAMOA              11 H  BEHIND UTC
-SAN MARINO          1 H  AHEAD OF UTC
-SAN MARINO          2 H  AHEAD OF UTC  MAR 27 - SEP 24
-SAN SALVADOR        6 H  BEHIND UTC
-SAO TOME ISLAND     ON UTC             AND PRINCIPE ISLAND
-SAUDI ARABIA        3 H  AHEAD OF UTC
-SCOTLAND            SEE ENGLAND
-SENEGAL             ON UTC
-SEYCHELLES          4 H  AHEAD OF UTC
-SIERRA LEONE        ON UTC
-SINGAPORE           8 H  AHEAD OF UTC
-SOLOMON ISLANDS    11 H  AHEAD OF UTC  EXCLUDING BOUGAINVILLE
-SOLOMON ISLANDS                        ISLAND
-SOMALI              3 H  AHEAD OF UTC
-SOUTH AFRICA        2 H  AHEAD OF UTC
-SPAIN  CANARY IS    ON UTC
-SPAIN  CANARY IS    1 H  AHEAD OF UTC  MAR 27 - SEP 24
-SPAIN               1 H  AHEAD OF UTC  CONTINENTAL, BALEARIC AND
-SPAIN                                  MALLORCA ISLANDS
-SPAIN               2 H  AHEAD OF UTC  CONTINENTAL, BALEARIC AND
-SPAIN                                  MALLORCA ISLANDS  MAR 27 -
-SPAIN                                  SEP 24
-SPAIN  MAINLAND     1 H  AHEAD OF UTC  MELILLA
-SPAIN  MAINLAND     2 H  AHEAD OF UTC  MAR 27 - SEP 24
-SRI LANKA          5H30M AHEAD OF UTC
-ST. MAARTEN
-ST. KITTS-NEVIS     4 H  BEHIND UTC
-ST. LUCIA           4 H  BEHIND UTC
-ST. PIERRE          3 H  BEHIND UTC    INCLUDING MIQUELON
-ST. PIERRE          2 H  BEHIND UTC    INLCUDING MIQUELON  APR 3
-ST. PIERRE                             - OCT 29
-ST. VINCENT         4 H  BEHIND UTC    INCLUDING THE GRENADINES
-ST. HELENA          ON UTC
-SUDAN               2 H  AHEAD OF UTC
-SURINAME            3 H  BEHIND UTC
-SWAZILAND           2 H  AHEAD OF UTC
-SWEDEN              1 H  AHEAD OF UTC
-SWEDEN              2 H  AHEAD OF UTC  MAR 27 - SEP 24
-SWITZERLAND         1 H  AHEAD OF UTC
-SWITZERLAND         2 H  AHEAD OF UTC  MAR 27 - SEP 24
-SYRIA               2 H  AHEAD OF UTC
-SYRIA               3 H  AHEAD OF UTC  MAR 15 - OCT 30
-TAHITI             10 H  BEHIND UTC
-TAIWAN              8 H  AHEAD OF UTC
-TANZANIA            3 H  AHEAD OF UTC
-THAILAND            7 H  AHEAD OF UTC
-TOGO                ON UTC
-TRINIDAD / TOBAGO   4 H  BEHIND UTC
-TUNISIA             1 H  AHEAD OF UTC
-TUNISIA             2 H  AHEAD OF UTC  APR 10 - SEP 24
-TURKEY              2 H  AHEAD OF UTC
-TURKEY              3 H  AHEAD OF UTC  MAR 27 - SEP 24
-TURKS AND CAICOS    5 H  BEHIND UTC
-TURKS AND CAICOS    4 H  BEHIND UTC    APR 3 - OCT 29
-TUVALU             12 H  AHEAD OF UTC
-UGANDA              3 H  AHEAD OF UTC
-UNITED ARAB EMIR.   4 H  AHEAD OF UTC  ABU DHABI, DUBAI, SHARJAH,
-UNITED ARAB EMIR                       RAS AL KHAIMAH
-UNITED KINGDOM      ON UTC             WALES, SCOTLAND, N.I., CH.
-UNITED KINGDOM                         IS.
-UNITED KINGDOM      1 H  AHEAD OF UTC  MAR 27 - OCT 22
-UNITED STATES       SEE USA
-UPPER VOLTA         ON UTC
-URUGUAY             3 H  BEHIND UTC
-URUGUAY             2 H  BEHIND UTC    DEC 11, '88-FEB 25, '89
-URAGUAY                                (ESTIMATED)
-USA   EASTERN       5 H  BEHIND UTC    NEW YORK, WASHINGTON
-USA   EASTERN       4 H  BEHIND UTC    APR 3 - OCT 30
-USA   CENTRAL       6 H  BEHIND UTC    CHICAGO, HOUSTON
-USA   CENTRAL       5 H  BEHIND UTC    APR 3 - OCT 30
-USA   MOUNTAIN      7 H  BEHIND UTC    DENVER
-USA   MOUNTAIN      6 H  BEHIND UTC    APR 3 - OCT 30
-USA   PACIFIC       8 H  BEHIND UTC    L.A., SAN FRANCISCO
-USA   PACIFIC       7 H  BEHIND UTC    APR 3 - OCT 30
-USA   ALASKA STD    9 H  BEHIND UTC    MOST OF ALASKA     (AKST)
-USA   ALASKA STD    8 H  BEHIND UTC    APR 3 - OCT 30 (AKDT)
-USA   ALEUTIAN     10 H  BEHIND UTC    ISLANDS WEST OF 170W
-USA   - " -         9 H  BEHIND UTC    APR 3 - OCT 30
-USA   HAWAII       10 H  BEHIND UTC
-USA   BERING       11 H  BEHIND UTC    SAMOA, MIDWAY
-USA  FOR SPECIFIC INFO ON USA ZONES/TIMES CALL DOT 202-426-4520
-USSR WEST EUROP     3 H  AHEAD OF UTC  LENINGRAD, MOSCOW
-USSR WEST EUROP     4 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR CENTRAL EUR    4 H  AHEAD OF UTC  ROSTOV, BAKU
-USSR CENTRAL EUR    5 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR EAST EUROP     5 H  AHEAD OF UTC  SVERDLOVSK
-USSR EAST EUROP     6 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR WEST SIBERIAN  6 H  AHEAD OF UTC  TASHKENT, ALMA ATA
-USSR WEST SIBERIAN  7 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR WEST-CENTRAL   7 H  AHEAD OF UTC  NOVOSIBIRSK
-USSR WEST-CENTRAL   8 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR WEST-CENTRAL   8 H  AHEAD OF UTC  IRKUTSK
-USSR WEST-CENTRAL   9 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR CENTRAL SIB    9 H  AHEAD OF UTC  YAKUTSK
-USSR CENTRAL SIB   10 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR CENTRAL SIB   10 H  AHEAD OF UTC  VLADIVOSTOK
-USSR CENTRAL SIB   11 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR EAST SIBERIA  11 H  AHEAD OF UTC  MAGADAN
-USSR EAST SIBERIA  12 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR EAST SIBERIA  12 H  AHEAD OF UTC  PETROPAVLOVSK
-USSR EAST SIBERIA  13 H  AHEAD OF UTC  APR 1 - SEP 30
-USSR EAST SIBERIA  13 H  AHEAD OF UTC  UELEN
-USSR EAST SIBERIA  14 H  AHEAD OF UTC  APR 1 - SEP 30
-VANUATU            11 H  AHEAD OF UTC  (NEW HEBRIDES)
-VANUATU            12 H  AHEAD OF UTC  SEP 25, '88-MAR 25, '89
-VANUATU                                (ESTIMATED)
-VATICAN             1 H  AHEAD OF UTC
-VATICAN             2 H  AHEAD OF UTC  MAR 27 - SEP 24
-VENEZUELA           4 H  BEHIND UTC
-VIETNAM             7 H  AHEAD OF UTC
-VIRGIN ISLANDS      4 H  BEHIND UTC    ST.CROIX, ST.THOMAS,
-VIRGIN ISLANDS                         ST.JOHN
-WAKE ISLAND        12 H  AHEAD OF UTC
-WALES               SEE ENGLAND
-WALLIS/FUTUNA IS.  12 H  AHEAD OF UTC
-WINDWARD ISLANDS    4 H  BEHIND UTC    GRENADA, ST. LUCIA
-YEMEN               3 H  AHEAD OF UTC  BOTH REPUBLICS
-YUGOSLAVIA          1 H  AHEAD OF UTC
-YUGOSLAVIA          2 H  AHEAD OF UTC  MAR 27 - SEP 24
-ZAIRE  EAST         1 H  AHEAD OF UTC  KINSHASA MBANDAKA
-ZAIRE  WEST         2 H  AHEAD OF UTC  LUBUMBASHI, KASAI, KIVU,
-ZAIRE  WEST                            HAUT-ZAIRE, SHABA
-ZAMBIA              2 H  AHEAD OF UTC
-ZIMBABWE            2 H  AHEAD OF UTC
diff --git a/usno1995 b/usno1995
deleted file mode 100644
index 8b9ec8d601d4..000000000000
--- a/usno1995
+++ /dev/null
@@ -1,326 +0,0 @@
-# @(#)usno1995	8.1
-#
-# From Arthur David Olson (1995-12-21):
-#
-# Here's time zone information from the United States Naval Observatory
-# via http://tycho.usno.navy.mil/tzones.html. See USNO's note at the end.
-World Time Zones
-For selected countries, the local standard time offset from UTC is given,
-with daylight savings time where observed.
-Time: Thu Dec 21 17:43:00 utc 1995
-Afghanistan: +4.5 hours
-Albania: +1 hours (Local summer +2 hours)
-Algeria: +1 hours (Local summer +2 hours)
-American Samoa: -11 hours
-Andorra: +1 hours (Local summer +2 hours)
-Angola: +1 hours
-Anguilla: -4 hours
-Antarctica: -2 hours (Local summer -3 hours)
-Antigua: -4 hours
-Argentina: -3 hours
-Argentina western prov: -4 hours
-Armenia: +4 hours (Local summer +5 hours)
-Aruba: -4 hours
-Ascension: 0 hours
-Australia Northern Territory: +9.5 hours
-Australia Lord Howe Island: +10.5 hours (Local summer +11 hours)
-Australia New South Wales: +10 hours (Local summer +11 hours)
-Australia Queensland: +10 hours
-Australia Victoria: +10 hours (Local summer +11 hours)
-Australia Australian Captial Territory: +10 hours (Local summer +11 hours)
-Australia South: +9.5 hours (Local summer +10.5 hours)
-Australia Tasmania: +10 hours (Local summer +11 hours)
-Australia Western: +8 hours
-Austria: +1 hours (Local summer +2 hours)
-Azerbajian: +3 hours
-Azores: -1 hours (Local summer 0 hours)
-Bahamas: -5 hours (Local summer -4 hours)
-Bahrain: +3 hours
-Balearic Islands: +1 hours (Local summer +2 hours)
-Bangladesh: +6 hours
-Barbados: -4 hours
-Belarus: +2 hours (Local summer +3 hours)
-Belgium: +1 hours (Local summer +2 hours)
-Belize: -6 hours
-Benin: +1 hours
-Bermuda: -4 hours (Local summer -3 hours)
-Bhutan: +6 hours
-Bolivia: -4 hours
-Bonaire: -4 hours
-Bosnia Hercegovina: +1 hours (Local summer +2 hours)
-Botswana: +2 hours
-Brazil Acre: -4 hours (Local summer -5 hours)
-Brazil Atlantic Islands: -1 hours (Local summer -2 hours)
-Brazil East: -3 hours (Local summer -1 hours)
-Brazil West: -4 hours (Local summer -3 hours)
-British Virgin Islands: -4 hours
-Brunei: +8 hours
-Bulgaria: +2 hours (Local summer +3 hours)
-Burkina Faso: 0 hours
-Burundi: +2 hours
-Cambodia: +7 hours
-Cameroon: +1 hours
-Canada Central: -6 hours (Local summer -5 hours)
-Canada Eastern: -5 hours (Local summer -4 hours)
-Canada Mountain: -7 hours (Local summer -6 hours)
-Canada Yukon & Pacific: -8 hours (Local summer -7 hours)
-Canada Atlantic: -4 hours (Local summer -3 hours)
-Canada Newfoundland: -3.5 hours (Local summer -2.5 hours)
-Canary Islands: 0 hours (Local summer +1 hours)
-Canton Enderbury Islands: -11 hours
-Cape Verde: -1 hours
-Caroline Island: +11 hours
-Cayman Islands: -5 hours
-Central African Rep: +1 hours
-Chad: +1 hours
-Channel Islands: 0 hours (Local summer +1 hours)
-Chatham Island: +12.75 hours (Local summer +13.75 hours)
-Chile: -4 hours (Local summer -3 hours)
-China People's Rep: +8 hours
-Christmas Islands: -10 hours
-Cocos (Keeling) Islands: ( hours (Local summer ) hours)
-Colombia: -5 hours
-Congo: +1 hours
-Cook Islands: -10 hours
-Costa Rica: -6 hours
-Cote d'Ivoire: 0 hours
-Croatia: +1 hours (Local summer +2 hours)
-Cuba: -5 hours (Local summer -4 hours)
-Curacao: -4 hours
-Cyprus: +2 hours (Local summer +3 hours)
-Czech Republic: +1 hours (Local summer +2 hours)
-Dahomey: +1 hours
-Denmark: +1 hours (Local summer +2 hours)
-Djibouti: +3 hours
-Dominica: -4 hours
-Dominican Republic: -4 hours
-Easter Island: -6 hours (Local summer -5 hours)
-Ecuador: -5 hours
-Egypt: +2 hours (Local summer +3 hours)
-El Salvador: -6 hours
-England: 0 hours (Local summer +1 hours)
-Equitorial Guinea: +1 hours
-Eritrea: +3 hours
-Estonia: +2 hours (Local summer +3 hours)
-Ethiopia: +3 hours
-Falkland Islands: -4 hours (Local summer -3 hours)
-Faroe Island: 0 hours (Local summer +1 hours)
-Fiji: +12 hours
-Finland: +2 hours (Local summer +3 hours)
-France: +1 hours (Local summer +2 hours)
-French Guiana: -3 hours
-French Polynesia: -10 hours
-Gabon: +1 hours
-Galapagos Islands: -6 hours
-Gambia: 0 hours
-Gambier Island: -9 hours
-Georgia: +4 hours
-Germany: +1 hours (Local summer +2 hours)
-Ghana: 0 hours
-Gibraltar: +1 hours (Local summer +2 hours)
-Greece: +2 hours (Local summer +3 hours)
-Greenland: -3 hours (Local summer -2 hours)
-Greenland Thule: -4 hours (Local summer -3 hours)
-Greenland Scoresbysun: -1 hours (Local summer 0 hours)
-Grenada: -4 hours
-Grenadines: -4 hours
-Guadeloupe: -4 hours
-Guam: +10 hours
-Guatemala: -6 hours
-Guinea: 0 hours
-Guinea Bissau: - hours (Local summer 0 hours)
-Guyana: -3 hours
-Haiti: -5 hours (Local summer -4 hours)
-Honduras: -6 hours
-Hong kong: +8 hours
-Hungary: +1 hours (Local summer +2 hours)
-Iceland: 0 hours
-India: +5.5 hours
-Indonesia Central: +8 hours
-Indonesia East: +9 hours
-Indonesia West: +7 hours
-Iran: +3.5 hours
-Iraq: +3 hours (Local summer +4 hours)
-Ireland Republic of: 0 hours (Local summer +1 hours)
-Israel: +2 hours (Local summer +3 hours)
-Italy: +1 hours (Local summer +2 hours)
-Jamaica: -5 hours
-Japan: +9 hours
-Johnston Island: -10 hours
-Jordan: +2 hours (Local summer +3 hours)
-Kazakhstan: +6 hours (Local summer +7 hours)
-Kenya: +3 hours
-Kiribati: +12 hours
-Korea Dem Republic of: +9 hours
-Korea Republic of: +9 hours
-Kusaie: +12 hours
-Kuwait: +3 hours
-Kwajalein: -12 hours
-Kyrgyzstan: +5 hours (Local summer +6 hours)
-Laos: +7 hours
-Latvia: +2 hours (Local summer +3 hours)
-Lebanon: +2 hours (Local summer +3 hours)
-Leeward Islands: -4 hours
-Lesotho: +2 hours
-Liberia: 0 hours
-Libya: +2 hours
-Lithuania: +2 hours (Local summer +3 hours)
-Luxembourg: +1 hours (Local summer +2 hours)
-Macedonia: +1 hours (Local summer +2 hours)
-Madagascar: +3 hours
-Madeira: 0 hours (Local summer +1 hours)
-Malawi: +2 hours
-Malaysia: +8 hours
-Maldives: +5 hours
-Mali: 0 hours
-Mallorca Islands: +1 hours (Local summer +2 hours)
-Malta: +1 hours (Local summer +2 hours)
-Mariana Island: +10 hours
-Marquesas Islands: -9.5 hours
-Marshall Islands: +12 hours
-Martinique: -4 hours
-Mauritania: 0 hours
-Mauritius: +4 hours
-Mayotte: +3 hours
-Melilla: +1 hours (Local summer +2 hours)
-Mexico: -6 hours
-Mexico Baja Calif Norte: -8 hours (Local summer -7 hours)
-Mexico Nayarit: -7 hours
-Mexico Sinaloa: -7 hours
-Mexico Sonora: -7 hours
-Midway Island: -11 hours
-Moldova: +2 hours (Local summer +3 hours)
-Moldovian Rep Pridnestrovye: +2 hours (Local summer +3 hours)
-Monaco: +1 hours (Local summer +2 hours)
-Mongolia: +8 hours
-Morocco: 0 hours
-Mozambique: +2 hours
-Myanmar: +6.5 hours
-Namibia: +1 hours (Local summer +2 hours)
-Nauru Republic of: +12 hours
-Nepal: +5.75 hours
-Netherlands: +1 hours (Local summer +2 hours)
-Netherlands Antilles: -4 hours
-Nevis Montserrat: -4 hours
-New Caledonia: +11 hours
-New Hebrides: +11 hours
-New Zealand: +12 hours (Local summer +13 hours)
-Nicaragua: -6 hours (Local summer -5 hours)
-Niger: +1 hours
-Nigeria: +1 hours
-Niue Island: -11 hours
-Norfolk Island: +11.5 hours
-Northern Ireland: 0 hours (Local summer +1 hours)
-Northern Mariana Islands: +10 hours
-Norway: +1 hours (Local summer +2 hours)
-Oman: +4 hours
-Pakistan: +5 hours
-Palau: +9 hours
-Panama: -5 hours
-Papua New Guinea: +10 hours
-Paraguay: -4 hours (Local summer -3 hours)
-Peru: -5 hours
-Philippines: +8 hours
-Pingelap: +12 hours
-Poland: +1 hours (Local summer +2 hours)
-Ponape Island: +11 hours
-Portugal: +1 hours (Local summer +2 hours)
-Principe Island: 0 hours
-Puerto Rico: -4 hours
-Qatar: +3 hours
-Reunion: +4 hours
-Romania: +2 hours (Local summer +3 hours)
-Russian Federation zone eight: +9 hours (Local summer +10 hours)
-Russian Federation zone eleven: +12 hours (Local summer +13 hours)
-Russian Federation zone five: +6 hours (Local summer +7 hours)
-Russian Federation zone four: +5 hours (Local summer +6 hours)
-Russian Federation zone nine: +10 hours (Local summer +11 hours)
-Russian Federation zone one: +2 hours (Local summer +3 hours)
-Russian Federation zone seven: +8 hours (Local summer +9 hours)
-Russian Federation zone six: +7 hours (Local summer +8 hours)
-Russian Federation zone ten: +11 hours (Local summer +12 hours)
-Russian Federation zone three: +4 hours (Local summer +5 hours)
-Russian Federation zone two: +4 hours (Local summer +5 hours)
-Rwanda: +2 hours
-Saba: -4 hours
-Samoa: -11 hours
-San Marino: +1 hours (Local summer +2 hours)
-Sao Tome e Principe: 0 hours
-Saudi Arabia: +3 hours
-Scotland: 0 hours
-Senegal: 0 hours
-Seychelles: +4 hours
-Sierra Leone: 0 hours
-Singapore: +8 hours
-Slovakia: +1 hours (Local summer +2 hours)
-Slovenia: +1 hours (Local summer +2 hours)
-Society Island: -10 hours
-Solomon Islands: +11 hours
-Somalia: +3 hours
-South Africa: +2 hours
-Spain: +1 hours (Local summer +2 hours)
-Sri Lanka: +5.5 hours
-St Christopher: -4 hours
-St Croix: -4 hours
-St Helena: 0 hours
-St John: -4 hours
-St Kitts Nevis: -4 hours
-St Lucia: -4 hours
-St Maarten: -4 hours
-St Pierre & Miquelon: -3 hours (Local summer -2 hours)
-St Thomas: -4 hours
-St Vincent: -4 hours
-Sudan: +2 hours
-Suriname: -3 hours
-Swaziland: +2 hours
-Sweden: +1 hours (Local summer +2 hours)
-Switzerland: +1 hours (Local summer +2 hours)
-Syria: +2 hours (Local summer +3 hours)
-Tahiti: -10 hours
-Taiwan: +8 hours
-Tajikistan: +6 hours
-Tanzania: +3 hours
-Thailand: +7 hours
-Togo: 0 hours
-Tonga: +13 hours
-Trinidad and Tobago: -4 hours
-Tuamotu Island: -10 hours
-Tubuai Island: -10 hours
-Tunisia: +1 hours
-Turkey: +2 hours (Local summer +3 hours)
-Turkmenistan: +5 hours
-Turks and Caicos Islands: -5 hours (Local summer -4 hours)
-Tuvalu: +12 hours
-Uganda: +3 hours
-Ukraine: +2 hours (Local summer +3 hours)
-United Arab Emirates: +4 hours
-United Kingdom: 0 hours (Local summer +1 hours)
-USA Central: -6 hours (Local summer -5 hours)
-USA Eastern: -5 hours (Local summer -4 hours)
-USA Mountain: -7 hours (Local summer -6 hours)
-USA Arizona: -7 hours
-USA Indiana East: -5 hours
-USA Pacific: -8 hours (Local summer -7 hours)
-USA Alaska: -9 hours (Local summer -8 hours)
-USA Hawaii Aleutian: - hours (Local summer -10 hours)
-Uruguay: -3 hours
-Uzbekistan: +5 hours
-Vanuatu: +11 hours (Local summer +12 hours)
-Vatican City: +1 hours (Local summer +2 hours)
-Venezuela: -4 hours
-Vietnam: +7 hours
-Virgin Islands: -4 hours
-Wake Island: +12 hours
-Wales: 0 hours (Local summer +1 hours)
-Wallis and Futuna Islands: +12 hours
-Windward Islands: -4 hours
-Yemen: +3 hours
-Yugoslavia: +1 hours (Local summer +2 hours)
-Zaire Kasai: +2 hours
-Zaire Kinshasa Mbandaka: +1 hours
-Zaire Haut Zaire: +2 hours
-Zaire Kivu: +2 hours
-Zaire Shaba: +2 hours
-Zambia: +2 hours
-Zimbabwe: +2 hours
-All timezone information is non-authoritative...
diff --git a/usno1997 b/usno1997
deleted file mode 100644
index e18fcdfcdcbf..000000000000
--- a/usno1997
+++ /dev/null
@@ -1,327 +0,0 @@
-# @(#)usno1997	8.1
-#
-# From Arthur David Olson (1997-03-07):
-#
-# Here's time zone information from the United States Naval Observatory
-# via http://tycho.usno.navy.mil/tzones.html. See USNO's note at the end.
-Unofficial Time Zone Information
-World Time Zones
-For selected countries, the local standard time offset from UTC is given, with  daylight savings time where observed.
-Time:  Fri Mar  7 22:38:58 UTC 1997
-Afghanistan: +4.5 hours
-Albania: +1 hours (Local summer +2 hours)
-Algeria: +1 hours (Local summer +2 hours)
-American Samoa: -11 hours
-Andorra: +1 hours (Local summer +2 hours)
-Angola: +1 hours
-Anguilla: -4 hours
-Antarctica: -2 hours (Local summer -3 hours)
-Antigua: -4 hours
-Argentina: -3 hours
-Argentina western prov: -4 hours
-Armenia: +4 hours (Local summer +5 hours)
-Aruba: -4 hours
-Ascension: 0 hours
-Australia Northern Territory: +9.5 hours
-Australia Lord Howe Island: +10.5 hours (Local summer +11 hours)
-Australia New South Wales: +10 hours (Local summer +11 hours)
-Australia Queensland: +10 hours
-Australia Victoria: +10 hours (Local summer +11 hours)
-Australia Australian Captial Territory: +10 hours (Local summer +11 hours)
-Australia South: +9.5 hours (Local summer +10.5 hours)
-Australia Tasmania: +10 hours (Local summer +11 hours)
-Australia Western: +8 hours
-Austria: +1 hours (Local summer +2 hours)
-Azerbajian: +3 hours
-Azores: -1 hours (Local summer 0 hours)
-Bahamas: -5 hours (Local summer -4 hours)
-Bahrain: +3 hours
-Balearic Islands: +1 hours (Local summer +2 hours)
-Bangladesh: +6 hours
-Barbados: -4 hours
-Belarus: +2 hours (Local summer +3 hours)
-Belgium: +1 hours (Local summer +2 hours)
-Belize: -6 hours
-Benin: +1 hours
-Bermuda: -4 hours (Local summer -3 hours)
-Bhutan: +6 hours
-Bolivia: -4 hours
-Bonaire: -4 hours
-Bosnia Hercegovina: +1 hours (Local summer +2 hours)
-Botswana: +2 hours
-Brazil Acre: -4 hours (Local summer -5 hours)
-Brazil Atlantic Islands: -1 hours (Local summer -2 hours)
-Brazil East: -3 hours (Local summer -1 hours)
-Brazil West: -4 hours (Local summer -3 hours)
-British Virgin Islands: -4 hours
-Brunei: +8 hours
-Bulgaria: +2 hours (Local summer +3 hours)
-Burkina Faso: 0 hours
-Burundi: +2 hours
-Cambodia: +7 hours
-Cameroon: +1 hours
-Canada Central: -6 hours (Local summer -5 hours)
-Canada Eastern: -5 hours (Local summer -4 hours)
-Canada Mountain: -7 hours (Local summer -6 hours)
-Canada Yukon & Pacific: -8 hours (Local summer -7 hours)
-Canada Atlantic: -4 hours (Local summer -3 hours)
-Canada Newfoundland: -3.5 hours (Local summer -2.5 hours)
-Canary Islands: 0 hours (Local summer +1 hours)
-Canton Enderbury Islands: -11 hours
-Cape Verde: -1 hours
-Caroline Island: +11 hours
-Cayman Islands: -5 hours
-Central African Rep: +1 hours
-Chad: +1 hours
-Channel Islands: 0 hours (Local summer +1 hours)
-Chatham Island: +12.75 hours (Local summer +13.75 hours)
-Chile: -4 hours (Local summer -3 hours)
-China People's Rep: +8 hours
-Christmas Islands: -10 hours
-Cocos (Keeling) Islands: ( hours (Local summer ) hours)
-Colombia: -5 hours
-Congo: +1 hours
-Cook Islands: -10 hours
-Costa Rica: -6 hours
-Cote d'Ivoire: 0 hours
-Croatia: +1 hours (Local summer +2 hours)
-Cuba: -5 hours (Local summer -4 hours)
-Curacao: -4 hours
-Cyprus: +2 hours (Local summer +3 hours)
-Czech Republic: +1 hours (Local summer +2 hours)
-Dahomey: +1 hours
-Denmark: +1 hours (Local summer +2 hours)
-Djibouti: +3 hours
-Dominica: -4 hours
-Dominican Republic: -4 hours
-Easter Island: -6 hours (Local summer -5 hours)
-Ecuador: -5 hours
-Egypt: +2 hours (Local summer +3 hours)
-El Salvador: -6 hours
-England: 0 hours (Local summer +1 hours)
-Equitorial Guinea: +1 hours
-Eritrea: +3 hours
-Estonia: +2 hours (Local summer +3 hours)
-Ethiopia: +3 hours
-Falkland Islands: -4 hours (Local summer -3 hours)
-Faroe Island: 0 hours (Local summer +1 hours)
-Fiji: +12 hours
-Finland: +2 hours (Local summer +3 hours)
-France: +1 hours (Local summer +2 hours)
-French Guiana: -3 hours
-French Polynesia: -10 hours
-Gabon: +1 hours
-Galapagos Islands: -5 hours
-Gambia: 0 hours
-Gambier Island: -9 hours
-Georgia: +4 hours
-Germany: +1 hours (Local summer +2 hours)
-Ghana: 0 hours
-Gibraltar: +1 hours (Local summer +2 hours)
-Greece: +2 hours (Local summer +3 hours)
-Greenland: -3 hours (Local summer -2 hours)
-Greenland Thule: -4 hours (Local summer -3 hours)
-Greenland Scoresbysun: -1 hours (Local summer 0 hours)
-Grenada: -4 hours
-Grenadines: -4 hours
-Guadeloupe: -4 hours
-Guam: +10 hours
-Guatemala: -6 hours
-Guinea: 0 hours
-Guinea Bissau: - hours (Local summer 0 hours)
-Guyana: -3 hours
-Haiti: -5 hours (Local summer -4 hours)
-Honduras: -6 hours
-Hong kong: +8 hours
-Hungary: +1 hours (Local summer +2 hours)
-Iceland: 0 hours
-India: +5.5 hours
-Indonesia Central: +8 hours
-Indonesia East: +9 hours
-Indonesia West: +7 hours
-Iran: +3.5 hours
-Iraq: +3 hours (Local summer +4 hours)
-Ireland Republic of: 0 hours (Local summer +1 hours)
-Israel: +2 hours (Local summer +3 hours)
-Italy: +1 hours (Local summer +2 hours)
-Jamaica: -5 hours
-Japan: +9 hours
-Johnston Island: -10 hours
-Jordan: +2 hours (Local summer +3 hours)
-Kazakhstan: +6 hours (Local summer +7 hours)
-Kenya: +3 hours
-Kiribati: +12 hours
-Korea Dem Republic of: +9 hours
-Korea Republic of: +9 hours
-Kusaie: +12 hours
-Kuwait: +3 hours
-Kwajalein: -12 hours
-Kyrgyzstan: +5 hours (Local summer +6 hours)
-Laos: +7 hours
-Latvia: +2 hours (Local summer +3 hours)
-Lebanon: +2 hours (Local summer +3 hours)
-Leeward Islands: -4 hours
-Lesotho: +2 hours
-Liberia: 0 hours
-Libya: +2 hours
-Lithuania: +2 hours (Local summer +3 hours)
-Luxembourg: +1 hours (Local summer +2 hours)
-Macedonia: +1 hours (Local summer +2 hours)
-Madagascar: +3 hours
-Madeira: 0 hours (Local summer +1 hours)
-Malawi: +2 hours
-Malaysia: +8 hours
-Maldives: +5 hours
-Mali: 0 hours
-Mallorca Islands: +1 hours (Local summer +2 hours)
-Malta: +1 hours (Local summer +2 hours)
-Mariana Island: +10 hours
-Marquesas Islands: -9.5 hours
-Marshall Islands: +12 hours
-Martinique: -4 hours
-Mauritania: 0 hours
-Mauritius: +4 hours
-Mayotte: +3 hours
-Melilla: +1 hours (Local summer +2 hours)
-Mexico: -6 hours
-Mexico Baja Calif Norte: -8 hours (Local summer -7 hours)
-Mexico Nayarit: -7 hours
-Mexico Sinaloa: -7 hours
-Mexico Sonora: -7 hours
-Midway Island: -11 hours
-Moldova: +2 hours (Local summer +3 hours)
-Moldovian Rep Pridnestrovye: +2 hours (Local summer +3 hours)
-Monaco: +1 hours (Local summer +2 hours)
-Mongolia: +8 hours
-Morocco: 0 hours
-Mozambique: +2 hours
-Myanmar: +6.5 hours
-Namibia: +1 hours (Local summer +2 hours)
-Nauru Republic of: +12 hours
-Nepal: +5.75 hours
-Netherlands: +1 hours (Local summer +2 hours)
-Netherlands Antilles: -4 hours
-Nevis Montserrat: -4 hours
-New Caledonia: +11 hours
-New Hebrides: +11 hours
-New Zealand: +12 hours (Local summer +13 hours)
-Nicaragua: -6 hours (Local summer -5 hours)
-Niger: +1 hours
-Nigeria: +1 hours
-Niue Island: -11 hours
-Norfolk Island: +11.5 hours
-Northern Ireland: 0 hours (Local summer +1 hours)
-Northern Mariana Islands: +10 hours
-Norway: +1 hours (Local summer +2 hours)
-Oman: +4 hours
-Pakistan: +5 hours
-Palau: +9 hours
-Panama: -5 hours
-Papua New Guinea: +10 hours
-Paraguay: -4 hours (Local summer -3 hours)
-Peru: -5 hours
-Philippines: +8 hours
-Pingelap: +12 hours
-Poland: +1 hours (Local summer +2 hours)
-Ponape Island: +11 hours
-Portugal: +1 hours (Local summer +2 hours)
-Principe Island: 0 hours
-Puerto Rico: -4 hours
-Qatar: +3 hours
-Reunion: +4 hours
-Romania: +2 hours (Local summer +3 hours)
-Russian Federation zone eight: +9 hours (Local summer +10 hours)
-Russian Federation zone eleven: +12 hours (Local summer +13 hours)
-Russian Federation zone five: +6 hours (Local summer +7 hours)
-Russian Federation zone four: +5 hours (Local summer +6 hours)
-Russian Federation zone nine: +10 hours (Local summer +11 hours)
-Russian Federation zone one: +2 hours (Local summer +3 hours)
-Russian Federation zone seven: +8 hours (Local summer +9 hours)
-Russian Federation zone six: +7 hours (Local summer +8 hours)
-Russian Federation zone ten: +11 hours (Local summer +12 hours)
-Russian Federation zone three: +4 hours (Local summer +5 hours)
-Russian Federation zone two: +4 hours (Local summer +5 hours)
-Rwanda: +2 hours
-Saba: -4 hours
-Samoa: -11 hours
-San Marino: +1 hours (Local summer +2 hours)
-Sao Tome e Principe: 0 hours
-Saudi Arabia: +3 hours
-Scotland: 0 hours (Local summer +1 hours)
-Senegal: 0 hours
-Seychelles: +4 hours
-Sierra Leone: 0 hours
-Singapore: +8 hours
-Slovakia: +1 hours (Local summer +2 hours)
-Slovenia: +1 hours (Local summer +2 hours)
-Society Island: -10 hours
-Solomon Islands: +11 hours
-Somalia: +3 hours
-South Africa: +2 hours
-Spain: +1 hours (Local summer +2 hours)
-Sri Lanka: +5.5 hours
-St Christopher: -4 hours
-St Croix: -4 hours
-St Helena: 0 hours
-St John: -4 hours
-St Kitts Nevis: -4 hours
-St Lucia: -4 hours
-St Maarten: -4 hours
-St Pierre & Miquelon: -3 hours (Local summer -2 hours)
-St Thomas: -4 hours
-St Vincent: -4 hours
-Sudan: +2 hours
-Suriname: -3 hours
-Swaziland: +2 hours
-Sweden: +1 hours (Local summer +2 hours)
-Switzerland: +1 hours (Local summer +2 hours)
-Syria: +2 hours (Local summer +3 hours)
-Tahiti: -10 hours
-Taiwan: +8 hours
-Tajikistan: +6 hours
-Tanzania: +3 hours
-Thailand: +7 hours
-Togo: 0 hours
-Tonga: +13 hours
-Trinidad and Tobago: -4 hours
-Tuamotu Island: -10 hours
-Tubuai Island: -10 hours
-Tunisia: +1 hours
-Turkey: +2 hours (Local summer +3 hours)
-Turkmenistan: +5 hours
-Turks and Caicos Islands: -5 hours (Local summer -4 hours)
-Tuvalu: +12 hours
-Uganda: +3 hours
-Ukraine: +2 hours (Local summer +3 hours)
-United Arab Emirates: +4 hours
-United Kingdom: 0 hours (Local summer +1 hours)
-USA Central: -6 hours (Local summer -5 hours)
-USA Eastern: -5 hours (Local summer -4 hours)
-USA Mountain: -7 hours (Local summer -6 hours)
-USA Arizona: -7 hours
-USA Indiana East: -5 hours
-USA Pacific: -8 hours (Local summer -7 hours)
-USA Alaska: -9 hours (Local summer -8 hours)
-USA Aleutian: -10 hours
-USA Hawaii: -10 hours
-Uruguay: -3 hours
-Uzbekistan: +5 hours
-Vanuatu: +11 hours (Local summer +12 hours)
-Vatican City: +1 hours (Local summer +2 hours)
-Venezuela: -4 hours
-Vietnam: +7 hours
-Virgin Islands: -4 hours
-Wake Island: +12 hours
-Wales: 0 hours (Local summer +1 hours)
-Wallis and Futuna Islands: +12 hours
-Windward Islands: -4 hours
-Yemen: +3 hours
-Yugoslavia: +1 hours (Local summer +2 hours)
-Zaire Kasai: +2 hours
-Zaire Kinshasa Mbandaka: +1 hours
-Zaire Haut Zaire: +2 hours
-Zaire Kivu: +2 hours
-Zaire Shaba: +2 hours
-Zambia: +2 hours
-Zimbabwe: +2 hours
-All timezone information is non-authoritative...
diff --git a/usno1998 b/usno1998
deleted file mode 100644
index c3c6991aa61e..000000000000
--- a/usno1998
+++ /dev/null
@@ -1,327 +0,0 @@
-# @(#)usno1998	8.1
-#
-# From Arthur David Olson (1998-05-26):
-#
-# Here's time zone information from the United States Naval Observatory
-# via http://tycho.usno.navy.mil/tzones.html. See USNO's note at the end.
-Unofficial Time Zone Information
-World Time Zones
-For selected countries, the local standard time offset from UTC is given, with  daylight savings time where observed.
-Time:  Mon May 25 21:14:24 UTC 1998
-Afghanistan: +4.5 hours
-Albania: +1 hours (Local summer +2 hours)
-Algeria: +1 hours (Local summer +2 hours)
-American Samoa: -11 hours
-Andorra: +1 hours (Local summer +2 hours)
-Angola: +1 hours
-Anguilla: -4 hours
-Antarctica: -2 hours (Local summer -3 hours)
-Antigua: -4 hours
-Argentina: -3 hours
-Argentina western prov: -4 hours
-Armenia: +4 hours (Local summer +5 hours)
-Aruba: -4 hours
-Ascension: 0 hours
-Australia Northern Territory: +9.5 hours
-Australia Lord Howe Island: +10.5 hours (Local summer +11 hours)
-Australia New South Wales: +10 hours (Local summer +11 hours)
-Australia Queensland: +10 hours
-Australia Victoria: +10 hours (Local summer +11 hours)
-Australia Australian Captial Territory: +10 hours (Local summer +11 hours)
-Australia South: +9.5 hours (Local summer +10.5 hours)
-Australia Tasmania: +10 hours (Local summer +11 hours)
-Australia Western: +8 hours
-Austria: +1 hours (Local summer +2 hours)
-Azerbajian: +3 hours
-Azores: -1 hours (Local summer 0 hours)
-Bahamas: -5 hours (Local summer -4 hours)
-Bahrain: +3 hours
-Balearic Islands: +1 hours (Local summer +2 hours)
-Bangladesh: +6 hours
-Barbados: -4 hours
-Belarus: +2 hours (Local summer +3 hours)
-Belgium: +1 hours (Local summer +2 hours)
-Belize: -6 hours
-Benin: +1 hours
-Bermuda: -4 hours (Local summer -3 hours)
-Bhutan: +6 hours
-Bolivia: -4 hours
-Bonaire: -4 hours
-Bosnia Hercegovina: +1 hours (Local summer +2 hours)
-Botswana: +2 hours
-Brazil Acre: -4 hours (Local summer -5 hours)
-Brazil Atlantic Islands: -1 hours (Local summer -2 hours)
-Brazil East: -3 hours (Local summer -1 hours)
-Brazil West: -4 hours (Local summer -3 hours)
-British Virgin Islands: -4 hours
-Brunei: +8 hours
-Bulgaria: +2 hours (Local summer +3 hours)
-Burkina Faso: 0 hours
-Burundi: +2 hours
-Cambodia: +7 hours
-Cameroon: +1 hours
-Canada Central: -6 hours (Local summer -5 hours)
-Canada Eastern: -5 hours (Local summer -4 hours)
-Canada Mountain: -7 hours (Local summer -6 hours)
-Canada Yukon & Pacific: -8 hours (Local summer -7 hours)
-Canada Atlantic: -4 hours (Local summer -3 hours)
-Canada Newfoundland: -3.5 hours (Local summer -2.5 hours)
-Canary Islands: 0 hours (Local summer +1 hours)
-Canton Enderbury Islands: -11 hours
-Cape Verde: -1 hours
-Caroline Island: +11 hours
-Cayman Islands: -5 hours
-Central African Rep: +1 hours
-Chad: +1 hours
-Channel Islands: 0 hours (Local summer +1 hours)
-Chatham Island: +12.75 hours (Local summer +13.75 hours)
-Chile: -4 hours (Local summer -3 hours)
-China People's Rep: +8 hours
-Christmas Islands: -10 hours
-Cocos (Keeling) Islands: ( hours (Local summer ) hours)
-Colombia: -5 hours
-Congo: +1 hours
-Cook Islands: -10 hours
-Costa Rica: -6 hours
-Cote d'Ivoire: 0 hours
-Croatia: +1 hours (Local summer +2 hours)
-Cuba: -5 hours (Local summer -4 hours)
-Curacao: -4 hours
-Cyprus: +2 hours (Local summer +3 hours)
-Czech Republic: +1 hours (Local summer +2 hours)
-Dahomey: +1 hours
-Denmark: +1 hours (Local summer +2 hours)
-Djibouti: +3 hours
-Dominica: -4 hours
-Dominican Republic: -4 hours
-Easter Island: -6 hours (Local summer -5 hours)
-Ecuador: -5 hours
-Egypt: +2 hours (Local summer +3 hours)
-El Salvador: -6 hours
-England: 0 hours (Local summer +1 hours)
-Equitorial Guinea: +1 hours
-Eritrea: +3 hours
-Estonia: +2 hours (Local summer +3 hours)
-Ethiopia: +3 hours
-Falkland Islands: -4 hours (Local summer -3 hours)
-Faroe Island: 0 hours (Local summer +1 hours)
-Fiji: +12 hours
-Finland: +2 hours (Local summer +3 hours)
-France: +1 hours (Local summer +2 hours)
-French Guiana: -3 hours
-French Polynesia: -10 hours
-Gabon: +1 hours
-Galapagos Islands: -5 hours
-Gambia: 0 hours
-Gambier Island: -9 hours
-Georgia: +4 hours
-Germany: +1 hours (Local summer +2 hours)
-Ghana: 0 hours
-Gibraltar: +1 hours (Local summer +2 hours)
-Greece: +2 hours (Local summer +3 hours)
-Greenland: -3 hours (Local summer -2 hours)
-Greenland Thule: -4 hours (Local summer -3 hours)
-Greenland Scoresbysun: -1 hours (Local summer 0 hours)
-Grenada: -4 hours
-Grenadines: -4 hours
-Guadeloupe: -4 hours
-Guam: +10 hours
-Guatemala: -6 hours
-Guinea: 0 hours
-Guinea Bissau: - hours (Local summer 0 hours)
-Guyana: -3 hours
-Haiti: -5 hours (Local summer -4 hours)
-Honduras: -6 hours
-Hong kong: +8 hours
-Hungary: +1 hours (Local summer +2 hours)
-Iceland: 0 hours
-India: +5.5 hours
-Indonesia Central: +8 hours
-Indonesia East: +9 hours
-Indonesia West: +7 hours
-Iran: +3.5 hours
-Iraq: +3 hours (Local summer +4 hours)
-Ireland Republic of: 0 hours (Local summer +1 hours)
-Israel: +2 hours (Local summer +3 hours)
-Italy: +1 hours (Local summer +2 hours)
-Jamaica: -5 hours
-Japan: +9 hours
-Johnston Island: -10 hours
-Jordan: +2 hours (Local summer +3 hours)
-Kazakhstan: +6 hours (Local summer +7 hours)
-Kenya: +3 hours
-Kiribati: +12 hours
-Korea Dem Republic of: +9 hours
-Korea Republic of: +9 hours
-Kusaie: +12 hours
-Kuwait: +3 hours
-Kwajalein: -12 hours
-Kyrgyzstan: +5 hours (Local summer +6 hours)
-Laos: +7 hours
-Latvia: +2 hours (Local summer +3 hours)
-Lebanon: +2 hours (Local summer +3 hours)
-Leeward Islands: -4 hours
-Lesotho: +2 hours
-Liberia: 0 hours
-Libya: +2 hours
-Lithuania: +2 hours (Local summer +3 hours)
-Luxembourg: +1 hours (Local summer +2 hours)
-Macedonia: +1 hours (Local summer +2 hours)
-Madagascar: +3 hours
-Madeira: 0 hours (Local summer +1 hours)
-Malawi: +2 hours
-Malaysia: +8 hours
-Maldives: +5 hours
-Mali: 0 hours
-Mallorca Islands: +1 hours (Local summer +2 hours)
-Malta: +1 hours (Local summer +2 hours)
-Mariana Island: +10 hours
-Marquesas Islands: -9.5 hours
-Marshall Islands: +12 hours
-Martinique: -4 hours
-Mauritania: 0 hours
-Mauritius: +4 hours
-Mayotte: +3 hours
-Melilla: +1 hours (Local summer +2 hours)
-Mexico: -6 hours
-Mexico Baja Calif Norte: -8 hours (Local summer -7 hours)
-Mexico Nayarit: -7 hours
-Mexico Sinaloa: -7 hours
-Mexico Sonora: -7 hours
-Midway Island: -11 hours
-Moldova: +2 hours (Local summer +3 hours)
-Moldovian Rep Pridnestrovye: +2 hours (Local summer +3 hours)
-Monaco: +1 hours (Local summer +2 hours)
-Mongolia: +8 hours
-Morocco: 0 hours
-Mozambique: +2 hours
-Myanmar: +6.5 hours
-Namibia: +1 hours (Local summer +2 hours)
-Nauru Republic of: +12 hours
-Nepal: +5.75 hours
-Netherlands: +1 hours (Local summer +2 hours)
-Netherlands Antilles: -4 hours
-Nevis Montserrat: -4 hours
-New Caledonia: +11 hours
-New Hebrides: +11 hours
-New Zealand: +12 hours (Local summer +13 hours)
-Nicaragua: -6 hours (Local summer -5 hours)
-Niger: +1 hours
-Nigeria: +1 hours
-Niue Island: -11 hours
-Norfolk Island: +11.5 hours
-Northern Ireland: 0 hours (Local summer +1 hours)
-Northern Mariana Islands: +10 hours
-Norway: +1 hours (Local summer +2 hours)
-Oman: +4 hours
-Pakistan: +5 hours
-Palau: +9 hours
-Panama: -5 hours
-Papua New Guinea: +10 hours
-Paraguay: -4 hours (Local summer -3 hours)
-Peru: -5 hours
-Philippines: +8 hours
-Pingelap: +12 hours
-Poland: +1 hours (Local summer +2 hours)
-Ponape Island: +11 hours
-Portugal: +1 hours (Local summer +2 hours)
-Principe Island: 0 hours
-Puerto Rico: -4 hours
-Qatar: +3 hours
-Reunion: +4 hours
-Romania: +2 hours (Local summer +3 hours)
-Russian Federation zone eight: +9 hours (Local summer +10 hours)
-Russian Federation zone eleven: +12 hours (Local summer +13 hours)
-Russian Federation zone five: +6 hours (Local summer +7 hours)
-Russian Federation zone four: +5 hours (Local summer +6 hours)
-Russian Federation zone nine: +10 hours (Local summer +11 hours)
-Russian Federation zone one: +2 hours (Local summer +3 hours)
-Russian Federation zone seven: +8 hours (Local summer +9 hours)
-Russian Federation zone six: +7 hours (Local summer +8 hours)
-Russian Federation zone ten: +11 hours (Local summer +12 hours)
-Russian Federation zone three: +4 hours (Local summer +5 hours)
-Russian Federation zone two: +4 hours (Local summer +5 hours)
-Rwanda: +2 hours
-Saba: -4 hours
-Samoa: -11 hours
-San Marino: +1 hours (Local summer +2 hours)
-Sao Tome e Principe: 0 hours
-Saudi Arabia: +3 hours
-Scotland: 0 hours (Local summer +1 hours)
-Senegal: 0 hours
-Seychelles: +4 hours
-Sierra Leone: 0 hours
-Singapore: +8 hours
-Slovakia: +1 hours (Local summer +2 hours)
-Slovenia: +1 hours (Local summer +2 hours)
-Society Island: -10 hours
-Solomon Islands: +11 hours
-Somalia: +3 hours
-South Africa: +2 hours
-Spain: +1 hours (Local summer +2 hours)
-Sri Lanka: +5.5 hours
-St Christopher: -4 hours
-St Croix: -4 hours
-St Helena: 0 hours
-St John: -4 hours
-St Kitts Nevis: -4 hours
-St Lucia: -4 hours
-St Maarten: -4 hours
-St Pierre & Miquelon: -3 hours (Local summer -2 hours)
-St Thomas: -4 hours
-St Vincent: -4 hours
-Sudan: +2 hours
-Suriname: -3 hours
-Swaziland: +2 hours
-Sweden: +1 hours (Local summer +2 hours)
-Switzerland: +1 hours (Local summer +2 hours)
-Syria: +2 hours (Local summer +3 hours)
-Tahiti: -10 hours
-Taiwan: +8 hours
-Tajikistan: +6 hours
-Tanzania: +3 hours
-Thailand: +7 hours
-Togo: 0 hours
-Tonga: +13 hours
-Trinidad and Tobago: -4 hours
-Tuamotu Island: -10 hours
-Tubuai Island: -10 hours
-Tunisia: +1 hours
-Turkey: +2 hours (Local summer +3 hours)
-Turkmenistan: +5 hours
-Turks and Caicos Islands: -5 hours (Local summer -4 hours)
-Tuvalu: +12 hours
-Uganda: +3 hours
-Ukraine: +2 hours (Local summer +3 hours)
-United Arab Emirates: +4 hours
-United Kingdom: 0 hours (Local summer +1 hours)
-USA Central: -6 hours (Local summer -5 hours)
-USA Eastern: -5 hours (Local summer -4 hours)
-USA Mountain: -7 hours (Local summer -6 hours)
-USA Arizona: -7 hours
-USA Indiana East: -5 hours
-USA Pacific: -8 hours (Local summer -7 hours)
-USA Alaska: -9 hours (Local summer -8 hours)
-USA Aleutian: -10 hours
-USA Hawaii: -10 hours
-Uruguay: -3 hours
-Uzbekistan: +5 hours
-Vanuatu: +11 hours (Local summer +12 hours)
-Vatican City: +1 hours (Local summer +2 hours)
-Venezuela: -4 hours
-Vietnam: +7 hours
-Virgin Islands: -4 hours
-Wake Island: +12 hours
-Wales: 0 hours (Local summer +1 hours)
-Wallis and Futuna Islands: +12 hours
-Windward Islands: -4 hours
-Yemen: +3 hours
-Yugoslavia: +1 hours (Local summer +2 hours)
-Zaire Kasai: +2 hours
-Zaire Kinshasa Mbandaka: +1 hours
-Zaire Haut Zaire: +2 hours
-Zaire Kivu: +2 hours
-Zaire Shaba: +2 hours
-Zambia: +2 hours
-Zimbabwe: +2 hours
-All timezone information is non-authoritative...
diff --git a/version b/version
new file mode 100644
index 000000000000..9fcedf24a675
--- /dev/null
+++ b/version
@@ -0,0 +1 @@
+2022c
diff --git a/workman.sh b/workman.sh
index 2fbb7e211c6c..6e2da3a80c8d 100644
--- a/workman.sh
+++ b/workman.sh
@@ -1,32 +1,41 @@
 #! /bin/sh
+# Convert manual page troff stdin to formatted .txt stdout.
 
-# -# @(#)workman.sh	8.2
 # This file is in the public domain, so clarified as of
 # 2009-05-17 by Arthur David Olson.
 
-# Tell groff not to emit SGR escape sequences (ANSI color escapes).
-GROFF_NO_SGR=1
-export GROFF_NO_SGR
+if (type nroff && type perl) >/dev/null 2>&1; then
 
-echo ".am TH
+  # Tell groff not to emit SGR escape sequences (ANSI color escapes).
+  GROFF_NO_SGR=1
+  export GROFF_NO_SGR
+
+  echo ".am TH
 .hy 0
 .na
 ..
 .rm }H
 .rm }F" | nroff -man - ${1+"$@"} | perl -ne '
+	binmode STDIN, '\'':encoding(utf8)'\'';
+	binmode STDOUT, '\'':encoding(utf8)'\'';
 	chomp;
 	s/.\010//g;
 	s/\s*$//;
 	if (/^$/) {
 		$sawblank = 1;
 		next;
 	} else {
 		if ($sawblank && $didprint) {
 			print "\n";
 			$sawblank = 0;
 		}
 		print "$_\n";
 		$didprint = 1;
 	}
-'
+  '
+elif (type mandoc && type col) >/dev/null 2>&1; then
+  mandoc -man -T ascii "$@" | col -bx
+else
+  echo >&2 "$0: please install nroff and perl, or mandoc and col"
+  exit 1
+fi
diff --git a/zdump.8 b/zdump.8
index 90940a6bce8b..131a6cbd269c 100644
--- a/zdump.8
+++ b/zdump.8
@@ -1,59 +1,231 @@
 .TH ZDUMP 8
 .SH NAME
-zdump \- time zone dumper
+zdump \- timezone dumper
 .SH SYNOPSIS
 .B zdump
 [
-.B \-\-version
-]
-[
-.B \-v
-] [
-.B \-c
-[loyear,]hiyear ] [ zonename ... ]
+.I option
+\&... ] [
+.I timezone
+\&... ]
 .SH DESCRIPTION
-.I Zdump
-prints the current time in each
-.I zonename
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
+.de q
+\\$3\*(lq\\$1\*(rq\\$2
+..
+.ie \n(.g .ds - \f(CW-\fP
+.el .ds - \-
+The
+.B zdump
+program prints the current time in each
+.I timezone
 named on the command line.
-.PP
-These options are available:
+.SH OPTIONS
 .TP
-.BI "\-\-version"
+.B \*-\*-version
 Output version information and exit.
 .TP
-.B \-v
+.B \*-\*-help
+Output short usage message and exit.
+.TP
+.B \*-i
+Output a description of time intervals.  For each
+.I timezone
+on the command line, output an interval-format description of the
+timezone.  See
+.q "INTERVAL FORMAT"
+below.
+.TP
+.B \*-v
+Output a verbose description of time intervals.
 For each
-.I zonename
+.I timezone
 on the command line,
-print the time at the lowest possible time value,
-the time one day after the lowest possible time value,
+print the times at the two extreme time values,
+the times (if present) at and just beyond the boundaries of years that
+.BR localtime (3)
+and
+.BR gmtime (3)
+can represent, and
 the times both one second before and exactly at
-each detected time discontinuity,
-the time at one day less than the highest possible time value,
-and the time at the highest possible time value,
-Each line ends with
-.B isdst=1
-if the given time is Daylight Saving Time or
-.B isdst=0
-otherwise.
+each detected time discontinuity.
+Each line is followed by
+.BI isdst= D
+where
+.I D
+is positive, zero, or negative depending on whether
+the given time is daylight saving time, standard time,
+or an unknown time type, respectively.
+Each line is also followed by
+.BI gmtoff= N
+if the given local time is known to be
+.I N
+seconds east of Greenwich.
 .TP
-.BI "\-c " [loyear,]hiyear
-Cut off verbose output near the start of the given year(s).
-By default,
-the program cuts off verbose output near the starts of the years -500 and 2500.
-.SH LIMITATIONS
+.B \*-V
+Like
+.BR \*-v ,
+except omit output concerning extreme time and year values.
+This generates output that is easier to compare to that of
+implementations with different time representations.
+.TP
+.BI "\*-c " \fR[\fIloyear , \fR]\fIhiyear
+Cut off interval output at the given year(s).
+Cutoff times are computed using the proleptic Gregorian calendar with year 0
+and with Universal Time (UT) ignoring leap seconds.
+Cutoffs are at the start of each year, where the lower-bound
+timestamp is inclusive and the upper is exclusive; for example,
+.B "\*-c 1970,2070"
+selects transitions on or after 1970-01-01 00:00:00 UTC
+and before 2070-01-01 00:00:00 UTC.
+The default cutoff is
+.BR \*-500,2500 .
+.TP
+.BI "\*-t " \fR[\fIlotime , \fR]\fIhitime
+Cut off interval output at the given time(s),
+given in decimal seconds since 1970-01-01 00:00:00
+Coordinated Universal Time (UTC).
 The
-.B \-v
-option may not be used on systems with floating-point time_t values
-that are neither float nor double.
+.I timezone
+determines whether the count includes leap seconds.
+As with
+.BR \*-c ,
+the cutoff's lower bound is inclusive and its upper bound is exclusive.
+.SH "INTERVAL FORMAT"
+The interval format is a compact text representation that is intended
+to be both human- and machine-readable.  It consists of an empty line,
+then a line
+.q "TZ=\fIstring\fP"
+where
+.I string
+is a double-quoted string giving the timezone, a second line
+.q "\*- \*- \fIinterval\fP"
+describing the time interval before the first transition if any, and
+zero or more following lines
+.q "\fIdate time interval\fP",
+one line for each transition time and following interval.  Fields are
+separated by single tabs.
+.PP
+Dates are in
+.IR yyyy - mm - dd
+format and times are in 24-hour
+.IR hh : mm : ss
+format where
+.IR hh <24.
+Times are in local time immediately after the transition.  A
+time interval description consists of a UT offset in signed
+.RI \(+- hhmmss
+format, a time zone abbreviation, and an isdst flag.  An abbreviation
+that equals the UT offset is omitted; other abbreviations are
+double-quoted strings unless they consist of one or more alphabetic
+characters.  An isdst flag is omitted for standard time, and otherwise
+is a decimal integer that is unsigned and positive (typically 1) for
+daylight saving time and negative for unknown.
+.PP
+In times and in UT offsets with absolute value less than 100 hours,
+the seconds are omitted if they are zero, and
+the minutes are also omitted if they are also zero.  Positive UT
+offsets are east of Greenwich.  The UT offset \*-00 denotes a UT
+placeholder in areas where the actual offset is unspecified; by
+convention, this occurs when the UT offset is zero and the time zone
+abbreviation begins with
+.q "\*-"
+or is
+.q "zzz".
+.PP
+In double-quoted strings, escape sequences represent unusual
+characters.  The escape sequences are \es for space, and \e", \e\e,
+\ef, \en, \er, \et, and \ev with their usual meaning in the C
+programming language.  E.g., the double-quoted string
+\*(lq"CET\es\e"\e\e"\*(rq represents the character sequence \*(lqCET
+"\e\*(rq.\""
 .PP
-Time discontinuities are found by sampling the results returned by localtime
+.ne 9
+Here is an example of the output, with the leading empty line omitted.
+(This example is shown with tab stops set far enough apart so that the
+tabbed columns line up.)
+.nf
+.sp
+.if \n(.g .ft CW
+.if t .in +.5i
+.if n .in +2
+.nr w \w'1896-01-13  'u+\n(.i
+.ta \w'1896-01-13  'u +\w'12:01:26  'u +\w'-103126  'u +\w'HWT  'u
+TZ="Pacific/Honolulu"
+-	-	-103126	LMT
+1896-01-13	12:01:26	-1030	HST
+1933-04-30	03	-0930	HDT	1
+1933-05-21	11	-1030	HST
+1942-02-09	03	-0930	HWT	1
+1945-08-14	13:30	-0930	HPT	1
+1945-09-30	01	-1030	HST
+1947-06-08	02:30	-10	HST
+.in
+.if \n(.g .ft
+.sp
+.fi
+Here, local time begins 10 hours, 31 minutes and 26 seconds west of
+UT, and is a standard time abbreviated LMT.  Immediately after the
+first transition, the date is 1896-01-13 and the time is 12:01:26, and
+the following time interval is 10.5 hours west of UT, a standard time
+abbreviated HST.  Immediately after the second transition, the date is
+1933-04-30 and the time is 03:00:00 and the following time interval is
+9.5 hours west of UT, is abbreviated HDT, and is daylight saving time.
+Immediately after the last transition the date is 1947-06-08 and the
+time is 02:30:00, and the following time interval is 10 hours west of
+UT, a standard time abbreviated HST.
+.PP
+.ne 10
+Here are excerpts from another example:
+.nf
+.sp
+.if \n(.g .ft CW
+.if t .in +.5i
+.if n .in +2
+TZ="Europe/Astrakhan"
+-	-	+031212	LMT
+1924-04-30	23:47:48	+03
+1930-06-21	01	+04
+1981-04-01	01	+05		1
+1981-09-30	23	+04
+\&...
+2014-10-26	01	+03
+2016-03-27	03	+04
+.in
+.if \n(.g .ft
+.sp
+.fi
+This time zone is east of UT, so its UT offsets are positive.  Also,
+many of its time zone abbreviations are omitted since they duplicate
+the text of the UT offset.
+.SH LIMITATIONS
+Time discontinuities are found by sampling the results returned by
+.BR localtime (3)
 at twelve-hour intervals.
 This works in all real-world cases;
 one can construct artificial time zones for which this fails.
-.SH "SEE ALSO"
-newctime(3), tzfile(5), zic(8)
-.\" @(#)zdump.8	8.2
+.PP
+In the
+.B \*-v
+and
+.B \*-V
+output,
+.q "UT"
+denotes the value returned by
+.BR gmtime (3),
+which uses UTC for modern timestamps and some other UT flavor for
+timestamps that predate the introduction of UTC.
+No attempt is currently made to have the output use
+.q "UTC"
+for newer and
+.q "UT"
+for older timestamps, partly because the exact date of the
+introduction of UTC is problematic.
+.SH SEE ALSO
+.BR tzfile (5),
+.BR zic (8)
 .\" This file is in the public domain, so clarified as of
 .\" 2009-05-17 by Arthur David Olson.
diff --git a/zdump.8.txt b/zdump.8.txt
index 78c647f7636b..65b6a287f3f8 100644
--- a/zdump.8.txt
+++ b/zdump.8.txt
@@ -1,43 +1,144 @@
-NAME
+ZDUMP(8)                    System Manager's Manual                   ZDUMP(8)
 
-     zdump - time zone dumper
+NAME
+       zdump - timezone dumper
 
 SYNOPSIS
-     zdump [ --version ] [ -v ] [ -c [loyear,]hiyear ] [ zonename
-     ... ]
+       zdump [ option ... ] [ timezone ... ]
 
 DESCRIPTION
-     Zdump prints the current time in each zonename named on the
-     command line.
+       The zdump program prints the current time in each timezone named on the
+       command line.
+
+OPTIONS
+       --version
+              Output version information and exit.
+
+       --help Output short usage message and exit.
+
+       -i     Output a description of time intervals.  For each timezone on
+              the command line, output an interval-format description of the
+              timezone.  See "INTERVAL FORMAT" below.
+
+       -v     Output a verbose description of time intervals.  For each
+              timezone on the command line, print the times at the two extreme
+              time values, the times (if present) at and just beyond the
+              boundaries of years that localtime(3) and gmtime(3) can
+              represent, and the times both one second before and exactly at
+              each detected time discontinuity.  Each line is followed by
+              isdst=D where D is positive, zero, or negative depending on
+              whether the given time is daylight saving time, standard time,
+              or an unknown time type, respectively.  Each line is also
+              followed by gmtoff=N if the given local time is known to be N
+              seconds east of Greenwich.
+
+       -V     Like -v, except omit output concerning extreme time and year
+              values.  This generates output that is easier to compare to that
+              of implementations with different time representations.
+
+       -c [loyear,]hiyear
+              Cut off interval output at the given year(s).  Cutoff times are
+              computed using the proleptic Gregorian calendar with year 0 and
+              with Universal Time (UT) ignoring leap seconds.  Cutoffs are at
+              the start of each year, where the lower-bound timestamp is
+              inclusive and the upper is exclusive; for example, -c 1970,2070
+              selects transitions on or after 1970-01-01 00:00:00 UTC and
+              before 2070-01-01 00:00:00 UTC.  The default cutoff is
+              -500,2500.
 
-     These options are available:
+       -t [lotime,]hitime
+              Cut off interval output at the given time(s), given in decimal
+              seconds since 1970-01-01 00:00:00 Coordinated Universal Time
+              (UTC).  The timezone determines whether the count includes leap
+              seconds.  As with -c, the cutoff's lower bound is inclusive and
+              its upper bound is exclusive.
 
-     --version
-          Output version information and exit.
+INTERVAL FORMAT
+       The interval format is a compact text representation that is intended
+       to be both human- and machine-readable.  It consists of an empty line,
+       then a line "TZ=string" where string is a double-quoted string giving
+       the timezone, a second line "- - interval" describing the time interval
+       before the first transition if any, and zero or more following lines
+       "date time interval", one line for each transition time and following
+       interval.  Fields are separated by single tabs.
 
-     -v   For each zonename on the command line, print the time
-          at the lowest possible time value, the time one day
-          after the lowest possible time value, the times both
-          one second before and exactly at each detected time
-          discontinuity, the time at one day less than the
-          highest possible time value, and the time at the
-          highest possible time value, Each line ends with
-          isdst=1 if the given time is Daylight Saving Time or
-          isdst=0 otherwise.
+       Dates are in yyyy-mm-dd format and times are in 24-hour hh:mm:ss format
+       where hh<24.  Times are in local time immediately after the transition.
+       A time interval description consists of a UT offset in signed +-hhmmss
+       format, a time zone abbreviation, and an isdst flag.  An abbreviation
+       that equals the UT offset is omitted; other abbreviations are double-
+       quoted strings unless they consist of one or more alphabetic
+       characters.  An isdst flag is omitted for standard time, and otherwise
+       is a decimal integer that is unsigned and positive (typically 1) for
+       daylight saving time and negative for unknown.
 
-     -c [loyear,]hiyear
-          Cut off verbose output near the start of the given
-          year(s).  By default, the program cuts off verbose
-          output near the starts of the years -500 and 2500.
+       In times and in UT offsets with absolute value less than 100 hours, the
+       seconds are omitted if they are zero, and the minutes are also omitted
+       if they are also zero.  Positive UT offsets are east of Greenwich.  The
+       UT offset -00 denotes a UT placeholder in areas where the actual offset
+       is unspecified; by convention, this occurs when the UT offset is zero
+       and the time zone abbreviation begins with "-" or is "zzz".
+
+       In double-quoted strings, escape sequences represent unusual
+       characters.  The escape sequences are \s for space, and \", \\, \f, \n,
+       \r, \t, and \v with their usual meaning in the C programming language.
+       E.g., the double-quoted string ""CET\s\"\\"" represents the character
+       sequence "CET "\".
+
+       Here is an example of the output, with the leading empty line omitted.
+       (This example is shown with tab stops set far enough apart so that the
+       tabbed columns line up.)
+
+         TZ="Pacific/Honolulu"
+         -           -         -103126  LMT
+         1896-01-13  12:01:26  -1030    HST
+         1933-04-30  03        -0930    HDT  1
+         1933-05-21  11        -1030    HST
+         1942-02-09  03        -0930    HWT  1
+         1945-08-14  13:30     -0930    HPT  1
+         1945-09-30  01        -1030    HST
+         1947-06-08  02:30     -10      HST
+
+       Here, local time begins 10 hours, 31 minutes and 26 seconds west of UT,
+       and is a standard time abbreviated LMT.  Immediately after the first
+       transition, the date is 1896-01-13 and the time is 12:01:26, and the
+       following time interval is 10.5 hours west of UT, a standard time
+       abbreviated HST.  Immediately after the second transition, the date is
+       1933-04-30 and the time is 03:00:00 and the following time interval is
+       9.5 hours west of UT, is abbreviated HDT, and is daylight saving time.
+       Immediately after the last transition the date is 1947-06-08 and the
+       time is 02:30:00, and the following time interval is 10 hours west of
+       UT, a standard time abbreviated HST.
+
+       Here are excerpts from another example:
+
+         TZ="Europe/Astrakhan"
+         -           -         +031212  LMT
+         1924-04-30  23:47:48  +03
+         1930-06-21  01        +04
+         1981-04-01  01        +05           1
+         1981-09-30  23        +04
+         ...
+         2014-10-26  01        +03
+         2016-03-27  03        +04
+
+       This time zone is east of UT, so its UT offsets are positive.  Also,
+       many of its time zone abbreviations are omitted since they duplicate
+       the text of the UT offset.
 
 LIMITATIONS
-     The -v option may not be used on systems with floating-point
-     time_t values that are neither float nor double.
+       Time discontinuities are found by sampling the results returned by
+       localtime(3) at twelve-hour intervals.  This works in all real-world
+       cases; one can construct artificial time zones for which this fails.
 
-     Time discontinuities are found by sampling the results
-     returned by localtime at twelve-hour intervals.  This works
-     in all real-world cases; one can construct artificial time
-     zones for which this fails.
+       In the -v and -V output, "UT" denotes the value returned by gmtime(3),
+       which uses UTC for modern timestamps and some other UT flavor for
+       timestamps that predate the introduction of UTC.  No attempt is
+       currently made to have the output use "UTC" for newer and "UT" for
+       older timestamps, partly because the exact date of the introduction of
+       UTC is problematic.
 
 SEE ALSO
-     newctime(3), tzfile(5), zic(8)
+       tzfile(5), zic(8)
+
+                                                                      ZDUMP(8)
diff --git a/zdump.c b/zdump.c
index 67bed06bc398..a63a3438f571 100644
--- a/zdump.c
+++ b/zdump.c
@@ -1,680 +1,1226 @@
+/* Dump time zone data in a textual format.  */
+
 /*
 ** This file is in the public domain, so clarified as of
 ** 2009-05-17 by Arthur David Olson.
 */
 
-static char	elsieid[] = "@(#)zdump.c	8.10";
+#include "version.h"
 
-/*
-** This code has been made independent of the rest of the time
-** conversion package to increase confidence in the verification it provides.
-** You can use this code to help in verifying other implementations.
-*/
+#ifndef NETBSD_INSPIRED
+# define NETBSD_INSPIRED 1
+#endif
 
-#include "stdio.h"	/* for stdout, stderr, perror */
-#include "string.h"	/* for strcpy */
-#include "sys/types.h"	/* for time_t */
-#include "time.h"	/* for struct tm */
-#include "stdlib.h"	/* for exit, malloc, atoi */
-#include "float.h"	/* for FLT_MAX and DBL_MAX */
-#include "ctype.h"	/* for isalpha et al. */
-#ifndef isascii
-#define isascii(x) 1
-#endif /* !defined isascii */
+#include "private.h"
+#include 
+
+#ifndef HAVE_SNPRINTF
+# define HAVE_SNPRINTF (199901 <= __STDC_VERSION__)
+#endif
+
+#ifndef HAVE_LOCALTIME_R
+# define HAVE_LOCALTIME_R 1
+#endif
+
+#ifndef HAVE_LOCALTIME_RZ
+# ifdef TM_ZONE
+#  define HAVE_LOCALTIME_RZ (NETBSD_INSPIRED && USE_LTZ)
+# else
+#  define HAVE_LOCALTIME_RZ 0
+# endif
+#endif
+
+#ifndef HAVE_TZSET
+# define HAVE_TZSET 1
+#endif
 
 #ifndef ZDUMP_LO_YEAR
-#define ZDUMP_LO_YEAR	(-500)
+# define ZDUMP_LO_YEAR (-500)
 #endif /* !defined ZDUMP_LO_YEAR */
 
 #ifndef ZDUMP_HI_YEAR
-#define ZDUMP_HI_YEAR	2500
+# define ZDUMP_HI_YEAR 2500
 #endif /* !defined ZDUMP_HI_YEAR */
 
-#ifndef MAX_STRING_LENGTH
-#define MAX_STRING_LENGTH	1024
-#endif /* !defined MAX_STRING_LENGTH */
+#define SECSPERNYEAR	(SECSPERDAY * DAYSPERNYEAR)
+#define SECSPERLYEAR	(SECSPERNYEAR + SECSPERDAY)
+#define SECSPER400YEARS	(SECSPERNYEAR * (intmax_t) (300 + 3)	\
+			 + SECSPERLYEAR * (intmax_t) (100 - 3))
 
-#ifndef TRUE
-#define TRUE		1
-#endif /* !defined TRUE */
+/*
+** True if SECSPER400YEARS is known to be representable as an
+** intmax_t.  It's OK that SECSPER400YEARS_FITS can in theory be false
+** even if SECSPER400YEARS is representable, because when that happens
+** the code merely runs a bit more slowly, and this slowness doesn't
+** occur on any practical platform.
+*/
+enum { SECSPER400YEARS_FITS = SECSPERLYEAR <= INTMAX_MAX / 400 };
 
-#ifndef FALSE
-#define FALSE		0
-#endif /* !defined FALSE */
+#if !defined HAVE_GENERIC && defined __has_extension
+# if __has_extension(c_generic_selections)
+#  define HAVE_GENERIC 1
+# else
+#  define HAVE_GENERIC 0
+# endif
+#endif
+/* _Generic is buggy in pre-4.9 GCC.  */
+#if !defined HAVE_GENERIC && defined __GNUC__
+# define HAVE_GENERIC (4 < __GNUC__ + (9 <= __GNUC_MINOR__))
+#endif
+#ifndef HAVE_GENERIC
+# define HAVE_GENERIC (201112 <= __STDC_VERSION__)
+#endif
 
-#ifndef EXIT_SUCCESS
-#define EXIT_SUCCESS	0
-#endif /* !defined EXIT_SUCCESS */
+#if HAVE_GETTEXT
+# include  /* for setlocale */
+#endif /* HAVE_GETTEXT */
 
-#ifndef EXIT_FAILURE
-#define EXIT_FAILURE	1
-#endif /* !defined EXIT_FAILURE */
+#if ! HAVE_LOCALTIME_RZ
+# undef  timezone_t
+# define timezone_t char **
+#endif
 
-#ifndef SECSPERMIN
-#define SECSPERMIN	60
-#endif /* !defined SECSPERMIN */
+#if !HAVE_POSIX_DECLS
+extern int	getopt(int argc, char * const argv[],
+			const char * options);
+extern char *	optarg;
+extern int	optind;
+#endif
+
+/* The minimum and maximum finite time values.  */
+enum { atime_shift = CHAR_BIT * sizeof(time_t) - 2 };
+static time_t const absolute_min_time =
+  ((time_t) -1 < 0
+   ? (- ((time_t) ~ (time_t) 0 < 0)
+      - (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift)))
+   : 0);
+static time_t const absolute_max_time =
+  ((time_t) -1 < 0
+   ? (((time_t) 1 << atime_shift) - 1 + ((time_t) 1 << atime_shift))
+   : -1);
+static int	longest;
+static char *	progname;
+static bool	warned;
+static bool	errout;
 
-#ifndef MINSPERHOUR
-#define MINSPERHOUR	60
-#endif /* !defined MINSPERHOUR */
+static char const *abbr(struct tm const *);
+static intmax_t	delta(struct tm *, struct tm *) ATTRIBUTE_PURE;
+static void dumptime(struct tm const *);
+static time_t hunt(timezone_t, char *, time_t, time_t, bool);
+static void show(timezone_t, char *, time_t, bool);
+static void showextrema(timezone_t, char *, time_t, struct tm *, time_t);
+static void showtrans(char const *, struct tm const *, time_t, char const *,
+		      char const *);
+static const char *tformat(void);
+static time_t yeartot(intmax_t) ATTRIBUTE_PURE;
 
-#ifndef SECSPERHOUR
-#define SECSPERHOUR	(SECSPERMIN * MINSPERHOUR)
-#endif /* !defined SECSPERHOUR */
+/* Is C an ASCII digit?  */
+static bool
+is_digit(char c)
+{
+  return '0' <= c && c <= '9';
+}
 
-#ifndef HOURSPERDAY
-#define HOURSPERDAY	24
-#endif /* !defined HOURSPERDAY */
+/* Is A an alphabetic character in the C locale?  */
+static bool
+is_alpha(char a)
+{
+	switch (a) {
+	  default:
+		return false;
+	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
+	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
+	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
+	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
+	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
+	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
+	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
+	  case 'v': case 'w': case 'x': case 'y': case 'z':
+		return true;
+	}
+}
 
-#ifndef EPOCH_YEAR
-#define EPOCH_YEAR	1970
-#endif /* !defined EPOCH_YEAR */
+/* Return A + B, exiting if the result would overflow.  */
+static size_t
+sumsize(size_t a, size_t b)
+{
+  size_t sum = a + b;
+  if (sum < a) {
+    fprintf(stderr, _("%s: size overflow\n"), progname);
+    exit(EXIT_FAILURE);
+  }
+  return sum;
+}
 
-#ifndef TM_YEAR_BASE
-#define TM_YEAR_BASE	1900
-#endif /* !defined TM_YEAR_BASE */
+/* Return a pointer to a newly allocated buffer of size SIZE, exiting
+   on failure.  SIZE should be nonzero.  */
+static void * ATTRIBUTE_MALLOC
+xmalloc(size_t size)
+{
+  void *p = malloc(size);
+  if (!p) {
+    fprintf(stderr, _("%s: Memory exhausted\n"), progname);
+    exit(EXIT_FAILURE);
+  }
+  return p;
+}
 
-#ifndef DAYSPERNYEAR
-#define DAYSPERNYEAR	365
-#endif /* !defined DAYSPERNYEAR */
+#if ! HAVE_TZSET
+# undef tzset
+# define tzset zdump_tzset
+static void tzset(void) { }
+#endif
 
-#ifndef isleap
-#define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0))
-#endif /* !defined isleap */
+/* Assume gmtime_r works if localtime_r does.
+   A replacement localtime_r is defined below if needed.  */
+#if ! HAVE_LOCALTIME_R
 
-#ifndef isleap_sum
-/*
-** See tzfile.h for details on isleap_sum.
-*/
-#define isleap_sum(a, b)	isleap((a) % 400 + (b) % 400)
-#endif /* !defined isleap_sum */
+# undef gmtime_r
+# define gmtime_r zdump_gmtime_r
 
-#define SECSPERDAY	((long) SECSPERHOUR * HOURSPERDAY)
-#define SECSPERNYEAR	(SECSPERDAY * DAYSPERNYEAR)
-#define SECSPERLYEAR	(SECSPERNYEAR + SECSPERDAY)
+static struct tm *
+gmtime_r(time_t *tp, struct tm *tmp)
+{
+  struct tm *r = gmtime(tp);
+  if (r) {
+    *tmp = *r;
+    r = tmp;
+  }
+  return r;
+}
 
-#ifndef HAVE_GETTEXT
-#define HAVE_GETTEXT 0
 #endif
-#if HAVE_GETTEXT
-#include "locale.h"	/* for setlocale */
-#include "libintl.h"
-#endif /* HAVE_GETTEXT */
 
-#ifndef GNUC_or_lint
-#ifdef lint
-#define GNUC_or_lint
-#else /* !defined lint */
-#ifdef __GNUC__
-#define GNUC_or_lint
-#endif /* defined __GNUC__ */
-#endif /* !defined lint */
-#endif /* !defined GNUC_or_lint */
-
-#ifndef INITIALIZE
-#ifdef GNUC_or_lint
-#define INITIALIZE(x)	((x) = 0)
-#else /* !defined GNUC_or_lint */
-#define INITIALIZE(x)
-#endif /* !defined GNUC_or_lint */
-#endif /* !defined INITIALIZE */
+/* Platforms with TM_ZONE don't need tzname, so they can use the
+   faster localtime_rz or localtime_r if available.  */
 
-/*
-** For the benefit of GNU folk...
-** `_(MSGID)' uses the current locale's message library string for MSGID.
-** The default is to use gettext if available, and use MSGID otherwise.
-*/
+#if defined TM_ZONE && HAVE_LOCALTIME_RZ
+# define USE_LOCALTIME_RZ true
+#else
+# define USE_LOCALTIME_RZ false
+#endif
 
-#ifndef _
-#if HAVE_GETTEXT
-#define _(msgid) gettext(msgid)
-#else /* !HAVE_GETTEXT */
-#define _(msgid) msgid
-#endif /* !HAVE_GETTEXT */
-#endif /* !defined _ */
+#if ! USE_LOCALTIME_RZ
 
-#ifndef TZ_DOMAIN
-#define TZ_DOMAIN "tz"
-#endif /* !defined TZ_DOMAIN */
+# if !defined TM_ZONE || ! HAVE_LOCALTIME_R || ! HAVE_TZSET
+#  undef localtime_r
+#  define localtime_r zdump_localtime_r
+static struct tm *
+localtime_r(time_t *tp, struct tm *tmp)
+{
+  struct tm *r = localtime(tp);
+  if (r) {
+    *tmp = *r;
+    r = tmp;
+  }
+  return r;
+}
+# endif
 
-extern char **	environ;
-extern int	getopt(int argc, char * const argv[],
-			const char * options);
-extern char *	optarg;
-extern int	optind;
-extern char *	tzname[2];
+# undef localtime_rz
+# define localtime_rz zdump_localtime_rz
+static struct tm *
+localtime_rz(timezone_t rz, time_t *tp, struct tm *tmp)
+{
+  return localtime_r(tp, tmp);
+}
 
-static time_t	absolute_min_time;
-static time_t	absolute_max_time;
-static size_t	longest;
-static char *	progname;
-static int	warned;
-
-static char *	abbr(struct tm * tmp);
-static void	abbrok(const char * abbrp, const char * zone);
-static long	delta(struct tm * newp, struct tm * oldp);
-static void	dumptime(const struct tm * tmp);
-static time_t	hunt(char * name, time_t lot, time_t	hit);
-static void	setabsolutes(void);
-static void	show(char * zone, time_t t, int v);
-static const char *	tformat(void);
-static time_t	yeartot(long y);
+# ifdef TYPECHECK
+#  undef mktime_z
+#  define mktime_z zdump_mktime_z
+static time_t
+mktime_z(timezone_t tz, struct tm *tmp)
+{
+  return mktime(tmp);
+}
+# endif
+
+# undef tzalloc
+# undef tzfree
+# define tzalloc zdump_tzalloc
+# define tzfree zdump_tzfree
+
+static timezone_t
+tzalloc(char const *val)
+{
+  static char **fakeenv;
+  char **env = fakeenv;
+  char *env0;
+  if (! env) {
+    char **e = environ;
+    int to;
+
+    while (*e++)
+      continue;
+    env = xmalloc(sumsize(sizeof *environ,
+			  (e - environ) * sizeof *environ));
+    to = 1;
+    for (e = environ; (env[to] = *e); e++)
+      to += strncmp(*e, "TZ=", 3) != 0;
+  }
+  env0 = xmalloc(sumsize(sizeof "TZ=", strlen(val)));
+  env[0] = strcat(strcpy(env0, "TZ="), val);
+  environ = fakeenv = env;
+  tzset();
+  return env;
+}
+
+static void
+tzfree(timezone_t env)
+{
+  environ = env + 1;
+  free(env[0]);
+}
+#endif /* ! USE_LOCALTIME_RZ */
+
+/* A UT time zone, and its initializer.  */
+static timezone_t gmtz;
+static void
+gmtzinit(void)
+{
+  if (USE_LOCALTIME_RZ) {
+    /* Try "GMT" first to find out whether this is one of the rare
+       platforms where time_t counts leap seconds; this works due to
+       the "Link Etc/GMT GMT" line in the "etcetera" file.  If "GMT"
+       fails, fall back on "GMT0" which might be similar due to the
+       "Link Etc/GMT GMT0" line in the "backward" file, and which
+       should work on all POSIX platforms.  The rest of zdump does not
+       use the "GMT" abbreviation that comes from this setting, so it
+       is OK to use "GMT" here rather than the more-modern "UTC" which
+       would not work on platforms that omit the "backward" file.  */
+    gmtz = tzalloc("GMT");
+    if (!gmtz) {
+      static char const gmt0[] = "GMT0";
+      gmtz = tzalloc(gmt0);
+      if (!gmtz) {
+	perror(gmt0);
+	exit(EXIT_FAILURE);
+      }
+    }
+  }
+}
+
+/* Convert *TP to UT, storing the broken-down time into *TMP.
+   Return TMP if successful, NULL otherwise.  This is like gmtime_r(TP, TMP),
+   except typically faster if USE_LOCALTIME_RZ.  */
+static struct tm *
+my_gmtime_r(time_t *tp, struct tm *tmp)
+{
+  return USE_LOCALTIME_RZ ? localtime_rz(gmtz, tp, tmp) : gmtime_r(tp, tmp);
+}
 
 #ifndef TYPECHECK
-#define my_localtime	localtime
+# define my_localtime_rz localtime_rz
 #else /* !defined TYPECHECK */
+
 static struct tm *
-my_localtime(tp)
-time_t *	tp;
+my_localtime_rz(timezone_t tz, time_t *tp, struct tm *tmp)
 {
-	register struct tm *	tmp;
-
-	tmp = localtime(tp);
-	if (tp != NULL && tmp != NULL) {
+	tmp = localtime_rz(tz, tp, tmp);
+	if (tmp) {
 		struct tm	tm;
 		register time_t	t;
 
 		tm = *tmp;
-		t = mktime(&tm);
-		if (t - *tp >= 1 || *tp - t >= 1) {
-			(void) fflush(stdout);
-			(void) fprintf(stderr, "\n%s: ", progname);
-			(void) fprintf(stderr, tformat(), *tp);
-			(void) fprintf(stderr, " ->");
-			(void) fprintf(stderr, " year=%d", tmp->tm_year);
-			(void) fprintf(stderr, " mon=%d", tmp->tm_mon);
-			(void) fprintf(stderr, " mday=%d", tmp->tm_mday);
-			(void) fprintf(stderr, " hour=%d", tmp->tm_hour);
-			(void) fprintf(stderr, " min=%d", tmp->tm_min);
-			(void) fprintf(stderr, " sec=%d", tmp->tm_sec);
-			(void) fprintf(stderr, " isdst=%d", tmp->tm_isdst);
-			(void) fprintf(stderr, " -> ");
-			(void) fprintf(stderr, tformat(), t);
-			(void) fprintf(stderr, "\n");
+		t = mktime_z(tz, &tm);
+		if (t != *tp) {
+			fflush(stdout);
+			fprintf(stderr, "\n%s: ", progname);
+			fprintf(stderr, tformat(), *tp);
+			fprintf(stderr, " ->");
+			fprintf(stderr, " year=%d", tmp->tm_year);
+			fprintf(stderr, " mon=%d", tmp->tm_mon);
+			fprintf(stderr, " mday=%d", tmp->tm_mday);
+			fprintf(stderr, " hour=%d", tmp->tm_hour);
+			fprintf(stderr, " min=%d", tmp->tm_min);
+			fprintf(stderr, " sec=%d", tmp->tm_sec);
+			fprintf(stderr, " isdst=%d", tmp->tm_isdst);
+			fprintf(stderr, " -> ");
+			fprintf(stderr, tformat(), t);
+			fprintf(stderr, "\n");
+			errout = true;
 		}
 	}
 	return tmp;
 }
 #endif /* !defined TYPECHECK */
 
 static void
-abbrok(abbrp, zone)
-const char * const	abbrp;
-const char * const	zone;
+abbrok(const char *const abbrp, const char *const zone)
 {
 	register const char *	cp;
-	register char *		wp;
+	register const char *	wp;
 
 	if (warned)
 		return;
 	cp = abbrp;
-	wp = NULL;
-	while (isascii((unsigned char) *cp) && isalpha((unsigned char) *cp))
+	while (is_alpha(*cp) || is_digit(*cp) || *cp == '-' || *cp == '+')
 		++cp;
-	if (cp - abbrp == 0)
-		wp = _("lacks alphabetic at start");
+	if (*cp)
+	  wp = _("has characters other than ASCII alphanumerics, '-' or '+'");
 	else if (cp - abbrp < 3)
-		wp = _("has fewer than 3 alphabetics");
+	  wp = _("has fewer than 3 characters");
 	else if (cp - abbrp > 6)
-		wp = _("has more than 6 alphabetics");
-	if (wp == NULL && (*cp == '+' || *cp == '-')) {
-		++cp;
-		if (isascii((unsigned char) *cp) &&
-			isdigit((unsigned char) *cp))
-				if (*cp++ == '1' && *cp >= '0' && *cp <= '4')
-					++cp;
-		if (*cp != '\0')
-			wp = _("differs from POSIX standard");
-	}
-	if (wp == NULL)
-		return;
-	(void) fflush(stdout);
-	(void) fprintf(stderr,
+	  wp = _("has more than 6 characters");
+	else
+	  return;
+	fflush(stdout);
+	fprintf(stderr,
 		_("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"),
 		progname, zone, abbrp, wp);
-	warned = TRUE;
+	warned = errout = true;
+}
+
+/* Return a time zone abbreviation.  If the abbreviation needs to be
+   saved, use *BUF (of size *BUFALLOC) to save it, and return the
+   abbreviation in the possibly-reallocated *BUF.  Otherwise, just
+   return the abbreviation.  Get the abbreviation from TMP.
+   Exit on memory allocation failure.  */
+static char const *
+saveabbr(char **buf, size_t *bufalloc, struct tm const *tmp)
+{
+  char const *ab = abbr(tmp);
+  if (HAVE_LOCALTIME_RZ)
+    return ab;
+  else {
+    size_t ablen = strlen(ab);
+    if (*bufalloc <= ablen) {
+      free(*buf);
+
+      /* Make the new buffer at least twice as long as the old,
+	 to avoid O(N**2) behavior on repeated calls.  */
+      *bufalloc = sumsize(*bufalloc, ablen + 1);
+
+      *buf = xmalloc(*bufalloc);
+    }
+    return strcpy(*buf, ab);
+  }
+}
+
+static void
+close_file(FILE *stream)
+{
+  char const *e = (ferror(stream) ? _("I/O error")
+		   : fclose(stream) != 0 ? strerror(errno) : NULL);
+  if (e) {
+    fprintf(stderr, "%s: %s\n", progname, e);
+    exit(EXIT_FAILURE);
+  }
 }
 
 static void
-usage(stream, status)
-FILE * const	stream;
-const int	status;
-{
-	(void) fprintf(stream,
-_("%s: usage is %s [ --version ] [ --help ] [ -v ] [ -c [loyear,]hiyear ] zonename ...\n\
-\n\
-Report bugs to tz@elsie.nci.nih.gov.\n"),
-		       progname, progname);
+usage(FILE * const stream, const int status)
+{
+	fprintf(stream,
+_("%s: usage: %s OPTIONS TIMEZONE ...\n"
+  "Options include:\n"
+  "  -c [L,]U   Start at year L (default -500), end before year U (default 2500)\n"
+  "  -t [L,]U   Start at time L, end before time U (in seconds since 1970)\n"
+  "  -i         List transitions briefly (format is experimental)\n" \
+  "  -v         List transitions verbosely\n"
+  "  -V         List transitions a bit less verbosely\n"
+  "  --help     Output this help\n"
+  "  --version  Output version info\n"
+  "\n"
+  "Report bugs to %s.\n"),
+		progname, progname, REPORT_BUGS_TO);
+	if (status == EXIT_SUCCESS)
+	  close_file(stream);
 	exit(status);
 }
 
 int
-main(argc, argv)
-int	argc;
-char *	argv[];
+main(int argc, char *argv[])
 {
+	/* These are static so that they're initially zero.  */
+	static char *		abbrev;
+	static size_t		abbrevsize;
+
 	register int		i;
-	register int		c;
-	register int		vflag;
+	register bool		vflag;
+	register bool		Vflag;
 	register char *		cutarg;
-	register long		cutloyear = ZDUMP_LO_YEAR;
-	register long		cuthiyear = ZDUMP_HI_YEAR;
+	register char *		cuttimes;
 	register time_t		cutlotime;
 	register time_t		cuthitime;
-	register char **	fakeenv;
 	time_t			now;
-	time_t			t;
-	time_t			newt;
-	struct tm		tm;
-	struct tm		newtm;
-	register struct tm *	tmp;
-	register struct tm *	newtmp;
+	bool iflag = false;
 
-	INITIALIZE(cutlotime);
-	INITIALIZE(cuthitime);
+	cutlotime = absolute_min_time;
+	cuthitime = absolute_max_time;
 #if HAVE_GETTEXT
-	(void) setlocale(LC_ALL, "");
-#ifdef TZ_DOMAINDIR
-	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
-#endif /* defined TEXTDOMAINDIR */
-	(void) textdomain(TZ_DOMAIN);
+	setlocale(LC_ALL, "");
+# ifdef TZ_DOMAINDIR
+	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
+# endif /* defined TEXTDOMAINDIR */
+	textdomain(TZ_DOMAIN);
 #endif /* HAVE_GETTEXT */
 	progname = argv[0];
 	for (i = 1; i < argc; ++i)
 		if (strcmp(argv[i], "--version") == 0) {
-			(void) printf("%s\n", elsieid);
-			exit(EXIT_SUCCESS);
+			printf("zdump %s%s\n", PKGVERSION, TZVERSION);
+			return EXIT_SUCCESS;
 		} else if (strcmp(argv[i], "--help") == 0) {
 			usage(stdout, EXIT_SUCCESS);
 		}
-	vflag = 0;
-	cutarg = NULL;
-	while ((c = getopt(argc, argv, "c:v")) == 'c' || c == 'v')
-		if (c == 'v')
-			vflag = 1;
-		else	cutarg = optarg;
-	if ((c != EOF && c != -1) ||
-		(optind == argc - 1 && strcmp(argv[optind], "=") == 0)) {
-			usage(stderr, EXIT_FAILURE);
-	}
-	if (vflag) {
-		if (cutarg != NULL) {
-			long	lo;
-			long	hi;
-			char	dummy;
+	vflag = Vflag = false;
+	cutarg = cuttimes = NULL;
+	for (;;)
+	  switch (getopt(argc, argv, "c:it:vV")) {
+	  case 'c': cutarg = optarg; break;
+	  case 't': cuttimes = optarg; break;
+	  case 'i': iflag = true; break;
+	  case 'v': vflag = true; break;
+	  case 'V': Vflag = true; break;
+	  case -1:
+	    if (! (optind == argc - 1 && strcmp(argv[optind], "=") == 0))
+	      goto arg_processing_done;
+	    /* Fall through.  */
+	  default:
+	    usage(stderr, EXIT_FAILURE);
+	  }
+ arg_processing_done:;
 
-			if (sscanf(cutarg, "%ld%c", &hi, &dummy) == 1) {
+	if (iflag | vflag | Vflag) {
+		intmax_t	lo;
+		intmax_t	hi;
+		char *loend, *hiend;
+		register intmax_t cutloyear = ZDUMP_LO_YEAR;
+		register intmax_t cuthiyear = ZDUMP_HI_YEAR;
+		if (cutarg != NULL) {
+			lo = strtoimax(cutarg, &loend, 10);
+			if (cutarg != loend && !*loend) {
+				hi = lo;
+				cuthiyear = hi;
+			} else if (cutarg != loend && *loend == ','
+				   && (hi = strtoimax(loend + 1, &hiend, 10),
+				       loend + 1 != hiend && !*hiend)) {
+				cutloyear = lo;
 				cuthiyear = hi;
-			} else if (sscanf(cutarg, "%ld,%ld%c",
-				&lo, &hi, &dummy) == 2) {
-					cutloyear = lo;
-					cuthiyear = hi;
 			} else {
-(void) fprintf(stderr, _("%s: wild -c argument %s\n"),
+				fprintf(stderr, _("%s: wild -c argument %s\n"),
 					progname, cutarg);
-				exit(EXIT_FAILURE);
+				return EXIT_FAILURE;
+			}
+		}
+		if (cutarg != NULL || cuttimes == NULL) {
+			cutlotime = yeartot(cutloyear);
+			cuthitime = yeartot(cuthiyear);
+		}
+		if (cuttimes != NULL) {
+			lo = strtoimax(cuttimes, &loend, 10);
+			if (cuttimes != loend && !*loend) {
+				hi = lo;
+				if (hi < cuthitime) {
+					if (hi < absolute_min_time + 1)
+					  hi = absolute_min_time + 1;
+					cuthitime = hi;
+				}
+			} else if (cuttimes != loend && *loend == ','
+				   && (hi = strtoimax(loend + 1, &hiend, 10),
+				       loend + 1 != hiend && !*hiend)) {
+				if (cutlotime < lo) {
+					if (absolute_max_time < lo)
+						lo = absolute_max_time;
+					cutlotime = lo;
+				}
+				if (hi < cuthitime) {
+					if (hi < absolute_min_time + 1)
+					  hi = absolute_min_time + 1;
+					cuthitime = hi;
+				}
+			} else {
+				fprintf(stderr,
+					_("%s: wild -t argument %s\n"),
+					progname, cuttimes);
+				return EXIT_FAILURE;
 			}
 		}
-		setabsolutes();
-		cutlotime = yeartot(cutloyear);
-		cuthitime = yeartot(cuthiyear);
 	}
-	(void) time(&now);
+	gmtzinit();
+	if (iflag | vflag | Vflag)
+	  now = 0;
+	else {
+	  now = time(NULL);
+	  now |= !now;
+	}
 	longest = 0;
-	for (i = optind; i < argc; ++i)
-		if (strlen(argv[i]) > longest)
-			longest = strlen(argv[i]);
-	{
-		register int	from;
-		register int	to;
-
-		for (i = 0; environ[i] != NULL; ++i)
-			continue;
-		fakeenv = (char **) malloc((size_t) ((i + 2) *
-			sizeof *fakeenv));
-		if (fakeenv == NULL ||
-			(fakeenv[0] = (char *) malloc(longest + 4)) == NULL) {
-					(void) perror(progname);
-					exit(EXIT_FAILURE);
-		}
-		to = 0;
-		(void) strcpy(fakeenv[to++], "TZ=");
-		for (from = 0; environ[from] != NULL; ++from)
-			if (strncmp(environ[from], "TZ=", 3) != 0)
-				fakeenv[to++] = environ[from];
-		fakeenv[to] = NULL;
-		environ = fakeenv;
+	for (i = optind; i < argc; i++) {
+	  size_t arglen = strlen(argv[i]);
+	  if (longest < arglen)
+	    longest = min(arglen, INT_MAX);
 	}
-	for (i = optind; i < argc; ++i) {
-		static char	buf[MAX_STRING_LENGTH];
 
-		(void) strcpy(&fakeenv[0][3], argv[i]);
-		if (!vflag) {
-			show(argv[i], now, FALSE);
+	for (i = optind; i < argc; ++i) {
+		timezone_t tz = tzalloc(argv[i]);
+		char const *ab;
+		time_t t;
+		struct tm tm, newtm;
+		bool tm_ok;
+		if (!tz) {
+		  perror(argv[i]);
+		  return EXIT_FAILURE;
+		}
+		if (now) {
+			show(tz, argv[i], now, false);
+			tzfree(tz);
 			continue;
 		}
-		warned = FALSE;
+		warned = false;
 		t = absolute_min_time;
-		show(argv[i], t, TRUE);
-		t += SECSPERHOUR * HOURSPERDAY;
-		show(argv[i], t, TRUE);
-		if (t < cutlotime)
-			t = cutlotime;
-		tmp = my_localtime(&t);
-		if (tmp != NULL) {
-			tm = *tmp;
-			(void) strncpy(buf, abbr(&tm), (sizeof buf) - 1);
-		}
-		for ( ; ; ) {
-			if (t >= cuthitime || t >= cuthitime - SECSPERHOUR * 12)
-				break;
-			newt = t + SECSPERHOUR * 12;
-			newtmp = localtime(&newt);
-			if (newtmp != NULL)
-				newtm = *newtmp;
-			if ((tmp == NULL || newtmp == NULL) ? (tmp != newtmp) :
-				(delta(&newtm, &tm) != (newt - t) ||
-				newtm.tm_isdst != tm.tm_isdst ||
-				strcmp(abbr(&newtm), buf) != 0)) {
-					newt = hunt(argv[i], t, newt);
-					newtmp = localtime(&newt);
-					if (newtmp != NULL) {
-						newtm = *newtmp;
-						(void) strncpy(buf,
-							abbr(&newtm),
-							(sizeof buf) - 1);
-					}
+		if (! (iflag | Vflag)) {
+			show(tz, argv[i], t, true);
+			if (my_localtime_rz(tz, &t, &tm) == NULL
+			    && t < cutlotime) {
+				time_t newt = cutlotime;
+				if (my_localtime_rz(tz, &newt, &newtm) != NULL)
+				  showextrema(tz, argv[i], t, NULL, newt);
 			}
-			t = newt;
-			tm = newtm;
-			tmp = newtmp;
 		}
-		t = absolute_max_time;
-		t -= SECSPERHOUR * HOURSPERDAY;
-		show(argv[i], t, TRUE);
-		t += SECSPERHOUR * HOURSPERDAY;
-		show(argv[i], t, TRUE);
-	}
-	if (fflush(stdout) || ferror(stdout)) {
-		(void) fprintf(stderr, "%s: ", progname);
-		(void) perror(_("Error writing to standard output"));
-		exit(EXIT_FAILURE);
-	}
-	exit(EXIT_SUCCESS);
-	/* If exit fails to exit... */
-	return EXIT_FAILURE;
-}
-
-static void
-setabsolutes(void)
-{
-	if (0.5 == (time_t) 0.5) {
-		/*
-		** time_t is floating.
-		*/
-		if (sizeof (time_t) == sizeof (float)) {
-			absolute_min_time = (time_t) -FLT_MAX;
-			absolute_max_time = (time_t) FLT_MAX;
-		} else if (sizeof (time_t) == sizeof (double)) {
-			absolute_min_time = (time_t) -DBL_MAX;
-			absolute_max_time = (time_t) DBL_MAX;
-		} else {
-			(void) fprintf(stderr,
-_("%s: use of -v on system with floating time_t other than float or double\n"),
-				progname);
-			exit(EXIT_FAILURE);
+		if (t + 1 < cutlotime)
+		  t = cutlotime - 1;
+		tm_ok = my_localtime_rz(tz, &t, &tm) != NULL;
+		if (tm_ok) {
+		  ab = saveabbr(&abbrev, &abbrevsize, &tm);
+		  if (iflag) {
+		    showtrans("\nTZ=%f", &tm, t, ab, argv[i]);
+		    showtrans("-\t-\t%Q", &tm, t, ab, argv[i]);
+		  }
+		} else
+		  ab = NULL;
+		while (t < cuthitime - 1) {
+		  time_t newt = ((t < absolute_max_time - SECSPERDAY / 2
+				  && t + SECSPERDAY / 2 < cuthitime - 1)
+				 ? t + SECSPERDAY / 2
+				 : cuthitime - 1);
+		  struct tm *newtmp = localtime_rz(tz, &newt, &newtm);
+		  bool newtm_ok = newtmp != NULL;
+		  if (tm_ok != newtm_ok
+		      || (ab && (delta(&newtm, &tm) != newt - t
+				 || newtm.tm_isdst != tm.tm_isdst
+				 || strcmp(abbr(&newtm), ab) != 0))) {
+		    newt = hunt(tz, argv[i], t, newt, false);
+		    newtmp = localtime_rz(tz, &newt, &newtm);
+		    newtm_ok = newtmp != NULL;
+		    if (iflag)
+		      showtrans("%Y-%m-%d\t%L\t%Q", newtmp, newt,
+				newtm_ok ? abbr(&newtm) : NULL, argv[i]);
+		    else {
+		      show(tz, argv[i], newt - 1, true);
+		      show(tz, argv[i], newt, true);
+		    }
+		  }
+		  t = newt;
+		  tm_ok = newtm_ok;
+		  if (newtm_ok) {
+		    ab = saveabbr(&abbrev, &abbrevsize, &newtm);
+		    tm = newtm;
+		  }
 		}
-	} else if (0 > (time_t) -1) {
-		/*
-		** time_t is signed.  Assume overflow wraps around.
-		*/
-		time_t t = 0;
-		time_t t1 = 1;
-
-		while (t < t1) {
-			t = t1;
-			t1 = 2 * t1 + 1;
+		if (! (iflag | Vflag)) {
+			time_t newt = absolute_max_time;
+			t = cuthitime;
+			if (t < newt) {
+			  struct tm *tmp = my_localtime_rz(tz, &t, &tm);
+			  if (tmp != NULL
+			      && my_localtime_rz(tz, &newt, &newtm) == NULL)
+			    showextrema(tz, argv[i], t, tmp, newt);
+			}
+			show(tz, argv[i], absolute_max_time, true);
 		}
-
-		absolute_max_time = t;
-		t = -t;
-		absolute_min_time = t - 1;
-		if (t < absolute_min_time)
-			absolute_min_time = t;
-	} else {
-		/*
-		** time_t is unsigned.
-		*/
-		absolute_min_time = 0;
-		absolute_max_time = absolute_min_time - 1;
+		tzfree(tz);
 	}
+	close_file(stdout);
+	if (errout && (ferror(stderr) || fclose(stderr) != 0))
+	  return EXIT_FAILURE;
+	return EXIT_SUCCESS;
 }
 
 static time_t
-yeartot(y)
-const long	y;
+yeartot(intmax_t y)
 {
-	register long	myy;
-	register long	seconds;
-	register time_t	t;
+	register intmax_t	myy, seconds, years;
+	register time_t		t;
 
 	myy = EPOCH_YEAR;
 	t = 0;
-	while (myy != y) {
-		if (myy < y) {
+	while (myy < y) {
+		if (SECSPER400YEARS_FITS && 400 <= y - myy) {
+			intmax_t diff400 = (y - myy) / 400;
+			if (INTMAX_MAX / SECSPER400YEARS < diff400)
+				return absolute_max_time;
+			seconds = diff400 * SECSPER400YEARS;
+			years = diff400 * 400;
+                } else {
 			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
-			++myy;
-			if (t > absolute_max_time - seconds) {
-				t = absolute_max_time;
-				break;
-			}
-			t += seconds;
+			years = 1;
+		}
+		myy += years;
+		if (t > absolute_max_time - seconds)
+			return absolute_max_time;
+		t += seconds;
+	}
+	while (y < myy) {
+		if (SECSPER400YEARS_FITS && y + 400 <= myy && myy < 0) {
+			intmax_t diff400 = (myy - y) / 400;
+			if (INTMAX_MAX / SECSPER400YEARS < diff400)
+				return absolute_min_time;
+			seconds = diff400 * SECSPER400YEARS;
+			years = diff400 * 400;
 		} else {
-			--myy;
-			seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR;
-			if (t < absolute_min_time + seconds) {
-				t = absolute_min_time;
-				break;
-			}
-			t -= seconds;
+			seconds = isleap(myy - 1) ? SECSPERLYEAR : SECSPERNYEAR;
+			years = 1;
 		}
+		myy -= years;
+		if (t < absolute_min_time + seconds)
+			return absolute_min_time;
+		t -= seconds;
 	}
 	return t;
 }
 
+/* Search for a discontinuity in timezone TZ with name NAME, in the
+   timestamps ranging from LOT through HIT.  LOT and HIT disagree
+   about some aspect of timezone.  If ONLY_OK, search only for
+   definedness changes, i.e., localtime succeeds on one side of the
+   transition but fails on the other side.  Return the timestamp just
+   before the transition from LOT's settings.  */
+
 static time_t
-hunt(char *name, time_t lot, time_t hit)
+hunt(timezone_t tz, char *name, time_t lot, time_t hit, bool only_ok)
 {
-	time_t			t;
-	long			diff;
+	static char *		loab;
+	static size_t		loabsize;
 	struct tm		lotm;
-	register struct tm *	lotmp;
 	struct tm		tm;
-	register struct tm *	tmp;
-	char			loab[MAX_STRING_LENGTH];
 
-	lotmp = my_localtime(&lot);
-	if (lotmp != NULL) {
-		lotm = *lotmp;
-		(void) strncpy(loab, abbr(&lotm), (sizeof loab) - 1);
-	}
+	/* Convert LOT into a broken-down time here, even though our
+	   caller already did that.  On platforms without TM_ZONE,
+	   tzname may have been altered since our caller broke down
+	   LOT, and tzname needs to be changed back.  */
+	bool lotm_ok = my_localtime_rz(tz, &lot, &lotm) != NULL;
+	bool tm_ok;
+	char const *ab = lotm_ok ? saveabbr(&loab, &loabsize, &lotm) : NULL;
+
 	for ( ; ; ) {
-		diff = (long) (hit - lot);
-		if (diff < 2)
+		/* T = average of LOT and HIT, rounding down.
+		   Avoid overflow, even on oddball C89 platforms
+		   where / rounds down and TIME_T_MIN == -TIME_T_MAX
+		   so lot / 2 + hit / 2 might overflow.  */
+		time_t t = (lot / 2
+			    - ((lot % 2 + hit % 2) < 0)
+			    + ((lot % 2 + hit % 2) == 2)
+			    + hit / 2);
+		if (t == lot)
 			break;
-		t = lot;
-		t += diff / 2;
-		if (t <= lot)
-			++t;
-		else if (t >= hit)
-			--t;
-		tmp = my_localtime(&t);
-		if (tmp != NULL)
-			tm = *tmp;
-		if ((lotmp == NULL || tmp == NULL) ? (lotmp == tmp) :
-			(delta(&tm, &lotm) == (t - lot) &&
-			tm.tm_isdst == lotm.tm_isdst &&
-			strcmp(abbr(&tm), loab) == 0)) {
-				lot = t;
-				lotm = tm;
-				lotmp = tmp;
+		tm_ok = my_localtime_rz(tz, &t, &tm) != NULL;
+		if (lotm_ok == tm_ok
+		    && (only_ok
+			|| (ab && tm.tm_isdst == lotm.tm_isdst
+			    && delta(&tm, &lotm) == t - lot
+			    && strcmp(abbr(&tm), ab) == 0))) {
+		  lot = t;
+		  if (tm_ok)
+		    lotm = tm;
 		} else	hit = t;
 	}
-	show(name, lot, TRUE);
-	show(name, hit, TRUE);
 	return hit;
 }
 
 /*
-** Thanks to Paul Eggert for logic used in delta.
+** Thanks to Paul Eggert for logic used in delta_nonneg.
 */
 
-static long
-delta(newp, oldp)
-struct tm *	newp;
-struct tm *	oldp;
+static intmax_t
+delta_nonneg(struct tm *newp, struct tm *oldp)
 {
-	register long	result;
-	register int	tmy;
-
-	if (newp->tm_year < oldp->tm_year)
-		return -delta(oldp, newp);
-	result = 0;
-	for (tmy = oldp->tm_year; tmy < newp->tm_year; ++tmy)
+	intmax_t oldy = oldp->tm_year;
+	int cycles = (newp->tm_year - oldy) / YEARSPERREPEAT;
+	intmax_t sec = SECSPERREPEAT, result = cycles * sec;
+	int tmy = oldp->tm_year + cycles * YEARSPERREPEAT;
+	for ( ; tmy < newp->tm_year; ++tmy)
 		result += DAYSPERNYEAR + isleap_sum(tmy, TM_YEAR_BASE);
 	result += newp->tm_yday - oldp->tm_yday;
 	result *= HOURSPERDAY;
 	result += newp->tm_hour - oldp->tm_hour;
 	result *= MINSPERHOUR;
 	result += newp->tm_min - oldp->tm_min;
 	result *= SECSPERMIN;
 	result += newp->tm_sec - oldp->tm_sec;
 	return result;
 }
 
+static intmax_t
+delta(struct tm *newp, struct tm *oldp)
+{
+  return (newp->tm_year < oldp->tm_year
+	  ? -delta_nonneg(oldp, newp)
+	  : delta_nonneg(newp, oldp));
+}
+
+#ifndef TM_GMTOFF
+/* Return A->tm_yday, adjusted to compare it fairly to B->tm_yday.
+   Assume A and B differ by at most one year.  */
+static int
+adjusted_yday(struct tm const *a, struct tm const *b)
+{
+  int yday = a->tm_yday;
+  if (b->tm_year < a->tm_year)
+    yday += 365 + isleap_sum(b->tm_year, TM_YEAR_BASE);
+  return yday;
+}
+#endif
+
+/* If A is the broken-down local time and B the broken-down UT for
+   the same instant, return A's UT offset in seconds, where positive
+   offsets are east of Greenwich.  On failure, return LONG_MIN.
+
+   If T is nonnull, *T is the timestamp that corresponds to A; call
+   my_gmtime_r and use its result instead of B.  Otherwise, B is the
+   possibly nonnull result of an earlier call to my_gmtime_r.  */
+static long
+gmtoff(struct tm const *a, time_t *t, struct tm const *b)
+{
+#ifdef TM_GMTOFF
+  return a->TM_GMTOFF;
+#else
+  struct tm tm;
+  if (t)
+    b = my_gmtime_r(t, &tm);
+  if (! b)
+    return LONG_MIN;
+  else {
+    int ayday = adjusted_yday(a, b);
+    int byday = adjusted_yday(b, a);
+    int days = ayday - byday;
+    long hours = a->tm_hour - b->tm_hour + 24 * days;
+    long minutes = a->tm_min - b->tm_min + 60 * hours;
+    long seconds = a->tm_sec - b->tm_sec + 60 * minutes;
+    return seconds;
+  }
+#endif
+}
+
 static void
-show(char *zone, time_t t, int v)
+show(timezone_t tz, char *zone, time_t t, bool v)
 {
 	register struct tm *	tmp;
+	register struct tm *	gmtmp;
+	struct tm tm, gmtm;
 
-	(void) printf("%-*s  ", (int) longest, zone);
+	printf("%-*s  ", longest, zone);
 	if (v) {
-		tmp = gmtime(&t);
-		if (tmp == NULL) {
-			(void) printf(tformat(), t);
+		gmtmp = my_gmtime_r(&t, &gmtm);
+		if (gmtmp == NULL) {
+			printf(tformat(), t);
+			printf(_(" (gmtime failed)"));
 		} else {
-			dumptime(tmp);
-			(void) printf(" UTC");
+			dumptime(gmtmp);
+			printf(" UT");
 		}
-		(void) printf(" = ");
+		printf(" = ");
 	}
-	tmp = my_localtime(&t);
-	dumptime(tmp);
-	if (tmp != NULL) {
+	tmp = my_localtime_rz(tz, &t, &tm);
+	if (tmp == NULL) {
+		printf(tformat(), t);
+		printf(_(" (localtime failed)"));
+	} else {
+		dumptime(tmp);
 		if (*abbr(tmp) != '\0')
-			(void) printf(" %s", abbr(tmp));
+			printf(" %s", abbr(tmp));
 		if (v) {
-			(void) printf(" isdst=%d", tmp->tm_isdst);
-#ifdef TM_GMTOFF
-			(void) printf(" gmtoff=%ld", tmp->TM_GMTOFF);
-#endif /* defined TM_GMTOFF */
+			long off = gmtoff(tmp, NULL, gmtmp);
+			printf(" isdst=%d", tmp->tm_isdst);
+			if (off != LONG_MIN)
+			  printf(" gmtoff=%ld", off);
 		}
 	}
-	(void) printf("\n");
+	printf("\n");
 	if (tmp != NULL && *abbr(tmp) != '\0')
 		abbrok(abbr(tmp), zone);
 }
 
-static char *
-abbr(tmp)
-struct tm *	tmp;
+/* Show timestamps just before and just after a transition between
+   defined and undefined (or vice versa) in either localtime or
+   gmtime.  These transitions are for timezone TZ with name ZONE, in
+   the range from LO (with broken-down time LOTMP if that is nonnull)
+   through HI.  LO and HI disagree on definedness.  */
+
+static void
+showextrema(timezone_t tz, char *zone, time_t lo, struct tm *lotmp, time_t hi)
+{
+  struct tm localtm[2], gmtm[2];
+  time_t t, boundary = hunt(tz, zone, lo, hi, true);
+  bool old = false;
+  hi = (SECSPERDAY < hi - boundary
+	? boundary + SECSPERDAY
+	: hi + (hi < TIME_T_MAX));
+  if (SECSPERDAY < boundary - lo) {
+    lo = boundary - SECSPERDAY;
+    lotmp = my_localtime_rz(tz, &lo, &localtm[old]);
+  }
+  if (lotmp)
+    localtm[old] = *lotmp;
+  else
+    localtm[old].tm_sec = -1;
+  if (! my_gmtime_r(&lo, &gmtm[old]))
+    gmtm[old].tm_sec = -1;
+
+  /* Search sequentially for definedness transitions.  Although this
+     could be sped up by refining 'hunt' to search for either
+     localtime or gmtime definedness transitions, it hardly seems
+     worth the trouble.  */
+  for (t = lo + 1; t < hi; t++) {
+    bool new = !old;
+    if (! my_localtime_rz(tz, &t, &localtm[new]))
+      localtm[new].tm_sec = -1;
+    if (! my_gmtime_r(&t, &gmtm[new]))
+      gmtm[new].tm_sec = -1;
+    if (((localtm[old].tm_sec < 0) != (localtm[new].tm_sec < 0))
+	| ((gmtm[old].tm_sec < 0) != (gmtm[new].tm_sec < 0))) {
+      show(tz, zone, t - 1, true);
+      show(tz, zone, t, true);
+    }
+    old = new;
+  }
+}
+
+#if HAVE_SNPRINTF
+# define my_snprintf snprintf
+#else
+# include 
+
+/* A substitute for snprintf that is good enough for zdump.  */
+static int ATTRIBUTE_FORMAT((printf, 3, 4))
+my_snprintf(char *s, size_t size, char const *format, ...)
+{
+  int n;
+  va_list args;
+  char const *arg;
+  size_t arglen, slen;
+  char buf[1024];
+  va_start(args, format);
+  if (strcmp(format, "%s") == 0) {
+    arg = va_arg(args, char const *);
+    arglen = strlen(arg);
+  } else {
+    n = vsprintf(buf, format, args);
+    if (n < 0) {
+      va_end(args);
+      return n;
+    }
+    arg = buf;
+    arglen = n;
+  }
+  slen = arglen < size ? arglen : size - 1;
+  memcpy(s, arg, slen);
+  s[slen] = '\0';
+  n = arglen <= INT_MAX ? arglen : -1;
+  va_end(args);
+  return n;
+}
+#endif
+
+/* Store into BUF, of size SIZE, a formatted local time taken from *TM.
+   Use ISO 8601 format +HH:MM:SS.  Omit :SS if SS is zero, and omit
+   :MM too if MM is also zero.
+
+   Return the length of the resulting string.  If the string does not
+   fit, return the length that the string would have been if it had
+   fit; do not overrun the output buffer.  */
+static int
+format_local_time(char *buf, size_t size, struct tm const *tm)
+{
+  int ss = tm->tm_sec, mm = tm->tm_min, hh = tm->tm_hour;
+  return (ss
+	  ? my_snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss)
+	  : mm
+	  ? my_snprintf(buf, size, "%02d:%02d", hh, mm)
+	  : my_snprintf(buf, size, "%02d", hh));
+}
+
+/* Store into BUF, of size SIZE, a formatted UT offset for the
+   localtime *TM corresponding to time T.  Use ISO 8601 format
+   +HHMMSS, or -HHMMSS for timestamps west of Greenwich; use the
+   format -00 for unknown UT offsets.  If the hour needs more than
+   two digits to represent, extend the length of HH as needed.
+   Otherwise, omit SS if SS is zero, and omit MM too if MM is also
+   zero.
+
+   Return the length of the resulting string, or -1 if the result is
+   not representable as a string.  If the string does not fit, return
+   the length that the string would have been if it had fit; do not
+   overrun the output buffer.  */
+static int
+format_utc_offset(char *buf, size_t size, struct tm const *tm, time_t t)
+{
+  long off = gmtoff(tm, &t, NULL);
+  char sign = ((off < 0
+		|| (off == 0
+		    && (*abbr(tm) == '-' || strcmp(abbr(tm), "zzz") == 0)))
+	       ? '-' : '+');
+  long hh;
+  int mm, ss;
+  if (off < 0)
+    {
+      if (off == LONG_MIN)
+	return -1;
+      off = -off;
+    }
+  ss = off % 60;
+  mm = off / 60 % 60;
+  hh = off / 60 / 60;
+  return (ss || 100 <= hh
+	  ? my_snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss)
+	  : mm
+	  ? my_snprintf(buf, size, "%c%02ld%02d", sign, hh, mm)
+	  : my_snprintf(buf, size, "%c%02ld", sign, hh));
+}
+
+/* Store into BUF (of size SIZE) a quoted string representation of P.
+   If the representation's length is less than SIZE, return the
+   length; the representation is not null terminated.  Otherwise
+   return SIZE, to indicate that BUF is too small.  */
+static size_t
+format_quoted_string(char *buf, size_t size, char const *p)
+{
+  char *b = buf;
+  size_t s = size;
+  if (!s)
+    return size;
+  *b++ = '"', s--;
+  for (;;) {
+    char c = *p++;
+    if (s <= 1)
+      return size;
+    switch (c) {
+    default: *b++ = c, s--; continue;
+    case '\0': *b++ = '"', s--; return size - s;
+    case '"': case '\\': break;
+    case ' ': c = 's'; break;
+    case '\f': c = 'f'; break;
+    case '\n': c = 'n'; break;
+    case '\r': c = 'r'; break;
+    case '\t': c = 't'; break;
+    case '\v': c = 'v'; break;
+    }
+    *b++ = '\\', *b++ = c, s -= 2;
+  }
+}
+
+/* Store into BUF (of size SIZE) a timestamp formatted by TIME_FMT.
+   TM is the broken-down time, T the seconds count, AB the time zone
+   abbreviation, and ZONE_NAME the zone name.  Return true if
+   successful, false if the output would require more than SIZE bytes.
+   TIME_FMT uses the same format that strftime uses, with these
+   additions:
+
+   %f zone name
+   %L local time as per format_local_time
+   %Q like "U\t%Z\tD" where U is the UT offset as for format_utc_offset
+      and D is the isdst flag; except omit D if it is zero, omit %Z if
+      it equals U, quote and escape %Z if it contains nonalphabetics,
+      and omit any trailing tabs.  */
+
+static bool
+istrftime(char *buf, size_t size, char const *time_fmt,
+	  struct tm const *tm, time_t t, char const *ab, char const *zone_name)
+{
+  char *b = buf;
+  size_t s = size;
+  char const *f = time_fmt, *p;
+
+  for (p = f; ; p++)
+    if (*p == '%' && p[1] == '%')
+      p++;
+    else if (!*p
+	     || (*p == '%'
+		 && (p[1] == 'f' || p[1] == 'L' || p[1] == 'Q'))) {
+      size_t formatted_len;
+      size_t f_prefix_len = p - f;
+      size_t f_prefix_copy_size = p - f + 2;
+      char fbuf[100];
+      bool oversized = sizeof fbuf <= f_prefix_copy_size;
+      char *f_prefix_copy = oversized ? xmalloc(f_prefix_copy_size) : fbuf;
+      memcpy(f_prefix_copy, f, f_prefix_len);
+      strcpy(f_prefix_copy + f_prefix_len, "X");
+      formatted_len = strftime(b, s, f_prefix_copy, tm);
+      if (oversized)
+	free(f_prefix_copy);
+      if (formatted_len == 0)
+	return false;
+      formatted_len--;
+      b += formatted_len, s -= formatted_len;
+      if (!*p++)
+	break;
+      switch (*p) {
+      case 'f':
+	formatted_len = format_quoted_string(b, s, zone_name);
+	break;
+      case 'L':
+	formatted_len = format_local_time(b, s, tm);
+	break;
+      case 'Q':
+	{
+	  bool show_abbr;
+	  int offlen = format_utc_offset(b, s, tm, t);
+	  if (! (0 <= offlen && offlen < s))
+	    return false;
+	  show_abbr = strcmp(b, ab) != 0;
+	  b += offlen, s -= offlen;
+	  if (show_abbr) {
+	    char const *abp;
+	    size_t len;
+	    if (s <= 1)
+	      return false;
+	    *b++ = '\t', s--;
+	    for (abp = ab; is_alpha(*abp); abp++)
+	      continue;
+	    len = (!*abp && *ab
+		   ? my_snprintf(b, s, "%s", ab)
+		   : format_quoted_string(b, s, ab));
+	    if (s <= len)
+	      return false;
+	    b += len, s -= len;
+	  }
+	  formatted_len
+	    = (tm->tm_isdst
+	       ? my_snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst)
+	       : 0);
+	}
+	break;
+      }
+      if (s <= formatted_len)
+	return false;
+      b += formatted_len, s -= formatted_len;
+      f = p + 1;
+    }
+  *b = '\0';
+  return true;
+}
+
+/* Show a time transition.  */
+static void
+showtrans(char const *time_fmt, struct tm const *tm, time_t t, char const *ab,
+	  char const *zone_name)
 {
-	register char *	result;
-	static char	nada;
+  if (!tm) {
+    printf(tformat(), t);
+    putchar('\n');
+  } else {
+    char stackbuf[1000];
+    size_t size = sizeof stackbuf;
+    char *buf = stackbuf;
+    char *bufalloc = NULL;
+    while (! istrftime(buf, size, time_fmt, tm, t, ab, zone_name)) {
+      size = sumsize(size, size);
+      free(bufalloc);
+      buf = bufalloc = xmalloc(size);
+    }
+    puts(buf);
+    free(bufalloc);
+  }
+}
 
-	if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1)
-		return &nada;
-	result = tzname[tmp->tm_isdst];
-	return (result == NULL) ? &nada : result;
+static char const *
+abbr(struct tm const *tmp)
+{
+#ifdef TM_ZONE
+	return tmp->TM_ZONE;
+#else
+# if HAVE_TZNAME
+	if (0 <= tmp->tm_isdst && tzname[0 < tmp->tm_isdst])
+	  return tzname[0 < tmp->tm_isdst];
+# endif
+	return "";
+#endif
 }
 
 /*
 ** The code below can fail on certain theoretical systems;
-** it works on all known real-world systems as of 2004-12-30.
+** it works on all known real-world systems as of 2022-01-25.
 */
 
 static const char *
 tformat(void)
 {
-	if (0.5 == (time_t) 0.5) {	/* floating */
-		if (sizeof (time_t) > sizeof (double))
-			return "%Lg";
-		return "%g";
-	}
+#if HAVE_GENERIC
+	/* C11-style _Generic is more likely to return the correct
+	   format when distinct types have the same size.  */
+	char const *fmt =
+	  _Generic(+ (time_t) 0,
+		   int: "%d", long: "%ld", long long: "%lld",
+		   unsigned: "%u", unsigned long: "%lu",
+		   unsigned long long: "%llu",
+		   default: NULL);
+	if (fmt)
+	  return fmt;
+	fmt = _Generic((time_t) 0,
+		       intmax_t: "%"PRIdMAX, uintmax_t: "%"PRIuMAX,
+		       default: NULL);
+	if (fmt)
+	  return fmt;
+#endif
 	if (0 > (time_t) -1) {		/* signed */
-		if (sizeof (time_t) > sizeof (long))
+		if (sizeof(time_t) == sizeof(intmax_t))
+			return "%"PRIdMAX;
+		if (sizeof(time_t) > sizeof(long))
 			return "%lld";
-		if (sizeof (time_t) > sizeof (int))
+		if (sizeof(time_t) > sizeof(int))
 			return "%ld";
 		return "%d";
 	}
-	if (sizeof (time_t) > sizeof (unsigned long))
+#ifdef PRIuMAX
+	if (sizeof(time_t) == sizeof(uintmax_t))
+		return "%"PRIuMAX;
+#endif
+	if (sizeof(time_t) > sizeof(unsigned long))
 		return "%llu";
-	if (sizeof (time_t) > sizeof (unsigned int))
+	if (sizeof(time_t) > sizeof(unsigned int))
 		return "%lu";
 	return "%u";
 }
 
 static void
-dumptime(timeptr)
-register const struct tm *	timeptr;
+dumptime(register const struct tm *timeptr)
 {
-	static const char	wday_name[][3] = {
+	static const char	wday_name[][4] = {
 		"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"
 	};
-	static const char	mon_name[][3] = {
+	static const char	mon_name[][4] = {
 		"Jan", "Feb", "Mar", "Apr", "May", "Jun",
 		"Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
 	};
-	register const char *	wn;
-	register const char *	mn;
 	register int		lead;
 	register int		trail;
+	int DIVISOR = 10;
 
-	if (timeptr == NULL) {
-		(void) printf("NULL");
-		return;
-	}
 	/*
-	** The packaged versions of localtime and gmtime never put out-of-range
+	** The packaged localtime_rz and gmtime_r never put out-of-range
 	** values in tm_wday or tm_mon, but since this code might be compiled
 	** with other (perhaps experimental) versions, paranoia is in order.
 	*/
-	if (timeptr->tm_wday < 0 || timeptr->tm_wday >=
-		(int) (sizeof wday_name / sizeof wday_name[0]))
-			wn = "???";
-	else		wn = wday_name[timeptr->tm_wday];
-	if (timeptr->tm_mon < 0 || timeptr->tm_mon >=
-		(int) (sizeof mon_name / sizeof mon_name[0]))
-			mn = "???";
-	else		mn = mon_name[timeptr->tm_mon];
-	(void) printf("%.3s %.3s%3d %.2d:%.2d:%.2d ",
-		wn, mn,
+	printf("%s %s%3d %.2d:%.2d:%.2d ",
+		((0 <= timeptr->tm_wday
+		  && timeptr->tm_wday < sizeof wday_name / sizeof wday_name[0])
+		 ? wday_name[timeptr->tm_wday] : "???"),
+		((0 <= timeptr->tm_mon
+		  && timeptr->tm_mon < sizeof mon_name / sizeof mon_name[0])
+		 ? mon_name[timeptr->tm_mon] : "???"),
 		timeptr->tm_mday, timeptr->tm_hour,
 		timeptr->tm_min, timeptr->tm_sec);
-#define DIVISOR	10
 	trail = timeptr->tm_year % DIVISOR + TM_YEAR_BASE % DIVISOR;
 	lead = timeptr->tm_year / DIVISOR + TM_YEAR_BASE / DIVISOR +
 		trail / DIVISOR;
 	trail %= DIVISOR;
 	if (trail < 0 && lead > 0) {
 		trail += DIVISOR;
 		--lead;
 	} else if (lead < 0 && trail > 0) {
 		trail -= DIVISOR;
 		++lead;
 	}
 	if (lead == 0)
-		(void) printf("%d", trail);
-	else	(void) printf("%d%d", lead, ((trail < 0) ? -trail : trail));
+		printf("%d", trail);
+	else	printf("%d%d", lead, ((trail < 0) ? -trail : trail));
 }
diff --git a/zic.8 b/zic.8
index 7a7324ab48ba..e46d0ab0d2ce 100644
--- a/zic.8
+++ b/zic.8
@@ -1,498 +1,877 @@
 .TH ZIC 8
 .SH NAME
-zic \- time zone compiler
+zic \- timezone compiler
 .SH SYNOPSIS
 .B zic
 [
-.B \-\-version
-]
-[
-.B \-v
-] [
-.B \-d
-.I directory
-] [
-.B \-l
-.I localtime
-] [
-.B \-p
-.I posixrules
-] [
-.B \-L
-.I leapsecondfilename
-] [
-.B \-s
-] [
-.B \-y
-.I command
-] [
+.I option
+\&... ] [
 .I filename
 \&... ]
 .SH DESCRIPTION
-.if t .ds lq ``
-.if t .ds rq ''
-.if n .ds lq \&"\"
-.if n .ds rq \&"\"
+.ie '\(lq'' .ds lq \&"\"
+.el .ds lq \(lq\"
+.ie '\(rq'' .ds rq \&"\"
+.el .ds rq \(rq\"
 .de q
 \\$3\*(lq\\$1\*(rq\\$2
 ..
-.I Zic
-reads text from the file(s) named on the command line
-and creates the time conversion information files specified in this input.
+.ie '\(la'' .ds < <
+.el .ds < \(la
+.ie '\(ra'' .ds > >
+.el .ds > \(ra
+.ie \n(.g \{\
+.  ds : \:
+.  ds - \f(CW-\fP
+.\}
+.el \{\
+.  ds :
+.  ds - \-
+.\}
+.ds d " degrees
+.ds m " minutes
+.ds s " seconds
+.ds _ " \&
+.if t \{\
+. if \n(.g .if c \(de .if c \(fm .if c \(sd \{\
+.  ds d \(de
+.  ds m \(fm
+.  ds s \(sd
+.  ds _ \|
+. \}
+.\}
+The
+.B zic
+program reads text from the file(s) named on the command line
+and creates the timezone information format (TZif) files
+specified in this input.
 If a
 .I filename
 is
-.BR \- ,
-the standard input is read.
-.PP
-These options are available:
+.q "\*-" ,
+standard input is read.
+.SH OPTIONS
 .TP
-.BI "\-\-version"
+.B "\*-\*-version"
 Output version information and exit.
 .TP
-.BI "\-d " directory
+.B \*-\*-help
+Output short usage message and exit.
+.TP
+.BI "\*-b " bloat
+Output backward-compatibility data as specified by
+.IR bloat .
+If
+.I bloat
+is
+.BR fat ,
+generate additional data entries that work around potential bugs or
+incompatibilities in older software, such as software that mishandles
+the 64-bit generated data.
+If
+.I bloat
+is
+.BR slim ,
+keep the output files small; this can help check for the bugs
+and incompatibilities.
+The default is
+.BR slim ,
+as software that mishandles 64-bit data typically
+mishandles timestamps after the year 2038 anyway.
+Also see the
+.B \*-r
+option for another way to alter output size.
+.TP
+.BI "\*-d " directory
 Create time conversion information files in the named directory rather than
 in the standard directory named below.
 .TP
-.BI "\-l " timezone
-Use the given time zone as local time.
-.I Zic
+.BI "\*-l " timezone
+Use
+.I timezone
+as local time.
+.B zic
 will act as if the input contained a link line of the form
 .sp
 .ti +.5i
+.ta \w'Link\0\0'u  +\w'\fItimezone\fP\0\0'u
 Link	\fItimezone\fP		localtime
+.sp
+If
+.I timezone
+is
+.BR \*- ,
+any already-existing link is removed.
+.TP
+.BI "\*-L " leapsecondfilename
+Read leap second information from the file with the given name.
+If this option is not used,
+no leap second information appears in output files.
 .TP
-.BI "\-p " timezone
-Use the given time zone's rules when handling POSIX-format
-time zone environment variables.
-.I Zic
+.BI "\*-p " timezone
+Use
+.IR timezone 's
+rules when handling nonstandard
+TZ strings like "EET\*-2EEST" that lack transition rules.
+.B zic
 will act as if the input contained a link line of the form
 .sp
 .ti +.5i
 Link	\fItimezone\fP		posixrules
+.sp
+This feature is obsolete and poorly supported.
+Among other things it should not be used for timestamps after the year 2037,
+and it should not be combined with
+.B "\*-b slim"
+if
+.IR timezone 's
+transitions are at standard time or Universal Time (UT) instead of local time.
+.sp
+If
+.I timezone
+is
+.BR \*- ,
+any already-existing link is removed.
 .TP
-.BI "\-L " leapsecondfilename
-Read leap second information from the file with the given name.
-If this option is not used,
-no leap second information appears in output files.
+.BR "\*-r " "[\fB@\fP\fIlo\fP][\fB/@\fP\fIhi\fP]"
+Limit the applicability of output files
+to timestamps in the range from
+.I lo
+(inclusive) to
+.I hi
+(exclusive), where
+.I lo
+and
+.I hi
+are possibly-signed decimal counts of seconds since the Epoch
+(1970-01-01 00:00:00 UTC).
+Omitted counts default to extreme values.
+The output files use UT offset 0 and abbreviation
+.q "\*-00"
+in place of the omitted timestamp data.
+For example,
+.q "zic \*-r @0"
+omits data intended for negative timestamps (i.e., before the Epoch), and
+.q "zic \*-r @0/@2147483648"
+outputs data intended only for nonnegative timestamps that fit into
+31-bit signed integers.
+On platforms with GNU
+.BR date ,
+.q "zic \*-r @$(date +%s)"
+omits data intended for past timestamps.
+Although this option typically reduces the output file's size,
+the size can increase due to the need to represent the timestamp range
+boundaries, particularly if
+.I hi
+causes a TZif file to contain explicit entries for
+.RI pre- hi
+transitions rather than concisely representing them
+with an extended POSIX TZ string.
+Also see the
+.B "\*-b slim"
+option for another way to shrink output size.
 .TP
-.B \-v
-Complain if a year that appears in a data file is outside the range
-of years representable by
-.IR time (2)
-values.
-Also complain if a time of 24:00
-(which cannot be handled by pre-1998 versions of
-.IR zic )
-appears in the input.
+.BI "\*-R @" hi
+Generate redundant trailing explicit transitions for timestamps
+that occur less than
+.I hi
+seconds since the Epoch, even though the transitions could be
+more concisely represented via the extended POSIX TZ string.
+This option does not affect the represented timestamps.
+Although it accommodates nonstandard TZif readers
+that ignore the extended POSIX TZ string,
+it increases the size of the altered output files.
 .TP
-.B \-s
-Limit time values stored in output files to values that are the same
-whether they're taken to be signed or unsigned.
-You can use this option to generate SVVS-compatible files.
+.BI "\*-t " file
+When creating local time information, put the configuration link in
+the named file rather than in the standard location.
 .TP
-.BI "\-y " command
-Use the given
-.I command
-rather than
-.B yearistype
-when checking year types (see below).
+.B \*-v
+Be more verbose, and complain about the following situations:
+.RS
+.PP
+The input specifies a link to a link.
+.PP
+A year that appears in a data file is outside the range
+of representable years.
+.PP
+A time of 24:00 or more appears in the input.
+Pre-1998 versions of
+.B zic
+prohibit 24:00, and pre-2007 versions prohibit times greater than 24:00.
+.PP
+A rule goes past the start or end of the month.
+Pre-2004 versions of
+.B zic
+prohibit this.
+.PP
+A time zone abbreviation uses a
+.B %z
+format.
+Pre-2015 versions of
+.B zic
+do not support this.
+.PP
+A timestamp contains fractional seconds.
+Pre-2018 versions of
+.B zic
+do not support this.
+.PP
+The input contains abbreviations that are mishandled by pre-2018 versions of
+.B zic
+due to a longstanding coding bug.
+These abbreviations include
+.q L
+for
+.q Link ,
+.q mi
+for
+.q min ,
+.q Sa
+for
+.q Sat ,
+and
+.q Su
+for
+.q Sun .
+.PP
+The output file does not contain all the information about the
+long-term future of a timezone, because the future cannot be summarized as
+an extended POSIX TZ string.  For example, as of 2019 this problem
+occurs for Iran's daylight-saving rules for the predicted future, as
+these rules are based on the Iranian calendar, which cannot be
+represented.
+.PP
+The output contains data that may not be handled properly by client
+code designed for older
+.B zic
+output formats.  These compatibility issues affect only timestamps
+before 1970 or after the start of 2038.
+.PP
+The output contains a truncated leap second table,
+which can cause some older TZif readers to misbehave.
+This can occur if the
+.B "\*-L"
+option is used, and either an Expires line is present or
+the
+.B "\*-r"
+option is also used.
+.PP
+The output file contains more than 1200 transitions,
+which may be mishandled by some clients.
+The current reference client supports at most 2000 transitions;
+pre-2014 versions of the reference client support at most 1200
+transitions.
+.PP
+A time zone abbreviation has fewer than 3 or more than 6 characters.
+POSIX requires at least 3, and requires implementations to support
+at least 6.
+.PP
+An output file name contains a byte that is not an ASCII letter,
+.q "\*-" ,
+.q "/" ,
+or
+.q "_" ;
+or it contains a file name component that contains more than 14 bytes
+or that starts with
+.q "\*-" .
+.RE
+.SH FILES
+Input files use the format described in this section; output files use
+.BR tzfile (5)
+format.
+.PP
+Input files should be text files, that is, they should be a series of
+zero or more lines, each ending in a newline byte and containing at
+most 2048 bytes counting the newline, and without any NUL bytes.
+The input text's encoding
+is typically UTF-8 or ASCII; it should have a unibyte representation
+for the POSIX Portable Character Set (PPCS)
+\*
+and the encoding's non-unibyte characters should consist entirely of
+non-PPCS bytes.  Non-PPCS characters typically occur only in comments:
+although output file names and time zone abbreviations can contain
+nearly any character, other software will work better if these are
+limited to the restricted syntax described under the
+.B \*-v
+option.
 .PP
 Input lines are made up of fields.
-Fields are separated from one another by any number of white space characters.
+Fields are separated from one another by one or more white space characters.
+The white space characters are space, form feed, carriage return, newline,
+tab, and vertical tab.
 Leading and trailing white space on input lines is ignored.
 An unquoted sharp character (#) in the input introduces a comment which extends
 to the end of the line the sharp character appears on.
 White space characters and sharp characters may be enclosed in double quotes
 (") if they're to be used as part of a field.
 Any line that is blank (after comment stripping) is ignored.
-Non-blank lines are expected to be of one of three types:
+Nonblank lines are expected to be of one of three types:
 rule lines, zone lines, and link lines.
 .PP
-Names (such as month names) must be in English and are case insensitive.
-Abbreviations, if used, must be unambiguous in context.
+Names must be in English and are case insensitive.
+They appear in several contexts, and include month and weekday names
+and keywords such as
+.BR "maximum" ,
+.BR "only" ,
+.BR "Rolling" ,
+and
+.BR "Zone" .
+A name can be abbreviated by omitting all but an initial prefix; any
+abbreviation must be unambiguous in context.
 .PP
 A rule line has the form
 .nf
 .ti +.5i
-.ta \w'Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
+.ta \w'Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'\*-\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00w\0\0'u +\w'1:00d\0\0'u
 .sp
-Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
+Rule	NAME	FROM	TO	\*-	IN	ON	AT	SAVE	LETTER/S
 .sp
 For example:
 .ti +.5i
 .sp
-Rule	US	1967	1973	\-	Apr	lastSun	2:00	1:00	D
+Rule	US	1967	1973	\*-	Apr	lastSun	2:00w	1:00d	D
 .sp
 .fi
 The fields that make up a rule line are:
 .TP "\w'LETTER/S'u"
 .B NAME
-Gives the (arbitrary) name of the set of rules this rule is part of.
+Gives the name of the rule set that contains this line.
+The name must start with a character that is neither
+an ASCII digit nor
+.q \*-
+nor
+.q + .
+To allow for future extensions,
+an unquoted name should not contain characters from the set
+.q !$%&'()*,/:;<=>?@[\e]^`{|}~ .
 .TP
 .B FROM
 Gives the first year in which the rule applies.
-Any integer year can be supplied; the Gregorian calendar is assumed.
+Any signed integer year can be supplied; the proleptic Gregorian calendar
+is assumed, with year 0 preceding year 1.
 The word
 .B minimum
-(or an abbreviation) means the minimum year representable as an integer.
+(or an abbreviation) means the indefinite past.
 The word
 .B maximum
-(or an abbreviation) means the maximum year representable as an integer.
+(or an abbreviation) means the indefinite future.
 Rules can describe times that are not representable as time values,
 with the unrepresentable times ignored; this allows rules to be portable
 among hosts with differing time value types.
 .TP
 .B TO
 Gives the final year in which the rule applies.
 In addition to
 .B minimum
 and
 .B maximum
 (as above),
 the word
 .B only
 (or an abbreviation)
 may be used to repeat the value of the
 .B FROM
 field.
 .TP
+.B \*-
+Is a reserved field and should always contain
+.q \*-
+for compatibility with older versions of
+.BR zic .
+It was previously known as the
 .B TYPE
-Gives the type of year in which the rule applies.
-If
-.B TYPE
-is
-.B \-
-then the rule applies in all years between
-.B FROM
-and
-.B TO
-inclusive.
-If
-.B TYPE
-is something else, then
-.I zic
-executes the command
-.ti +.5i
-\fByearistype\fP \fIyear\fP \fItype\fP
-.br
-to check the type of a year:
-an exit status of zero is taken to mean that the year is of the given type;
-an exit status of one is taken to mean that the year is not of the given type.
+field, which could contain values to allow a
+separate script to further restrict in which
+.q types
+of years the rule would apply.
 .TP
 .B IN
 Names the month in which the rule takes effect.
 Month names may be abbreviated.
 .TP
 .B ON
 Gives the day on which the rule takes effect.
 Recognized forms include:
 .nf
 .in +.5i
 .sp
 .ta \w'Sun<=25\0\0'u
 5	the fifth of the month
 lastSun	the last Sunday in the month
 lastMon	the last Monday in the month
 Sun>=8	first Sunday on or after the eighth
 Sun<=25	last Sunday on or before the 25th
 .fi
 .in -.5i
 .sp
-Names of days of the week may be abbreviated or spelled out in full.
-Note that there must be no spaces within the
+A weekday name (e.g.,
+.BR "Sunday" )
+or a weekday name preceded by
+.q "last"
+(e.g.,
+.BR "lastSunday" )
+may be abbreviated or spelled out in full.
+There must be no white space characters within the
 .B ON
 field.
+The
+.q <=
+and
+.q >=
+constructs can result in a day in the neighboring month;
+for example, the IN-ON combination
+.q "Oct Sun>=31"
+stands for the first Sunday on or after October 31,
+even if that Sunday occurs in November.
 .TP
 .B AT
-Gives the time of day at which the rule takes effect.
+Gives the time of day at which the rule takes effect,
+relative to 00:00, the start of a calendar day.
 Recognized forms include:
 .nf
 .in +.5i
 .sp
-.ta \w'1:28:13\0\0'u
+.ta \w'00:19:32.13\0\0'u
 2	time in hours
 2:00	time in hours and minutes
-15:00	24-hour format time (for times after noon)
-1:28:14	time in hours, minutes, and seconds
-\-	equivalent to 0
+01:28:14	time in hours, minutes, and seconds
+00:19:32.13	time with fractional seconds
+12:00	midday, 12 hours after 00:00
+15:00	3 PM, 15 hours after 00:00
+24:00	end of day, 24 hours after 00:00
+260:00	260 hours after 00:00
+\*-2:30	2.5 hours before 00:00
+\*-	equivalent to 0
 .fi
 .in -.5i
 .sp
-where hour 0 is midnight at the start of the day,
-and hour 24 is midnight at the end of the day.
+Although
+.B zic
+rounds times to the nearest integer second
+(breaking ties to the even integer), the fractions may be useful
+to other applications requiring greater precision.
+The source format does not specify any maximum precision.
 Any of these forms may be followed by the letter
 .B w
-if the given time is local
+if the given time is local or
 .q "wall clock"
 time,
 .B s
-if the given time is local
-.q standard
-time, or
+if the given time is standard time without any adjustment for daylight saving,
+or
 .B u
 (or
 .B g
 or
 .BR z )
 if the given time is universal time;
 in the absence of an indicator,
-wall clock time is assumed.
+local (wall clock) time is assumed.
+These forms ignore leap seconds; for example,
+if a leap second occurs at 00:59:60 local time,
+.q "1:00"
+stands for 3601 seconds after local midnight instead of the usual 3600 seconds.
+The intent is that a rule line describes the instants when a
+clock/calendar set to the type of time specified in the
+.B AT
+field would show the specified date and time of day.
 .TP
 .B SAVE
 Gives the amount of time to be added to local standard time when the rule is in
-effect.
+effect, and whether the resulting time is standard or daylight saving.
 This field has the same format as the
 .B AT
 field
-(although, of course, the
-.B w
-and
+except with a different set of suffix letters:
+.B s
+for standard time and
+.B d
+for daylight saving time.
+The suffix letter is typically omitted, and defaults to
 .B s
-suffixes are not used).
+if the offset is zero and to
+.B d
+otherwise.
+Negative offsets are allowed; in Ireland, for example, daylight saving
+time is observed in winter and has a negative offset relative to
+Irish Standard Time.
+The offset is merely added to standard time; for example,
+.B zic
+does not distinguish a 10:30 standard time plus an 0:30
+.B SAVE
+from a 10:00 standard time plus a 1:00
+.BR SAVE .
 .TP
 .B LETTER/S
 Gives the
 .q "variable part"
 (for example, the
-.q S
+.q "S"
 or
-.q D
+.q "D"
 in
-.q EST
+.q "EST"
 or
-.q EDT )
+.q "EDT" )
 of time zone abbreviations to be used when this rule is in effect.
 If this field is
-.BR \- ,
+.q \*- ,
 the variable part is null.
 .PP
 A zone line has the form
 .sp
 .nf
 .ti +.5i
-.ta \w'Zone\0\0'u +\w'Australia/Adelaide\0\0'u +\w'GMTOFF\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u
-Zone	NAME	GMTOFF	RULES/SAVE	FORMAT	[UNTILYEAR [MONTH [DAY [TIME]]]]
+.ta \w'Zone\0\0'u +\w'Asia/Amman\0\0'u +\w'STDOFF\0\0'u +\w'Jordan\0\0'u +\w'FORMAT\0\0'u
+Zone	NAME	STDOFF	RULES	FORMAT	[UNTIL]
 .sp
 For example:
 .sp
 .ti +.5i
-Zone	Australia/Adelaide	9:30	Aus	CST	1971 Oct 31 2:00
+Zone	Asia/Amman	2:00	Jordan	EE%sT	2017 Oct 27 01:00
 .sp
 .fi
 The fields that make up a zone line are:
-.TP "\w'GMTOFF'u"
+.TP "\w'STDOFF'u"
 .B NAME
-The name of the time zone.
+The name of the timezone.
 This is the name used in creating the time conversion information file for the
-zone.
+timezone.
+It should not contain a file name component
+.q ".\&"
+or
+.q ".." ;
+a file name component is a maximal substring that does not contain
+.q "/" .
 .TP
-.B GMTOFF
-The amount of time to add to UTC to get standard time in this zone.
+.B STDOFF
+The amount of time to add to UT to get standard time,
+without any adjustment for daylight saving.
 This field has the same format as the
 .B AT
 and
 .B SAVE
-fields of rule lines;
-begin the field with a minus sign if time must be subtracted from UTC.
+fields of rule lines, except without suffix letters;
+begin the field with a minus sign if time must be subtracted from UT.
 .TP
-.B RULES/SAVE
-The name of the rule(s) that apply in the time zone or,
-alternately, an amount of time to add to local standard time.
+.B RULES
+The name of the rules that apply in the timezone or,
+alternatively, a field in the same format as a rule-line SAVE column,
+giving the amount of time to be added to local standard time
+and whether the resulting time is standard or daylight saving.
 If this field is
-.B \-
-then standard time always applies in the time zone.
+.B \*-
+then standard time always applies.
+When an amount of time is given, only the sum of standard time and
+this amount matters.
 .TP
 .B FORMAT
-The format for time zone abbreviations in this time zone.
+The format for time zone abbreviations.
 The pair of characters
 .B %s
 is used to show where the
 .q "variable part"
 of the time zone abbreviation goes.
-Alternately,
+Alternatively, a format can use the pair of characters
+.B %z
+to stand for the UT offset in the form
+.RI \(+- hh ,
+.RI \(+- hhmm ,
+or
+.RI \(+- hhmmss ,
+using the shortest form that does not lose information, where
+.IR hh ,
+.IR mm ,
+and
+.I ss
+are the hours, minutes, and seconds east (+) or west (\-) of UT.
+Alternatively,
 a slash (/)
 separates standard and daylight abbreviations.
+To conform to POSIX, a time zone abbreviation should contain only
+alphanumeric ASCII characters,
+.q "+"
+and
+.q "\*-".
+By convention, the time zone abbreviation
+.q "\*-00"
+is a placeholder that means local time is unspecified.
 .TP
-.B UNTILYEAR [MONTH [DAY [TIME]]]
-The time at which the UTC offset or the rule(s) change for a location.
-It is specified as a year, a month, a day, and a time of day.
+.B UNTIL
+The time at which the UT offset or the rule(s) change for a location.
+It takes the form of one to four fields YEAR [MONTH [DAY [TIME]]].
 If this is specified,
-the time zone information is generated from the given UTC offset
-and rule change until the time specified.
+the time zone information is generated from the given UT offset
+and rule change until the time specified, which is interpreted using
+the rules in effect just before the transition.
 The month, day, and time of day have the same format as the IN, ON, and AT
 fields of a rule; trailing fields can be omitted, and default to the
 earliest possible value for the missing fields.
 .IP
 The next line must be a
-.q continuation
+.q "continuation"
 line; this has the same form as a zone line except that the
 string
-.q Zone
+.q "Zone"
 and the name are omitted, as the continuation line will
 place information starting at the time specified as the
-.q until
+.q "until"
 information in the previous line in the file used by the previous line.
 Continuation lines may contain
-.q until
+.q "until"
 information, just as zone lines do, indicating that the next line is a further
 continuation.
 .PP
+If a zone changes at the same instant that a rule would otherwise take
+effect in the earlier zone or continuation line, the rule is ignored.
+A zone or continuation line
+.I L
+with a named rule set starts with standard time by default:
+that is, any of
+.IR L 's
+timestamps preceding
+.IR L 's
+earliest rule use the rule in effect after
+.IR L 's
+first transition into standard time.
+In a single zone it is an error if two rules take effect at the same
+instant, or if two zone changes take effect at the same instant.
+.PP
+If a continuation line subtracts
+.I N
+seconds from the UT offset after a transition that would be
+interpreted to be later if using the continuation line's UT offset and
+rules, the
+.q "until"
+time of the previous zone or continuation line is interpreted
+according to the continuation line's UT offset and rules, and any rule
+that would otherwise take effect in the next
+.I N
+seconds is instead assumed to take effect simultaneously.
+For example:
+.br
+.ne 7
+.nf
+.in +2m
+.ta \w'# Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'2006\0\0'u +\w'\*-\0\0'u +\w'Oct\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
+.sp
+# Rule	NAME	FROM	TO	\*-	IN	ON	AT	SAVE	LETTER/S
+Rule	US	1967	2006	-	Oct	lastSun	2:00	0	S
+Rule	US	1967	1973	-	Apr	lastSun	2:00	1:00	D
+.ta \w'Zone\0\0America/Menominee\0\0'u +\w'STDOFF\0\0'u +\w'RULES\0\0'u +\w'FORMAT\0\0'u
+# Zone\0\0NAME	STDOFF	RULES	FORMAT	[UNTIL]
+Zone\0\0America/Menominee	\*-5:00	\*-	EST	1973 Apr 29 2:00
+	\*-6:00	US	C%sT
+.sp
+.in
+.fi
+Here, an incorrect reading would be there were two clock changes on 1973-04-29,
+the first from 02:00 EST (\*-05) to 01:00 CST (\*-06),
+and the second an hour later from 02:00 CST (\*-06) to 03:00 CDT (\*-05).
+However,
+.B zic
+interprets this more sensibly as a single transition from 02:00 CST (\*-05) to
+02:00 CDT (\*-05).
+.PP
 A link line has the form
 .sp
 .nf
 .ti +.5i
 .ta \w'Link\0\0'u +\w'Europe/Istanbul\0\0'u
-Link	LINK-FROM	LINK-TO
+Link	TARGET	LINK-NAME
 .sp
 For example:
 .sp
 .ti +.5i
 Link	Europe/Istanbul	Asia/Istanbul
 .sp
 .fi
 The
-.B LINK-FROM
+.B TARGET
 field should appear as the
 .B NAME
-field in some zone line;
-the
-.B LINK-TO
-field is used as an alternate name for that zone.
+field in some zone line.
+The
+.B LINK-NAME
+field is used as an alternative name for that zone;
+it has the same syntax as a zone line's
+.B NAME
+field.
 .PP
 Except for continuation lines,
 lines may appear in any order in the input.
+However, the behavior is unspecified if multiple zone or link lines
+define the same name, or if the source of one link line is the target
+of another.
 .PP
-Lines in the file that describes leap seconds have the following form:
+The file that describes leap seconds can have leap lines and an
+expiration line.
+Leap lines have the following form:
 .nf
 .ti +.5i
 .ta \w'Leap\0\0'u +\w'YEAR\0\0'u +\w'MONTH\0\0'u +\w'DAY\0\0'u +\w'HH:MM:SS\0\0'u +\w'CORR\0\0'u
 .sp
 Leap	YEAR	MONTH	DAY	HH:MM:SS	CORR	R/S
 .sp
 For example:
 .ti +.5i
 .sp
-Leap	1974	Dec	31	23:59:60	+	S
+Leap	2016	Dec	31	23:59:60	+	S
 .sp
 .fi
 The
 .BR YEAR ,
 .BR MONTH ,
 .BR DAY ,
 and
 .B HH:MM:SS
 fields tell when the leap second happened.
 The
 .B CORR
 field
 should be
-.q +
+.q "+"
 if a second was added
 or
-.q -
+.q "\*-"
 if a second was skipped.
-.\" There's no need to document the following, since it's impossible for more
-.\" than one leap second to be inserted or deleted at a time.
-.\" The C Standard is in error in suggesting the possibility.
-.\" See Terry J Quinn, The BIPM and the accurate measure of time,
-.\" Proc IEEE 79, 7 (July 1991), 894-905.
-.\"	or
-.\"	.q ++
-.\"	if two seconds were added
-.\"	or
-.\"	.q --
-.\"	if two seconds were skipped.
 The
 .B R/S
 field
 should be (an abbreviation of)
-.q Stationary
+.q "Stationary"
 if the leap second time given by the other fields should be interpreted as UTC
 or
 (an abbreviation of)
-.q Rolling
+.q "Rolling"
 if the leap second time given by the other fields should be interpreted as
-local wall clock time.
+local (wall clock) time.
+.PP
+Rolling leap seconds were implemented back when it was not
+clear whether common practice was rolling or stationary,
+with concerns that one would see
+Times Square ball drops where there'd be a
+.q "3... 2... 1... leap... Happy New Year"
+countdown, placing the leap second at
+midnight New York time rather than midnight UTC.
+However, this countdown style does not seem to have caught on,
+which means rolling leap seconds are not used in practice;
+also, they are not supported if the
+.B \*-r
+option is used.
+.PP
+The expiration line, if present, has the form:
+.nf
+.ti +.5i
+.ta \w'Expires\0\0'u +\w'YEAR\0\0'u +\w'MONTH\0\0'u +\w'DAY\0\0'u
+.sp
+Expires	YEAR	MONTH	DAY	HH:MM:SS
+.sp
+For example:
+.ti +.5i
+.sp
+Expires	2020	Dec	28	00:00:00
+.sp
+.fi
+The
+.BR YEAR ,
+.BR MONTH ,
+.BR DAY ,
+and
+.B HH:MM:SS
+fields give the expiration timestamp in UTC for the leap second table.
+.br
+.ne 22
 .SH "EXTENDED EXAMPLE"
 Here is an extended example of
-.I zic
+.B zic
 input, intended to illustrate many of its features.
-.br
-.ne 22
 .nf
 .in +2m
-.ta \w'# Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'TYPE\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
+.ta \w'# Rule\0\0'u +\w'NAME\0\0'u +\w'FROM\0\0'u +\w'1973\0\0'u +\w'\*-\0\0'u +\w'Apr\0\0'u +\w'lastSun\0\0'u +\w'2:00\0\0'u +\w'SAVE\0\0'u
 .sp
-# Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
-Rule	Swiss	1940	only	-	Nov	2	0:00	1:00	S
-Rule	Swiss	1940	only	-	Dec	31	0:00	0	-
-Rule	Swiss	1941	1942	-	May	Sun>=1	2:00	1:00	S
-Rule	Swiss	1941	1942	-	Oct	Sun>=1	0:00	0
+# Rule	NAME	FROM	TO	\*-	IN	ON	AT	SAVE	LETTER/S
+Rule	Swiss	1941	1942	\*-	May	Mon>=1	1:00	1:00	S
+Rule	Swiss	1941	1942	\*-	Oct	Mon>=1	2:00	0	\*-
 .sp .5
-Rule	EU	1977	1980	-	Apr	Sun>=1	1:00u	1:00	S
-Rule	EU	1977	only	-	Sep	lastSun	1:00u	0	-
-Rule	EU	1978	only	-	Oct	 1	1:00u	0	-
-Rule	EU	1979	1995	-	Sep	lastSun	1:00u	0	-
-Rule	EU	1981	max	-	Mar	lastSun	1:00u	1:00	S
-Rule	EU	1996	max	-	Oct	lastSun	1:00u	0	-
-.sp
-.ta \w'# Zone\0\0'u +\w'Europe/Zurich\0\0'u +\w'0:34:08\0\0'u +\w'RULES/SAVE\0\0'u +\w'FORMAT\0\0'u
-# Zone	NAME	GMTOFF	RULES	FORMAT	UNTIL
-Zone	Europe/Zurich	0:34:08	-	LMT	1848 Sep 12
-		0:29:44	-	BMT	1894 Jun
+Rule	EU	1977	1980	\*-	Apr	Sun>=1	1:00u	1:00	S
+Rule	EU	1977	only	\*-	Sep	lastSun	1:00u	0	\*-
+Rule	EU	1978	only	\*-	Oct	 1	1:00u	0	\*-
+Rule	EU	1979	1995	\*-	Sep	lastSun	1:00u	0	\*-
+Rule	EU	1981	max	\*-	Mar	lastSun	1:00u	1:00	S
+Rule	EU	1996	max	\*-	Oct	lastSun	1:00u	0	\*-
+.sp
+.ta \w'# Zone\0\0'u +\w'Europe/Zurich\0\0'u +\w'0:29:45.50\0\0'u +\w'RULES\0\0'u +\w'FORMAT\0\0'u
+# Zone	NAME	STDOFF	RULES	FORMAT	[UNTIL]
+Zone	Europe/Zurich	0:34:08	\*-	LMT	1853 Jul 16
+		0:29:45.50	\*-	BMT	1894 Jun
 		1:00	Swiss	CE%sT	1981
 		1:00	EU	CE%sT
 .sp
-Link	Europe/Zurich	Switzerland
+Link	Europe/Zurich	Europe/Vaduz
 .sp
 .in
 .fi
-In this example, the zone is named Europe/Zurich but it has an alias
-as Switzerland.  Zurich was 34 minutes and 8 seconds west of GMT until
-1848-09-12 at 00:00, when the offset changed to 29 minutes and 44
-seconds.  After 1894-06-01 at 00:00 Swiss daylight saving rules (defined
-with lines beginning with "Rule Swiss") apply, and the GMT offset
-became one hour.  From 1981 to the present, EU daylight saving rules have
+In this example, the EU rules are for the European Union
+and for its predecessor organization, the European Communities.
+The timezone is named Europe/Zurich and it has the alias Europe/Vaduz.
+This example says that Zurich was 34 minutes and 8
+seconds east of UT until 1853-07-16 at 00:00, when the legal offset
+was changed to
+7\*d\*_26\*m\*_22.50\*s,
+which works out to 0:29:45.50;
+.B zic
+treats this by rounding it to 0:29:46.
+After 1894-06-01 at 00:00 the UT offset became one hour
+and Swiss daylight saving rules (defined with lines beginning with
+.q "Rule Swiss")
+apply.  From 1981 to the present, EU daylight saving rules have
 applied, and the UTC offset has remained at one hour.
 .PP
-In 1940, daylight saving time applied from November 2 at 00:00 to
-December 31 at 00:00.  In 1941 and 1942, daylight saving time applied
-from the first Sunday in May at 02:00 to the first Sunday in October
-at 00:00.
+In 1941 and 1942, daylight saving time applied from the first Monday
+in May at 01:00 to the first Monday in October at 02:00.
 The pre-1981 EU daylight-saving rules have no effect
 here, but are included for completeness.  Since 1981, daylight
 saving has begun on the last Sunday in March at 01:00 UTC.
 Until 1995 it ended the last Sunday in September at 01:00 UTC,
 but this changed to the last Sunday in October starting in 1996.
 .PP
-For purposes of
-display, "LMT" and "BMT" were initially used, respectively.  Since
-Swiss rules and later EU rules were applied, the display name for the
-timezone has been CET for standard time and CEST for daylight saving
+For purposes of display,
+.q "LMT"
+and
+.q "BMT"
+were initially used, respectively.  Since
+Swiss rules and later EU rules were applied, the time zone abbreviation
+has been CET for standard time and CEST for daylight saving
 time.
+.SH FILES
+.TP
+.I /etc/localtime
+Default local timezone file.
+.TP
+.I /usr/share/zoneinfo
+Default timezone information directory.
 .SH NOTES
 For areas with more than two types of local time,
 you may need to use local standard time in the
 .B AT
 field of the earliest transition time's rule to ensure that
 the earliest transition time recorded in the compiled file is correct.
 .PP
 If,
-for a particular zone,
+for a particular timezone,
 a clock advance caused by the start of daylight saving
 coincides with and is equal to
-a clock retreat caused by a change in UTC offset,
-.IR zic
-produces a single transition to daylight saving at the new UTC offset
-(without any change in wall clock time).
+a clock retreat caused by a change in UT offset,
+.B zic
+produces a single transition to daylight saving at the new UT offset
+without any change in local (wall clock) time.
 To get separate transitions
 use multiple zone continuation lines
 specifying transition instants using universal time.
-.SH FILE
-/usr/local/etc/zoneinfo	standard directory used for created files
-.SH "SEE ALSO"
-newctime(3), tzfile(5), zdump(8)
-.\" @(#)zic.8	8.6
+.SH SEE ALSO
+.BR tzfile (5),
+.BR zdump (8)
 .\" This file is in the public domain, so clarified as of
 .\" 2009-05-17 by Arthur David Olson.
diff --git a/zic.8.txt b/zic.8.txt
index 1feada21482b..854ca579995d 100644
--- a/zic.8.txt
+++ b/zic.8.txt
@@ -1,313 +1,505 @@
-NAME
+ZIC(8)                      System Manager's Manual                     ZIC(8)
 
-     zic - time zone compiler
+NAME
+       zic - timezone compiler
 
 SYNOPSIS
-     zic [ --version ] [ -v ] [ -d directory ] [ -l localtime ] [
-     -p posixrules ] [ -L leapsecondfilename ] [ -s ] [ -y
-     command ] [ filename ... ]
+       zic [ option ... ] [ filename ... ]
 
 DESCRIPTION
-     Zic reads text from the file(s) named on the command line
-     and creates the time conversion information files specified
-     in this input.  If a filename is -, the standard input is
-     read.
-
-     These options are available:
-
-     --version
-          Output version information and exit.
-
-     -d directory
-          Create time conversion information files in the named
-          directory rather than in the standard directory named
-          below.
-
-     -l timezone
-          Use the given time zone as local time.  Zic will act as
-          if the input contained a link line of the form
-
-               Link timezone       localtime
-
-     -p timezone
-          Use the given time zone's rules when handling POSIX-
-          format time zone environment variables.  Zic will act
-          as if the input contained a link line of the form
-
-               Link timezone       posixrules
-
-     -L leapsecondfilename
-          Read leap second information from the file with the
-          given name.  If this option is not used, no leap second
-          information appears in output files.
-
-     -v   Complain if a year that appears in a data file is
-          outside the range of years representable by time(2)
-          values.  Also complain if a time of 24:00 (which cannot
-          be handled by pre-1998 versions of zic) appears in the
-          input.
-
-     -s   Limit time values stored in output files to values that
-          are the same whether they're taken to be signed or
-          unsigned.  You can use this option to generate SVVS-
-          compatible files.
-
-     -y command
-          Use the given command rather than yearistype when
-          checking year types (see below).
-
-     Input lines are made up of fields.  Fields are separated
-     from one another by any number of white space characters.
-     Leading and trailing white space on input lines is ignored.
-     An unquoted sharp character (#) in the input introduces a
-     comment which extends to the end of the line the sharp
-     character appears on.  White space characters and sharp
-     characters may be enclosed in double quotes (") if they're
-     to be used as part of a field.  Any line that is blank
-     (after comment stripping) is ignored.  Non-blank lines are
-     expected to be of one of three types: rule lines, zone
-     lines, and link lines.
-
-     Names (such as month names) must be in English and are case
-     insensitive.  Abbreviations, if used, must be unambiguous in
-     context.
-
-     A rule line has the form
-
-          Rule  NAME  FROM  TO    TYPE  IN   ON       AT    SAVE  LETTER/S
-
-     For example:
-
-          Rule  US    1967  1973  -     Apr  lastSun  2:00  1:00  D
-
-     The fields that make up a rule line are:
-
-     NAME    Gives the (arbitrary) name of the set of rules this
-             rule is part of.
-
-     FROM    Gives the first year in which the rule applies.  Any
-             integer year can be supplied; the Gregorian calendar
-             is assumed.  The word minimum (or an abbreviation)
-             means the minimum year representable as an integer.
-             The word maximum (or an abbreviation) means the
-             maximum year representable as an integer.  Rules can
-             describe times that are not representable as time
-             values, with the unrepresentable times ignored; this
-             allows rules to be portable among hosts with
-             differing time value types.
-
-     TO      Gives the final year in which the rule applies.  In
-             addition to minimum and maximum (as above), the word
-             only (or an abbreviation) may be used to repeat the
-             value of the FROM field.
-
-     TYPE    Gives the type of year in which the rule applies.
-             If TYPE is - then the rule applies in all years
-             between FROM and TO inclusive.  If TYPE is something
-             else, then zic executes the command
-                  yearistype year type
-             to check the type of a year: an exit status of zero
-             is taken to mean that the year is of the given type;
-             an exit status of one is taken to mean that the year
-             is not of the given type.
-
-     IN      Names the month in which the rule takes effect.
-             Month names may be abbreviated.
-
-     ON      Gives the day on which the rule takes effect.
-             Recognized forms include:
-
-                  5        the fifth of the month
-                  lastSun  the last Sunday in the month
-                  lastMon  the last Monday in the month
-                  Sun>=8   first Sunday on or after the eighth
-                  Sun<=25  last Sunday on or before the 25th
-
-             Names of days of the week may be abbreviated or
-             spelled out in full.  Note that there must be no
-             spaces within the ON field.
-
-     AT      Gives the time of day at which the rule takes
-             effect.  Recognized forms include:
-
-                  2        time in hours
-                  2:00     time in hours and minutes
-                  15:00    24-hour format time (for times after noon)
-                  1:28:14  time in hours, minutes, and seconds
-                  -        equivalent to 0
-
-             where hour 0 is midnight at the start of the day,
-             and hour 24 is midnight at the end of the day.  Any
-             of these forms may be followed by the letter w if
-             the given time is local "wall clock" time, s if the
-             given time is local "standard" time, or u (or g or
-             z) if the given time is universal time; in the
-             absence of an indicator, wall clock time is assumed.
-
-     SAVE    Gives the amount of time to be added to local
-             standard time when the rule is in effect.  This
-             field has the same format as the AT field (although,
-             of course, the w and s suffixes are not used).
-
-     LETTER/S
-             Gives the "variable part" (for example, the "S" or
-             "D" in "EST" or "EDT") of time zone abbreviations to
-             be used when this rule is in effect.  If this field
-             is -, the variable part is null.
-
-     A zone line has the form
-
-          Zone  NAME                GMTOFF  RULES/SAVE  FORMAT  [UNTILYEAR [MONTH [DAY [TIME]]]]
-
-     For example:
-
-          Zone  Australia/Adelaide  9:30    Aus         CST     1971 Oct 31 2:00
-
-     The fields that make up a zone line are:
-
-     NAME  The name of the time zone.  This is the name used in
-           creating the time conversion information file for the
-           zone.
-
-     GMTOFF
-           The amount of time to add to UTC to get standard time
-           in this zone.  This field has the same format as the
-           AT and SAVE fields of rule lines; begin the field with
-           a minus sign if time must be subtracted from UTC.
-
-     RULES/SAVE
-           The name of the rule(s) that apply in the time zone
-           or, alternately, an amount of time to add to local
-           standard time.  If this field is - then standard time
-           always applies in the time zone.
-
-     FORMAT
-           The format for time zone abbreviations in this time
-           zone.  The pair of characters %s is used to show where
-           the "variable part" of the time zone abbreviation
-           goes.  Alternately, a slash (/) separates standard and
-           daylight abbreviations.
-
-     UNTILYEAR [MONTH [DAY [TIME]]]
-           The time at which the UTC offset or the rule(s) change
-           for a location.  It is specified as a year, a month, a
-           day, and a time of day.  If this is specified, the
-           time zone information is generated from the given UTC
-           offset and rule change until the time specified.  The
-           month, day, and time of day have the same format as
-           the IN, ON, and AT fields of a rule; trailing fields
-           can be omitted, and default to the earliest possible
-           value for the missing fields.
-
-           The next line must be a "continuation" line; this has
-           the same form as a zone line except that the string
-           "Zone" and the name are omitted, as the continuation
-           line will place information starting at the time
-           specified as the "until" information in the previous
-           line in the file used by the previous line.
-           Continuation lines may contain "until" information,
-           just as zone lines do, indicating that the next line
-           is a further continuation.
-
-     A link line has the form
-
-          Link  LINK-FROM        LINK-TO
-
-     For example:
-
-          Link  Europe/Istanbul  Asia/Istanbul
-
-     The LINK-FROM field should appear as the NAME field in some
-     zone line; the LINK-TO field is used as an alternate name
-     for that zone.
-
-     Except for continuation lines, lines may appear in any order
-     in the input.
-
-     Lines in the file that describes leap seconds have the
-     following form:
-
-          Leap  YEAR  MONTH  DAY  HH:MM:SS  CORR  R/S
-
-     For example:
-
-          Leap  1974  Dec    31   23:59:60  +     S
-
-     The YEAR, MONTH, DAY, and HH:MM:SS fields tell when the leap
-     second happened.  The CORR field should be "+" if a second
-     was added or "-" if a second was skipped.  The R/S field
-     should be (an abbreviation of) "Stationary" if the leap
-     second time given by the other fields should be interpreted
-     as UTC or (an abbreviation of) "Rolling" if the leap second
-     time given by the other fields should be interpreted as
-     local wall clock time.
+       The zic program reads text from the file(s) named on the command line
+       and creates the timezone information format (TZif) files specified in
+       this input.  If a filename is "-", standard input is read.
+
+OPTIONS
+       --version
+              Output version information and exit.
+
+       --help Output short usage message and exit.
+
+       -b bloat
+              Output backward-compatibility data as specified by bloat.  If
+              bloat is fat, generate additional data entries that work around
+              potential bugs or incompatibilities in older software, such as
+              software that mishandles the 64-bit generated data.  If bloat is
+              slim, keep the output files small; this can help check for the
+              bugs and incompatibilities.  The default is slim, as software
+              that mishandles 64-bit data typically mishandles timestamps
+              after the year 2038 anyway.  Also see the -r option for another
+              way to alter output size.
+
+       -d directory
+              Create time conversion information files in the named directory
+              rather than in the standard directory named below.
+
+       -l timezone
+              Use timezone as local time.  zic will act as if the input
+              contained a link line of the form
+
+                   Link  timezone  localtime
+
+              If timezone is -, any already-existing link is removed.
+
+       -L leapsecondfilename
+              Read leap second information from the file with the given name.
+              If this option is not used, no leap second information appears
+              in output files.
+
+       -p timezone
+              Use timezone's rules when handling nonstandard TZ strings like
+              "EET-2EEST" that lack transition rules.  zic will act as if the
+              input contained a link line of the form
+
+                   Link  timezone  posixrules
+
+              This feature is obsolete and poorly supported.  Among other
+              things it should not be used for timestamps after the year 2037,
+              and it should not be combined with -b slim if timezone's
+              transitions are at standard time or Universal Time (UT) instead
+              of local time.
+
+              If timezone is -, any already-existing link is removed.
+
+       -r [@lo][/@hi]
+              Limit the applicability of output files to timestamps in the
+              range from lo (inclusive) to hi (exclusive), where lo and hi are
+              possibly-signed decimal counts of seconds since the Epoch
+              (1970-01-01 00:00:00 UTC).  Omitted counts default to extreme
+              values.  The output files use UT offset 0 and abbreviation "-00"
+              in place of the omitted timestamp data.  For example, "zic -r
+              @0" omits data intended for negative timestamps (i.e., before
+              the Epoch), and "zic -r @0/@2147483648" outputs data intended
+              only for nonnegative timestamps that fit into 31-bit signed
+              integers.  On platforms with GNU date, "zic -r @$(date +%s)"
+              omits data intended for past timestamps.  Although this option
+              typically reduces the output file's size, the size can increase
+              due to the need to represent the timestamp range boundaries,
+              particularly if hi causes a TZif file to contain explicit
+              entries for pre-hi transitions rather than concisely
+              representing them with an extended POSIX TZ string.  Also see
+              the -b slim option for another way to shrink output size.
+
+       -R @hi Generate redundant trailing explicit transitions for timestamps
+              that occur less than hi seconds since the Epoch, even though the
+              transitions could be more concisely represented via the extended
+              POSIX TZ string.  This option does not affect the represented
+              timestamps.  Although it accommodates nonstandard TZif readers
+              that ignore the extended POSIX TZ string, it increases the size
+              of the altered output files.
+
+       -t file
+              When creating local time information, put the configuration link
+              in the named file rather than in the standard location.
+
+       -v     Be more verbose, and complain about the following situations:
+
+              The input specifies a link to a link.
+
+              A year that appears in a data file is outside the range of
+              representable years.
+
+              A time of 24:00 or more appears in the input.  Pre-1998 versions
+              of zic prohibit 24:00, and pre-2007 versions prohibit times
+              greater than 24:00.
+
+              A rule goes past the start or end of the month.  Pre-2004
+              versions of zic prohibit this.
+
+              A time zone abbreviation uses a %z format.  Pre-2015 versions of
+              zic do not support this.
+
+              A timestamp contains fractional seconds.  Pre-2018 versions of
+              zic do not support this.
+
+              The input contains abbreviations that are mishandled by pre-2018
+              versions of zic due to a longstanding coding bug.  These
+              abbreviations include "L" for "Link", "mi" for "min", "Sa" for
+              "Sat", and "Su" for "Sun".
+
+              The output file does not contain all the information about the
+              long-term future of a timezone, because the future cannot be
+              summarized as an extended POSIX TZ string.  For example, as of
+              2019 this problem occurs for Iran's daylight-saving rules for
+              the predicted future, as these rules are based on the Iranian
+              calendar, which cannot be represented.
+
+              The output contains data that may not be handled properly by
+              client code designed for older zic output formats.  These
+              compatibility issues affect only timestamps before 1970 or after
+              the start of 2038.
+
+              The output contains a truncated leap second table, which can
+              cause some older TZif readers to misbehave.  This can occur if
+              the -L option is used, and either an Expires line is present or
+              the -r option is also used.
+
+              The output file contains more than 1200 transitions, which may
+              be mishandled by some clients.  The current reference client
+              supports at most 2000 transitions; pre-2014 versions of the
+              reference client support at most 1200 transitions.
+
+              A time zone abbreviation has fewer than 3 or more than 6
+              characters.  POSIX requires at least 3, and requires
+              implementations to support at least 6.
+
+              An output file name contains a byte that is not an ASCII letter,
+              "-", "/", or "_"; or it contains a file name component that
+              contains more than 14 bytes or that starts with "-".
+
+FILES
+       Input files use the format described in this section; output files use
+       tzfile(5) format.
+
+       Input files should be text files, that is, they should be a series of
+       zero or more lines, each ending in a newline byte and containing at
+       most 2048 bytes counting the newline, and without any NUL bytes.  The
+       input text's encoding is typically UTF-8 or ASCII; it should have a
+       unibyte representation for the POSIX Portable Character Set (PPCS)
+        and the encoding's non-unibyte characters should consist
+       entirely of non-PPCS bytes.  Non-PPCS characters typically occur only
+       in comments: although output file names and time zone abbreviations can
+       contain nearly any character, other software will work better if these
+       are limited to the restricted syntax described under the -v option.
+
+       Input lines are made up of fields.  Fields are separated from one
+       another by one or more white space characters.  The white space
+       characters are space, form feed, carriage return, newline, tab, and
+       vertical tab.  Leading and trailing white space on input lines is
+       ignored.  An unquoted sharp character (#) in the input introduces a
+       comment which extends to the end of the line the sharp character
+       appears on.  White space characters and sharp characters may be
+       enclosed in double quotes (") if they're to be used as part of a field.
+       Any line that is blank (after comment stripping) is ignored.  Nonblank
+       lines are expected to be of one of three types: rule lines, zone lines,
+       and link lines.
+
+       Names must be in English and are case insensitive.  They appear in
+       several contexts, and include month and weekday names and keywords such
+       as maximum, only, Rolling, and Zone.  A name can be abbreviated by
+       omitting all but an initial prefix; any abbreviation must be
+       unambiguous in context.
+
+       A rule line has the form
+
+            Rule  NAME  FROM  TO    -  IN   ON       AT     SAVE   LETTER/S
+
+       For example:
+
+            Rule  US    1967  1973  -  Apr  lastSun  2:00w  1:00d  D
+
+       The fields that make up a rule line are:
+
+       NAME    Gives the name of the rule set that contains this line.  The
+               name must start with a character that is neither an ASCII digit
+               nor "-" nor "+".  To allow for future extensions, an unquoted
+               name should not contain characters from the set
+               "!$%&'()*,/:;<=>?@[\]^`{|}~".
+
+       FROM    Gives the first year in which the rule applies.  Any signed
+               integer year can be supplied; the proleptic Gregorian calendar
+               is assumed, with year 0 preceding year 1.  The word minimum (or
+               an abbreviation) means the indefinite past.  The word maximum
+               (or an abbreviation) means the indefinite future.  Rules can
+               describe times that are not representable as time values, with
+               the unrepresentable times ignored; this allows rules to be
+               portable among hosts with differing time value types.
+
+       TO      Gives the final year in which the rule applies.  In addition to
+               minimum and maximum (as above), the word only (or an
+               abbreviation) may be used to repeat the value of the FROM
+               field.
+
+       -       Is a reserved field and should always contain "-" for
+               compatibility with older versions of zic.  It was previously
+               known as the TYPE field, which could contain values to allow a
+               separate script to further restrict in which "types" of years
+               the rule would apply.
+
+       IN      Names the month in which the rule takes effect.  Month names
+               may be abbreviated.
+
+       ON      Gives the day on which the rule takes effect.  Recognized forms
+               include:
+
+                    5        the fifth of the month
+                    lastSun  the last Sunday in the month
+                    lastMon  the last Monday in the month
+                    Sun>=8   first Sunday on or after the eighth
+                    Sun<=25  last Sunday on or before the 25th
+
+               A weekday name (e.g., Sunday) or a weekday name preceded by
+               "last" (e.g., lastSunday) may be abbreviated or spelled out in
+               full.  There must be no white space characters within the ON
+               field.  The "<=" and ">=" constructs can result in a day in the
+               neighboring month; for example, the IN-ON combination "Oct
+               Sun>=31" stands for the first Sunday on or after October 31,
+               even if that Sunday occurs in November.
+
+       AT      Gives the time of day at which the rule takes effect, relative
+               to 00:00, the start of a calendar day.  Recognized forms
+               include:
+
+                    2            time in hours
+                    2:00         time in hours and minutes
+                    01:28:14     time in hours, minutes, and seconds
+                    00:19:32.13  time with fractional seconds
+                    12:00        midday, 12 hours after 00:00
+                    15:00        3 PM, 15 hours after 00:00
+                    24:00        end of day, 24 hours after 00:00
+                    260:00       260 hours after 00:00
+                    -2:30        2.5 hours before 00:00
+                    -            equivalent to 0
+
+               Although zic rounds times to the nearest integer second
+               (breaking ties to the even integer), the fractions may be
+               useful to other applications requiring greater precision.  The
+               source format does not specify any maximum precision.  Any of
+               these forms may be followed by the letter w if the given time
+               is local or "wall clock" time, s if the given time is standard
+               time without any adjustment for daylight saving, or u (or g or
+               z) if the given time is universal time; in the absence of an
+               indicator, local (wall clock) time is assumed.  These forms
+               ignore leap seconds; for example, if a leap second occurs at
+               00:59:60 local time, "1:00" stands for 3601 seconds after local
+               midnight instead of the usual 3600 seconds.  The intent is that
+               a rule line describes the instants when a clock/calendar set to
+               the type of time specified in the AT field would show the
+               specified date and time of day.
+
+       SAVE    Gives the amount of time to be added to local standard time
+               when the rule is in effect, and whether the resulting time is
+               standard or daylight saving.  This field has the same format as
+               the AT field except with a different set of suffix letters: s
+               for standard time and d for daylight saving time.  The suffix
+               letter is typically omitted, and defaults to s if the offset is
+               zero and to d otherwise.  Negative offsets are allowed; in
+               Ireland, for example, daylight saving time is observed in
+               winter and has a negative offset relative to Irish Standard
+               Time.  The offset is merely added to standard time; for
+               example, zic does not distinguish a 10:30 standard time plus an
+               0:30 SAVE from a 10:00 standard time plus a 1:00 SAVE.
+
+       LETTER/S
+               Gives the "variable part" (for example, the "S" or "D" in "EST"
+               or "EDT") of time zone abbreviations to be used when this rule
+               is in effect.  If this field is "-", the variable part is null.
+
+       A zone line has the form
+
+            Zone  NAME        STDOFF  RULES   FORMAT  [UNTIL]
+
+       For example:
+
+            Zone  Asia/Amman  2:00    Jordan  EE%sT   2017 Oct 27 01:00
+
+       The fields that make up a zone line are:
+
+       NAME  The name of the timezone.  This is the name used in creating the
+             time conversion information file for the timezone.  It should not
+             contain a file name component "." or ".."; a file name component
+             is a maximal substring that does not contain "/".
+
+       STDOFF
+             The amount of time to add to UT to get standard time, without any
+             adjustment for daylight saving.  This field has the same format
+             as the AT and SAVE fields of rule lines, except without suffix
+             letters; begin the field with a minus sign if time must be
+             subtracted from UT.
+
+       RULES The name of the rules that apply in the timezone or,
+             alternatively, a field in the same format as a rule-line SAVE
+             column, giving the amount of time to be added to local standard
+             time and whether the resulting time is standard or daylight
+             saving.  If this field is - then standard time always applies.
+             When an amount of time is given, only the sum of standard time
+             and this amount matters.
+
+       FORMAT
+             The format for time zone abbreviations.  The pair of characters
+             %s is used to show where the "variable part" of the time zone
+             abbreviation goes.  Alternatively, a format can use the pair of
+             characters %z to stand for the UT offset in the form +-hh,
+             +-hhmm, or +-hhmmss, using the shortest form that does not lose
+             information, where hh, mm, and ss are the hours, minutes, and
+             seconds east (+) or west (-) of UT.  Alternatively, a slash (/)
+             separates standard and daylight abbreviations.  To conform to
+             POSIX, a time zone abbreviation should contain only alphanumeric
+             ASCII characters, "+" and "-".  By convention, the time zone
+             abbreviation "-00" is a placeholder that means local time is
+             unspecified.
+
+       UNTIL The time at which the UT offset or the rule(s) change for a
+             location.  It takes the form of one to four fields YEAR [MONTH
+             [DAY [TIME]]].  If this is specified, the time zone information
+             is generated from the given UT offset and rule change until the
+             time specified, which is interpreted using the rules in effect
+             just before the transition.  The month, day, and time of day have
+             the same format as the IN, ON, and AT fields of a rule; trailing
+             fields can be omitted, and default to the earliest possible value
+             for the missing fields.
+
+             The next line must be a "continuation" line; this has the same
+             form as a zone line except that the string "Zone" and the name
+             are omitted, as the continuation line will place information
+             starting at the time specified as the "until" information in the
+             previous line in the file used by the previous line.
+             Continuation lines may contain "until" information, just as zone
+             lines do, indicating that the next line is a further
+             continuation.
+
+       If a zone changes at the same instant that a rule would otherwise take
+       effect in the earlier zone or continuation line, the rule is ignored.
+       A zone or continuation line L with a named rule set starts with
+       standard time by default: that is, any of L's timestamps preceding L's
+       earliest rule use the rule in effect after L's first transition into
+       standard time.  In a single zone it is an error if two rules take
+       effect at the same instant, or if two zone changes take effect at the
+       same instant.
+
+       If a continuation line subtracts N seconds from the UT offset after a
+       transition that would be interpreted to be later if using the
+       continuation line's UT offset and rules, the "until" time of the
+       previous zone or continuation line is interpreted according to the
+       continuation line's UT offset and rules, and any rule that would
+       otherwise take effect in the next N seconds is instead assumed to take
+       effect simultaneously.  For example:
+
+         # Rule  NAME  FROM  TO    -  IN   ON       AT    SAVE  LETTER/S
+         Rule    US    1967  2006  -  Oct  lastSun  2:00  0     S
+         Rule    US    1967  1973  -  Apr  lastSun  2:00  1:00  D
+         # Zone  NAME             STDOFF  RULES  FORMAT  [UNTIL]
+         Zone  America/Menominee  -5:00   -      EST     1973 Apr 29 2:00
+                                  -6:00   US     C%sT
+
+       Here, an incorrect reading would be there were two clock changes on
+       1973-04-29, the first from 02:00 EST (-05) to 01:00 CST (-06), and the
+       second an hour later from 02:00 CST (-06) to 03:00 CDT (-05).  However,
+       zic interprets this more sensibly as a single transition from 02:00 CST
+       (-05) to 02:00 CDT (-05).
+
+       A link line has the form
+
+            Link  TARGET           LINK-NAME
+
+       For example:
+
+            Link  Europe/Istanbul  Asia/Istanbul
+
+       The TARGET field should appear as the NAME field in some zone line.
+       The LINK-NAME field is used as an alternative name for that zone; it
+       has the same syntax as a zone line's NAME field.
+
+       Except for continuation lines, lines may appear in any order in the
+       input.  However, the behavior is unspecified if multiple zone or link
+       lines define the same name, or if the source of one link line is the
+       target of another.
+
+       The file that describes leap seconds can have leap lines and an
+       expiration line.  Leap lines have the following form:
+
+            Leap  YEAR  MONTH  DAY  HH:MM:SS  CORR  R/S
+
+       For example:
+
+            Leap  2016  Dec    31   23:59:60  +     S
+
+       The YEAR, MONTH, DAY, and HH:MM:SS fields tell when the leap second
+       happened.  The CORR field should be "+" if a second was added or "-" if
+       a second was skipped.  The R/S field should be (an abbreviation of)
+       "Stationary" if the leap second time given by the other fields should
+       be interpreted as UTC or (an abbreviation of) "Rolling" if the leap
+       second time given by the other fields should be interpreted as local
+       (wall clock) time.
+
+       Rolling leap seconds were implemented back when it was not clear
+       whether common practice was rolling or stationary, with concerns that
+       one would see Times Square ball drops where there'd be a "3... 2...
+       1... leap... Happy New Year" countdown, placing the leap second at
+       midnight New York time rather than midnight UTC.  However, this
+       countdown style does not seem to have caught on, which means rolling
+       leap seconds are not used in practice; also, they are not supported if
+       the -r option is used.
+
+       The expiration line, if present, has the form:
+
+            Expires  YEAR  MONTH  DAY  HH:MM:SS
+
+       For example:
+
+            Expires  2020  Dec    28   00:00:00
+
+       The YEAR, MONTH, DAY, and HH:MM:SS fields give the expiration timestamp
+       in UTC for the leap second table.
 
 EXTENDED EXAMPLE
-     Here is an extended example of zic input, intended to
-     illustrate many of its features.
-
-       # Rule  NAME  FROM  TO    TYPE  IN   ON       AT    SAVE  LETTER/S
-       Rule    Swiss 1940  only  -     Nov  2        0:00  1:00  S
-       Rule    Swiss 1940  only  -     Dec  31       0:00  0     -
-       Rule    Swiss 1941  1942  -     May  Sun>=1   2:00  1:00  S
-       Rule    Swiss 1941  1942  -     Oct  Sun>=1   0:00  0
-       Rule    EU    1977  1980  -     Apr  Sun>=1   1:00u 1:00  S
-       Rule    EU    1977  only  -     Sep  lastSun  1:00u 0     -
-       Rule    EU    1978  only  -     Oct   1       1:00u 0     -
-       Rule    EU    1979  1995  -     Sep  lastSun  1:00u 0     -
-       Rule    EU    1981  max   -     Mar  lastSun  1:00u 1:00  S
-       Rule    EU    1996  max   -     Oct  lastSun  1:00u 0     -
-
-       # Zone  NAME           GMTOFF   RULES       FORMAT  UNTIL
-       Zone    Europe/Zurich  0:34:08  -           LMT     1848 Sep 12
-                              0:29:44  -           BMT     1894 Jun
-                              1:00     Swiss       CE%sT   1981
-                              1:00     EU          CE%sT
-
-       Link    Europe/Zurich  Switzerland
-
-     In this example, the zone is named Europe/Zurich but it has
-     an alias as Switzerland.  Zurich was 34 minutes and 8
-     seconds west of GMT until 1848-09-12 at 00:00, when the
-     offset changed to 29 minutes and 44 seconds.  After
-     1894-06-01 at 00:00 Swiss daylight saving rules (defined
-     with lines beginning with "Rule Swiss") apply, and the GMT
-     offset became one hour.  From 1981 to the present, EU
-     daylight saving rules have applied, and the UTC offset has
-     remained at one hour.
-
-     In 1940, daylight saving time applied from November 2 at
-     00:00 to December 31 at 00:00.  In 1941 and 1942, daylight
-     saving time applied from the first Sunday in May at 02:00 to
-     the first Sunday in October at 00:00.  The pre-1981 EU
-     daylight-saving rules have no effect here, but are included
-     for completeness.  Since 1981, daylight saving has begun on
-     the last Sunday in March at 01:00 UTC.  Until 1995 it ended
-     the last Sunday in September at 01:00 UTC, but this changed
-     to the last Sunday in October starting in 1996.
-
-     For purposes of display, "LMT" and "BMT" were initially
-     used, respectively.  Since Swiss rules and later EU rules
-     were applied, the display name for the timezone has been CET
-     for standard time and CEST for daylight saving time.
+       Here is an extended example of zic input, intended to illustrate many
+       of its features.
+
+         # Rule  NAME  FROM  TO    -  IN   ON       AT    SAVE  LETTER/S
+         Rule    Swiss 1941  1942  -  May  Mon>=1   1:00  1:00  S
+         Rule    Swiss 1941  1942  -  Oct  Mon>=1   2:00  0     -
+         Rule    EU    1977  1980  -  Apr  Sun>=1   1:00u 1:00  S
+         Rule    EU    1977  only  -  Sep  lastSun  1:00u 0     -
+         Rule    EU    1978  only  -  Oct   1       1:00u 0     -
+         Rule    EU    1979  1995  -  Sep  lastSun  1:00u 0     -
+         Rule    EU    1981  max   -  Mar  lastSun  1:00u 1:00  S
+         Rule    EU    1996  max   -  Oct  lastSun  1:00u 0     -
+
+         # Zone  NAME           STDOFF      RULES  FORMAT  [UNTIL]
+         Zone    Europe/Zurich  0:34:08     -      LMT     1853 Jul 16
+                                0:29:45.50  -      BMT     1894 Jun
+                                1:00        Swiss  CE%sT   1981
+                                1:00        EU     CE%sT
+
+         Link    Europe/Zurich  Europe/Vaduz
+
+       In this example, the EU rules are for the European Union and for its
+       predecessor organization, the European Communities.  The timezone is
+       named Europe/Zurich and it has the alias Europe/Vaduz.  This example
+       says that Zurich was 34 minutes and 8 seconds east of UT until
+       1853-07-16 at 00:00, when the legal offset was changed to 7 degrees 26
+       minutes 22.50 seconds, which works out to 0:29:45.50; zic treats this
+       by rounding it to 0:29:46.  After 1894-06-01 at 00:00 the UT offset
+       became one hour and Swiss daylight saving rules (defined with lines
+       beginning with "Rule Swiss") apply.  From 1981 to the present, EU
+       daylight saving rules have applied, and the UTC offset has remained at
+       one hour.
+
+       In 1941 and 1942, daylight saving time applied from the first Monday in
+       May at 01:00 to the first Monday in October at 02:00.  The pre-1981 EU
+       daylight-saving rules have no effect here, but are included for
+       completeness.  Since 1981, daylight saving has begun on the last Sunday
+       in March at 01:00 UTC.  Until 1995 it ended the last Sunday in
+       September at 01:00 UTC, but this changed to the last Sunday in October
+       starting in 1996.
+
+       For purposes of display, "LMT" and "BMT" were initially used,
+       respectively.  Since Swiss rules and later EU rules were applied, the
+       time zone abbreviation has been CET for standard time and CEST for
+       daylight saving time.
+
+FILES
+       /etc/localtime
+              Default local timezone file.
+
+       /usr/share/zoneinfo
+              Default timezone information directory.
 
 NOTES
-     For areas with more than two types of local time, you may
-     need to use local standard time in the AT field of the
-     earliest transition time's rule to ensure that the earliest
-     transition time recorded in the compiled file is correct.
-
-     If, for a particular zone, a clock advance caused by the
-     start of daylight saving coincides with and is equal to a
-     clock retreat caused by a change in UTC offset, zic produces
-     a single transition to daylight saving at the new UTC offset
-     (without any change in wall clock time).  To get separate
-     transitions use multiple zone continuation lines specifying
-     transition instants using universal time.
-
-FILE
-     /usr/local/etc/zoneinfo         standard directory used for
-     created files
+       For areas with more than two types of local time, you may need to use
+       local standard time in the AT field of the earliest transition time's
+       rule to ensure that the earliest transition time recorded in the
+       compiled file is correct.
+
+       If, for a particular timezone, a clock advance caused by the start of
+       daylight saving coincides with and is equal to a clock retreat caused
+       by a change in UT offset, zic produces a single transition to daylight
+       saving at the new UT offset without any change in local (wall clock)
+       time.  To get separate transitions use multiple zone continuation lines
+       specifying transition instants using universal time.
 
 SEE ALSO
-     newctime(3), tzfile(5), zdump(8)
+       tzfile(5), zdump(8)
+
+                                                                        ZIC(8)
diff --git a/zic.c b/zic.c
index a75d8c75e88c..ff0479374515 100644
--- a/zic.c
+++ b/zic.c
@@ -1,2771 +1,3690 @@
+/* Compile .zi time zone data into TZif binary files.  */
+
 /*
 ** This file is in the public domain, so clarified as of
 ** 2006-07-17 by Arthur David Olson.
 */
 
-static char	elsieid[] = "@(#)zic.c	8.24";
+/* Use the system 'time' function, instead of any private replacement.
+   This avoids creating an unnecessary dependency on localtime.c.  */
+#undef EPOCH_LOCAL
+#undef EPOCH_OFFSET
+#undef RESERVE_STD_EXT_IDS
+#undef time_tz
 
+#include "version.h"
 #include "private.h"
-#include "locale.h"
 #include "tzfile.h"
 
-#define	ZIC_VERSION	'2'
+#include 
+#include 
+#include 
+#include 
+#include 
+#include 
 
 typedef int_fast64_t	zic_t;
+#define ZIC_MIN INT_FAST64_MIN
+#define ZIC_MAX INT_FAST64_MAX
+#define SCNdZIC SCNdFAST64
 
 #ifndef ZIC_MAX_ABBR_LEN_WO_WARN
-#define ZIC_MAX_ABBR_LEN_WO_WARN	6
+# define ZIC_MAX_ABBR_LEN_WO_WARN 6
 #endif /* !defined ZIC_MAX_ABBR_LEN_WO_WARN */
 
+#ifdef HAVE_DIRECT_H
+# include 
+# include 
+# undef mkdir
+# define mkdir(name, mode) _mkdir(name)
+#endif
+
 #if HAVE_SYS_STAT_H
-#include "sys/stat.h"
+# include 
 #endif
 #ifdef S_IRUSR
-#define MKDIR_UMASK (S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
+# define MKDIR_UMASK (S_IRUSR|S_IWUSR|S_IXUSR|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
 #else
-#define MKDIR_UMASK 0755
+# define MKDIR_UMASK 0755
 #endif
 
-/*
-** On some ancient hosts, predicates like `isspace(C)' are defined
-** only if isascii(C) || C == EOF. Modern hosts obey the C Standard,
-** which says they are defined only if C == ((unsigned char) C) || C == EOF.
-** Neither the C Standard nor Posix require that `isascii' exist.
-** For portability, we check both ancient and modern requirements.
-** If isascii is not defined, the isascii check succeeds trivially.
-*/
-#include "ctype.h"
-#ifndef isascii
-#define isascii(x) 1
+/* The maximum ptrdiff_t value, for pre-C99 platforms.  */
+#ifndef PTRDIFF_MAX
+static ptrdiff_t const PTRDIFF_MAX = MAXVAL(ptrdiff_t, TYPE_BIT(ptrdiff_t));
+#endif
+
+/* The minimum alignment of a type, for pre-C11 platforms.  */
+#if __STDC_VERSION__ < 201112
+# define _Alignof(type) offsetof(struct { char a; type b; }, b)
 #endif
 
-#define OFFSET_STRLEN_MAXIMUM	(7 + INT_STRLEN_MAXIMUM(long))
-#define RULE_STRLEN_MAXIMUM	8	/* "Mdd.dd.d" */
+/* The maximum length of a text line, including the trailing newline.  */
+#ifndef _POSIX2_LINE_MAX
+# define _POSIX2_LINE_MAX 2048
+#endif
 
-#define end(cp)	(strchr((cp), '\0'))
+/* The type for line numbers.  Use PRIdMAX to format them; formerly
+   there was also "#define PRIdLINENO PRIdMAX" and formats used
+   PRIdLINENO, but xgettext cannot grok that.  */
+typedef intmax_t lineno;
 
 struct rule {
 	const char *	r_filename;
-	int		r_linenum;
+	lineno		r_linenum;
 	const char *	r_name;
 
-	int		r_loyear;	/* for example, 1986 */
-	int		r_hiyear;	/* for example, 1986 */
-	const char *	r_yrtype;
-	int		r_lowasnum;
-	int		r_hiwasnum;
+	zic_t		r_loyear;	/* for example, 1986 */
+	zic_t		r_hiyear;	/* for example, 1986 */
+	bool		r_lowasnum;
+	bool		r_hiwasnum;
 
 	int		r_month;	/* 0..11 */
 
 	int		r_dycode;	/* see below */
 	int		r_dayofmonth;
 	int		r_wday;
 
-	long		r_tod;		/* time from midnight */
-	int		r_todisstd;	/* above is standard time if TRUE */
-					/* or wall clock time if FALSE */
-	int		r_todisgmt;	/* above is GMT if TRUE */
-					/* or local time if FALSE */
-	long		r_stdoff;	/* offset from standard time */
+	zic_t		r_tod;		/* time from midnight */
+	bool		r_todisstd;	/* is r_tod standard time? */
+	bool		r_todisut;	/* is r_tod UT? */
+	bool		r_isdst;	/* is this daylight saving time? */
+	zic_t		r_save;		/* offset from standard time */
 	const char *	r_abbrvar;	/* variable part of abbreviation */
 
-	int		r_todo;		/* a rule to do (used in outzone) */
+	bool		r_todo;		/* a rule to do (used in outzone) */
 	zic_t		r_temp;		/* used in outzone */
 };
 
 /*
-**	r_dycode		r_dayofmonth	r_wday
+** r_dycode	r_dayofmonth	r_wday
 */
-
-#define DC_DOM		0	/* 1..31 */	/* unused */
-#define DC_DOWGEQ	1	/* 1..31 */	/* 0..6 (Sun..Sat) */
-#define DC_DOWLEQ	2	/* 1..31 */	/* 0..6 (Sun..Sat) */
+enum {
+  DC_DOM,	/* 1..31 */	/* unused */
+  DC_DOWGEQ,	/* 1..31 */	/* 0..6 (Sun..Sat) */
+  DC_DOWLEQ	/* 1..31 */	/* 0..6 (Sun..Sat) */
+};
 
 struct zone {
 	const char *	z_filename;
-	int		z_linenum;
+	lineno		z_linenum;
 
 	const char *	z_name;
-	long		z_gmtoff;
-	const char *	z_rule;
+	zic_t		z_stdoff;
+	char *		z_rule;
 	const char *	z_format;
+	char		z_format_specifier;
 
-	long		z_stdoff;
+	bool		z_isdst;
+	zic_t		z_save;
 
 	struct rule *	z_rules;
-	int		z_nrules;
+	ptrdiff_t	z_nrules;
 
 	struct rule	z_untilrule;
 	zic_t		z_untiltime;
 };
 
+#if !HAVE_POSIX_DECLS
 extern int	getopt(int argc, char * const argv[],
 			const char * options);
-extern int	link(const char * fromname, const char * toname);
+extern int	link(const char * target, const char * linkname);
 extern char *	optarg;
 extern int	optind;
+#endif
+
+#if ! HAVE_LINK
+# define link(target, linkname) (errno = ENOTSUP, -1)
+#endif
+#if ! HAVE_SYMLINK
+# define readlink(file, buf, size) (errno = ENOTSUP, -1)
+# define symlink(target, linkname) (errno = ENOTSUP, -1)
+# define S_ISLNK(m) 0
+#endif
+#ifndef AT_SYMLINK_FOLLOW
+# define linkat(targetdir, target, linknamedir, linkname, flag) \
+    (itssymlink(target) ? (errno = ENOTSUP, -1) : link(target, linkname))
+#endif
 
 static void	addtt(zic_t starttime, int type);
-static int	addtype(long gmtoff, const char * abbr, int isdst,
-				int ttisstd, int ttisgmt);
-static void	leapadd(zic_t t, int positive, int rolling, int count);
+static int	addtype(zic_t, char const *, bool, bool, bool);
+static void	leapadd(zic_t, int, int);
 static void	adjleap(void);
 static void	associate(void);
-static int	ciequal(const char * ap, const char * bp);
-static void	convert(long val, char * buf);
-static void	convert64(zic_t val, char * buf);
-static void	dolink(const char * fromfield, const char * tofield);
-static void	doabbr(char * abbr, const char * format,
-			const char * letters, int isdst, int doquotes);
-static void	eat(const char * name, int num);
-static void	eats(const char * name, int num,
-			const char * rname, int rnum);
-static long	eitol(int i);
-static void	error(const char * message);
-static char **	getfields(char * buf);
-static long	gethms(const char * string, const char * errstrng,
-			int signable);
+static void	dolink(const char *, const char *, bool);
+static int	getfields(char *, char **, int);
+static zic_t	gethms(const char * string, const char * errstring);
+static zic_t	getsave(char *, bool *);
+static void	inexpires(char **, int);
 static void	infile(const char * filename);
 static void	inleap(char ** fields, int nfields);
 static void	inlink(char ** fields, int nfields);
 static void	inrule(char ** fields, int nfields);
-static int	inzcont(char ** fields, int nfields);
-static int	inzone(char ** fields, int nfields);
-static int	inzsub(char ** fields, int nfields, int iscont);
-static int	is32(zic_t x);
-static int	itsabbr(const char * abbr, const char * word);
-static int	itsdir(const char * name);
-static int	lowerit(int c);
-static char *	memcheck(char * tocheck);
-static int	mkdirs(char * filename);
+static bool	inzcont(char ** fields, int nfields);
+static bool	inzone(char ** fields, int nfields);
+static bool	inzsub(char **, int, bool);
+static bool	itssymlink(char const *);
+static bool	is_alpha(char a);
+static char	lowerit(char);
+static void	mkdirs(char const *, bool);
 static void	newabbr(const char * abbr);
-static long	oadd(long t1, long t2);
-static void	outzone(const struct zone * zp, int ntzones);
-static void	puttzcode(long code, FILE * fp);
-static void	puttzcode64(zic_t code, FILE * fp);
-static int	rcomp(const void * leftp, const void * rightp);
-static zic_t	rpytime(const struct rule * rp, int wantedy);
-static void	rulesub(struct rule * rp,
+static zic_t	oadd(zic_t t1, zic_t t2);
+static void	outzone(const struct zone * zp, ptrdiff_t ntzones);
+static zic_t	rpytime(const struct rule * rp, zic_t wantedy);
+static bool	rulesub(struct rule * rp,
 			const char * loyearp, const char * hiyearp,
 			const char * typep, const char * monthp,
 			const char * dayp, const char * timep);
-static int 	stringoffset(char * result, long offset);
-static int	stringrule(char * result, const struct rule * rp,
-			long dstoff, long gmtoff);
-static void 	stringzone(char * result,
-			const struct zone * zp, int ntzones);
-static void	setboundaries(void);
-static zic_t	tadd(zic_t t1, long t2);
-static void	usage(FILE *stream, int status);
-static void	writezone(const char * name, const char * string);
-static int	yearistype(int year, const char * type);
+static zic_t	tadd(zic_t t1, zic_t t2);
+
+/* Bound on length of what %z can expand to.  */
+enum { PERCENT_Z_LEN_BOUND = sizeof "+995959" - 1 };
+
+/* If true, work around a bug in Qt 5.6.1 and earlier, which mishandles
+   TZif files whose POSIX-TZ-style strings contain '<'; see
+   QTBUG-53071 .  This
+   workaround will no longer be needed when Qt 5.6.1 and earlier are
+   obsolete, say in the year 2021.  */
+#ifndef WORK_AROUND_QTBUG_53071
+enum { WORK_AROUND_QTBUG_53071 = true };
+#endif
 
 static int		charcnt;
-static int		errors;
+static bool		errors;
+static bool		warnings;
 static const char *	filename;
 static int		leapcnt;
-static int		leapseen;
-static int		leapminyear;
-static int		leapmaxyear;
-static int		linenum;
-static int		max_abbrvar_len;
+static bool		leapseen;
+static zic_t		leapminyear;
+static zic_t		leapmaxyear;
+static lineno		linenum;
+static int		max_abbrvar_len = PERCENT_Z_LEN_BOUND;
 static int		max_format_len;
-static zic_t		max_time;
-static int		max_year;
-static zic_t		min_time;
-static int		min_year;
-static int		noise;
+static zic_t		max_year;
+static zic_t		min_year;
+static bool		noise;
 static const char *	rfilename;
-static int		rlinenum;
+static lineno		rlinenum;
 static const char *	progname;
-static int		timecnt;
+static ptrdiff_t	timecnt;
+static ptrdiff_t	timecnt_alloc;
 static int		typecnt;
+static int		unspecifiedtype;
 
 /*
 ** Line codes.
 */
 
-#define LC_RULE		0
-#define LC_ZONE		1
-#define LC_LINK		2
-#define LC_LEAP		3
+enum {
+  LC_RULE,
+  LC_ZONE,
+  LC_LINK,
+  LC_LEAP,
+  LC_EXPIRES
+};
 
 /*
 ** Which fields are which on a Zone line.
 */
 
-#define ZF_NAME		1
-#define ZF_GMTOFF	2
-#define ZF_RULE		3
-#define ZF_FORMAT	4
-#define ZF_TILYEAR	5
-#define ZF_TILMONTH	6
-#define ZF_TILDAY	7
-#define ZF_TILTIME	8
-#define ZONE_MINFIELDS	5
-#define ZONE_MAXFIELDS	9
+enum {
+  ZF_NAME = 1,
+  ZF_STDOFF,
+  ZF_RULE,
+  ZF_FORMAT,
+  ZF_TILYEAR,
+  ZF_TILMONTH,
+  ZF_TILDAY,
+  ZF_TILTIME,
+  ZONE_MAXFIELDS,
+  ZONE_MINFIELDS = ZF_TILYEAR
+};
 
 /*
 ** Which fields are which on a Zone continuation line.
 */
 
-#define ZFC_GMTOFF	0
-#define ZFC_RULE	1
-#define ZFC_FORMAT	2
-#define ZFC_TILYEAR	3
-#define ZFC_TILMONTH	4
-#define ZFC_TILDAY	5
-#define ZFC_TILTIME	6
-#define ZONEC_MINFIELDS	3
-#define ZONEC_MAXFIELDS	7
+enum {
+  ZFC_STDOFF,
+  ZFC_RULE,
+  ZFC_FORMAT,
+  ZFC_TILYEAR,
+  ZFC_TILMONTH,
+  ZFC_TILDAY,
+  ZFC_TILTIME,
+  ZONEC_MAXFIELDS,
+  ZONEC_MINFIELDS = ZFC_TILYEAR
+};
 
 /*
 ** Which files are which on a Rule line.
 */
 
-#define RF_NAME		1
-#define RF_LOYEAR	2
-#define RF_HIYEAR	3
-#define RF_COMMAND	4
-#define RF_MONTH	5
-#define RF_DAY		6
-#define RF_TOD		7
-#define RF_STDOFF	8
-#define RF_ABBRVAR	9
-#define RULE_FIELDS	10
+enum {
+  RF_NAME = 1,
+  RF_LOYEAR,
+  RF_HIYEAR,
+  RF_COMMAND,
+  RF_MONTH,
+  RF_DAY,
+  RF_TOD,
+  RF_SAVE,
+  RF_ABBRVAR,
+  RULE_FIELDS
+};
 
 /*
 ** Which fields are which on a Link line.
 */
 
-#define LF_FROM		1
-#define LF_TO		2
-#define LINK_FIELDS	3
+enum {
+  LF_TARGET = 1,
+  LF_LINKNAME,
+  LINK_FIELDS
+};
 
 /*
 ** Which fields are which on a Leap line.
 */
 
-#define LP_YEAR		1
-#define LP_MONTH	2
-#define LP_DAY		3
-#define LP_TIME		4
-#define LP_CORR		5
-#define LP_ROLL		6
-#define LEAP_FIELDS	7
+enum {
+  LP_YEAR = 1,
+  LP_MONTH,
+  LP_DAY,
+  LP_TIME,
+  LP_CORR,
+  LP_ROLL,
+  LEAP_FIELDS,
+
+  /* Expires lines are like Leap lines, except without CORR and ROLL fields.  */
+  EXPIRES_FIELDS = LP_TIME + 1
+};
+
+/* The maximum number of fields on any of the above lines.
+   (The "+"s pacify gcc -Wenum-compare.)  */
+enum {
+  MAX_FIELDS = max(max(+RULE_FIELDS, +LINK_FIELDS),
+		   max(+LEAP_FIELDS, +EXPIRES_FIELDS))
+};
 
 /*
 ** Year synonyms.
 */
 
-#define YR_MINIMUM	0
-#define YR_MAXIMUM	1
-#define YR_ONLY		2
+enum {
+  YR_MINIMUM,
+  YR_MAXIMUM,
+  YR_ONLY
+};
 
 static struct rule *	rules;
-static int		nrules;	/* number of rules */
+static ptrdiff_t	nrules;	/* number of rules */
+static ptrdiff_t	nrules_alloc;
 
 static struct zone *	zones;
-static int		nzones;	/* number of zones */
+static ptrdiff_t	nzones;	/* number of zones */
+static ptrdiff_t	nzones_alloc;
 
 struct link {
 	const char *	l_filename;
-	int		l_linenum;
-	const char *	l_from;
-	const char *	l_to;
+	lineno		l_linenum;
+	const char *	l_target;
+	const char *	l_linkname;
 };
 
 static struct link *	links;
-static int		nlinks;
+static ptrdiff_t	nlinks;
+static ptrdiff_t	nlinks_alloc;
 
 struct lookup {
 	const char *	l_word;
 	const int	l_value;
 };
 
 static struct lookup const *	byword(const char * string,
 					const struct lookup * lp);
 
-static struct lookup const	line_codes[] = {
+static struct lookup const zi_line_codes[] = {
 	{ "Rule",	LC_RULE },
 	{ "Zone",	LC_ZONE },
 	{ "Link",	LC_LINK },
+	{ NULL,		0 }
+};
+static struct lookup const leap_line_codes[] = {
 	{ "Leap",	LC_LEAP },
+	{ "Expires",	LC_EXPIRES },
 	{ NULL,		0}
 };
 
 static struct lookup const	mon_names[] = {
 	{ "January",	TM_JANUARY },
 	{ "February",	TM_FEBRUARY },
 	{ "March",	TM_MARCH },
 	{ "April",	TM_APRIL },
 	{ "May",	TM_MAY },
 	{ "June",	TM_JUNE },
 	{ "July",	TM_JULY },
 	{ "August",	TM_AUGUST },
 	{ "September",	TM_SEPTEMBER },
 	{ "October",	TM_OCTOBER },
 	{ "November",	TM_NOVEMBER },
 	{ "December",	TM_DECEMBER },
 	{ NULL,		0 }
 };
 
 static struct lookup const	wday_names[] = {
 	{ "Sunday",	TM_SUNDAY },
 	{ "Monday",	TM_MONDAY },
 	{ "Tuesday",	TM_TUESDAY },
 	{ "Wednesday",	TM_WEDNESDAY },
 	{ "Thursday",	TM_THURSDAY },
 	{ "Friday",	TM_FRIDAY },
 	{ "Saturday",	TM_SATURDAY },
 	{ NULL,		0 }
 };
 
 static struct lookup const	lasts[] = {
 	{ "last-Sunday",	TM_SUNDAY },
 	{ "last-Monday",	TM_MONDAY },
 	{ "last-Tuesday",	TM_TUESDAY },
 	{ "last-Wednesday",	TM_WEDNESDAY },
 	{ "last-Thursday",	TM_THURSDAY },
 	{ "last-Friday",	TM_FRIDAY },
 	{ "last-Saturday",	TM_SATURDAY },
 	{ NULL,			0 }
 };
 
 static struct lookup const	begin_years[] = {
 	{ "minimum",	YR_MINIMUM },
 	{ "maximum",	YR_MAXIMUM },
 	{ NULL,		0 }
 };
 
 static struct lookup const	end_years[] = {
 	{ "minimum",	YR_MINIMUM },
 	{ "maximum",	YR_MAXIMUM },
 	{ "only",	YR_ONLY },
 	{ NULL,		0 }
 };
 
 static struct lookup const	leap_types[] = {
-	{ "Rolling",	TRUE },
-	{ "Stationary",	FALSE },
+	{ "Rolling",	true },
+	{ "Stationary",	false },
 	{ NULL,		0 }
 };
 
 static const int	len_months[2][MONSPERYEAR] = {
 	{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
 	{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
 };
 
 static const int	len_years[2] = {
 	DAYSPERNYEAR, DAYSPERLYEAR
 };
 
 static struct attype {
 	zic_t		at;
+	bool		dontmerge;
 	unsigned char	type;
-}			attypes[TZ_MAX_TIMES];
-static long		gmtoffs[TZ_MAX_TYPES];
+} *			attypes;
+static zic_t		utoffs[TZ_MAX_TYPES];
 static char		isdsts[TZ_MAX_TYPES];
-static unsigned char	abbrinds[TZ_MAX_TYPES];
-static char		ttisstds[TZ_MAX_TYPES];
-static char		ttisgmts[TZ_MAX_TYPES];
+static unsigned char	desigidx[TZ_MAX_TYPES];
+static bool		ttisstds[TZ_MAX_TYPES];
+static bool		ttisuts[TZ_MAX_TYPES];
 static char		chars[TZ_MAX_CHARS];
 static zic_t		trans[TZ_MAX_LEAPS];
-static long		corr[TZ_MAX_LEAPS];
+static zic_t		corr[TZ_MAX_LEAPS];
 static char		roll[TZ_MAX_LEAPS];
 
 /*
 ** Memory allocation.
 */
 
+static _Noreturn void
+memory_exhausted(const char *msg)
+{
+	fprintf(stderr, _("%s: Memory exhausted: %s\n"), progname, msg);
+	exit(EXIT_FAILURE);
+}
+
+static ATTRIBUTE_PURE size_t
+size_product(size_t nitems, size_t itemsize)
+{
+	if (SIZE_MAX / itemsize < nitems)
+		memory_exhausted(_("size overflow"));
+	return nitems * itemsize;
+}
+
+static ATTRIBUTE_PURE size_t
+align_to(size_t size, size_t alignment)
+{
+  size_t aligned_size = size + alignment - 1;
+  aligned_size -= aligned_size % alignment;
+  if (aligned_size < size)
+    memory_exhausted(_("alignment overflow"));
+  return aligned_size;
+}
+
+#if !HAVE_STRDUP
 static char *
-memcheck(ptr)
-char * const	ptr;
+strdup(char const *str)
 {
-	if (ptr == NULL) {
-		const char *e = strerror(errno);
+  char *result = malloc(strlen(str) + 1);
+  return result ? strcpy(result, str) : result;
+}
+#endif
 
-		(void) fprintf(stderr, _("%s: Memory exhausted: %s\n"),
-			progname, e);
-		exit(EXIT_FAILURE);
-	}
+static void *
+memcheck(void *ptr)
+{
+	if (ptr == NULL)
+	  memory_exhausted(strerror(HAVE_MALLOC_ERRNO ? errno : ENOMEM));
 	return ptr;
 }
 
-#define emalloc(size)		memcheck(imalloc(size))
-#define erealloc(ptr, size)	memcheck(irealloc((ptr), (size)))
-#define ecpyalloc(ptr)		memcheck(icpyalloc(ptr))
-#define ecatalloc(oldp, newp)	memcheck(icatalloc((oldp), (newp)))
+static void * ATTRIBUTE_MALLOC
+emalloc(size_t size)
+{
+  return memcheck(malloc(size));
+}
+
+static void *
+erealloc(void *ptr, size_t size)
+{
+  return memcheck(realloc(ptr, size));
+}
+
+static char * ATTRIBUTE_MALLOC
+ecpyalloc(char const *str)
+{
+  return memcheck(strdup(str));
+}
+
+static void *
+growalloc(void *ptr, size_t itemsize, ptrdiff_t nitems, ptrdiff_t *nitems_alloc)
+{
+	if (nitems < *nitems_alloc)
+		return ptr;
+	else {
+		ptrdiff_t nitems_max = PTRDIFF_MAX - WORK_AROUND_QTBUG_53071;
+		ptrdiff_t amax = min(nitems_max, SIZE_MAX);
+		if ((amax - 1) / 3 * 2 < *nitems_alloc)
+			memory_exhausted(_("integer overflow"));
+		*nitems_alloc += (*nitems_alloc >> 1) + 1;
+		return erealloc(ptr, size_product(*nitems_alloc, itemsize));
+	}
+}
 
 /*
 ** Error handling.
 */
 
 static void
-eats(name, num, rname, rnum)
-const char * const	name;
-const int		num;
-const char * const	rname;
-const int		rnum;
+eats(char const *name, lineno num, char const *rname, lineno rnum)
 {
 	filename = name;
 	linenum = num;
 	rfilename = rname;
 	rlinenum = rnum;
 }
 
 static void
-eat(name, num)
-const char * const	name;
-const int		num;
+eat(char const *name, lineno num)
 {
-	eats(name, num, (char *) NULL, -1);
+	eats(name, num, NULL, -1);
 }
 
-static void
-error(string)
-const char * const	string;
+static void ATTRIBUTE_FORMAT((printf, 1, 0))
+verror(const char *const string, va_list args)
 {
 	/*
 	** Match the format of "cc" to allow sh users to
 	**	zic ... 2>&1 | error -t "*" -v
 	** on BSD systems.
 	*/
-	(void) fprintf(stderr, _("\"%s\", line %d: %s"),
-		filename, linenum, string);
+	if (filename)
+	  fprintf(stderr, _("\"%s\", line %"PRIdMAX": "), filename, linenum);
+	vfprintf(stderr, string, args);
 	if (rfilename != NULL)
-		(void) fprintf(stderr, _(" (rule from \"%s\", line %d)"),
+		fprintf(stderr, _(" (rule from \"%s\", line %"PRIdMAX")"),
 			rfilename, rlinenum);
-	(void) fprintf(stderr, "\n");
-	++errors;
+	fprintf(stderr, "\n");
 }
 
-static void
-warning(string)
-const char * const	string;
+static void ATTRIBUTE_FORMAT((printf, 1, 2))
+error(const char *const string, ...)
 {
-	char *	cp;
+	va_list args;
+	va_start(args, string);
+	verror(string, args);
+	va_end(args);
+	errors = true;
+}
 
-	cp = ecpyalloc(_("warning: "));
-	cp = ecatalloc(cp, string);
-	error(cp);
-	ifree(cp);
-	--errors;
+static void ATTRIBUTE_FORMAT((printf, 1, 2))
+warning(const char *const string, ...)
+{
+	va_list args;
+	fprintf(stderr, _("warning: "));
+	va_start(args, string);
+	verror(string, args);
+	va_end(args);
+	warnings = true;
 }
 
+/* Close STREAM.  If it had an I/O error, report it against DIR/NAME,
+   remove TEMPNAME if nonnull, and then exit.  */
 static void
+close_file(FILE *stream, char const *dir, char const *name,
+	   char const *tempname)
+{
+  char const *e = (ferror(stream) ? _("I/O error")
+		   : fclose(stream) != 0 ? strerror(errno) : NULL);
+  if (e) {
+    fprintf(stderr, "%s: %s%s%s%s%s\n", progname,
+	    dir ? dir : "", dir ? "/" : "",
+	    name ? name : "", name ? ": " : "",
+	    e);
+    if (tempname)
+      remove(tempname);
+    exit(EXIT_FAILURE);
+  }
+}
+
+static _Noreturn void
 usage(FILE *stream, int status)
 {
-	(void) fprintf(stream, _("%s: usage is %s \
-[ --version ] [ --help ] [ -v ] [ -l localtime ] [ -p posixrules ] \\\n\
-\t[ -d directory ] [ -L leapseconds ] [ -y yearistype ] [ filename ... ]\n\
-\n\
-Report bugs to tz@elsie.nci.nih.gov.\n"),
-		       progname, progname);
-	exit(status);
+  fprintf(stream,
+	  _("%s: usage is %s [ --version ] [ --help ] [ -v ] \\\n"
+	    "\t[ -b {slim|fat} ] [ -d directory ] [ -l localtime ]"
+	    " [ -L leapseconds ] \\\n"
+	    "\t[ -p posixrules ] [ -r '[@lo][/@hi]' ] [ -R '@hi' ] \\\n"
+	    "\t[ -t localtime-link ] \\\n"
+	    "\t[ filename ... ]\n\n"
+	    "Report bugs to %s.\n"),
+	  progname, progname, REPORT_BUGS_TO);
+  if (status == EXIT_SUCCESS)
+    close_file(stream, NULL, NULL, NULL);
+  exit(status);
+}
+
+/* Change the working directory to DIR, possibly creating DIR and its
+   ancestors.  After this is done, all files are accessed with names
+   relative to DIR.  */
+static void
+change_directory(char const *dir)
+{
+  if (chdir(dir) != 0) {
+    int chdir_errno = errno;
+    if (chdir_errno == ENOENT) {
+      mkdirs(dir, false);
+      chdir_errno = chdir(dir) == 0 ? 0 : errno;
+    }
+    if (chdir_errno != 0) {
+      fprintf(stderr, _("%s: Can't chdir to %s: %s\n"),
+	      progname, dir, strerror(chdir_errno));
+      exit(EXIT_FAILURE);
+    }
+  }
+}
+
+/* Simple signal handling: just set a flag that is checked
+   periodically outside critical sections.  To set up the handler,
+   prefer sigaction if available to close a signal race.  */
+
+static sig_atomic_t got_signal;
+
+static void
+signal_handler(int sig)
+{
+#ifndef SA_SIGINFO
+  signal(sig, signal_handler);
+#endif
+  got_signal = sig;
+}
+
+/* Arrange for SIGINT etc. to be caught by the handler.  */
+static void
+catch_signals(void)
+{
+  static int const signals[] = {
+#ifdef SIGHUP
+    SIGHUP,
+#endif
+    SIGINT,
+#ifdef SIGPIPE
+    SIGPIPE,
+#endif
+    SIGTERM
+  };
+  int i;
+  for (i = 0; i < sizeof signals / sizeof signals[0]; i++) {
+#ifdef SA_SIGINFO
+    struct sigaction act0, act;
+    act.sa_handler = signal_handler;
+    sigemptyset(&act.sa_mask);
+    act.sa_flags = 0;
+    if (sigaction(signals[i], &act, &act0) == 0
+	&& ! (act0.sa_flags & SA_SIGINFO) && act0.sa_handler == SIG_IGN) {
+      sigaction(signals[i], &act0, NULL);
+      got_signal = 0;
+    }
+#else
+    if (signal(signals[i], signal_handler) == SIG_IGN) {
+      signal(signals[i], SIG_IGN);
+      got_signal = 0;
+    }
+#endif
+  }
+}
+
+/* If a signal has arrived, terminate zic with appropriate status.  */
+static void
+check_for_signal(void)
+{
+  int sig = got_signal;
+  if (sig) {
+    signal(sig, SIG_DFL);
+    raise(sig);
+    abort(); /* A bug in 'raise'.  */
+  }
+}
+
+enum { TIME_T_BITS_IN_FILE = 64 };
+
+/* The minimum and maximum values representable in a TZif file.  */
+static zic_t const min_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
+static zic_t const max_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);
+
+/* The minimum, and one less than the maximum, values specified by
+   the -r option.  These default to MIN_TIME and MAX_TIME.  */
+static zic_t lo_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
+static zic_t hi_time = MAXVAL(zic_t, TIME_T_BITS_IN_FILE);
+
+/* The time specified by the -R option, defaulting to MIN_TIME.  */
+static zic_t redundant_time = MINVAL(zic_t, TIME_T_BITS_IN_FILE);
+
+/* The time specified by an Expires line, or negative if no such line.  */
+static zic_t leapexpires = -1;
+
+/* Set the time range of the output to TIMERANGE.
+   Return true if successful.  */
+static bool
+timerange_option(char *timerange)
+{
+  intmax_t lo = min_time, hi = max_time;
+  char *lo_end = timerange, *hi_end;
+  if (*timerange == '@') {
+    errno = 0;
+    lo = strtoimax(timerange + 1, &lo_end, 10);
+    if (lo_end == timerange + 1 || (lo == INTMAX_MAX && errno == ERANGE))
+      return false;
+  }
+  hi_end = lo_end;
+  if (lo_end[0] == '/' && lo_end[1] == '@') {
+    errno = 0;
+    hi = strtoimax(lo_end + 2, &hi_end, 10);
+    if (hi_end == lo_end + 2 || hi == INTMAX_MIN)
+      return false;
+    hi -= ! (hi == INTMAX_MAX && errno == ERANGE);
+  }
+  if (*hi_end || hi < lo || max_time < lo || hi < min_time)
+    return false;
+  lo_time = max(lo, min_time);
+  hi_time = min(hi, max_time);
+  return true;
+}
+
+/* Generate redundant time stamps up to OPT.  Return true if successful.  */
+static bool
+redundant_time_option(char *opt)
+{
+  if (*opt == '@') {
+    intmax_t redundant;
+    char *opt_end;
+    redundant = strtoimax(opt + 1, &opt_end, 10);
+    if (opt_end != opt + 1 && !*opt_end) {
+      redundant_time = max(redundant_time, redundant);
+      return true;
+    }
+  }
+  return false;
 }
 
 static const char *	psxrules;
 static const char *	lcltime;
 static const char *	directory;
 static const char *	leapsec;
-static const char *	yitcommand;
+static const char *	tzdefault;
+
+/* -1 if the TZif output file should be slim, 0 if default, 1 if the
+   output should be fat for backward compatibility.  ZIC_BLOAT_DEFAULT
+   determines the default.  */
+static int bloat;
+
+static bool
+want_bloat(void)
+{
+  return 0 <= bloat;
+}
+
+#ifndef ZIC_BLOAT_DEFAULT
+# define ZIC_BLOAT_DEFAULT "slim"
+#endif
 
 int
-main(argc, argv)
-int	argc;
-char *	argv[];
+main(int argc, char **argv)
 {
-	register int	i;
-	register int	j;
-	register int	c;
+	register int c, k;
+	register ptrdiff_t i, j;
+	bool timerange_given = false;
 
-#ifdef unix
-	(void) umask(umask(S_IWGRP | S_IWOTH) | (S_IWGRP | S_IWOTH));
-#endif /* defined unix */
+#ifdef S_IWGRP
+	umask(umask(S_IWGRP | S_IWOTH) | (S_IWGRP | S_IWOTH));
+#endif
 #if HAVE_GETTEXT
-	(void) setlocale(LC_ALL, "");
-#ifdef TZ_DOMAINDIR
-	(void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
-#endif /* defined TEXTDOMAINDIR */
-	(void) textdomain(TZ_DOMAIN);
+	setlocale(LC_ALL, "");
+# ifdef TZ_DOMAINDIR
+	bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR);
+# endif /* defined TEXTDOMAINDIR */
+	textdomain(TZ_DOMAIN);
 #endif /* HAVE_GETTEXT */
 	progname = argv[0];
 	if (TYPE_BIT(zic_t) < 64) {
-		(void) fprintf(stderr, "%s: %s\n", progname,
+		fprintf(stderr, "%s: %s\n", progname,
 			_("wild compilation-time specification of zic_t"));
-		exit(EXIT_FAILURE);
-	}
-	for (i = 1; i < argc; ++i)
-		if (strcmp(argv[i], "--version") == 0) {
-			(void) printf("%s\n", elsieid);
-			exit(EXIT_SUCCESS);
-		} else if (strcmp(argv[i], "--help") == 0) {
+		return EXIT_FAILURE;
+	}
+	for (k = 1; k < argc; k++)
+		if (strcmp(argv[k], "--version") == 0) {
+			printf("zic %s%s\n", PKGVERSION, TZVERSION);
+			close_file(stdout, NULL, NULL, NULL);
+			return EXIT_SUCCESS;
+		} else if (strcmp(argv[k], "--help") == 0) {
 			usage(stdout, EXIT_SUCCESS);
 		}
-	while ((c = getopt(argc, argv, "d:l:p:L:vsy:")) != EOF && c != -1)
+	while ((c = getopt(argc, argv, "b:d:l:L:p:r:R:st:vy:")) != EOF
+	       && c != -1)
 		switch (c) {
 			default:
 				usage(stderr, EXIT_FAILURE);
+			case 'b':
+				if (strcmp(optarg, "slim") == 0) {
+				  if (0 < bloat)
+				    error(_("incompatible -b options"));
+				  bloat = -1;
+				} else if (strcmp(optarg, "fat") == 0) {
+				  if (bloat < 0)
+				    error(_("incompatible -b options"));
+				  bloat = 1;
+				} else
+				  error(_("invalid option: -b '%s'"), optarg);
+				break;
 			case 'd':
 				if (directory == NULL)
 					directory = optarg;
 				else {
-					(void) fprintf(stderr,
+					fprintf(stderr,
 _("%s: More than one -d option specified\n"),
 						progname);
-					exit(EXIT_FAILURE);
+					return EXIT_FAILURE;
 				}
 				break;
 			case 'l':
 				if (lcltime == NULL)
 					lcltime = optarg;
 				else {
-					(void) fprintf(stderr,
+					fprintf(stderr,
 _("%s: More than one -l option specified\n"),
 						progname);
-					exit(EXIT_FAILURE);
+					return EXIT_FAILURE;
 				}
 				break;
 			case 'p':
 				if (psxrules == NULL)
 					psxrules = optarg;
 				else {
-					(void) fprintf(stderr,
+					fprintf(stderr,
 _("%s: More than one -p option specified\n"),
 						progname);
-					exit(EXIT_FAILURE);
+					return EXIT_FAILURE;
 				}
 				break;
-			case 'y':
-				if (yitcommand == NULL)
-					yitcommand = optarg;
-				else {
-					(void) fprintf(stderr,
-_("%s: More than one -y option specified\n"),
-						progname);
-					exit(EXIT_FAILURE);
+			case 't':
+				if (tzdefault != NULL) {
+				  fprintf(stderr,
+					  _("%s: More than one -t option"
+					    " specified\n"),
+					  progname);
+				  return EXIT_FAILURE;
 				}
+				tzdefault = optarg;
+				break;
+			case 'y':
+				warning(_("-y ignored"));
 				break;
 			case 'L':
 				if (leapsec == NULL)
 					leapsec = optarg;
 				else {
-					(void) fprintf(stderr,
+					fprintf(stderr,
 _("%s: More than one -L option specified\n"),
 						progname);
-					exit(EXIT_FAILURE);
+					return EXIT_FAILURE;
 				}
 				break;
 			case 'v':
-				noise = TRUE;
+				noise = true;
+				break;
+			case 'r':
+				if (timerange_given) {
+				  fprintf(stderr,
+_("%s: More than one -r option specified\n"),
+					  progname);
+				  return EXIT_FAILURE;
+				}
+				if (! timerange_option(optarg)) {
+				  fprintf(stderr,
+_("%s: invalid time range: %s\n"),
+					  progname, optarg);
+				  return EXIT_FAILURE;
+				}
+				timerange_given = true;
+				break;
+			case 'R':
+				if (! redundant_time_option(optarg)) {
+				  fprintf(stderr, _("%s: invalid time: %s\n"),
+					  progname, optarg);
+				  return EXIT_FAILURE;
+				}
 				break;
 			case 's':
-				(void) printf("%s: -s ignored\n", progname);
+				warning(_("-s ignored"));
 				break;
 		}
 	if (optind == argc - 1 && strcmp(argv[optind], "=") == 0)
 		usage(stderr, EXIT_FAILURE);	/* usage message by request */
+	if (hi_time + (hi_time < ZIC_MAX) < redundant_time) {
+	  fprintf(stderr, _("%s: -R time exceeds -r cutoff\n"), progname);
+	  return EXIT_FAILURE;
+	}
+	if (bloat == 0) {
+	  static char const bloat_default[] = ZIC_BLOAT_DEFAULT;
+	  if (strcmp(bloat_default, "slim") == 0)
+	    bloat = -1;
+	  else if (strcmp(bloat_default, "fat") == 0)
+	    bloat = 1;
+	  else
+	    abort(); /* Configuration error.  */
+	}
 	if (directory == NULL)
 		directory = TZDIR;
-	if (yitcommand == NULL)
-		yitcommand = "yearistype";
-
-	setboundaries();
+	if (tzdefault == NULL)
+		tzdefault = TZDEFAULT;
 
 	if (optind < argc && leapsec != NULL) {
 		infile(leapsec);
 		adjleap();
 	}
 
-	for (i = optind; i < argc; ++i)
-		infile(argv[i]);
+	for (k = optind; k < argc; k++)
+		infile(argv[k]);
 	if (errors)
-		exit(EXIT_FAILURE);
+		return EXIT_FAILURE;
 	associate();
+	change_directory(directory);
+	catch_signals();
 	for (i = 0; i < nzones; i = j) {
 		/*
 		** Find the next non-continuation zone entry.
 		*/
 		for (j = i + 1; j < nzones && zones[j].z_name == NULL; ++j)
 			continue;
 		outzone(&zones[i], j - i);
 	}
 	/*
 	** Make links.
 	*/
 	for (i = 0; i < nlinks; ++i) {
 		eat(links[i].l_filename, links[i].l_linenum);
-		dolink(links[i].l_from, links[i].l_to);
+		dolink(links[i].l_target, links[i].l_linkname, false);
 		if (noise)
 			for (j = 0; j < nlinks; ++j)
-				if (strcmp(links[i].l_to,
-					links[j].l_from) == 0)
+				if (strcmp(links[i].l_linkname,
+					links[j].l_target) == 0)
 						warning(_("link to link"));
 	}
 	if (lcltime != NULL) {
-		eat("command line", 1);
-		dolink(lcltime, TZDEFAULT);
+		eat(_("command line"), 1);
+		dolink(lcltime, tzdefault, true);
 	}
 	if (psxrules != NULL) {
-		eat("command line", 1);
-		dolink(psxrules, TZDEFRULES);
+		eat(_("command line"), 1);
+		dolink(psxrules, TZDEFRULES, true);
 	}
-	return (errors == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
+	if (warnings && (ferror(stderr) || fclose(stderr) != 0))
+	  return EXIT_FAILURE;
+	return errors ? EXIT_FAILURE : EXIT_SUCCESS;
 }
 
-static void
-dolink(fromfield, tofield)
-const char * const	fromfield;
-const char * const	tofield;
+static bool
+componentcheck(char const *name, char const *component,
+	       char const *component_end)
 {
-	register char *	fromname;
-	register char *	toname;
-
-	if (fromfield[0] == '/')
-		fromname = ecpyalloc(fromfield);
-	else {
-		fromname = ecpyalloc(directory);
-		fromname = ecatalloc(fromname, "/");
-		fromname = ecatalloc(fromname, fromfield);
-	}
-	if (tofield[0] == '/')
-		toname = ecpyalloc(tofield);
-	else {
-		toname = ecpyalloc(directory);
-		toname = ecatalloc(toname, "/");
-		toname = ecatalloc(toname, tofield);
-	}
-	/*
-	** We get to be careful here since
-	** there's a fair chance of root running us.
-	*/
-	if (!itsdir(toname))
-		(void) remove(toname);
-	if (link(fromname, toname) != 0) {
-		int	result;
-
-		if (mkdirs(toname) != 0)
-			exit(EXIT_FAILURE);
+	enum { component_len_max = 14 };
+	ptrdiff_t component_len = component_end - component;
+	if (component_len == 0) {
+	  if (!*name)
+	    error(_("empty file name"));
+	  else
+	    error(_(component == name
+		     ? "file name '%s' begins with '/'"
+		     : *component_end
+		     ? "file name '%s' contains '//'"
+		     : "file name '%s' ends with '/'"),
+		   name);
+	  return false;
+	}
+	if (0 < component_len && component_len <= 2
+	    && component[0] == '.' && component_end[-1] == '.') {
+	  int len = component_len;
+	  error(_("file name '%s' contains '%.*s' component"),
+		name, len, component);
+	  return false;
+	}
+	if (noise) {
+	  if (0 < component_len && component[0] == '-')
+	    warning(_("file name '%s' component contains leading '-'"),
+		    name);
+	  if (component_len_max < component_len)
+	    warning(_("file name '%s' contains overlength component"
+		      " '%.*s...'"),
+		    name, component_len_max, component);
+	}
+	return true;
+}
 
-		result = link(fromname, toname);
-#if HAVE_SYMLINK
-		if (result != 0 &&
-			access(fromname, F_OK) == 0 &&
-			!itsdir(fromname)) {
-				const char *s = tofield;
-				register char * symlinkcontents = NULL;
-
-				while ((s = strchr(s+1, '/')) != NULL)
-					symlinkcontents =
-						ecatalloc(symlinkcontents,
-						"../");
-				symlinkcontents =
-					ecatalloc(symlinkcontents,
-					fromname);
-				result = symlink(symlinkcontents,
-					toname);
-				if (result == 0)
-warning(_("hard link failed, symbolic link used"));
-				ifree(symlinkcontents);
+static bool
+namecheck(const char *name)
+{
+	register char const *cp;
+
+	/* Benign characters in a portable file name.  */
+	static char const benign[] =
+	  "-/_"
+	  "abcdefghijklmnopqrstuvwxyz"
+	  "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+	/* Non-control chars in the POSIX portable character set,
+	   excluding the benign characters.  */
+	static char const printable_and_not_benign[] =
+	  " !\"#$%&'()*+,.0123456789:;<=>?@[\\]^`{|}~";
+
+	register char const *component = name;
+	for (cp = name; *cp; cp++) {
+		unsigned char c = *cp;
+		if (noise && !strchr(benign, c)) {
+			warning((strchr(printable_and_not_benign, c)
+				 ? _("file name '%s' contains byte '%c'")
+				 : _("file name '%s' contains byte '\\%o'")),
+				name, c);
 		}
-#endif /* HAVE_SYMLINK */
-		if (result != 0) {
-			const char *e = strerror(errno);
-
-			(void) fprintf(stderr,
-				_("%s: Can't link from %s to %s: %s\n"),
-				progname, fromname, toname, e);
-			exit(EXIT_FAILURE);
+		if (c == '/') {
+			if (!componentcheck(name, component, cp))
+			  return false;
+			component = cp + 1;
 		}
 	}
-	ifree(fromname);
-	ifree(toname);
+	return componentcheck(name, component, cp);
 }
 
-#define TIME_T_BITS_IN_FILE	64
+/* Generate a randomish name in the same directory as *NAME.  If
+   *NAMEALLOC, put the name into *NAMEALLOC which is assumed to be
+   that returned by a previous call and is thus already almost set up
+   and equal to *NAME; otherwise, allocate a new name and put its
+   address into both *NAMEALLOC and *NAME.  */
+static void
+random_dirent(char const **name, char **namealloc)
+{
+  char const *src = *name;
+  char *dst = *namealloc;
+  static char const prefix[] = ".zic";
+  static char const alphabet[] =
+    "abcdefghijklmnopqrstuvwxyz"
+    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    "0123456789";
+  enum { prefixlen = sizeof prefix - 1, alphabetlen = sizeof alphabet - 1 };
+  int suffixlen = 6;
+  char const *lastslash = strrchr(src, '/');
+  ptrdiff_t dirlen = lastslash ? lastslash + 1 - src : 0;
+  static unsigned short initialized;
+  int i;
+
+  if (!dst) {
+    dst = emalloc(dirlen + prefixlen + suffixlen + 1);
+    memcpy(dst, src, dirlen);
+    memcpy(dst + dirlen, prefix, prefixlen);
+    dst[dirlen + prefixlen + suffixlen] = '\0';
+    *name = *namealloc = dst;
+  }
+
+  /* This randomization is not the best, but is portable to C89.  */
+  if (!initialized++) {
+    unsigned now = time(NULL);
+    srand(rand() ^ now);
+  }
+  for (i = 0; i < suffixlen; i++)
+    dst[dirlen + prefixlen + i] = alphabet[rand() % alphabetlen];
+}
 
+/* Prepare to write to the file *OUTNAME, using *TEMPNAME to store the
+   name of the temporary file that will eventually be renamed to
+   *OUTNAME.  Assign the temporary file's name to both *OUTNAME and
+   *TEMPNAME.  If *TEMPNAME is null, allocate the name of any such
+   temporary file; otherwise, reuse *TEMPNAME's storage, which is
+   already set up and only needs its trailing suffix updated.  */
+static FILE *
+open_outfile(char const **outname, char **tempname)
+{
+#if __STDC_VERSION__ < 201112
+  static char const fopen_mode[] = "wb";
+#else
+  static char const fopen_mode[] = "wbx";
+#endif
+
+  FILE *fp;
+  bool dirs_made = false;
+  if (!*tempname)
+    random_dirent(outname, tempname);
+
+  while (! (fp = fopen(*outname, fopen_mode))) {
+    int fopen_errno = errno;
+    if (fopen_errno == ENOENT && !dirs_made) {
+      mkdirs(*outname, true);
+      dirs_made = true;
+    } else if (fopen_errno == EEXIST)
+      random_dirent(outname, tempname);
+    else {
+      fprintf(stderr, _("%s: Can't create %s/%s: %s\n"),
+	      progname, directory, *outname, strerror(fopen_errno));
+      exit(EXIT_FAILURE);
+    }
+  }
+
+  return fp;
+}
+
+/* If TEMPNAME, the result is in the temporary file TEMPNAME even
+   though the user wanted it in NAME, so rename TEMPNAME to NAME.
+   Report an error and exit if there is trouble.  Also, free TEMPNAME.  */
 static void
-setboundaries(void)
+rename_dest(char *tempname, char const *name)
 {
-	register int	i;
+  if (tempname) {
+    if (rename(tempname, name) != 0) {
+      int rename_errno = errno;
+      remove(tempname);
+      fprintf(stderr, _("%s: rename to %s/%s: %s\n"),
+	      progname, directory, name, strerror(rename_errno));
+      exit(EXIT_FAILURE);
+    }
+    free(tempname);
+  }
+}
 
-	min_time = -1;
-	for (i = 0; i < TIME_T_BITS_IN_FILE - 1; ++i)
-		min_time *= 2;
-	max_time = -(min_time + 1);
+/* Create symlink contents suitable for symlinking FROM to TO, as a
+   freshly allocated string.  FROM should be a relative file name, and
+   is relative to the global variable DIRECTORY.  TO can be either
+   relative or absolute.  */
+static char *
+relname(char const *target, char const *linkname)
+{
+  size_t i, taillen, dotdotetcsize;
+  size_t dir_len = 0, dotdots = 0, linksize = SIZE_MAX;
+  char const *f = target;
+  char *result = NULL;
+  if (*linkname == '/') {
+    /* Make F absolute too.  */
+    size_t len = strlen(directory);
+    bool needslash = len && directory[len - 1] != '/';
+    linksize = len + needslash + strlen(target) + 1;
+    f = result = emalloc(linksize);
+    strcpy(result, directory);
+    result[len] = '/';
+    strcpy(result + len + needslash, target);
+  }
+  for (i = 0; f[i] && f[i] == linkname[i]; i++)
+    if (f[i] == '/')
+      dir_len = i + 1;
+  for (; linkname[i]; i++)
+    dotdots += linkname[i] == '/' && linkname[i - 1] != '/';
+  taillen = strlen(f + dir_len);
+  dotdotetcsize = 3 * dotdots + taillen + 1;
+  if (dotdotetcsize <= linksize) {
+    if (!result)
+      result = emalloc(dotdotetcsize);
+    for (i = 0; i < dotdots; i++)
+      memcpy(result + 3 * i, "../", 3);
+    memmove(result + 3 * dotdots, f + dir_len, taillen + 1);
+  }
+  return result;
 }
 
-static int
-itsdir(name)
-const char * const	name;
+static void
+dolink(char const *target, char const *linkname, bool staysymlink)
 {
-	register char *	myname;
-	register int	accres;
+	bool linkdirs_made = false;
+	int link_errno;
+	char *tempname = NULL;
+	char const *outname = linkname;
+
+	check_for_signal();
+
+	if (strcmp(target, "-") == 0) {
+	  if (remove(linkname) == 0 || errno == ENOENT || errno == ENOTDIR)
+	    return;
+	  else {
+	    char const *e = strerror(errno);
+	    fprintf(stderr, _("%s: Can't remove %s/%s: %s\n"),
+		    progname, directory, linkname, e);
+	    exit(EXIT_FAILURE);
+	  }
+	}
+
+	while (true) {
+	  if (linkat(AT_FDCWD, target, AT_FDCWD, outname, AT_SYMLINK_FOLLOW)
+	      == 0) {
+	    link_errno = 0;
+	    break;
+	  }
+	  link_errno = errno;
+	  if (link_errno == EXDEV || link_errno == ENOTSUP)
+	    break;
+
+	  if (link_errno == EEXIST) {
+	    staysymlink &= !tempname;
+	    random_dirent(&outname, &tempname);
+	    if (staysymlink && itssymlink(linkname))
+	      break;
+	  } else if (link_errno == ENOENT && !linkdirs_made) {
+	    mkdirs(linkname, true);
+	    linkdirs_made = true;
+	  } else {
+	    fprintf(stderr, _("%s: Can't link %s/%s to %s/%s: %s\n"),
+		    progname, directory, target, directory, outname,
+		    strerror(link_errno));
+	    exit(EXIT_FAILURE);
+	  }
+	}
+	if (link_errno != 0) {
+	  bool absolute = *target == '/';
+	  char *linkalloc = absolute ? NULL : relname(target, linkname);
+	  char const *contents = absolute ? target : linkalloc;
+	  int symlink_errno;
+
+	  while (true) {
+	    if (symlink(contents, outname) == 0) {
+	      symlink_errno = 0;
+	      break;
+	    }
+	    symlink_errno = errno;
+	    if (symlink_errno == EEXIST)
+	      random_dirent(&outname, &tempname);
+	    else if (symlink_errno == ENOENT && !linkdirs_made) {
+	      mkdirs(linkname, true);
+	      linkdirs_made = true;
+	    } else
+	      break;
+	  }
+	  free(linkalloc);
+	  if (symlink_errno == 0) {
+	    if (link_errno != ENOTSUP && link_errno != EEXIST)
+	      warning(_("symbolic link used because hard link failed: %s"),
+		      strerror(link_errno));
+	  } else {
+	    FILE *fp, *tp;
+	    int c;
+	    fp = fopen(target, "rb");
+	    if (!fp) {
+	      char const *e = strerror(errno);
+	      fprintf(stderr, _("%s: Can't read %s/%s: %s\n"),
+		      progname, directory, target, e);
+	      exit(EXIT_FAILURE);
+	    }
+	    tp = open_outfile(&outname, &tempname);
+	    while ((c = getc(fp)) != EOF)
+	      putc(c, tp);
+	    close_file(tp, directory, linkname, tempname);
+	    close_file(fp, directory, target, NULL);
+	    if (link_errno != ENOTSUP)
+	      warning(_("copy used because hard link failed: %s"),
+		      strerror(link_errno));
+	    else if (symlink_errno != ENOTSUP)
+	      warning(_("copy used because symbolic link failed: %s"),
+		      strerror(symlink_errno));
+	  }
+	}
+	rename_dest(tempname, linkname);
+}
 
-	myname = ecpyalloc(name);
-	myname = ecatalloc(myname, "/.");
-	accres = access(myname, F_OK);
-	ifree(myname);
-	return accres == 0;
+/* Return true if NAME is a symbolic link.  */
+static bool
+itssymlink(char const *name)
+{
+  char c;
+  return 0 <= readlink(name, &c, 1);
 }
 
 /*
 ** Associate sets of rules with zones.
 */
 
 /*
 ** Sort by rule name.
 */
 
 static int
-rcomp(cp1, cp2)
-const void *	cp1;
-const void *	cp2;
+rcomp(const void *cp1, const void *cp2)
 {
-	return strcmp(((const struct rule *) cp1)->r_name,
-		((const struct rule *) cp2)->r_name);
+  struct rule const *r1 = cp1, *r2 = cp2;
+  return strcmp(r1->r_name, r2->r_name);
 }
 
 static void
 associate(void)
 {
 	register struct zone *	zp;
 	register struct rule *	rp;
-	register int		base, out;
-	register int		i, j;
+	register ptrdiff_t i, j, base, out;
 
 	if (nrules != 0) {
-		(void) qsort((void *) rules, (size_t) nrules,
-			(size_t) sizeof *rules, rcomp);
+		qsort(rules, nrules, sizeof *rules, rcomp);
 		for (i = 0; i < nrules - 1; ++i) {
 			if (strcmp(rules[i].r_name,
 				rules[i + 1].r_name) != 0)
 					continue;
 			if (strcmp(rules[i].r_filename,
 				rules[i + 1].r_filename) == 0)
 					continue;
 			eat(rules[i].r_filename, rules[i].r_linenum);
 			warning(_("same rule name in multiple files"));
 			eat(rules[i + 1].r_filename, rules[i + 1].r_linenum);
 			warning(_("same rule name in multiple files"));
 			for (j = i + 2; j < nrules; ++j) {
 				if (strcmp(rules[i].r_name,
 					rules[j].r_name) != 0)
 						break;
 				if (strcmp(rules[i].r_filename,
 					rules[j].r_filename) == 0)
 						continue;
 				if (strcmp(rules[i + 1].r_filename,
 					rules[j].r_filename) == 0)
 						continue;
 				break;
 			}
 			i = j - 1;
 		}
 	}
 	for (i = 0; i < nzones; ++i) {
 		zp = &zones[i];
 		zp->z_rules = NULL;
 		zp->z_nrules = 0;
 	}
 	for (base = 0; base < nrules; base = out) {
 		rp = &rules[base];
 		for (out = base + 1; out < nrules; ++out)
 			if (strcmp(rp->r_name, rules[out].r_name) != 0)
 				break;
 		for (i = 0; i < nzones; ++i) {
 			zp = &zones[i];
 			if (strcmp(zp->z_rule, rp->r_name) != 0)
 				continue;
 			zp->z_rules = rp;
 			zp->z_nrules = out - base;
 		}
 	}
 	for (i = 0; i < nzones; ++i) {
 		zp = &zones[i];
 		if (zp->z_nrules == 0) {
 			/*
 			** Maybe we have a local standard time offset.
 			*/
 			eat(zp->z_filename, zp->z_linenum);
-			zp->z_stdoff = gethms(zp->z_rule, _("unruly zone"),
-				TRUE);
+			zp->z_save = getsave(zp->z_rule, &zp->z_isdst);
 			/*
 			** Note, though, that if there's no rule,
 			** a '%s' in the format is a bad thing.
 			*/
-			if (strchr(zp->z_format, '%') != 0)
-				error(_("%s in ruleless zone"));
+			if (zp->z_format_specifier == 's')
+				error("%s", _("%s in ruleless zone"));
 		}
 	}
 	if (errors)
 		exit(EXIT_FAILURE);
 }
 
+/* Read a text line from FP into BUF, which is of size BUFSIZE.
+   Terminate it with a NUL byte instead of a newline.
+   Return the line's length, not counting the NUL byte.
+   On EOF, return a negative number.
+   On error, report the error and exit.  */
+static ptrdiff_t
+inputline(FILE *fp, char *buf, ptrdiff_t bufsize)
+{
+  ptrdiff_t linelen = 0, ch;
+  while ((ch = getc(fp)) != '\n') {
+    if (ch < 0) {
+      if (ferror(fp)) {
+	error(_("input error"));
+	exit(EXIT_FAILURE);
+      }
+      if (linelen == 0)
+	return -1;
+      error(_("unterminated line"));
+      exit(EXIT_FAILURE);
+    }
+    if (!ch) {
+      error(_("NUL input byte"));
+      exit(EXIT_FAILURE);
+    }
+    buf[linelen++] = ch;
+    if (linelen == bufsize) {
+      error(_("line too long"));
+      exit(EXIT_FAILURE);
+    }
+  }
+  buf[linelen] = '\0';
+  return linelen;
+}
+
 static void
-infile(name)
-const char *	name;
+infile(const char *name)
 {
 	register FILE *			fp;
-	register char **		fields;
-	register char *			cp;
 	register const struct lookup *	lp;
-	register int			nfields;
-	register int			wantcont;
-	register int			num;
-	char				buf[BUFSIZ];
+	register bool			wantcont;
+	register lineno			num;
 
 	if (strcmp(name, "-") == 0) {
 		name = _("standard input");
 		fp = stdin;
 	} else if ((fp = fopen(name, "r")) == NULL) {
 		const char *e = strerror(errno);
 
-		(void) fprintf(stderr, _("%s: Can't open %s: %s\n"),
+		fprintf(stderr, _("%s: Can't open %s: %s\n"),
 			progname, name, e);
 		exit(EXIT_FAILURE);
 	}
-	wantcont = FALSE;
+	wantcont = false;
 	for (num = 1; ; ++num) {
+		ptrdiff_t linelen;
+		char buf[_POSIX2_LINE_MAX];
+		int nfields;
+		char *fields[MAX_FIELDS];
 		eat(name, num);
-		if (fgets(buf, (int) sizeof buf, fp) != buf)
-			break;
-		cp = strchr(buf, '\n');
-		if (cp == NULL) {
-			error(_("line too long"));
-			exit(EXIT_FAILURE);
-		}
-		*cp = '\0';
-		fields = getfields(buf);
-		nfields = 0;
-		while (fields[nfields] != NULL) {
-			static char	nada;
-
-			if (strcmp(fields[nfields], "-") == 0)
-				fields[nfields] = &nada;
-			++nfields;
-		}
+		linelen = inputline(fp, buf, sizeof buf);
+		if (linelen < 0)
+		  break;
+		nfields = getfields(buf, fields,
+				    sizeof fields / sizeof *fields);
 		if (nfields == 0) {
 			/* nothing to do */
 		} else if (wantcont) {
 			wantcont = inzcont(fields, nfields);
 		} else {
+			struct lookup const *line_codes
+			  = name == leapsec ? leap_line_codes : zi_line_codes;
 			lp = byword(fields[0], line_codes);
 			if (lp == NULL)
 				error(_("input line of unknown type"));
-			else switch ((int) (lp->l_value)) {
+			else switch (lp->l_value) {
 				case LC_RULE:
 					inrule(fields, nfields);
-					wantcont = FALSE;
+					wantcont = false;
 					break;
 				case LC_ZONE:
 					wantcont = inzone(fields, nfields);
 					break;
 				case LC_LINK:
 					inlink(fields, nfields);
-					wantcont = FALSE;
+					wantcont = false;
 					break;
 				case LC_LEAP:
-					if (name != leapsec)
-						(void) fprintf(stderr,
-_("%s: Leap line in non leap seconds file %s\n"),
-							progname, name);
-					else	inleap(fields, nfields);
-					wantcont = FALSE;
+					inleap(fields, nfields);
+					wantcont = false;
 					break;
-				default:	/* "cannot happen" */
-					(void) fprintf(stderr,
-_("%s: panic: Invalid l_value %d\n"),
-						progname, lp->l_value);
-					exit(EXIT_FAILURE);
+				case LC_EXPIRES:
+					inexpires(fields, nfields);
+					wantcont = false;
+					break;
+				default: UNREACHABLE();
 			}
 		}
-		ifree((char *) fields);
-	}
-	if (ferror(fp)) {
-		(void) fprintf(stderr, _("%s: Error reading %s\n"),
-			progname, filename);
-		exit(EXIT_FAILURE);
-	}
-	if (fp != stdin && fclose(fp)) {
-		const char *e = strerror(errno);
-
-		(void) fprintf(stderr, _("%s: Error closing %s: %s\n"),
-			progname, filename, e);
-		exit(EXIT_FAILURE);
 	}
+	close_file(fp, NULL, filename, NULL);
 	if (wantcont)
 		error(_("expected continuation line not found"));
 }
 
 /*
 ** Convert a string of one of the forms
 **	h	-h	hh:mm	-hh:mm	hh:mm:ss	-hh:mm:ss
 ** into a number of seconds.
 ** A null string maps to zero.
 ** Call error with errstring and return zero on errors.
 */
 
-static long
-gethms(string, errstring, signable)
-const char *		string;
-const char * const	errstring;
-const int		signable;
+static zic_t
+gethms(char const *string, char const *errstring)
 {
-	long	hh;
-	int	mm, ss, sign;
+	zic_t	hh;
+	int sign, mm = 0, ss = 0;
+	char hhx, mmx, ssx, xr = '0', xs;
+	int tenths = 0;
+	bool ok = true;
 
 	if (string == NULL || *string == '\0')
 		return 0;
-	if (!signable)
-		sign = 1;
-	else if (*string == '-') {
+	if (*string == '-') {
 		sign = -1;
 		++string;
 	} else	sign = 1;
-	if (sscanf(string, scheck(string, "%ld"), &hh) == 1)
-		mm = ss = 0;
-	else if (sscanf(string, scheck(string, "%ld:%d"), &hh, &mm) == 2)
-		ss = 0;
-	else if (sscanf(string, scheck(string, "%ld:%d:%d"),
-		&hh, &mm, &ss) != 3) {
-			error(errstring);
+	switch (sscanf(string,
+		       "%"SCNdZIC"%c%d%c%d%c%1d%*[0]%c%*[0123456789]%c",
+		       &hh, &hhx, &mm, &mmx, &ss, &ssx, &tenths, &xr, &xs)) {
+	  default: ok = false; break;
+	  case 8:
+	    ok = '0' <= xr && xr <= '9';
+	    /* fallthrough */
+	  case 7:
+	    ok &= ssx == '.';
+	    if (ok && noise)
+	      warning(_("fractional seconds rejected by"
+			" pre-2018 versions of zic"));
+	    /* fallthrough */
+	  case 5: ok &= mmx == ':'; /* fallthrough */
+	  case 3: ok &= hhx == ':'; /* fallthrough */
+	  case 1: break;
+	}
+	if (!ok) {
+			error("%s", errstring);
 			return 0;
 	}
 	if (hh < 0 ||
 		mm < 0 || mm >= MINSPERHOUR ||
 		ss < 0 || ss > SECSPERMIN) {
-			error(errstring);
+			error("%s", errstring);
 			return 0;
 	}
-	if (LONG_MAX / SECSPERHOUR < hh) {
+	if (ZIC_MAX / SECSPERHOUR < hh) {
 		error(_("time overflow"));
 		return 0;
 	}
-	if (noise && hh == HOURSPERDAY && mm == 0 && ss == 0)
-		warning(_("24:00 not handled by pre-1998 versions of zic"));
+	ss += 5 + ((ss ^ 1) & (xr == '0')) <= tenths; /* Round to even.  */
 	if (noise && (hh > HOURSPERDAY ||
 		(hh == HOURSPERDAY && (mm != 0 || ss != 0))))
 warning(_("values over 24 hours not handled by pre-2007 versions of zic"));
-	return oadd(eitol(sign) * hh * eitol(SECSPERHOUR),
-		    eitol(sign) * (eitol(mm) * eitol(SECSPERMIN) + eitol(ss)));
+	return oadd(sign * hh * SECSPERHOUR,
+		    sign * (mm * SECSPERMIN + ss));
+}
+
+static zic_t
+getsave(char *field, bool *isdst)
+{
+  int dst = -1;
+  zic_t save;
+  size_t fieldlen = strlen(field);
+  if (fieldlen != 0) {
+    char *ep = field + fieldlen - 1;
+    switch (*ep) {
+      case 'd': dst = 1; *ep = '\0'; break;
+      case 's': dst = 0; *ep = '\0'; break;
+    }
+  }
+  save = gethms(field, _("invalid saved time"));
+  *isdst = dst < 0 ? save != 0 : dst;
+  return save;
 }
 
 static void
-inrule(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+inrule(char **fields, int nfields)
 {
-	static struct rule	r;
+	struct rule r;
 
 	if (nfields != RULE_FIELDS) {
 		error(_("wrong number of fields on Rule line"));
 		return;
 	}
-	if (*fields[RF_NAME] == '\0') {
-		error(_("nameless rule"));
+	switch (*fields[RF_NAME]) {
+	  case '\0':
+	  case ' ': case '\f': case '\n': case '\r': case '\t': case '\v':
+	  case '+': case '-':
+	  case '0': case '1': case '2': case '3': case '4':
+	  case '5': case '6': case '7': case '8': case '9':
+		error(_("Invalid rule name \"%s\""), fields[RF_NAME]);
 		return;
 	}
 	r.r_filename = filename;
 	r.r_linenum = linenum;
-	r.r_stdoff = gethms(fields[RF_STDOFF], _("invalid saved time"), TRUE);
-	rulesub(&r, fields[RF_LOYEAR], fields[RF_HIYEAR], fields[RF_COMMAND],
-		fields[RF_MONTH], fields[RF_DAY], fields[RF_TOD]);
+	r.r_save = getsave(fields[RF_SAVE], &r.r_isdst);
+	if (!rulesub(&r, fields[RF_LOYEAR], fields[RF_HIYEAR],
+		     fields[RF_COMMAND], fields[RF_MONTH], fields[RF_DAY],
+		     fields[RF_TOD]))
+	  return;
 	r.r_name = ecpyalloc(fields[RF_NAME]);
 	r.r_abbrvar = ecpyalloc(fields[RF_ABBRVAR]);
 	if (max_abbrvar_len < strlen(r.r_abbrvar))
 		max_abbrvar_len = strlen(r.r_abbrvar);
-	rules = (struct rule *) (void *) erealloc((char *) rules,
-		(int) ((nrules + 1) * sizeof *rules));
+	rules = growalloc(rules, sizeof *rules, nrules, &nrules_alloc);
 	rules[nrules++] = r;
 }
 
-static int
-inzone(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+static bool
+inzone(char **fields, int nfields)
 {
-	register int	i;
-	static char *	buf;
+	register ptrdiff_t i;
 
 	if (nfields < ZONE_MINFIELDS || nfields > ZONE_MAXFIELDS) {
 		error(_("wrong number of fields on Zone line"));
-		return FALSE;
+		return false;
 	}
-	if (strcmp(fields[ZF_NAME], TZDEFAULT) == 0 && lcltime != NULL) {
-		buf = erealloc(buf, (int) (132 + strlen(TZDEFAULT)));
-		(void) sprintf(buf,
+	if (lcltime != NULL && strcmp(fields[ZF_NAME], tzdefault) == 0) {
+		error(
 _("\"Zone %s\" line and -l option are mutually exclusive"),
-			TZDEFAULT);
-		error(buf);
-		return FALSE;
+			tzdefault);
+		return false;
 	}
 	if (strcmp(fields[ZF_NAME], TZDEFRULES) == 0 && psxrules != NULL) {
-		buf = erealloc(buf, (int) (132 + strlen(TZDEFRULES)));
-		(void) sprintf(buf,
+		error(
 _("\"Zone %s\" line and -p option are mutually exclusive"),
 			TZDEFRULES);
-		error(buf);
-		return FALSE;
+		return false;
 	}
 	for (i = 0; i < nzones; ++i)
 		if (zones[i].z_name != NULL &&
 			strcmp(zones[i].z_name, fields[ZF_NAME]) == 0) {
-				buf = erealloc(buf, (int) (132 +
-					strlen(fields[ZF_NAME]) +
-					strlen(zones[i].z_filename)));
-				(void) sprintf(buf,
-_("duplicate zone name %s (file \"%s\", line %d)"),
+				error(_("duplicate zone name %s"
+					" (file \"%s\", line %"PRIdMAX")"),
 					fields[ZF_NAME],
 					zones[i].z_filename,
 					zones[i].z_linenum);
-				error(buf);
-				return FALSE;
+				return false;
 		}
-	return inzsub(fields, nfields, FALSE);
+	return inzsub(fields, nfields, false);
 }
 
-static int
-inzcont(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+static bool
+inzcont(char **fields, int nfields)
 {
 	if (nfields < ZONEC_MINFIELDS || nfields > ZONEC_MAXFIELDS) {
 		error(_("wrong number of fields on Zone continuation line"));
-		return FALSE;
+		return false;
 	}
-	return inzsub(fields, nfields, TRUE);
+	return inzsub(fields, nfields, true);
 }
 
-static int
-inzsub(fields, nfields, iscont)
-register char ** const	fields;
-const int		nfields;
-const int		iscont;
+static bool
+inzsub(char **fields, int nfields, bool iscont)
 {
 	register char *		cp;
-	static struct zone	z;
-	register int		i_gmtoff, i_rule, i_format;
+	char *			cp1;
+	struct zone z;
+	size_t format_len;
+	register int		i_stdoff, i_rule, i_format;
 	register int		i_untilyear, i_untilmonth;
 	register int		i_untilday, i_untiltime;
-	register int		hasuntil;
+	register bool		hasuntil;
 
 	if (iscont) {
-		i_gmtoff = ZFC_GMTOFF;
+		i_stdoff = ZFC_STDOFF;
 		i_rule = ZFC_RULE;
 		i_format = ZFC_FORMAT;
 		i_untilyear = ZFC_TILYEAR;
 		i_untilmonth = ZFC_TILMONTH;
 		i_untilday = ZFC_TILDAY;
 		i_untiltime = ZFC_TILTIME;
-		z.z_name = NULL;
-	} else {
-		i_gmtoff = ZF_GMTOFF;
+	} else if (!namecheck(fields[ZF_NAME]))
+		return false;
+	else {
+		i_stdoff = ZF_STDOFF;
 		i_rule = ZF_RULE;
 		i_format = ZF_FORMAT;
 		i_untilyear = ZF_TILYEAR;
 		i_untilmonth = ZF_TILMONTH;
 		i_untilday = ZF_TILDAY;
 		i_untiltime = ZF_TILTIME;
-		z.z_name = ecpyalloc(fields[ZF_NAME]);
 	}
 	z.z_filename = filename;
 	z.z_linenum = linenum;
-	z.z_gmtoff = gethms(fields[i_gmtoff], _("invalid UTC offset"), TRUE);
+	z.z_stdoff = gethms(fields[i_stdoff], _("invalid UT offset"));
 	if ((cp = strchr(fields[i_format], '%')) != 0) {
-		if (*++cp != 's' || strchr(cp, '%') != 0) {
+		if ((*++cp != 's' && *cp != 'z') || strchr(cp, '%')
+		    || strchr(fields[i_format], '/')) {
 			error(_("invalid abbreviation format"));
-			return FALSE;
+			return false;
 		}
 	}
-	z.z_rule = ecpyalloc(fields[i_rule]);
-	z.z_format = ecpyalloc(fields[i_format]);
-	if (max_format_len < strlen(z.z_format))
-		max_format_len = strlen(z.z_format);
+	z.z_format_specifier = cp ? *cp : '\0';
+	format_len = strlen(fields[i_format]);
+	if (max_format_len < format_len)
+	  max_format_len = format_len;
 	hasuntil = nfields > i_untilyear;
 	if (hasuntil) {
 		z.z_untilrule.r_filename = filename;
 		z.z_untilrule.r_linenum = linenum;
-		rulesub(&z.z_untilrule,
+		if (!rulesub(
+			&z.z_untilrule,
 			fields[i_untilyear],
 			"only",
 			"",
 			(nfields > i_untilmonth) ?
 			fields[i_untilmonth] : "Jan",
 			(nfields > i_untilday) ? fields[i_untilday] : "1",
-			(nfields > i_untiltime) ? fields[i_untiltime] : "0");
+			(nfields > i_untiltime) ? fields[i_untiltime] : "0"))
+		  return false;
 		z.z_untiltime = rpytime(&z.z_untilrule,
 			z.z_untilrule.r_loyear);
 		if (iscont && nzones > 0 &&
 			z.z_untiltime > min_time &&
 			z.z_untiltime < max_time &&
 			zones[nzones - 1].z_untiltime > min_time &&
 			zones[nzones - 1].z_untiltime < max_time &&
 			zones[nzones - 1].z_untiltime >= z.z_untiltime) {
 				error(_(
 "Zone continuation line end time is not after end time of previous line"
 					));
-				return FALSE;
+				return false;
 		}
 	}
-	zones = (struct zone *) (void *) erealloc((char *) zones,
-		(int) ((nzones + 1) * sizeof *zones));
+	z.z_name = iscont ? NULL : ecpyalloc(fields[ZF_NAME]);
+	z.z_rule = ecpyalloc(fields[i_rule]);
+	z.z_format = cp1 = ecpyalloc(fields[i_format]);
+	if (z.z_format_specifier == 'z') {
+	  cp1[cp - fields[i_format]] = 's';
+	  if (noise)
+	    warning(_("format '%s' not handled by pre-2015 versions of zic"),
+		    fields[i_format]);
+	}
+	zones = growalloc(zones, sizeof *zones, nzones, &nzones_alloc);
 	zones[nzones++] = z;
 	/*
 	** If there was an UNTIL field on this line,
 	** there's more information about the zone on the next line.
 	*/
 	return hasuntil;
 }
 
-static void
-inleap(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+static zic_t
+getleapdatetime(char **fields, int nfields, bool expire_line)
 {
 	register const char *		cp;
 	register const struct lookup *	lp;
-	register int			i, j;
-	int				year, month, day;
-	long				dayoff, tod;
+	register zic_t			i, j;
+	zic_t				year;
+	int				month, day;
+	zic_t				dayoff, tod;
 	zic_t				t;
+	char xs;
 
-	if (nfields != LEAP_FIELDS) {
-		error(_("wrong number of fields on Leap line"));
-		return;
-	}
 	dayoff = 0;
 	cp = fields[LP_YEAR];
-	if (sscanf(cp, scheck(cp, "%d"), &year) != 1) {
+	if (sscanf(cp, "%"SCNdZIC"%c", &year, &xs) != 1) {
 		/*
 		** Leapin' Lizards!
 		*/
 		error(_("invalid leaping year"));
-		return;
+		return -1;
 	}
-	if (!leapseen || leapmaxyear < year)
+	if (!expire_line) {
+	    if (!leapseen || leapmaxyear < year)
 		leapmaxyear = year;
-	if (!leapseen || leapminyear > year)
+	    if (!leapseen || leapminyear > year)
 		leapminyear = year;
-	leapseen = TRUE;
+	    leapseen = true;
+	}
 	j = EPOCH_YEAR;
 	while (j != year) {
 		if (year > j) {
 			i = len_years[isleap(j)];
 			++j;
 		} else {
 			--j;
 			i = -len_years[isleap(j)];
 		}
-		dayoff = oadd(dayoff, eitol(i));
+		dayoff = oadd(dayoff, i);
 	}
 	if ((lp = byword(fields[LP_MONTH], mon_names)) == NULL) {
 		error(_("invalid month name"));
-		return;
+		return -1;
 	}
 	month = lp->l_value;
 	j = TM_JANUARY;
 	while (j != month) {
 		i = len_months[isleap(year)][j];
-		dayoff = oadd(dayoff, eitol(i));
+		dayoff = oadd(dayoff, i);
 		++j;
 	}
 	cp = fields[LP_DAY];
-	if (sscanf(cp, scheck(cp, "%d"), &day) != 1 ||
+	if (sscanf(cp, "%d%c", &day, &xs) != 1 ||
 		day <= 0 || day > len_months[isleap(year)][month]) {
 			error(_("invalid day of month"));
-			return;
-	}
-	dayoff = oadd(dayoff, eitol(day - 1));
-	if (dayoff < 0 && !TYPE_SIGNED(zic_t)) {
-		error(_("time before zero"));
-		return;
+			return -1;
 	}
+	dayoff = oadd(dayoff, day - 1);
 	if (dayoff < min_time / SECSPERDAY) {
 		error(_("time too small"));
-		return;
+		return -1;
 	}
 	if (dayoff > max_time / SECSPERDAY) {
 		error(_("time too large"));
-		return;
-	}
-	t = (zic_t) dayoff * SECSPERDAY;
-	tod = gethms(fields[LP_TIME], _("invalid time of day"), FALSE);
-	cp = fields[LP_CORR];
-	{
-		register int	positive;
-		int		count;
-
-		if (strcmp(cp, "") == 0) { /* infile() turns "-" into "" */
-			positive = FALSE;
-			count = 1;
-		} else if (strcmp(cp, "--") == 0) {
-			positive = FALSE;
-			count = 2;
-		} else if (strcmp(cp, "+") == 0) {
-			positive = TRUE;
-			count = 1;
-		} else if (strcmp(cp, "++") == 0) {
-			positive = TRUE;
-			count = 2;
-		} else {
-			error(_("illegal CORRECTION field on Leap line"));
-			return;
-		}
-		if ((lp = byword(fields[LP_ROLL], leap_types)) == NULL) {
-			error(_(
-				"illegal Rolling/Stationary field on Leap line"
-				));
-			return;
-		}
-		leapadd(tadd(t, tod), positive, lp->l_value, count);
+		return -1;
 	}
+	t = dayoff * SECSPERDAY;
+	tod = gethms(fields[LP_TIME], _("invalid time of day"));
+	t = tadd(t, tod);
+	if (t < 0)
+	  error(_("leap second precedes Epoch"));
+	return t;
+}
+
+static void
+inleap(char **fields, int nfields)
+{
+  if (nfields != LEAP_FIELDS)
+    error(_("wrong number of fields on Leap line"));
+  else {
+    zic_t t = getleapdatetime(fields, nfields, false);
+    if (0 <= t) {
+      struct lookup const *lp = byword(fields[LP_ROLL], leap_types);
+      if (!lp)
+	error(_("invalid Rolling/Stationary field on Leap line"));
+      else {
+	int correction = 0;
+	if (!fields[LP_CORR][0]) /* infile() turns "-" into "".  */
+	  correction = -1;
+	else if (strcmp(fields[LP_CORR], "+") == 0)
+	  correction = 1;
+	else
+	  error(_("invalid CORRECTION field on Leap line"));
+	if (correction)
+	  leapadd(t, correction, lp->l_value);
+      }
+    }
+  }
 }
 
 static void
-inlink(fields, nfields)
-register char ** const	fields;
-const int		nfields;
+inexpires(char **fields, int nfields)
+{
+  if (nfields != EXPIRES_FIELDS)
+    error(_("wrong number of fields on Expires line"));
+  else if (0 <= leapexpires)
+    error(_("multiple Expires lines"));
+  else
+    leapexpires = getleapdatetime(fields, nfields, true);
+}
+
+static void
+inlink(char **fields, int nfields)
 {
 	struct link	l;
 
 	if (nfields != LINK_FIELDS) {
 		error(_("wrong number of fields on Link line"));
 		return;
 	}
-	if (*fields[LF_FROM] == '\0') {
-		error(_("blank FROM field on Link line"));
-		return;
-	}
-	if (*fields[LF_TO] == '\0') {
-		error(_("blank TO field on Link line"));
+	if (*fields[LF_TARGET] == '\0') {
+		error(_("blank TARGET field on Link line"));
 		return;
 	}
+	if (! namecheck(fields[LF_LINKNAME]))
+	  return;
 	l.l_filename = filename;
 	l.l_linenum = linenum;
-	l.l_from = ecpyalloc(fields[LF_FROM]);
-	l.l_to = ecpyalloc(fields[LF_TO]);
-	links = (struct link *) (void *) erealloc((char *) links,
-		(int) ((nlinks + 1) * sizeof *links));
+	l.l_target = ecpyalloc(fields[LF_TARGET]);
+	l.l_linkname = ecpyalloc(fields[LF_LINKNAME]);
+	links = growalloc(links, sizeof *links, nlinks, &nlinks_alloc);
 	links[nlinks++] = l;
 }
 
-static void
-rulesub(rp, loyearp, hiyearp, typep, monthp, dayp, timep)
-register struct rule * const	rp;
-const char * const		loyearp;
-const char * const		hiyearp;
-const char * const		typep;
-const char * const		monthp;
-const char * const		dayp;
-const char * const		timep;
+static bool
+rulesub(struct rule *rp, const char *loyearp, const char *hiyearp,
+	const char *typep, const char *monthp, const char *dayp,
+	const char *timep)
 {
 	register const struct lookup *	lp;
 	register const char *		cp;
 	register char *			dp;
 	register char *			ep;
+	char xs;
 
 	if ((lp = byword(monthp, mon_names)) == NULL) {
 		error(_("invalid month name"));
-		return;
+		return false;
 	}
 	rp->r_month = lp->l_value;
-	rp->r_todisstd = FALSE;
-	rp->r_todisgmt = FALSE;
+	rp->r_todisstd = false;
+	rp->r_todisut = false;
 	dp = ecpyalloc(timep);
 	if (*dp != '\0') {
 		ep = dp + strlen(dp) - 1;
 		switch (lowerit(*ep)) {
 			case 's':	/* Standard */
-				rp->r_todisstd = TRUE;
-				rp->r_todisgmt = FALSE;
+				rp->r_todisstd = true;
+				rp->r_todisut = false;
 				*ep = '\0';
 				break;
 			case 'w':	/* Wall */
-				rp->r_todisstd = FALSE;
-				rp->r_todisgmt = FALSE;
+				rp->r_todisstd = false;
+				rp->r_todisut = false;
 				*ep = '\0';
 				break;
 			case 'g':	/* Greenwich */
 			case 'u':	/* Universal */
 			case 'z':	/* Zulu */
-				rp->r_todisstd = TRUE;
-				rp->r_todisgmt = TRUE;
+				rp->r_todisstd = true;
+				rp->r_todisut = true;
 				*ep = '\0';
 				break;
 		}
 	}
-	rp->r_tod = gethms(dp, _("invalid time of day"), FALSE);
-	ifree(dp);
+	rp->r_tod = gethms(dp, _("invalid time of day"));
+	free(dp);
 	/*
 	** Year work.
 	*/
 	cp = loyearp;
 	lp = byword(cp, begin_years);
 	rp->r_lowasnum = lp == NULL;
-	if (!rp->r_lowasnum) switch ((int) lp->l_value) {
+	if (!rp->r_lowasnum) switch (lp->l_value) {
 		case YR_MINIMUM:
-			rp->r_loyear = INT_MIN;
+			rp->r_loyear = ZIC_MIN;
 			break;
 		case YR_MAXIMUM:
-			rp->r_loyear = INT_MAX;
+			rp->r_loyear = ZIC_MAX;
 			break;
-		default:	/* "cannot happen" */
-			(void) fprintf(stderr,
-				_("%s: panic: Invalid l_value %d\n"),
-				progname, lp->l_value);
-			exit(EXIT_FAILURE);
-	} else if (sscanf(cp, scheck(cp, "%d"), &rp->r_loyear) != 1) {
+		default: UNREACHABLE();
+	} else if (sscanf(cp, "%"SCNdZIC"%c", &rp->r_loyear, &xs) != 1) {
 		error(_("invalid starting year"));
-		return;
+		return false;
 	}
 	cp = hiyearp;
 	lp = byword(cp, end_years);
 	rp->r_hiwasnum = lp == NULL;
-	if (!rp->r_hiwasnum) switch ((int) lp->l_value) {
+	if (!rp->r_hiwasnum) switch (lp->l_value) {
 		case YR_MINIMUM:
-			rp->r_hiyear = INT_MIN;
+			rp->r_hiyear = ZIC_MIN;
 			break;
 		case YR_MAXIMUM:
-			rp->r_hiyear = INT_MAX;
+			rp->r_hiyear = ZIC_MAX;
 			break;
 		case YR_ONLY:
 			rp->r_hiyear = rp->r_loyear;
 			break;
-		default:	/* "cannot happen" */
-			(void) fprintf(stderr,
-				_("%s: panic: Invalid l_value %d\n"),
-				progname, lp->l_value);
-			exit(EXIT_FAILURE);
-	} else if (sscanf(cp, scheck(cp, "%d"), &rp->r_hiyear) != 1) {
+		default: UNREACHABLE();
+	} else if (sscanf(cp, "%"SCNdZIC"%c", &rp->r_hiyear, &xs) != 1) {
 		error(_("invalid ending year"));
-		return;
+		return false;
 	}
 	if (rp->r_loyear > rp->r_hiyear) {
 		error(_("starting year greater than ending year"));
-		return;
+		return false;
 	}
-	if (*typep == '\0')
-		rp->r_yrtype = NULL;
-	else {
-		if (rp->r_loyear == rp->r_hiyear) {
-			error(_("typed single year"));
-			return;
-		}
-		rp->r_yrtype = ecpyalloc(typep);
+	if (*typep != '\0') {
+		error(_("year type \"%s\" is unsupported; use \"-\" instead"),
+			typep);
+		return false;
 	}
 	/*
 	** Day work.
 	** Accept things such as:
 	**	1
-	**	last-Sunday
+	**	lastSunday
+	**	last-Sunday (undocumented; warn about this)
 	**	Sun<=20
 	**	Sun>=7
 	*/
 	dp = ecpyalloc(dayp);
 	if ((lp = byword(dp, lasts)) != NULL) {
 		rp->r_dycode = DC_DOWLEQ;
 		rp->r_wday = lp->l_value;
 		rp->r_dayofmonth = len_months[1][rp->r_month];
 	} else {
 		if ((ep = strchr(dp, '<')) != 0)
 			rp->r_dycode = DC_DOWLEQ;
 		else if ((ep = strchr(dp, '>')) != 0)
 			rp->r_dycode = DC_DOWGEQ;
 		else {
 			ep = dp;
 			rp->r_dycode = DC_DOM;
 		}
 		if (rp->r_dycode != DC_DOM) {
 			*ep++ = 0;
 			if (*ep++ != '=') {
 				error(_("invalid day of month"));
-				ifree(dp);
-				return;
+				free(dp);
+				return false;
 			}
 			if ((lp = byword(dp, wday_names)) == NULL) {
 				error(_("invalid weekday name"));
-				ifree(dp);
-				return;
+				free(dp);
+				return false;
 			}
 			rp->r_wday = lp->l_value;
 		}
-		if (sscanf(ep, scheck(ep, "%d"), &rp->r_dayofmonth) != 1 ||
+		if (sscanf(ep, "%d%c", &rp->r_dayofmonth, &xs) != 1 ||
 			rp->r_dayofmonth <= 0 ||
 			(rp->r_dayofmonth > len_months[1][rp->r_month])) {
 				error(_("invalid day of month"));
-				ifree(dp);
-				return;
+				free(dp);
+				return false;
 		}
 	}
-	ifree(dp);
+	free(dp);
+	return true;
 }
 
 static void
-convert(val, buf)
-const long	val;
-char * const	buf;
+convert(uint_fast32_t val, char *buf)
 {
 	register int	i;
 	register int	shift;
+	unsigned char *const b = (unsigned char *) buf;
 
 	for (i = 0, shift = 24; i < 4; ++i, shift -= 8)
-		buf[i] = val >> shift;
+	  b[i] = (val >> shift) & 0xff;
 }
 
 static void
-convert64(val, buf)
-const zic_t	val;
-char * const	buf;
+convert64(uint_fast64_t val, char *buf)
 {
 	register int	i;
 	register int	shift;
+	unsigned char *const b = (unsigned char *) buf;
 
 	for (i = 0, shift = 56; i < 8; ++i, shift -= 8)
-		buf[i] = val >> shift;
+	  b[i] = (val >> shift) & 0xff;
 }
 
 static void
-puttzcode(val, fp)
-const long	val;
-FILE * const	fp;
+puttzcode(const int_fast32_t val, FILE *const fp)
 {
 	char	buf[4];
 
 	convert(val, buf);
-	(void) fwrite((void *) buf, (size_t) sizeof buf, (size_t) 1, fp);
+	fwrite(buf, sizeof buf, 1, fp);
 }
 
 static void
-puttzcode64(val, fp)
-const zic_t	val;
-FILE * const	fp;
+puttzcodepass(zic_t val, FILE *fp, int pass)
 {
+  if (pass == 1)
+    puttzcode(val, fp);
+  else {
 	char	buf[8];
 
 	convert64(val, buf);
-	(void) fwrite((void *) buf, (size_t) sizeof buf, (size_t) 1, fp);
+	fwrite(buf, sizeof buf, 1, fp);
+  }
 }
 
 static int
-atcomp(avp, bvp)
-const void *	avp;
-const void *	bvp;
+atcomp(const void *avp, const void *bvp)
 {
-	const zic_t	a = ((const struct attype *) avp)->at;
-	const zic_t	b = ((const struct attype *) bvp)->at;
-
-	return (a < b) ? -1 : (a > b);
+  struct attype const *ap = avp, *bp = bvp;
+  zic_t a = ap->at, b = bp->at;
+  return a < b ? -1 : a > b;
 }
 
-static int
-is32(x)
-const zic_t	x;
+struct timerange {
+  int defaulttype;
+  ptrdiff_t base, count;
+  int leapbase, leapcount;
+  bool leapexpiry;
+};
+
+static struct timerange
+limitrange(struct timerange r, zic_t lo, zic_t hi,
+	   zic_t const *ats, unsigned char const *types)
 {
-	return INT32_MIN <= x && x <= INT32_MAX;
+  /* Omit ordinary transitions < LO.  */
+  while (0 < r.count && ats[r.base] < lo) {
+    r.defaulttype = types[r.base];
+    r.count--;
+    r.base++;
+  }
+
+  /* Omit as many initial leap seconds as possible, such that the
+     first leap second in the truncated list is <= LO, and is a
+     positive leap second if and only if it has a positive correction.
+     This supports common TZif readers that assume that the first leap
+     second is positive if and only if its correction is positive.  */
+  while (1 < r.leapcount && trans[r.leapbase + 1] <= lo) {
+    r.leapcount--;
+    r.leapbase++;
+  }
+  while (0 < r.leapbase
+	 && ((corr[r.leapbase - 1] < corr[r.leapbase])
+	     != (0 < corr[r.leapbase]))) {
+    r.leapcount++;
+    r.leapbase--;
+  }
+
+
+  /* Omit ordinary and leap second transitions greater than HI + 1.  */
+  if (hi < max_time) {
+    while (0 < r.count && hi + 1 < ats[r.base + r.count - 1])
+      r.count--;
+    while (0 < r.leapcount && hi + 1 < trans[r.leapbase + r.leapcount - 1])
+      r.leapcount--;
+  }
+
+  /* Determine whether to append an expiration to the leap second table.  */
+  r.leapexpiry = 0 <= leapexpires && leapexpires - 1 <= hi;
+
+  return r;
 }
 
 static void
-writezone(name, string)
-const char * const	name;
-const char * const	string;
+writezone(const char *const name, const char *const string, char version,
+	  int defaulttype)
 {
 	register FILE *			fp;
-	register int			i, j;
-	register int			leapcnt32, leapi32;
-	register int			timecnt32, timei32;
+	register ptrdiff_t		i, j;
 	register int			pass;
-	static char *			fullname;
-	static const struct tzhead	tzh0;
-	static struct tzhead		tzh;
-	zic_t				ats[TZ_MAX_TIMES];
-	unsigned char			types[TZ_MAX_TIMES];
+	zic_t one = 1;
+	zic_t y2038_boundary = one << 31;
+	ptrdiff_t nats = timecnt + WORK_AROUND_QTBUG_53071;
+	char *tempname = NULL;
+	char const *outname = name;
+
+	/* Allocate the ATS and TYPES arrays via a single malloc,
+	   as this is a bit faster.  */
+	zic_t *ats = emalloc(align_to(size_product(nats, sizeof *ats + 1),
+				      _Alignof(zic_t)));
+	void *typesptr = ats + nats;
+	unsigned char *types = typesptr;
+	struct timerange rangeall = {0}, range32, range64;
 
 	/*
 	** Sort.
 	*/
 	if (timecnt > 1)
-		(void) qsort((void *) attypes, (size_t) timecnt,
-			(size_t) sizeof *attypes, atcomp);
+		qsort(attypes, timecnt, sizeof *attypes, atcomp);
 	/*
 	** Optimize.
 	*/
 	{
-		int	fromi;
-		int	toi;
+		ptrdiff_t fromi, toi;
 
 		toi = 0;
 		fromi = 0;
-		while (fromi < timecnt && attypes[fromi].at < min_time)
-			++fromi;
-		if (isdsts[0] == 0)
-			while (fromi < timecnt && attypes[fromi].type == 0)
-				++fromi;	/* handled by default rule */
 		for ( ; fromi < timecnt; ++fromi) {
-			if (toi != 0 && ((attypes[fromi].at +
-				gmtoffs[attypes[toi - 1].type]) <=
-				(attypes[toi - 1].at + gmtoffs[toi == 1 ? 0
-				: attypes[toi - 2].type]))) {
+			if (toi != 0
+			    && ((attypes[fromi].at
+				 + utoffs[attypes[toi - 1].type])
+				<= (attypes[toi - 1].at
+				    + utoffs[toi == 1 ? 0
+					     : attypes[toi - 2].type]))) {
 					attypes[toi - 1].type =
 						attypes[fromi].type;
 					continue;
 			}
-			if (toi == 0 ||
-				attypes[toi - 1].type != attypes[fromi].type)
+			if (toi == 0
+			    || attypes[fromi].dontmerge
+			    || (utoffs[attypes[toi - 1].type]
+				!= utoffs[attypes[fromi].type])
+			    || (isdsts[attypes[toi - 1].type]
+				!= isdsts[attypes[fromi].type])
+			    || (desigidx[attypes[toi - 1].type]
+				!= desigidx[attypes[fromi].type]))
 					attypes[toi++] = attypes[fromi];
 		}
 		timecnt = toi;
 	}
+
+	if (noise && timecnt > 1200) {
+	  if (timecnt > TZ_MAX_TIMES)
+		warning(_("reference clients mishandle"
+			  " more than %d transition times"),
+			TZ_MAX_TIMES);
+	  else
+		warning(_("pre-2014 clients may mishandle"
+			  " more than 1200 transition times"));
+	}
 	/*
 	** Transfer.
 	*/
 	for (i = 0; i < timecnt; ++i) {
 		ats[i] = attypes[i].at;
 		types[i] = attypes[i].type;
 	}
+
 	/*
 	** Correct for leap seconds.
 	*/
 	for (i = 0; i < timecnt; ++i) {
 		j = leapcnt;
 		while (--j >= 0)
 			if (ats[i] > trans[j] - corr[j]) {
 				ats[i] = tadd(ats[i], corr[j]);
 				break;
 			}
 	}
-	/*
-	** Figure out 32-bit-limited starts and counts.
-	*/
-	timecnt32 = timecnt;
-	timei32 = 0;
-	leapcnt32 = leapcnt;
-	leapi32 = 0;
-	while (timecnt32 > 0 && !is32(ats[timecnt32 - 1]))
-		--timecnt32;
-	while (timecnt32 > 0 && !is32(ats[timei32])) {
-		--timecnt32;
-		++timei32;
-	}
-	while (leapcnt32 > 0 && !is32(trans[leapcnt32 - 1]))
-		--leapcnt32;
-	while (leapcnt32 > 0 && !is32(trans[leapi32])) {
-		--leapcnt32;
-		++leapi32;
-	}
-	fullname = erealloc(fullname,
-		(int) (strlen(directory) + 1 + strlen(name) + 1));
-	(void) sprintf(fullname, "%s/%s", directory, name);
-	/*
-	** Remove old file, if any, to snap links.
-	*/
-	if (!itsdir(fullname) && remove(fullname) != 0 && errno != ENOENT) {
-		const char *e = strerror(errno);
 
-		(void) fprintf(stderr, _("%s: Can't remove %s: %s\n"),
-			progname, fullname, e);
-		exit(EXIT_FAILURE);
-	}
-	if ((fp = fopen(fullname, "wb")) == NULL) {
-		if (mkdirs(fullname) != 0)
-			exit(EXIT_FAILURE);
-		if ((fp = fopen(fullname, "wb")) == NULL) {
-			const char *e = strerror(errno);
+	/* Work around QTBUG-53071 for timestamps less than y2038_boundary - 1,
+	   by inserting a no-op transition at time y2038_boundary - 1.
+	   This works only for timestamps before the boundary, which
+	   should be good enough in practice as QTBUG-53071 should be
+	   long-dead by 2038.  Do this after correcting for leap
+	   seconds, as the idea is to insert a transition just before
+	   32-bit time_t rolls around, and this occurs at a slightly
+	   different moment if transitions are leap-second corrected.  */
+	if (WORK_AROUND_QTBUG_53071 && timecnt != 0 && want_bloat()
+	    && ats[timecnt - 1] < y2038_boundary - 1 && strchr(string, '<')) {
+	  ats[timecnt] = y2038_boundary - 1;
+	  types[timecnt] = types[timecnt - 1];
+	  timecnt++;
+	}
+
+	rangeall.defaulttype = defaulttype;
+	rangeall.count = timecnt;
+	rangeall.leapcount = leapcnt;
+	range64 = limitrange(rangeall, lo_time,
+			     max(hi_time,
+				 redundant_time - (ZIC_MIN < redundant_time)),
+			     ats, types);
+	range32 = limitrange(range64, INT32_MIN, INT32_MAX, ats, types);
+
+	/* TZif version 4 is needed if a no-op transition is appended to
+	   indicate the expiration of the leap second table, or if the first
+	   leap second transition is not to a +1 or -1 correction.  */
+	for (pass = 1; pass <= 2; pass++) {
+	  struct timerange const *r = pass == 1 ? &range32 : &range64;
+	  if (pass == 1 && !want_bloat())
+	    continue;
+	  if (r->leapexpiry) {
+	    if (noise)
+	      warning(_("%s: pre-2021b clients may mishandle"
+			" leap second expiry"),
+		      name);
+	    version = '4';
+	  }
+	  if (0 < r->leapcount
+	      && corr[r->leapbase] != 1 && corr[r->leapbase] != -1) {
+	    if (noise)
+	      warning(_("%s: pre-2021b clients may mishandle"
+			" leap second table truncation"),
+		      name);
+	    version = '4';
+	  }
+	  if (version == '4')
+	    break;
+	}
+
+	fp = open_outfile(&outname, &tempname);
 
-			(void) fprintf(stderr, _("%s: Can't create %s: %s\n"),
-				progname, fullname, e);
-			exit(EXIT_FAILURE);
-		}
-	}
 	for (pass = 1; pass <= 2; ++pass) {
-		register int	thistimei, thistimecnt;
-		register int	thisleapi, thisleapcnt;
-		register int	thistimelim, thisleaplim;
-		int		writetype[TZ_MAX_TIMES];
+		register ptrdiff_t thistimei, thistimecnt, thistimelim;
+		register int	thisleapi, thisleapcnt, thisleaplim;
+		struct tzhead tzh;
+		int pretranstype = -1, thisdefaulttype;
+		bool locut, hicut, thisleapexpiry;
+		zic_t lo, thismin, thismax;
+		int old0;
+		char		omittype[TZ_MAX_TYPES];
 		int		typemap[TZ_MAX_TYPES];
-		register int	thistypecnt;
+		int		thistypecnt, stdcnt, utcnt;
 		char		thischars[TZ_MAX_CHARS];
-		char		thischarcnt;
-		int 		indmap[TZ_MAX_CHARS];
+		int		thischarcnt;
+		bool		toomanytimes;
+		int		indmap[TZ_MAX_CHARS];
 
 		if (pass == 1) {
-			thistimei = timei32;
-			thistimecnt = timecnt32;
-			thisleapi = leapi32;
-			thisleapcnt = leapcnt32;
+			thisdefaulttype = range32.defaulttype;
+			thistimei = range32.base;
+			thistimecnt = range32.count;
+			toomanytimes = thistimecnt >> 31 >> 1 != 0;
+			thisleapi = range32.leapbase;
+			thisleapcnt = range32.leapcount;
+			thisleapexpiry = range32.leapexpiry;
+			thismin = INT32_MIN;
+			thismax = INT32_MAX;
 		} else {
-			thistimei = 0;
-			thistimecnt = timecnt;
-			thisleapi = 0;
-			thisleapcnt = leapcnt;
+			thisdefaulttype = range64.defaulttype;
+			thistimei = range64.base;
+			thistimecnt = range64.count;
+			toomanytimes = thistimecnt >> 31 >> 31 >> 2 != 0;
+			thisleapi = range64.leapbase;
+			thisleapcnt = range64.leapcount;
+			thisleapexpiry = range64.leapexpiry;
+			thismin = min_time;
+			thismax = max_time;
 		}
+		if (toomanytimes)
+		  error(_("too many transition times"));
+
+		locut = thismin < lo_time && lo_time <= thismax;
+		hicut = thismin <= hi_time && hi_time < thismax;
 		thistimelim = thistimei + thistimecnt;
-		thisleaplim = thisleapi + thisleapcnt;
-		for (i = 0; i < typecnt; ++i)
-			writetype[i] = thistimecnt == timecnt;
-		if (thistimecnt == 0) {
-			/*
-			** No transition times fall in the current
-			** (32- or 64-bit) window.
-			*/
-			if (typecnt != 0)
-				writetype[typecnt - 1] = TRUE;
-		} else {
-			for (i = thistimei - 1; i < thistimelim; ++i)
-				if (i >= 0)
-					writetype[types[i]] = TRUE;
-			/*
-			** For America/Godthab and Antarctica/Palmer
-			*/
-			if (thistimei == 0)
-				writetype[0] = TRUE;
+		memset(omittype, true, typecnt);
+
+		/* Determine whether to output a transition before the first
+		   transition in range.  This is needed when the output is
+		   truncated at the start, and is also useful when catering to
+		   buggy 32-bit clients that do not use time type 0 for
+		   timestamps before the first transition.  */
+		if ((locut || (pass == 1 && thistimei))
+		    && ! (thistimecnt && ats[thistimei] == lo_time)) {
+		  pretranstype = thisdefaulttype;
+		  omittype[pretranstype] = false;
 		}
+
+		/* Arguably the default time type in the 32-bit data
+		   should be range32.defaulttype, which is suited for
+		   timestamps just before INT32_MIN.  However, zic
+		   traditionally used the time type of the indefinite
+		   past instead.  Internet RFC 8532 says readers should
+		   ignore 32-bit data, so this discrepancy matters only
+		   to obsolete readers where the traditional type might
+		   be more appropriate even if it's "wrong".  So, use
+		   the historical zic value, unless -r specifies a low
+		   cutoff that excludes some 32-bit timestamps.  */
+		if (pass == 1 && lo_time <= thismin)
+		  thisdefaulttype = range64.defaulttype;
+
+		if (locut)
+		  thisdefaulttype = unspecifiedtype;
+		omittype[thisdefaulttype] = false;
+		for (i = thistimei; i < thistimelim; i++)
+		  omittype[types[i]] = false;
+		if (hicut)
+		  omittype[unspecifiedtype] = false;
+
+		/* Reorder types to make THISDEFAULTTYPE type 0.
+		   Use TYPEMAP to swap OLD0 and THISDEFAULTTYPE so that
+		   THISDEFAULTTYPE appears as type 0 in the output instead
+		   of OLD0.  TYPEMAP also omits unused types.  */
+		old0 = strlen(omittype);
+
 #ifndef LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH
 		/*
 		** For some pre-2011 systems: if the last-to-be-written
 		** standard (or daylight) type has an offset different from the
 		** most recently used offset,
 		** append an (unused) copy of the most recently used type
 		** (to help get global "altzone" and "timezone" variables
 		** set correctly).
 		*/
-		{
+		if (want_bloat()) {
 			register int	mrudst, mrustd, hidst, histd, type;
 
 			hidst = histd = mrudst = mrustd = -1;
-			for (i = thistimei; i < thistimelim; ++i)
+			if (0 <= pretranstype) {
+			  if (isdsts[pretranstype])
+			    mrudst = pretranstype;
+			  else
+			    mrustd = pretranstype;
+			}
+			for (i = thistimei; i < thistimelim; i++)
 				if (isdsts[types[i]])
 					mrudst = types[i];
 				else	mrustd = types[i];
-			for (i = 0; i < typecnt; ++i)
-				if (writetype[i])
-					if (isdsts[i])
-						hidst = i;
-					else	histd = i;
+			for (i = old0; i < typecnt; i++) {
+			  int h = (i == old0 ? thisdefaulttype
+				   : i == thisdefaulttype ? old0 : i);
+			  if (!omittype[h]) {
+			    if (isdsts[h])
+			      hidst = i;
+			    else
+			      histd = i;
+			  }
+			}
 			if (hidst >= 0 && mrudst >= 0 && hidst != mrudst &&
-				gmtoffs[hidst] != gmtoffs[mrudst]) {
+				utoffs[hidst] != utoffs[mrudst]) {
 					isdsts[mrudst] = -1;
-					type = addtype(gmtoffs[mrudst],
-						&chars[abbrinds[mrudst]],
-						TRUE,
+					type = addtype(utoffs[mrudst],
+						&chars[desigidx[mrudst]],
+						true,
 						ttisstds[mrudst],
-						ttisgmts[mrudst]);
-					isdsts[mrudst] = TRUE;
-					writetype[type] = TRUE;
+						ttisuts[mrudst]);
+					isdsts[mrudst] = 1;
+					omittype[type] = false;
 			}
 			if (histd >= 0 && mrustd >= 0 && histd != mrustd &&
-				gmtoffs[histd] != gmtoffs[mrustd]) {
+				utoffs[histd] != utoffs[mrustd]) {
 					isdsts[mrustd] = -1;
-					type = addtype(gmtoffs[mrustd],
-						&chars[abbrinds[mrustd]],
-						FALSE,
+					type = addtype(utoffs[mrustd],
+						&chars[desigidx[mrustd]],
+						false,
 						ttisstds[mrustd],
-						ttisgmts[mrustd]);
-					isdsts[mrustd] = FALSE;
-					writetype[type] = TRUE;
+						ttisuts[mrustd]);
+					isdsts[mrustd] = 0;
+					omittype[type] = false;
 			}
 		}
 #endif /* !defined LEAVE_SOME_PRE_2011_SYSTEMS_IN_THE_LURCH */
 		thistypecnt = 0;
-		for (i = 0; i < typecnt; ++i)
-			typemap[i] = writetype[i] ?  thistypecnt++ : -1;
+		for (i = old0; i < typecnt; i++)
+		  if (!omittype[i])
+		    typemap[i == old0 ? thisdefaulttype
+			    : i == thisdefaulttype ? old0 : i]
+		      = thistypecnt++;
+
 		for (i = 0; i < sizeof indmap / sizeof indmap[0]; ++i)
 			indmap[i] = -1;
-		thischarcnt = 0;
-		for (i = 0; i < typecnt; ++i) {
+		thischarcnt = stdcnt = utcnt = 0;
+		for (i = old0; i < typecnt; i++) {
 			register char *	thisabbr;
 
-			if (!writetype[i])
+			if (omittype[i])
 				continue;
-			if (indmap[abbrinds[i]] >= 0)
+			if (ttisstds[i])
+			  stdcnt = thistypecnt;
+			if (ttisuts[i])
+			  utcnt = thistypecnt;
+			if (indmap[desigidx[i]] >= 0)
 				continue;
-			thisabbr = &chars[abbrinds[i]];
+			thisabbr = &chars[desigidx[i]];
 			for (j = 0; j < thischarcnt; ++j)
 				if (strcmp(&thischars[j], thisabbr) == 0)
 					break;
 			if (j == thischarcnt) {
-				(void) strcpy(&thischars[(int) thischarcnt],
-					thisabbr);
+				strcpy(&thischars[thischarcnt], thisabbr);
 				thischarcnt += strlen(thisabbr) + 1;
 			}
-			indmap[abbrinds[i]] = j;
+			indmap[desigidx[i]] = j;
 		}
-#define DO(field)	(void) fwrite((void *) tzh.field, \
-				(size_t) sizeof tzh.field, (size_t) 1, fp)
-		tzh = tzh0;
-		(void) strncpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
-		tzh.tzh_version[0] = ZIC_VERSION;
-		convert(eitol(thistypecnt), tzh.tzh_ttisgmtcnt);
-		convert(eitol(thistypecnt), tzh.tzh_ttisstdcnt);
-		convert(eitol(thisleapcnt), tzh.tzh_leapcnt);
-		convert(eitol(thistimecnt), tzh.tzh_timecnt);
-		convert(eitol(thistypecnt), tzh.tzh_typecnt);
-		convert(eitol(thischarcnt), tzh.tzh_charcnt);
+		if (pass == 1 && !want_bloat()) {
+		  hicut = thisleapexpiry = false;
+		  pretranstype = -1;
+		  thistimecnt = thisleapcnt = 0;
+		  thistypecnt = thischarcnt = 1;
+		}
+#define DO(field)	fwrite(tzh.field, sizeof tzh.field, 1, fp)
+		memset(&tzh, 0, sizeof tzh);
+		memcpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
+		tzh.tzh_version[0] = version;
+		convert(utcnt, tzh.tzh_ttisutcnt);
+		convert(stdcnt, tzh.tzh_ttisstdcnt);
+		convert(thisleapcnt + thisleapexpiry, tzh.tzh_leapcnt);
+		convert((0 <= pretranstype) + thistimecnt + hicut,
+			tzh.tzh_timecnt);
+		convert(thistypecnt, tzh.tzh_typecnt);
+		convert(thischarcnt, tzh.tzh_charcnt);
 		DO(tzh_magic);
 		DO(tzh_version);
 		DO(tzh_reserved);
-		DO(tzh_ttisgmtcnt);
+		DO(tzh_ttisutcnt);
 		DO(tzh_ttisstdcnt);
 		DO(tzh_leapcnt);
 		DO(tzh_timecnt);
 		DO(tzh_typecnt);
 		DO(tzh_charcnt);
 #undef DO
-		for (i = thistimei; i < thistimelim; ++i)
-			if (pass == 1)
-				puttzcode((long) ats[i], fp);
-			else	puttzcode64(ats[i], fp);
-		for (i = thistimei; i < thistimelim; ++i) {
-			unsigned char	uc;
+		if (pass == 1 && !want_bloat()) {
+		  /* Output a minimal data block with just one time type.  */
+		  puttzcode(0, fp);	/* utoff */
+		  putc(0, fp);		/* dst */
+		  putc(0, fp);		/* index of abbreviation */
+		  putc(0, fp);		/* empty-string abbreviation */
+		  continue;
+		}
 
-			uc = typemap[types[i]];
-			(void) fwrite((void *) &uc,
-				(size_t) sizeof uc,
-				(size_t) 1,
-				fp);
+		/* Output a LO_TIME transition if needed; see limitrange.
+		   But do not go below the minimum representable value
+		   for this pass.  */
+		lo = pass == 1 && lo_time < INT32_MIN ? INT32_MIN : lo_time;
+
+		if (0 <= pretranstype)
+		  puttzcodepass(lo, fp, pass);
+		for (i = thistimei; i < thistimelim; ++i) {
+		  puttzcodepass(ats[i], fp, pass);
+		}
+		if (hicut)
+		  puttzcodepass(hi_time + 1, fp, pass);
+		if (0 <= pretranstype)
+		  putc(typemap[pretranstype], fp);
+		for (i = thistimei; i < thistimelim; i++)
+		  putc(typemap[types[i]], fp);
+		if (hicut)
+		  putc(typemap[unspecifiedtype], fp);
+
+		for (i = old0; i < typecnt; i++) {
+		  int h = (i == old0 ? thisdefaulttype
+			   : i == thisdefaulttype ? old0 : i);
+		  if (!omittype[h]) {
+		    puttzcode(utoffs[h], fp);
+		    putc(isdsts[h], fp);
+		    putc(indmap[desigidx[h]], fp);
+		  }
 		}
-		for (i = 0; i < typecnt; ++i)
-			if (writetype[i]) {
-				puttzcode(gmtoffs[i], fp);
-				(void) putc(isdsts[i], fp);
-				(void) putc((unsigned char) indmap[abbrinds[i]], fp);
-			}
 		if (thischarcnt != 0)
-			(void) fwrite((void *) thischars,
-				(size_t) sizeof thischars[0],
-				(size_t) thischarcnt, fp);
+			fwrite(thischars, sizeof thischars[0],
+				      thischarcnt, fp);
+		thisleaplim = thisleapi + thisleapcnt;
 		for (i = thisleapi; i < thisleaplim; ++i) {
 			register zic_t	todo;
 
 			if (roll[i]) {
 				if (timecnt == 0 || trans[i] < ats[0]) {
 					j = 0;
 					while (isdsts[j])
 						if (++j >= typecnt) {
 							j = 0;
 							break;
 						}
 				} else {
 					j = 1;
 					while (j < timecnt &&
 						trans[i] >= ats[j])
 							++j;
 					j = types[j - 1];
 				}
-				todo = tadd(trans[i], -gmtoffs[j]);
+				todo = tadd(trans[i], -utoffs[j]);
 			} else	todo = trans[i];
-			if (pass == 1)
-				puttzcode((long) todo, fp);
-			else	puttzcode64(todo, fp);
+			puttzcodepass(todo, fp, pass);
 			puttzcode(corr[i], fp);
 		}
-		for (i = 0; i < typecnt; ++i)
-			if (writetype[i])
-				(void) putc(ttisstds[i], fp);
-		for (i = 0; i < typecnt; ++i)
-			if (writetype[i])
-				(void) putc(ttisgmts[i], fp);
-	}
-	(void) fprintf(fp, "\n%s\n", string);
-	if (ferror(fp) || fclose(fp)) {
-		(void) fprintf(stderr, _("%s: Error writing %s\n"),
-			progname, fullname);
-		exit(EXIT_FAILURE);
-	}
+		if (thisleapexpiry) {
+		  /* Append a no-op leap correction indicating when the leap
+		     second table expires.  Although this does not conform to
+		     Internet RFC 8536, most clients seem to accept this and
+		     the plan is to amend the RFC to allow this in version 4
+		     TZif files.  */
+		  puttzcodepass(leapexpires, fp, pass);
+		  puttzcode(thisleaplim ? corr[thisleaplim - 1] : 0, fp);
+		}
+		if (stdcnt != 0)
+		  for (i = old0; i < typecnt; i++)
+			if (!omittype[i])
+				putc(ttisstds[i], fp);
+		if (utcnt != 0)
+		  for (i = old0; i < typecnt; i++)
+			if (!omittype[i])
+				putc(ttisuts[i], fp);
+	}
+	fprintf(fp, "\n%s\n", string);
+	close_file(fp, directory, name, tempname);
+	rename_dest(tempname, name);
+	free(ats);
 }
 
-static void
-doabbr(abbr, format, letters, isdst, doquotes)
-char * const		abbr;
-const char * const	format;
-const char * const	letters;
-const int		isdst;
-const int		doquotes;
+static char const *
+abbroffset(char *buf, zic_t offset)
+{
+  char sign = '+';
+  int seconds, minutes;
+
+  if (offset < 0) {
+    offset = -offset;
+    sign = '-';
+  }
+
+  seconds = offset % SECSPERMIN;
+  offset /= SECSPERMIN;
+  minutes = offset % MINSPERHOUR;
+  offset /= MINSPERHOUR;
+  if (100 <= offset) {
+    error(_("%%z UT offset magnitude exceeds 99:59:59"));
+    return "%z";
+  } else {
+    char *p = buf;
+    *p++ = sign;
+    *p++ = '0' + offset / 10;
+    *p++ = '0' + offset % 10;
+    if (minutes | seconds) {
+      *p++ = '0' + minutes / 10;
+      *p++ = '0' + minutes % 10;
+      if (seconds) {
+	*p++ = '0' + seconds / 10;
+	*p++ = '0' + seconds % 10;
+      }
+    }
+    *p = '\0';
+    return buf;
+  }
+}
+
+static char const disable_percent_s[] = "";
+
+static size_t
+doabbr(char *abbr, struct zone const *zp, char const *letters,
+       bool isdst, zic_t save, bool doquotes)
 {
 	register char *	cp;
 	register char *	slashp;
-	register int	len;
+	register size_t	len;
+	char const *format = zp->z_format;
 
 	slashp = strchr(format, '/');
 	if (slashp == NULL) {
-		if (letters == NULL)
-			(void) strcpy(abbr, format);
-		else	(void) sprintf(abbr, format, letters);
+	  char letterbuf[PERCENT_Z_LEN_BOUND + 1];
+	  if (zp->z_format_specifier == 'z')
+	    letters = abbroffset(letterbuf, zp->z_stdoff + save);
+	  else if (!letters)
+	    letters = "%s";
+	  else if (letters == disable_percent_s)
+	    return 0;
+	  sprintf(abbr, format, letters);
 	} else if (isdst) {
-		(void) strcpy(abbr, slashp + 1);
+		strcpy(abbr, slashp + 1);
 	} else {
-		if (slashp > format)
-			(void) strncpy(abbr, format,
-				(unsigned) (slashp - format));
+		memcpy(abbr, format, slashp - format);
 		abbr[slashp - format] = '\0';
 	}
-	if (!doquotes)
-		return;
-	for (cp = abbr; *cp != '\0'; ++cp)
-		if (strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ", *cp) == NULL &&
-			strchr("abcdefghijklmnopqrstuvwxyz", *cp) == NULL)
-				break;
 	len = strlen(abbr);
+	if (!doquotes)
+		return len;
+	for (cp = abbr; is_alpha(*cp); cp++)
+		continue;
 	if (len > 0 && *cp == '\0')
-		return;
+		return len;
 	abbr[len + 2] = '\0';
 	abbr[len + 1] = '>';
-	for ( ; len > 0; --len)
-		abbr[len] = abbr[len - 1];
+	memmove(abbr + 1, abbr, len);
 	abbr[0] = '<';
+	return len + 2;
 }
 
 static void
-updateminmax(x)
-const int	x;
+updateminmax(const zic_t x)
 {
 	if (min_year > x)
 		min_year = x;
 	if (max_year < x)
 		max_year = x;
 }
 
 static int
-stringoffset(result, offset)
-char *	result;
-long	offset;
+stringoffset(char *result, zic_t offset)
 {
 	register int	hours;
 	register int	minutes;
 	register int	seconds;
+	bool negative = offset < 0;
+	int len = negative;
 
-	result[0] = '\0';
-	if (offset < 0) {
-		(void) strcpy(result, "-");
+	if (negative) {
 		offset = -offset;
+		result[0] = '-';
 	}
 	seconds = offset % SECSPERMIN;
 	offset /= SECSPERMIN;
 	minutes = offset % MINSPERHOUR;
 	offset /= MINSPERHOUR;
 	hours = offset;
-	if (hours >= HOURSPERDAY) {
+	if (hours >= HOURSPERDAY * DAYSPERWEEK) {
 		result[0] = '\0';
-		return -1;
+		return 0;
 	}
-	(void) sprintf(end(result), "%d", hours);
+	len += sprintf(result + len, "%d", hours);
 	if (minutes != 0 || seconds != 0) {
-		(void) sprintf(end(result), ":%02d", minutes);
+		len += sprintf(result + len, ":%02d", minutes);
 		if (seconds != 0)
-			(void) sprintf(end(result), ":%02d", seconds);
+			len += sprintf(result + len, ":%02d", seconds);
 	}
-	return 0;
+	return len;
 }
 
 static int
-stringrule(result, rp, dstoff, gmtoff)
-char *				result;
-const struct rule * const	rp;
-const long			dstoff;
-const long			gmtoff;
+stringrule(char *result, struct rule *const rp, zic_t save, zic_t stdoff)
 {
-	register long	tod;
+	register zic_t	tod = rp->r_tod;
+	register int	compat = 0;
 
-	result = end(result);
 	if (rp->r_dycode == DC_DOM) {
 		register int	month, total;
 
 		if (rp->r_dayofmonth == 29 && rp->r_month == TM_FEBRUARY)
 			return -1;
 		total = 0;
 		for (month = 0; month < rp->r_month; ++month)
 			total += len_months[0][month];
-		(void) sprintf(result, "J%d", total + rp->r_dayofmonth);
+		/* Omit the "J" in Jan and Feb, as that's shorter.  */
+		if (rp->r_month <= 1)
+		  result += sprintf(result, "%d", total + rp->r_dayofmonth - 1);
+		else
+		  result += sprintf(result, "J%d", total + rp->r_dayofmonth);
 	} else {
 		register int	week;
+		register int	wday = rp->r_wday;
+		register int	wdayoff;
 
 		if (rp->r_dycode == DC_DOWGEQ) {
-			if ((rp->r_dayofmonth % DAYSPERWEEK) != 1)
-				return -1;
-			week = 1 + rp->r_dayofmonth / DAYSPERWEEK;
+			wdayoff = (rp->r_dayofmonth - 1) % DAYSPERWEEK;
+			if (wdayoff)
+				compat = 2013;
+			wday -= wdayoff;
+			tod += wdayoff * SECSPERDAY;
+			week = 1 + (rp->r_dayofmonth - 1) / DAYSPERWEEK;
 		} else if (rp->r_dycode == DC_DOWLEQ) {
 			if (rp->r_dayofmonth == len_months[1][rp->r_month])
 				week = 5;
 			else {
-				if ((rp->r_dayofmonth % DAYSPERWEEK) != 0)
-					return -1;
+				wdayoff = rp->r_dayofmonth % DAYSPERWEEK;
+				if (wdayoff)
+					compat = 2013;
+				wday -= wdayoff;
+				tod += wdayoff * SECSPERDAY;
 				week = rp->r_dayofmonth / DAYSPERWEEK;
 			}
 		} else	return -1;	/* "cannot happen" */
-		(void) sprintf(result, "M%d.%d.%d",
-			rp->r_month + 1, week, rp->r_wday);
-	}
-	tod = rp->r_tod;
-	if (rp->r_todisgmt)
-		tod += gmtoff;
-	if (rp->r_todisstd && rp->r_stdoff == 0)
-		tod += dstoff;
-	if (tod < 0) {
-		result[0] = '\0';
-		return -1;
-	}
+		if (wday < 0)
+			wday += DAYSPERWEEK;
+		result += sprintf(result, "M%d.%d.%d",
+				  rp->r_month + 1, week, wday);
+	}
+	if (rp->r_todisut)
+	  tod += stdoff;
+	if (rp->r_todisstd && !rp->r_isdst)
+	  tod += save;
 	if (tod != 2 * SECSPERMIN * MINSPERHOUR) {
-		(void) strcat(result, "/");
-		if (stringoffset(end(result), tod) != 0)
+		*result++ = '/';
+		if (! stringoffset(result, tod))
 			return -1;
+		if (tod < 0) {
+			if (compat < 2013)
+				compat = 2013;
+		} else if (SECSPERDAY <= tod) {
+			if (compat < 1994)
+				compat = 1994;
+		}
 	}
-	return 0;
+	return compat;
 }
 
-static void
-stringzone(result, zpfirst, zonecount)
-char *				result;
-const struct zone * const	zpfirst;
-const int			zonecount;
+static int
+rule_cmp(struct rule const *a, struct rule const *b)
+{
+	if (!a)
+		return -!!b;
+	if (!b)
+		return 1;
+	if (a->r_hiyear != b->r_hiyear)
+		return a->r_hiyear < b->r_hiyear ? -1 : 1;
+	if (a->r_hiyear == ZIC_MAX)
+		return 0;
+	if (a->r_month - b->r_month != 0)
+		return a->r_month - b->r_month;
+	return a->r_dayofmonth - b->r_dayofmonth;
+}
+
+static int
+stringzone(char *result, struct zone const *zpfirst, ptrdiff_t zonecount)
 {
 	register const struct zone *	zp;
 	register struct rule *		rp;
 	register struct rule *		stdrp;
 	register struct rule *		dstrp;
-	register int			i;
-	register const char *		abbrvar;
+	register ptrdiff_t		i;
+	register int			compat = 0;
+	register int			c;
+	size_t				len;
+	int				offsetlen;
+	struct rule			stdr, dstr;
+	int dstcmp;
+	struct rule *lastrp[2] = { NULL, NULL };
+	struct zone zstr[2];
+	struct zone const *stdzp;
+	struct zone const *dstzp;
 
 	result[0] = '\0';
+
+	/* Internet RFC 8536 section 5.1 says to use an empty TZ string if
+	   future timestamps are truncated.  */
+	if (hi_time < max_time)
+	  return -1;
+
 	zp = zpfirst + zonecount - 1;
-	stdrp = dstrp = NULL;
 	for (i = 0; i < zp->z_nrules; ++i) {
+		struct rule **last;
+		int cmp;
 		rp = &zp->z_rules[i];
-		if (rp->r_hiwasnum || rp->r_hiyear != INT_MAX)
-			continue;
-		if (rp->r_yrtype != NULL)
-			continue;
-		if (rp->r_stdoff == 0) {
-			if (stdrp == NULL)
-				stdrp = rp;
-			else	return;
-		} else {
-			if (dstrp == NULL)
-				dstrp = rp;
-			else	return;
-		}
-	}
-	if (stdrp == NULL && dstrp == NULL) {
-		/*
-		** There are no rules running through "max".
-		** Let's find the latest rule.
-		*/
-		for (i = 0; i < zp->z_nrules; ++i) {
-			rp = &zp->z_rules[i];
-			if (stdrp == NULL || rp->r_hiyear > stdrp->r_hiyear ||
-				(rp->r_hiyear == stdrp->r_hiyear &&
-				rp->r_month > stdrp->r_month))
-					stdrp = rp;
-		}
-		if (stdrp != NULL && stdrp->r_stdoff != 0)
-			return;	/* We end up in DST (a POSIX no-no). */
-		/*
-		** Horrid special case: if year is 2037,
-		** presume this is a zone handled on a year-by-year basis;
-		** do not try to apply a rule to the zone.
-		*/
-		if (stdrp != NULL && stdrp->r_hiyear == 2037)
-			return;
-	}
-	if (stdrp == NULL && (zp->z_nrules != 0 || zp->z_stdoff != 0))
-		return;
-	abbrvar = (stdrp == NULL) ? "" : stdrp->r_abbrvar;
-	doabbr(result, zp->z_format, abbrvar, FALSE, TRUE);
-	if (stringoffset(end(result), -zp->z_gmtoff) != 0) {
+		last = &lastrp[rp->r_isdst];
+		cmp = rule_cmp(*last, rp);
+		if (cmp < 0)
+		  *last = rp;
+		else if (cmp == 0)
+		  return -1;
+	}
+	stdrp = lastrp[false];
+	dstrp = lastrp[true];
+	dstcmp = zp->z_nrules ? rule_cmp(dstrp, stdrp) : zp->z_isdst ? 1 : -1;
+	stdzp = dstzp = zp;
+
+	if (dstcmp < 0) {
+	  /* Standard time all year.  */
+	  dstrp = NULL;
+	} else if (0 < dstcmp) {
+	  /* DST all year.  Use an abbreviation like
+	     "XXX3EDT4,0/0,J365/23" for EDT (-04) all year.  */
+	  zic_t save = dstrp ? dstrp->r_save : zp->z_save;
+	  if (0 <= save)
+	    {
+	      /* Positive DST, the typical case for all-year DST.
+		 Fake a timezone with negative DST.  */
+	      stdzp = &zstr[0];
+	      dstzp = &zstr[1];
+	      zstr[0].z_stdoff = zp->z_stdoff + 2 * save;
+	      zstr[0].z_format = "XXX";  /* Any 3 letters will do.  */
+	      zstr[0].z_format_specifier = 0;
+	      zstr[1].z_stdoff = zstr[0].z_stdoff;
+	      zstr[1].z_format = zp->z_format;
+	      zstr[1].z_format_specifier = zp->z_format_specifier;
+	    }
+	  dstr.r_month = TM_JANUARY;
+	  dstr.r_dycode = DC_DOM;
+	  dstr.r_dayofmonth = 1;
+	  dstr.r_tod = 0;
+	  dstr.r_todisstd = dstr.r_todisut = false;
+	  dstr.r_isdst = true;
+	  dstr.r_save = save < 0 ? save : -save;
+	  dstr.r_abbrvar = dstrp ? dstrp->r_abbrvar : NULL;
+	  stdr.r_month = TM_DECEMBER;
+	  stdr.r_dycode = DC_DOM;
+	  stdr.r_dayofmonth = 31;
+	  stdr.r_tod = SECSPERDAY + dstr.r_save;
+	  stdr.r_todisstd = stdr.r_todisut = false;
+	  stdr.r_isdst = false;
+	  stdr.r_save = 0;
+	  stdr.r_abbrvar = save < 0 && stdrp ? stdrp->r_abbrvar : NULL;
+	  dstrp = &dstr;
+	  stdrp = &stdr;
+	}
+	len = doabbr(result, stdzp, stdrp ? stdrp->r_abbrvar : NULL,
+		     false, 0, true);
+	offsetlen = stringoffset(result + len, - stdzp->z_stdoff);
+	if (! offsetlen) {
 		result[0] = '\0';
-		return;
+		return -1;
 	}
+	len += offsetlen;
 	if (dstrp == NULL)
-		return;
-	doabbr(end(result), zp->z_format, dstrp->r_abbrvar, TRUE, TRUE);
-	if (dstrp->r_stdoff != SECSPERMIN * MINSPERHOUR)
-		if (stringoffset(end(result),
-			-(zp->z_gmtoff + dstrp->r_stdoff)) != 0) {
-				result[0] = '\0';
-				return;
-		}
-	(void) strcat(result, ",");
-	if (stringrule(result, dstrp, dstrp->r_stdoff, zp->z_gmtoff) != 0) {
+		return compat;
+	len += doabbr(result + len, dstzp, dstrp->r_abbrvar,
+		      dstrp->r_isdst, dstrp->r_save, true);
+	if (dstrp->r_save != SECSPERMIN * MINSPERHOUR) {
+	  offsetlen = stringoffset(result + len,
+				   - (dstzp->z_stdoff + dstrp->r_save));
+	  if (! offsetlen) {
+	    result[0] = '\0';
+	    return -1;
+	  }
+	  len += offsetlen;
+	}
+	result[len++] = ',';
+	c = stringrule(result + len, dstrp, dstrp->r_save, stdzp->z_stdoff);
+	if (c < 0) {
 		result[0] = '\0';
-		return;
+		return -1;
 	}
-	(void) strcat(result, ",");
-	if (stringrule(result, stdrp, dstrp->r_stdoff, zp->z_gmtoff) != 0) {
+	if (compat < c)
+		compat = c;
+	len += strlen(result + len);
+	result[len++] = ',';
+	c = stringrule(result + len, stdrp, dstrp->r_save, stdzp->z_stdoff);
+	if (c < 0) {
 		result[0] = '\0';
-		return;
+		return -1;
 	}
+	if (compat < c)
+		compat = c;
+	return compat;
 }
 
 static void
-outzone(zpfirst, zonecount)
-const struct zone * const	zpfirst;
-const int			zonecount;
+outzone(const struct zone *zpfirst, ptrdiff_t zonecount)
 {
-	register const struct zone *	zp;
-	register struct rule *		rp;
-	register int			i, j;
-	register int			usestart, useuntil;
+	register ptrdiff_t		i, j;
 	register zic_t			starttime, untiltime;
-	register long			gmtoff;
-	register long			stdoff;
-	register int			year;
-	register long			startoff;
-	register int			startttisstd;
-	register int			startttisgmt;
-	register int			type;
+	register bool			startttisstd;
+	register bool			startttisut;
 	register char *			startbuf;
 	register char *			ab;
 	register char *			envvar;
 	register int			max_abbr_len;
 	register int			max_envvar_len;
-	register int			prodstic; /* all rules are min to max */
+	register bool			prodstic; /* all rules are min to max */
+	register int			compat;
+	register bool			do_extend;
+	register char			version;
+	ptrdiff_t lastatmax = -1;
+	zic_t max_year0;
+	int defaulttype = -1;
+
+	check_for_signal();
 
 	max_abbr_len = 2 + max_format_len + max_abbrvar_len;
 	max_envvar_len = 2 * max_abbr_len + 5 * 9;
 	startbuf = emalloc(max_abbr_len + 1);
 	ab = emalloc(max_abbr_len + 1);
 	envvar = emalloc(max_envvar_len + 1);
 	INITIALIZE(untiltime);
 	INITIALIZE(starttime);
 	/*
 	** Now. . .finally. . .generate some useful data!
 	*/
 	timecnt = 0;
 	typecnt = 0;
 	charcnt = 0;
 	prodstic = zonecount == 1;
 	/*
 	** Thanks to Earl Chew
 	** for noting the need to unconditionally initialize startttisstd.
 	*/
-	startttisstd = FALSE;
-	startttisgmt = FALSE;
+	startttisstd = false;
+	startttisut = false;
 	min_year = max_year = EPOCH_YEAR;
 	if (leapseen) {
 		updateminmax(leapminyear);
-		updateminmax(leapmaxyear + (leapmaxyear < INT_MAX));
+		updateminmax(leapmaxyear + (leapmaxyear < ZIC_MAX));
 	}
 	for (i = 0; i < zonecount; ++i) {
-		zp = &zpfirst[i];
+		struct zone const *zp = &zpfirst[i];
 		if (i < zonecount - 1)
 			updateminmax(zp->z_untilrule.r_loyear);
 		for (j = 0; j < zp->z_nrules; ++j) {
-			rp = &zp->z_rules[j];
+			struct rule *rp = &zp->z_rules[j];
 			if (rp->r_lowasnum)
 				updateminmax(rp->r_loyear);
 			if (rp->r_hiwasnum)
 				updateminmax(rp->r_hiyear);
 			if (rp->r_lowasnum || rp->r_hiwasnum)
-				prodstic = FALSE;
+				prodstic = false;
 		}
 	}
 	/*
 	** Generate lots of data if a rule can't cover all future times.
 	*/
-	stringzone(envvar, zpfirst, zonecount);
-	if (noise && envvar[0] == '\0') {
-		register char *	wp;
-
-wp = ecpyalloc(_("no POSIX environment variable for zone"));
-		wp = ecatalloc(wp, " ");
-		wp = ecatalloc(wp, zpfirst->z_name);
-		warning(wp);
-		ifree(wp);
-	}
-	if (envvar[0] == '\0') {
-		if (min_year >= INT_MIN + YEARSPERREPEAT)
-			min_year -= YEARSPERREPEAT;
-		else	min_year = INT_MIN;
-		if (max_year <= INT_MAX - YEARSPERREPEAT)
-			max_year += YEARSPERREPEAT;
-		else	max_year = INT_MAX;
+	compat = stringzone(envvar, zpfirst, zonecount);
+	version = compat < 2013 ? '2' : '3';
+	do_extend = compat < 0;
+	if (noise) {
+		if (!*envvar)
+			warning("%s %s",
+				_("no POSIX environment variable for zone"),
+				zpfirst->z_name);
+		else if (compat != 0) {
+			/* Circa-COMPAT clients, and earlier clients, might
+			   not work for this zone when given dates before
+			   1970 or after 2038.  */
+			warning(_("%s: pre-%d clients may mishandle"
+				  " distant timestamps"),
+				zpfirst->z_name, compat);
+		}
+	}
+	if (do_extend) {
+		/*
+		** Search through a couple of extra years past the obvious
+		** 400, to avoid edge cases.  For example, suppose a non-POSIX
+		** rule applies from 2012 onwards and has transitions in March
+		** and September, plus some one-off transitions in November
+		** 2013.  If zic looked only at the last 400 years, it would
+		** set max_year=2413, with the intent that the 400 years 2014
+		** through 2413 will be repeated.  The last transition listed
+		** in the tzfile would be in 2413-09, less than 400 years
+		** after the last one-off transition in 2013-11.  Two years
+		** might be overkill, but with the kind of edge cases
+		** available we're not sure that one year would suffice.
+		*/
+		enum { years_of_observations = YEARSPERREPEAT + 2 };
+
+		if (min_year >= ZIC_MIN + years_of_observations)
+			min_year -= years_of_observations;
+		else	min_year = ZIC_MIN;
+		if (max_year <= ZIC_MAX - years_of_observations)
+			max_year += years_of_observations;
+		else	max_year = ZIC_MAX;
 		/*
 		** Regardless of any of the above,
 		** for a "proDSTic" zone which specifies that its rules
 		** always have and always will be in effect,
 		** we only need one cycle to define the zone.
 		*/
 		if (prodstic) {
 			min_year = 1900;
-			max_year = min_year + YEARSPERREPEAT;
+			max_year = min_year + years_of_observations;
 		}
 	}
-	/*
-	** For the benefit of older systems,
-	** generate data from 1900 through 2037.
-	*/
-	if (min_year > 1900)
+	max_year = max(max_year, (redundant_time / (SECSPERDAY * DAYSPERNYEAR)
+				  + EPOCH_YEAR + 1));
+	max_year0 = max_year;
+	if (want_bloat()) {
+	  /* For the benefit of older systems,
+	     generate data from 1900 through 2038.  */
+	  if (min_year > 1900)
 		min_year = 1900;
-	if (max_year < 2037)
-		max_year = 2037;
+	  if (max_year < 2038)
+		max_year = 2038;
+	}
+
+	if (min_time < lo_time || hi_time < max_time)
+	  unspecifiedtype = addtype(0, "-00", false, false, false);
+
 	for (i = 0; i < zonecount; ++i) {
+		struct rule *prevrp = NULL;
 		/*
 		** A guess that may well be corrected later.
 		*/
-		stdoff = 0;
-		zp = &zpfirst[i];
-		usestart = i > 0 && (zp - 1)->z_untiltime > min_time;
-		useuntil = i < (zonecount - 1);
+		zic_t save = 0;
+		struct zone const *zp = &zpfirst[i];
+		bool usestart = i > 0 && (zp - 1)->z_untiltime > min_time;
+		bool useuntil = i < (zonecount - 1);
+		zic_t stdoff = zp->z_stdoff;
+		zic_t startoff = stdoff;
+		zic_t prevktime;
+		INITIALIZE(prevktime);
 		if (useuntil && zp->z_untiltime <= min_time)
 			continue;
-		gmtoff = zp->z_gmtoff;
 		eat(zp->z_filename, zp->z_linenum);
 		*startbuf = '\0';
-		startoff = zp->z_gmtoff;
 		if (zp->z_nrules == 0) {
-			stdoff = zp->z_stdoff;
-			doabbr(startbuf, zp->z_format,
-				(char *) NULL, stdoff != 0, FALSE);
-			type = addtype(oadd(zp->z_gmtoff, stdoff),
-				startbuf, stdoff != 0, startttisstd,
-				startttisgmt);
+			int type;
+			save = zp->z_save;
+			doabbr(startbuf, zp, NULL, zp->z_isdst, save, false);
+			type = addtype(oadd(zp->z_stdoff, save),
+				startbuf, zp->z_isdst, startttisstd,
+				startttisut);
 			if (usestart) {
 				addtt(starttime, type);
-				usestart = FALSE;
-			} else if (stdoff != 0)
-				addtt(min_time, type);
-		} else for (year = min_year; year <= max_year; ++year) {
+				usestart = false;
+			} else
+				defaulttype = type;
+		} else {
+		  zic_t year;
+		  for (year = min_year; year <= max_year; ++year) {
 			if (useuntil && year > zp->z_untilrule.r_hiyear)
 				break;
 			/*
 			** Mark which rules to do in the current year.
 			** For those to do, calculate rpytime(rp, year);
+			** The former TYPE field was also considered here.
 			*/
 			for (j = 0; j < zp->z_nrules; ++j) {
-				rp = &zp->z_rules[j];
+				zic_t one = 1;
+				zic_t y2038_boundary = one << 31;
+				struct rule *rp = &zp->z_rules[j];
 				eats(zp->z_filename, zp->z_linenum,
 					rp->r_filename, rp->r_linenum);
 				rp->r_todo = year >= rp->r_loyear &&
-						year <= rp->r_hiyear &&
-						yearistype(year, rp->r_yrtype);
-				if (rp->r_todo)
+						year <= rp->r_hiyear;
+				if (rp->r_todo) {
 					rp->r_temp = rpytime(rp, year);
+					rp->r_todo
+					  = (rp->r_temp < y2038_boundary
+					     || year <= max_year0);
+				}
 			}
 			for ( ; ; ) {
-				register int	k;
+				register ptrdiff_t k;
 				register zic_t	jtime, ktime;
-				register long	offset;
+				register zic_t	offset;
+				struct rule *rp;
+				int type;
 
 				INITIALIZE(ktime);
 				if (useuntil) {
 					/*
-					** Turn untiltime into UTC
-					** assuming the current gmtoff and
-					** stdoff values.
+					** Turn untiltime into UT
+					** assuming the current stdoff and
+					** save values.
 					*/
 					untiltime = zp->z_untiltime;
-					if (!zp->z_untilrule.r_todisgmt)
+					if (!zp->z_untilrule.r_todisut)
 						untiltime = tadd(untiltime,
-							-gmtoff);
+								 -stdoff);
 					if (!zp->z_untilrule.r_todisstd)
 						untiltime = tadd(untiltime,
-							-stdoff);
+								 -save);
 				}
 				/*
 				** Find the rule (of those to do, if any)
 				** that takes effect earliest in the year.
 				*/
 				k = -1;
 				for (j = 0; j < zp->z_nrules; ++j) {
-					rp = &zp->z_rules[j];
-					if (!rp->r_todo)
+					struct rule *r = &zp->z_rules[j];
+					if (!r->r_todo)
 						continue;
 					eats(zp->z_filename, zp->z_linenum,
-						rp->r_filename, rp->r_linenum);
-					offset = rp->r_todisgmt ? 0 : gmtoff;
-					if (!rp->r_todisstd)
-						offset = oadd(offset, stdoff);
-					jtime = rp->r_temp;
+						r->r_filename, r->r_linenum);
+					offset = r->r_todisut ? 0 : stdoff;
+					if (!r->r_todisstd)
+						offset = oadd(offset, save);
+					jtime = r->r_temp;
 					if (jtime == min_time ||
 						jtime == max_time)
 							continue;
 					jtime = tadd(jtime, -offset);
 					if (k < 0 || jtime < ktime) {
 						k = j;
 						ktime = jtime;
+					} else if (jtime == ktime) {
+					  char const *dup_rules_msg =
+					    _("two rules for same instant");
+					  eats(zp->z_filename, zp->z_linenum,
+					       r->r_filename, r->r_linenum);
+					  warning("%s", dup_rules_msg);
+					  r = &zp->z_rules[k];
+					  eats(zp->z_filename, zp->z_linenum,
+					       r->r_filename, r->r_linenum);
+					  error("%s", dup_rules_msg);
 					}
 				}
 				if (k < 0)
 					break;	/* go on to next year */
 				rp = &zp->z_rules[k];
-				rp->r_todo = FALSE;
-				if (useuntil && ktime >= untiltime)
+				rp->r_todo = false;
+				if (useuntil && ktime >= untiltime) {
+					if (!*startbuf
+					    && (oadd(zp->z_stdoff, rp->r_save)
+						== startoff))
+					  doabbr(startbuf, zp, rp->r_abbrvar,
+						 rp->r_isdst, rp->r_save,
+						 false);
 					break;
-				stdoff = rp->r_stdoff;
+				}
+				save = rp->r_save;
 				if (usestart && ktime == starttime)
-					usestart = FALSE;
+					usestart = false;
 				if (usestart) {
 					if (ktime < starttime) {
-						startoff = oadd(zp->z_gmtoff,
-							stdoff);
-						doabbr(startbuf, zp->z_format,
+						startoff = oadd(zp->z_stdoff,
+								save);
+						doabbr(startbuf, zp,
 							rp->r_abbrvar,
-							rp->r_stdoff != 0,
-							FALSE);
+							rp->r_isdst,
+							rp->r_save,
+							false);
 						continue;
 					}
-					if (*startbuf == '\0' &&
-						startoff == oadd(zp->z_gmtoff,
-						stdoff)) {
+					if (*startbuf == '\0'
+					    && startoff == oadd(zp->z_stdoff,
+								save)) {
 							doabbr(startbuf,
-								zp->z_format,
+								zp,
 								rp->r_abbrvar,
-								rp->r_stdoff !=
-								0,
-								FALSE);
+								rp->r_isdst,
+								rp->r_save,
+								false);
 					}
 				}
 				eats(zp->z_filename, zp->z_linenum,
 					rp->r_filename, rp->r_linenum);
-				doabbr(ab, zp->z_format, rp->r_abbrvar,
-					rp->r_stdoff != 0, FALSE);
-				offset = oadd(zp->z_gmtoff, rp->r_stdoff);
-				type = addtype(offset, ab, rp->r_stdoff != 0,
-					rp->r_todisstd, rp->r_todisgmt);
+				doabbr(ab, zp, rp->r_abbrvar,
+				       rp->r_isdst, rp->r_save, false);
+				offset = oadd(zp->z_stdoff, rp->r_save);
+				if (!want_bloat() && !useuntil && !do_extend
+				    && prevrp && lo_time <= prevktime
+				    && redundant_time <= ktime
+				    && rp->r_hiyear == ZIC_MAX
+				    && prevrp->r_hiyear == ZIC_MAX)
+				  break;
+				type = addtype(offset, ab, rp->r_isdst,
+					rp->r_todisstd, rp->r_todisut);
+				if (defaulttype < 0 && !rp->r_isdst)
+				  defaulttype = type;
+				if (rp->r_hiyear == ZIC_MAX
+				    && ! (0 <= lastatmax
+					  && ktime < attypes[lastatmax].at))
+				  lastatmax = timecnt;
 				addtt(ktime, type);
+				prevrp = rp;
+				prevktime = ktime;
 			}
+		  }
 		}
 		if (usestart) {
-			if (*startbuf == '\0' &&
-				zp->z_format != NULL &&
-				strchr(zp->z_format, '%') == NULL &&
-				strchr(zp->z_format, '/') == NULL)
-					(void) strcpy(startbuf, zp->z_format);
+			bool isdst = startoff != zp->z_stdoff;
+			if (*startbuf == '\0' && zp->z_format)
+			  doabbr(startbuf, zp, disable_percent_s,
+				 isdst, save, false);
 			eat(zp->z_filename, zp->z_linenum);
 			if (*startbuf == '\0')
 error(_("can't determine time zone abbreviation to use just after until time"));
-			else	addtt(starttime,
-					addtype(startoff, startbuf,
-						startoff != zp->z_gmtoff,
-						startttisstd,
-						startttisgmt));
+			else {
+			  int type = addtype(startoff, startbuf, isdst,
+					     startttisstd, startttisut);
+			  if (defaulttype < 0 && !isdst)
+			    defaulttype = type;
+			  addtt(starttime, type);
+			}
 		}
 		/*
 		** Now we may get to set starttime for the next zone line.
 		*/
 		if (useuntil) {
 			startttisstd = zp->z_untilrule.r_todisstd;
-			startttisgmt = zp->z_untilrule.r_todisgmt;
+			startttisut = zp->z_untilrule.r_todisut;
 			starttime = zp->z_untiltime;
 			if (!startttisstd)
-				starttime = tadd(starttime, -stdoff);
-			if (!startttisgmt)
-				starttime = tadd(starttime, -gmtoff);
+			  starttime = tadd(starttime, -save);
+			if (!startttisut)
+			  starttime = tadd(starttime, -stdoff);
 		}
 	}
-	writezone(zpfirst->z_name, envvar);
-	ifree(startbuf);
-	ifree(ab);
-	ifree(envvar);
+	if (defaulttype < 0)
+	  defaulttype = 0;
+	if (0 <= lastatmax)
+	  attypes[lastatmax].dontmerge = true;
+	if (do_extend) {
+		/*
+		** If we're extending the explicitly listed observations
+		** for 400 years because we can't fill the POSIX-TZ field,
+		** check whether we actually ended up explicitly listing
+		** observations through that period.  If there aren't any
+		** near the end of the 400-year period, add a redundant
+		** one at the end of the final year, to make it clear
+		** that we are claiming to have definite knowledge of
+		** the lack of transitions up to that point.
+		*/
+		struct rule xr;
+		struct attype *lastat;
+		xr.r_month = TM_JANUARY;
+		xr.r_dycode = DC_DOM;
+		xr.r_dayofmonth = 1;
+		xr.r_tod = 0;
+		for (lastat = attypes, i = 1; i < timecnt; i++)
+			if (attypes[i].at > lastat->at)
+				lastat = &attypes[i];
+		if (!lastat || lastat->at < rpytime(&xr, max_year - 1)) {
+			addtt(rpytime(&xr, max_year + 1),
+			      lastat ? lastat->type : defaulttype);
+			attypes[timecnt - 1].dontmerge = true;
+		}
+	}
+	writezone(zpfirst->z_name, envvar, version, defaulttype);
+	free(startbuf);
+	free(ab);
+	free(envvar);
 }
 
 static void
-addtt(starttime, type)
-const zic_t	starttime;
-int		type;
-{
-	if (starttime <= min_time ||
-		(timecnt == 1 && attypes[0].at < min_time)) {
-		gmtoffs[0] = gmtoffs[type];
-		isdsts[0] = isdsts[type];
-		ttisstds[0] = ttisstds[type];
-		ttisgmts[0] = ttisgmts[type];
-		if (abbrinds[type] != 0)
-			(void) strcpy(chars, &chars[abbrinds[type]]);
-		abbrinds[0] = 0;
-		charcnt = strlen(chars) + 1;
-		typecnt = 1;
-		timecnt = 0;
-		type = 0;
-	}
-	if (timecnt >= TZ_MAX_TIMES) {
-		error(_("too many transitions?!"));
-		exit(EXIT_FAILURE);
-	}
+addtt(zic_t starttime, int type)
+{
+	attypes = growalloc(attypes, sizeof *attypes, timecnt, &timecnt_alloc);
 	attypes[timecnt].at = starttime;
+	attypes[timecnt].dontmerge = false;
 	attypes[timecnt].type = type;
 	++timecnt;
 }
 
 static int
-addtype(gmtoff, abbr, isdst, ttisstd, ttisgmt)
-const long		gmtoff;
-const char * const	abbr;
-const int		isdst;
-const int		ttisstd;
-const int		ttisgmt;
+addtype(zic_t utoff, char const *abbr, bool isdst, bool ttisstd, bool ttisut)
 {
 	register int	i, j;
 
-	if (isdst != TRUE && isdst != FALSE) {
-		error(_("internal error - addtype called with bad isdst"));
-		exit(EXIT_FAILURE);
-	}
-	if (ttisstd != TRUE && ttisstd != FALSE) {
-		error(_("internal error - addtype called with bad ttisstd"));
-		exit(EXIT_FAILURE);
-	}
-	if (ttisgmt != TRUE && ttisgmt != FALSE) {
-		error(_("internal error - addtype called with bad ttisgmt"));
+	if (! (-1L - 2147483647L <= utoff && utoff <= 2147483647L)) {
+		error(_("UT offset out of range"));
 		exit(EXIT_FAILURE);
 	}
-	/*
-	** See if there's already an entry for this zone type.
-	** If so, just return its index.
-	*/
-	for (i = 0; i < typecnt; ++i) {
-		if (gmtoff == gmtoffs[i] && isdst == isdsts[i] &&
-			strcmp(abbr, &chars[abbrinds[i]]) == 0 &&
-			ttisstd == ttisstds[i] &&
-			ttisgmt == ttisgmts[i])
-				return i;
+	if (!want_bloat())
+	  ttisstd = ttisut = false;
+
+	for (j = 0; j < charcnt; ++j)
+		if (strcmp(&chars[j], abbr) == 0)
+			break;
+	if (j == charcnt)
+		newabbr(abbr);
+	else {
+	  /* If there's already an entry, return its index.  */
+	  for (i = 0; i < typecnt; i++)
+	    if (utoff == utoffs[i] && isdst == isdsts[i] && j == desigidx[i]
+		&& ttisstd == ttisstds[i] && ttisut == ttisuts[i])
+	      return i;
 	}
 	/*
 	** There isn't one; add a new one, unless there are already too
 	** many.
 	*/
 	if (typecnt >= TZ_MAX_TYPES) {
 		error(_("too many local time types"));
 		exit(EXIT_FAILURE);
 	}
-	if (! (-1L - 2147483647L <= gmtoff && gmtoff <= 2147483647L)) {
-		error(_("UTC offset out of range"));
-		exit(EXIT_FAILURE);
-	}
-	gmtoffs[i] = gmtoff;
+	i = typecnt++;
+	utoffs[i] = utoff;
 	isdsts[i] = isdst;
 	ttisstds[i] = ttisstd;
-	ttisgmts[i] = ttisgmt;
-
-	for (j = 0; j < charcnt; ++j)
-		if (strcmp(&chars[j], abbr) == 0)
-			break;
-	if (j == charcnt)
-		newabbr(abbr);
-	abbrinds[i] = j;
-	++typecnt;
+	ttisuts[i] = ttisut;
+	desigidx[i] = j;
 	return i;
 }
 
 static void
-leapadd(t, positive, rolling, count)
-const zic_t	t;
-const int	positive;
-const int	rolling;
-int		count;
+leapadd(zic_t t, int correction, int rolling)
 {
-	register int	i, j;
+	register int i;
 
-	if (leapcnt + (positive ? count : 1) > TZ_MAX_LEAPS) {
+	if (TZ_MAX_LEAPS <= leapcnt) {
 		error(_("too many leap seconds"));
 		exit(EXIT_FAILURE);
 	}
+	if (rolling && (lo_time != min_time || hi_time != max_time)) {
+	  error(_("Rolling leap seconds not supported with -r"));
+	  exit(EXIT_FAILURE);
+	}
 	for (i = 0; i < leapcnt; ++i)
-		if (t <= trans[i]) {
-			if (t == trans[i]) {
-				error(_("repeated leap second moment"));
-				exit(EXIT_FAILURE);
-			}
+		if (t <= trans[i])
 			break;
-		}
-	do {
-		for (j = leapcnt; j > i; --j) {
-			trans[j] = trans[j - 1];
-			corr[j] = corr[j - 1];
-			roll[j] = roll[j - 1];
-		}
-		trans[i] = t;
-		corr[i] = positive ? 1L : eitol(-count);
-		roll[i] = rolling;
-		++leapcnt;
-	} while (positive && --count != 0);
+	memmove(&trans[i + 1], &trans[i], (leapcnt - i) * sizeof *trans);
+	memmove(&corr[i + 1], &corr[i], (leapcnt - i) * sizeof *corr);
+	memmove(&roll[i + 1], &roll[i], (leapcnt - i) * sizeof *roll);
+	trans[i] = t;
+	corr[i] = correction;
+	roll[i] = rolling;
+	++leapcnt;
 }
 
 static void
 adjleap(void)
 {
 	register int	i;
-	register long	last = 0;
+	register zic_t	last = 0;
+	register zic_t	prevtrans = 0;
 
 	/*
 	** propagate leap seconds forward
 	*/
 	for (i = 0; i < leapcnt; ++i) {
+		if (trans[i] - prevtrans < 28 * SECSPERDAY) {
+		  error(_("Leap seconds too close together"));
+		  exit(EXIT_FAILURE);
+		}
+		prevtrans = trans[i];
 		trans[i] = tadd(trans[i], last);
 		last = corr[i] += last;
 	}
+
+	if (0 <= leapexpires) {
+	  leapexpires = oadd(leapexpires, last);
+	  if (! (leapcnt == 0 || (trans[leapcnt - 1] < leapexpires))) {
+	    error(_("last Leap time does not precede Expires time"));
+	    exit(EXIT_FAILURE);
+	  }
+	}
 }
 
-static int
-yearistype(year, type)
-const int		year;
-const char * const	type;
-{
-	static char *	buf;
-	int		result;
-
-	if (type == NULL || *type == '\0')
-		return TRUE;
-	buf = erealloc(buf, (int) (132 + strlen(yitcommand) + strlen(type)));
-	(void) sprintf(buf, "%s %d %s", yitcommand, year, type);
-	result = system(buf);
-	if (WIFEXITED(result)) switch (WEXITSTATUS(result)) {
-		case 0:
-			return TRUE;
-		case 1:
-			return FALSE;
-	}
-	error(_("Wild result from command execution"));
-	(void) fprintf(stderr, _("%s: command was '%s', result was %d\n"),
-		progname, buf, result);
-	for ( ; ; )
-		exit(EXIT_FAILURE);
+/* Is A a space character in the C locale?  */
+static bool
+is_space(char a)
+{
+	switch (a) {
+	  default:
+		return false;
+	  case ' ': case '\f': case '\n': case '\r': case '\t': case '\v':
+		return true;
+	}
 }
 
-static int
-lowerit(a)
-int	a;
+/* Is A an alphabetic character in the C locale?  */
+static bool
+is_alpha(char a)
 {
-	a = (unsigned char) a;
-	return (isascii(a) && isupper(a)) ? tolower(a) : a;
+	switch (a) {
+	  default:
+		return false;
+	  case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
+	  case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
+	  case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
+	  case 'V': case 'W': case 'X': case 'Y': case 'Z':
+	  case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
+	  case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
+	  case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
+	  case 'v': case 'w': case 'x': case 'y': case 'z':
+		return true;
+	}
 }
 
-static int
-ciequal(ap, bp)		/* case-insensitive equality */
-register const char *	ap;
-register const char *	bp;
+/* If A is an uppercase character in the C locale, return its lowercase
+   counterpart.  Otherwise, return A.  */
+static char
+lowerit(char a)
+{
+	switch (a) {
+	  default: return a;
+	  case 'A': return 'a'; case 'B': return 'b'; case 'C': return 'c';
+	  case 'D': return 'd'; case 'E': return 'e'; case 'F': return 'f';
+	  case 'G': return 'g'; case 'H': return 'h'; case 'I': return 'i';
+	  case 'J': return 'j'; case 'K': return 'k'; case 'L': return 'l';
+	  case 'M': return 'm'; case 'N': return 'n'; case 'O': return 'o';
+	  case 'P': return 'p'; case 'Q': return 'q'; case 'R': return 'r';
+	  case 'S': return 's'; case 'T': return 't'; case 'U': return 'u';
+	  case 'V': return 'v'; case 'W': return 'w'; case 'X': return 'x';
+	  case 'Y': return 'y'; case 'Z': return 'z';
+	}
+}
+
+/* case-insensitive equality */
+static ATTRIBUTE_PURE bool
+ciequal(register const char *ap, register const char *bp)
 {
 	while (lowerit(*ap) == lowerit(*bp++))
 		if (*ap++ == '\0')
-			return TRUE;
-	return FALSE;
+			return true;
+	return false;
 }
 
-static int
-itsabbr(abbr, word)
-register const char *	abbr;
-register const char *	word;
+static ATTRIBUTE_PURE bool
+itsabbr(register const char *abbr, register const char *word)
 {
 	if (lowerit(*abbr) != lowerit(*word))
-		return FALSE;
+		return false;
 	++word;
 	while (*++abbr != '\0')
 		do {
 			if (*word == '\0')
-				return FALSE;
+				return false;
 		} while (lowerit(*word++) != lowerit(*abbr));
-	return TRUE;
+	return true;
+}
+
+/* Return true if ABBR is an initial prefix of WORD, ignoring ASCII case.  */
+
+static ATTRIBUTE_PURE bool
+ciprefix(char const *abbr, char const *word)
+{
+  do
+    if (!*abbr)
+      return true;
+  while (lowerit(*abbr++) == lowerit(*word++));
+
+  return false;
 }
 
 static const struct lookup *
-byword(word, table)
-register const char * const		word;
-register const struct lookup * const	table;
+byword(const char *word, const struct lookup *table)
 {
 	register const struct lookup *	foundlp;
 	register const struct lookup *	lp;
 
 	if (word == NULL || table == NULL)
 		return NULL;
+
+	/* If TABLE is LASTS and the word starts with "last" followed
+	   by a non-'-', skip the "last" and look in WDAY_NAMES instead.
+	   Warn about any usage of the undocumented prefix "last-".  */
+	if (table == lasts && ciprefix("last", word) && word[4]) {
+	  if (word[4] == '-')
+	    warning(_("\"%s\" is undocumented; use \"last%s\" instead"),
+		    word, word + 5);
+	  else {
+	    word += 4;
+	    table = wday_names;
+	  }
+	}
+
 	/*
 	** Look for exact match.
 	*/
 	for (lp = table; lp->l_word != NULL; ++lp)
 		if (ciequal(word, lp->l_word))
 			return lp;
 	/*
 	** Look for inexact match.
 	*/
 	foundlp = NULL;
 	for (lp = table; lp->l_word != NULL; ++lp)
-		if (itsabbr(word, lp->l_word)) {
+		if (ciprefix(word, lp->l_word)) {
 			if (foundlp == NULL)
 				foundlp = lp;
 			else	return NULL;	/* multiple inexact matches */
 		}
+
+	if (foundlp && noise) {
+	  /* Warn about any backward-compatibility issue with pre-2017c zic.  */
+	  bool pre_2017c_match = false;
+	  for (lp = table; lp->l_word; lp++)
+	    if (itsabbr(word, lp->l_word)) {
+	      if (pre_2017c_match) {
+		warning(_("\"%s\" is ambiguous in pre-2017c zic"), word);
+		break;
+	      }
+	      pre_2017c_match = true;
+	    }
+	}
+
 	return foundlp;
 }
 
-static char **
-getfields(cp)
-register char *	cp;
+static int
+getfields(char *cp, char **array, int arrayelts)
 {
 	register char *		dp;
-	register char **	array;
 	register int		nsubs;
 
-	if (cp == NULL)
-		return NULL;
-	array = (char **) (void *)
-		emalloc((int) ((strlen(cp) + 1) * sizeof *array));
 	nsubs = 0;
 	for ( ; ; ) {
-		while (isascii((unsigned char) *cp) &&
-			isspace((unsigned char) *cp))
+		char *dstart;
+		while (is_space(*cp))
 				++cp;
 		if (*cp == '\0' || *cp == '#')
 			break;
-		array[nsubs++] = dp = cp;
+		dstart = dp = cp;
 		do {
 			if ((*dp = *cp++) != '"')
 				++dp;
 			else while ((*dp = *cp++) != '"')
 				if (*dp != '\0')
 					++dp;
 				else {
-					error(_(
-						"Odd number of quotation marks"
-						));
-					exit(1);
+				  error(_("Odd number of quotation marks"));
+				  exit(EXIT_FAILURE);
 				}
-		} while (*cp != '\0' && *cp != '#' &&
-			(!isascii(*cp) || !isspace((unsigned char) *cp)));
-		if (isascii(*cp) && isspace((unsigned char) *cp))
+		} while (*cp && *cp != '#' && !is_space(*cp));
+		if (is_space(*cp))
 			++cp;
 		*dp = '\0';
+		if (nsubs == arrayelts) {
+		  error(_("Too many input fields"));
+		  exit(EXIT_FAILURE);
+		}
+		array[nsubs++] = dstart + (*dstart == '-' && dp == dstart + 1);
 	}
-	array[nsubs] = NULL;
-	return array;
+	return nsubs;
 }
 
-static long
-oadd(t1, t2)
-const long	t1;
-const long	t2;
+static _Noreturn void
+time_overflow(void)
 {
-	register long	t;
-
-	t = t1 + t2;
-	if ((t2 > 0 && t <= t1) || (t2 < 0 && t >= t1)) {
-		error(_("time overflow"));
-		exit(EXIT_FAILURE);
-	}
-	return t;
+  error(_("time overflow"));
+  exit(EXIT_FAILURE);
 }
 
-static zic_t
-tadd(t1, t2)
-const zic_t	t1;
-const long	t2;
+static ATTRIBUTE_PURE zic_t
+oadd(zic_t t1, zic_t t2)
 {
-	register zic_t	t;
+	if (t1 < 0 ? t2 < ZIC_MIN - t1 : ZIC_MAX - t1 < t2)
+	  time_overflow();
+	return t1 + t2;
+}
 
-	if (t1 == max_time && t2 > 0)
-		return max_time;
-	if (t1 == min_time && t2 < 0)
-		return min_time;
-	t = t1 + t2;
-	if ((t2 > 0 && t <= t1) || (t2 < 0 && t >= t1)) {
-		error(_("time overflow"));
-		exit(EXIT_FAILURE);
-	}
-	return t;
+static ATTRIBUTE_PURE zic_t
+tadd(zic_t t1, zic_t t2)
+{
+  if (t1 < 0) {
+    if (t2 < min_time - t1) {
+      if (t1 != min_time)
+	time_overflow();
+      return min_time;
+    }
+  } else {
+    if (max_time - t1 < t2) {
+      if (t1 != max_time)
+	time_overflow();
+      return max_time;
+    }
+  }
+  return t1 + t2;
 }
 
 /*
-** Given a rule, and a year, compute the date - in seconds since January 1,
-** 1970, 00:00 LOCAL time - in that year that the rule refers to.
+** Given a rule, and a year, compute the date (in seconds since January 1,
+** 1970, 00:00 LOCAL time) in that year that the rule refers to.
 */
 
 static zic_t
-rpytime(rp, wantedy)
-register const struct rule * const	rp;
-register const int			wantedy;
+rpytime(const struct rule *rp, zic_t wantedy)
 {
-	register int	y, m, i;
-	register long	dayoff;			/* with a nod to Margaret O. */
-	register zic_t	t;
+	register int	m, i;
+	register zic_t	dayoff;			/* with a nod to Margaret O. */
+	register zic_t	t, y;
+	int yrem;
 
-	if (wantedy == INT_MIN)
+	if (wantedy == ZIC_MIN)
 		return min_time;
-	if (wantedy == INT_MAX)
+	if (wantedy == ZIC_MAX)
 		return max_time;
-	dayoff = 0;
 	m = TM_JANUARY;
 	y = EPOCH_YEAR;
+
+	/* dayoff = floor((wantedy - y) / YEARSPERREPEAT) * DAYSPERREPEAT,
+	   sans overflow.  */
+	yrem = wantedy % YEARSPERREPEAT - y % YEARSPERREPEAT;
+	dayoff = ((wantedy / YEARSPERREPEAT - y / YEARSPERREPEAT
+		   + yrem / YEARSPERREPEAT - (yrem % YEARSPERREPEAT < 0))
+		  * DAYSPERREPEAT);
+	/* wantedy = y + ((wantedy - y) mod YEARSPERREPEAT), sans overflow.  */
+	wantedy = y + (yrem + 2 * YEARSPERREPEAT) % YEARSPERREPEAT;
+
 	while (wantedy != y) {
-		if (wantedy > y) {
-			i = len_years[isleap(y)];
-			++y;
-		} else {
-			--y;
-			i = -len_years[isleap(y)];
-		}
-		dayoff = oadd(dayoff, eitol(i));
+		i = len_years[isleap(y)];
+		dayoff = oadd(dayoff, i);
+		y++;
 	}
 	while (m != rp->r_month) {
 		i = len_months[isleap(y)][m];
-		dayoff = oadd(dayoff, eitol(i));
+		dayoff = oadd(dayoff, i);
 		++m;
 	}
 	i = rp->r_dayofmonth;
 	if (m == TM_FEBRUARY && i == 29 && !isleap(y)) {
 		if (rp->r_dycode == DC_DOWLEQ)
 			--i;
 		else {
 			error(_("use of 2/29 in non leap-year"));
 			exit(EXIT_FAILURE);
 		}
 	}
 	--i;
-	dayoff = oadd(dayoff, eitol(i));
+	dayoff = oadd(dayoff, i);
 	if (rp->r_dycode == DC_DOWGEQ || rp->r_dycode == DC_DOWLEQ) {
-		register long	wday;
-
-#define LDAYSPERWEEK	((long) DAYSPERWEEK)
-		wday = eitol(EPOCH_WDAY);
 		/*
 		** Don't trust mod of negative numbers.
 		*/
-		if (dayoff >= 0)
-			wday = (wday + dayoff) % LDAYSPERWEEK;
-		else {
-			wday -= ((-dayoff) % LDAYSPERWEEK);
-			if (wday < 0)
-				wday += LDAYSPERWEEK;
-		}
-		while (wday != eitol(rp->r_wday))
+		zic_t wday = ((EPOCH_WDAY + dayoff % DAYSPERWEEK + DAYSPERWEEK)
+			      % DAYSPERWEEK);
+		while (wday != rp->r_wday)
 			if (rp->r_dycode == DC_DOWGEQ) {
-				dayoff = oadd(dayoff, (long) 1);
-				if (++wday >= LDAYSPERWEEK)
+				dayoff = oadd(dayoff, 1);
+				if (++wday >= DAYSPERWEEK)
 					wday = 0;
 				++i;
 			} else {
-				dayoff = oadd(dayoff, (long) -1);
+				dayoff = oadd(dayoff, -1);
 				if (--wday < 0)
-					wday = LDAYSPERWEEK - 1;
+					wday = DAYSPERWEEK - 1;
 				--i;
 			}
 		if (i < 0 || i >= len_months[isleap(y)][m]) {
 			if (noise)
-				warning(_("rule goes past start/end of month--\
+				warning(_("rule goes past start/end of month; \
 will not work with pre-2004 versions of zic"));
 		}
 	}
 	if (dayoff < min_time / SECSPERDAY)
 		return min_time;
 	if (dayoff > max_time / SECSPERDAY)
 		return max_time;
 	t = (zic_t) dayoff * SECSPERDAY;
 	return tadd(t, rp->r_tod);
 }
 
 static void
-newabbr(string)
-const char * const	string;
+newabbr(const char *string)
 {
 	register int	i;
 
 	if (strcmp(string, GRANDPARENTED) != 0) {
 		register const char *	cp;
-		register char *		wp;
+		const char *		mp;
 
-		/*
-		** Want one to ZIC_MAX_ABBR_LEN_WO_WARN alphabetics
-		** optionally followed by a + or - and a number from 1 to 14.
-		*/
 		cp = string;
-		wp = NULL;
-		while (isascii((unsigned char) *cp) &&
-			isalpha((unsigned char) *cp))
+		mp = NULL;
+		while (is_alpha(*cp) || ('0' <= *cp && *cp <= '9')
+		       || *cp == '-' || *cp == '+')
 				++cp;
-		if (cp - string == 0)
-wp = _("time zone abbreviation lacks alphabetic at start");
-		if (noise && cp - string > 3)
-wp = _("time zone abbreviation has more than 3 alphabetics");
+		if (noise && cp - string < 3)
+		  mp = _("time zone abbreviation has fewer than 3 characters");
 		if (cp - string > ZIC_MAX_ABBR_LEN_WO_WARN)
-wp = _("time zone abbreviation has too many alphabetics");
-		if (wp == NULL && (*cp == '+' || *cp == '-')) {
-			++cp;
-			if (isascii((unsigned char) *cp) &&
-				isdigit((unsigned char) *cp))
-					if (*cp++ == '1' &&
-						*cp >= '0' && *cp <= '4')
-							++cp;
-		}
+		  mp = _("time zone abbreviation has too many characters");
 		if (*cp != '\0')
-wp = _("time zone abbreviation differs from POSIX standard");
-		if (wp != NULL) {
-			wp = ecpyalloc(wp);
-			wp = ecatalloc(wp, " (");
-			wp = ecatalloc(wp, string);
-			wp = ecatalloc(wp, ")");
-			warning(wp);
-			ifree(wp);
-		}
+mp = _("time zone abbreviation differs from POSIX standard");
+		if (mp != NULL)
+			warning("%s (%s)", mp, string);
 	}
 	i = strlen(string) + 1;
 	if (charcnt + i > TZ_MAX_CHARS) {
 		error(_("too many, or too long, time zone abbreviations"));
 		exit(EXIT_FAILURE);
 	}
-	(void) strcpy(&chars[charcnt], string);
-	charcnt += eitol(i);
+	strcpy(&chars[charcnt], string);
+	charcnt += i;
 }
 
-static int
-mkdirs(argname)
-char *		argname;
+/* Ensure that the directories of ARGNAME exist, by making any missing
+   ones.  If ANCESTORS, do this only for ARGNAME's ancestors; otherwise,
+   do it for ARGNAME too.  Exit with failure if there is trouble.
+   Do not consider an existing file to be trouble.  */
+static void
+mkdirs(char const *argname, bool ancestors)
 {
 	register char *	name;
 	register char *	cp;
 
-	if (argname == NULL || *argname == '\0')
-		return 0;
 	cp = name = ecpyalloc(argname);
-	while ((cp = strchr(cp + 1, '/')) != 0) {
-		*cp = '\0';
-#ifndef unix
+
+	/* On MS-Windows systems, do not worry about drive letters or
+	   backslashes, as this should suffice in practice.  Time zone
+	   names do not use drive letters and backslashes.  If the -d
+	   option of zic does not name an already-existing directory,
+	   it can use slashes to separate the already-existing
+	   ancestor prefix from the to-be-created subdirectories.  */
+
+	/* Do not mkdir a root directory, as it must exist.  */
+	while (*cp == '/')
+	  cp++;
+
+	while (cp && ((cp = strchr(cp, '/')) || !ancestors)) {
+		if (cp)
+		  *cp = '\0';
 		/*
-		** DOS drive specifier?
+		** Try to create it.  It's OK if creation fails because
+		** the directory already exists, perhaps because some
+		** other process just created it.  For simplicity do
+		** not check first whether it already exists, as that
+		** is checked anyway if the mkdir fails.
 		*/
-		if (isalpha((unsigned char) name[0]) &&
-			name[1] == ':' && name[2] == '\0') {
-				*cp = '/';
-				continue;
-		}
-#endif /* !defined unix */
-		if (!itsdir(name)) {
-			/*
-			** It doesn't seem to exist, so we try to create it.
-			** Creation may fail because of the directory being
-			** created by some other multiprocessor, so we get
-			** to do extra checking.
-			*/
-			if (mkdir(name, MKDIR_UMASK) != 0) {
-				const char *e = strerror(errno);
-
-				if (errno != EEXIST || !itsdir(name)) {
-					(void) fprintf(stderr,
-_("%s: Can't create directory %s: %s\n"),
-						progname, name, e);
-					ifree(name);
-					return -1;
-				}
+		if (mkdir(name, MKDIR_UMASK) != 0) {
+			/* Do not report an error if err == EEXIST, because
+			   some other process might have made the directory
+			   in the meantime.  Likewise for ENOSYS, because
+			   Solaris 10 mkdir fails with ENOSYS if the
+			   directory is an automounted mount point.
+			   Likewise for EACCES, since mkdir can fail
+			   with EACCES merely because the parent directory
+			   is unwritable.  Likewise for most other error
+			   numbers.  */
+			int err = errno;
+			if (err == ELOOP || err == ENAMETOOLONG
+			    || err == ENOENT || err == ENOTDIR) {
+				error(_("%s: Can't create directory %s: %s"),
+				      progname, name, strerror(err));
+				exit(EXIT_FAILURE);
 			}
 		}
-		*cp = '/';
+		if (cp)
+		  *cp++ = '/';
 	}
-	ifree(name);
-	return 0;
+	free(name);
 }
-
-static long
-eitol(i)
-const int	i;
-{
-	long	l;
-
-	l = i;
-	if ((i < 0 && l >= 0) || (i == 0 && l != 0) || (i > 0 && l <= 0)) {
-		(void) fprintf(stderr,
-			_("%s: %d did not sign extend correctly\n"),
-			progname, i);
-		exit(EXIT_FAILURE);
-	}
-	return l;
-}
-
-/*
-** UNIX was a registered trademark of The Open Group in 2003.
-*/
diff --git a/zoneinfo2tdf.pl b/zoneinfo2tdf.pl
deleted file mode 100755
index f34ca3e99c31..000000000000
--- a/zoneinfo2tdf.pl
+++ /dev/null
@@ -1,54 +0,0 @@
-#! /usr/bin/perl -w
-
-# @(#)zoneinfo2tdf.pl	8.2
-
-# Courtesy Ken Pizzini.
-
-use strict;
-
-#This file released to the public domain.
-
-#Note: error checking is poor --- only trust the output if the input
-#has been checked by zic.
-
-my $contZone = '';
-while (<>) {
-  my $origline = $_;
-  my @fields = ();
-  while (s/^\s*((?:"[^"]*"|[^\s#])+)//) {
-    push @fields, $1;
-  }
-  next unless @fields;
-
-  my $type = lc($fields[0]);
-  if ($contZone) {
-    @fields >= 3 or warn "bad continuation line";
-    unshift @fields, '+', $contZone;
-    $type = 'zone';
-  }
-
-  $contZone = '';
-  if ($type eq 'zone') {
-    # Zone  NAME  GMTOFF  RULES/SAVE  FORMAT  [UNTIL]
-    my $nfields = @fields;
-    $nfields >= 5 or warn "bad zone line";
-    if ($nfields > 6) {
-      #this splice is optional, depending on one's preference
-      #(one big date-time field, or componentized date and time):
-      splice(@fields, 5, $nfields-5, "@fields[5..$nfields-1]");
-    }
-    $contZone = $fields[1] if @fields > 5;
-  } elsif ($type eq 'rule') {
-    # Rule  NAME  FROM  TO  TYPE  IN  ON  AT  SAVE  LETTER/S
-    @fields == 10 or warn "bad rule line";
-  } elsif ($type eq 'link') {
-    # Link  LINK-FROM  LINK-TO
-    @fields == 3 or warn "bad link line";
-  } elsif ($type eq 'leap') {
-    # Leap  YEAR  MONTH  DAY  HH:MM:SS  CORR  R/S
-    @fields == 7 or warn "bad leap line";
-  } else {
-    warn "Fubar at input line $.: $origline";
-  }
-  print join("\t", @fields), "\n";
-}


Artist	Karrin Allyson
CD	I Didn't Know About You
Copyright Date	1993
Label	Concord Jazz, Inc.
ID	CCD-4543
Track Time	3:44
Personnel	Karrin Allyson, vocal; -Russ Long, piano; -Gerald Spaits, bass; -Todd Strait, drums
Notes	CD notes "additional lyric by Karrin Allyson; -arranged by Russ Long and Karrin Allyson"
ADO Rating	1 star
AMG Rating	4 stars
Penguin Rating	3.5 stars

Artist	Kevin Mahogany
CD	Double Rainbow
Copyright Date	1993
Label	Enja Records
ID	ENJ-7097 2
Track Time	6:27
Personnel	Kevin Mahogany, vocal; -Kenny Barron, piano; -Ray Drummond, bass; -Ralph Moore, tenor saxophone; -Lewis Nash, drums
ADO Rating	1.5 stars
AMG Rating	3 stars
Penguin Rating	3 stars

Artist	Joe Williams
CD	Here's to Life
Copyright Date	1994
Label	Telarc International Corporation
ID	CD-83357
Track Time	3:58
Personnel	Joe Williams, vocal -The Robert Farnon [39 piece] Orchestra
Notes	This CD is also available as part of a 3-CD package from -Telarc, "Triple Play" (CD-83461)
ADO Rating	black dot
AMG Rating	2 stars
Penguin Rating	3 stars

Artist	Charles Fambrough
CD	Keeper of the Spirit
Copyright Date	1995
Label	AudioQuest Music
ID	AQ-CD1033
Track Time	7:07
Personnel	Charles Fambrough, bass; -Joel Levine, tenor recorder; -Edward Simon, piano; -Lenny White, drums; -Marion Simon, percussion
Notes	On-line information and samples available at -http://wwmusic.com/~music/audioq/rel/1033.html
ADO Rating	2 stars
AMG Rating	unrated
Penguin Rating	3 stars

Artist	Holly Cole Trio
CD	Blame It On My Youth
Copyright Date	1992
Label	Manhattan
ID	CDP 7 97349 2
Total Time	37:45
Personnel	Holly Cole, voice; -Aaron Davis, piano; -David Piltch, string bass
Notes	Lyrical reference to "Eastern Standard Time" in -Tom Waits' "Purple Avenue"
ADO Rating	2.5 stars
AMG Rating	3 stars
Penguin Rating	unrated

Artist	Milt Hinton
CD	Old Man Time
Copyright Date	1990
Label	Chiaroscuro
ID	CR(D) 310
Total Time	149:38 (two CDs)
Personnel	Milt Hinton, bass; -Doc Cheatham, Dizzy Gillespie, Clark Terry, trumpet; -Al Grey, trombone; -Eddie Barefield, Joe Camel (Flip Phillips), Buddy Tate, -clarinet and saxophone; -John Bunch, Red Richards, Norman Simmons, Derek Smith, -Ralph Sutton, piano; -Danny Barker, Al Casey, guitar; -Gus Johnson, Gerryck King, Bob Rosengarden, Jackie Williams, -drums; -Lionel Hampton, vibraphone; -Cab Calloway, Joe Williams, vocal; -Buck Clayton, arrangements
Notes	tunes include Old Man Time, Time After Time, -Sometimes I'm Happy, -A Hot Time in the Old Town Tonight, -Four or Five Times, Now's the Time, -Time on My Hands, This Time It's Us, -and Good Time Charlie -On-line samples available at -http://www.chiaroscurojazz.com/albuminfo.php3?albumid=49
ADO Rating	3 stars
AMG Rating	4.5 stars
Penguin Rating	3 stars

Artist	Alan Broadbent
CD	Pacific Standard Time
Copyright Date	1995
Label	Concord Jazz, Inc.
ID	CCD-4664
Total Time	62:42
Personnel	Alan Broadbent, piano; -Putter Smith, Bass; -Frank Gibson, Jr., drums
Notes	The CD cover features an analemma for equation-of-time fans
ADO Rating	1 star
AMG Rating	4 stars
Penguin Rating	3.5 stars

Artist	Anthony Braxton/Richard Teitelbaum
CD	Silence/Time Zones
Copyright Date	1996
Label	Black Lion
ID	BLCD 760221
Total Time	72:58
Personnel	Anthony Braxton, sopranino and alto saxophones, -contrebasse clarinet, miscellaneous instruments; -Leo Smith, trumpet and miscellaneous instruments; -Leroy Jenkins, violin and miscellaneous instruments; -Richard Teitelbaum, modular moog and micromoog synthesizer
ADO Rating	black dot
AMG Rating	unrated

Artist	Charles Gayle
CD	Time Zones
Copyright Date	2006
Label	Tompkins Square
ID	TSQ2839
Total Time	49:06
Personnel	Charles Gayle, piano
ADO Rating	1 star
AMG Rating	4.5 stars

Artist	The Get Up Kids
CD	Eudora
Copyright Date	2001
Label	Vagrant
ID	357
Total Time	65:12
Notes	Includes the song "Central Standard Time." Thanks to Colin Bowern for this information.
AMG Rating	2.5 stars

Artist	Coldplay
Song	Clocks
Copyright Date	2003
Label	Capitol Records
ID	52608
Total Time	4:13
Notes	Won the 2004 Record of the Year honor at the -Grammy Awards. Co-written and performed by Chris Martin, -great-great-grandson of DST inventor William Willett. The song's first -line is "Lights go out and I can't be saved".

Artist	Irving Kahal and Harry Richman
Song	There Ought to be a Moonlight Saving Time
Copyright Date	1931
Notes	This musical standard was a #1 hit for Guy Lombardo -in 1931, and was also performed by Maurice Chevalier, Blossom Dearie -and many others. The phrase "Moonlight saving time" also appears in -the 1995 country song "Not Enough Hours in the Night" written by Aaron -Barker, Kim Williams and Rob Harbin and performed by Doug -Supernaw.

Artist	The Microscopic Septet
CD	Lobster Leaps In
Copyright Date	2008
Label	Cuneiform
ID	272
Total Time	73:05
Notes	Includes the song "Twilight Time Zone."
AMG Rating	3.5 stars
ADO Rating	2 stars

Artist	Bob Dylan
CD	The Time They Are A-Changin'
Copyright Date	1964
Label	Columbia
ID	CK-8905
Total Time	45:36
AMG Rating	4.5 stars
ADO Rating	1.5 stars
Notes	The title song is also available on "Bob Dylan's Greatest Hits" and "The Essential Bob Dylan."

Artist	Luciana Souza
CD	Tide
Copyright Date	2009
Label	Universal Jazz France
ID	B0012688-02
Total Time	42:31
AMG Rating	3.5 stars
ADO Rating	2.5 stars
Notes	Includes the song "Fire and Wood" with the lyric -"The clocks were turned back you remeber/Think it's still November." -

TV episode title	The Lost Hour
TV series	Eerie, Indiana
TV episode number	10
Network	NBC
Air date	1991-12-01
Notes	Despite Indiana's then-lack of DST, Marshall changes his clock with unusual consequences.

TV episode title	Time Tunnel
TV series	The Adventures of Pete & Pete
TV episode number	5, season 2
Network	Nickelodeon
Air date	1994-10-23
Notes	The two Petes travel back in time an hour on the day that DST ends.

TV episode title	King-Size Homer
TV series	The Simpsons
TV episode number	135
Network	Fox
Air date	1995-11-05
Notes	Homer, working from home, remarks "8:58, first -time I've ever been early for work. Except for all those daylight -savings days. Lousy farmers."

Artist	Jules Verne
Book	Le Tour du Monde en Quatre-Vingts Jours -(Around the World in Eighty Days)
Notes	Wall-clock time plays a central role in the plot. -European readers of the 1870s clearly held the U.S. press in -deep contempt; the protagonists cross the U.S. without once -reading a paper. -An on-line French-language version of the book -"with illustrations from the original 1873 French-language edition" -is available at -http://fourmilab.ch/etexts/www/tdm80j -An on-line English-language translation of the book is available at -http://www.literature.org/Works/Jules-Verne/eighty

Artist	Umberto Eco
Book	The Island of the Day Before -(L'isola del giorno prima)
Copyright Date	1994
Notes	-"...the story of a 17th century Italian nobleman trapped near an island -on the International Date Line. Time and time zones play an integral -part in the novel." (Paul Eggert, 2006-04-22) -

Artist	David Jebb
Book	-The Thirteenth Time Zone
Notes	-"It's fiction, but it's based on his experiences and travels." (Paul Eggert, 2006-04-22) -

Artist	John Dunning
Book	Two -O'Clock, Eastern Wartime
Copyright Date	2001
Notes	-Mystery, history, daylight saving time, and old-time radio. -

Film	Bell Science - About Time
Notes	The Frank Baxter/Richard Deacon extravaganza. -Information is available at -http://www.videoflicks.com/titles/1035/1035893.htm

Theory and pragmatics of the tz code and data

Outline

Scope of the tz database

Timezone identifiers

Time zone abbreviations

Accuracy of the tz database

Time and date functions

POSIX properties and limitations

Extensions to POSIX in the +tz code

POSIX features no longer needed

Other portability notes

Interface stability

Leap seconds

Calendrical issues

Time and time zones on other planets

Time and the Arts

Time and the Arts

Documentaries

Movies

TV episodes

Books, plays, and magazines

Music

Comics

Jokes

See also

How to Read the tz +Database Source Files

by Bill Seymour

Sources for Time Zone and Daylight Saving Time Data

The tz database

Web pages using recent versions of the tz database

Other time zone database formats

Other tz compilers

Other tz binary file readers

Other tz-based time zone software

Other time zone databases

Maps

Time zone boundaries

Civil time concepts and history

National histories of legal time

Precision timekeeping

Time notation

Related indexes

Time zone and daylight saving time data

Outline

The tz database

Downloading the tz database

Changes to the tz database

Commentary on the tz database

Web sites using recent versions of the +tz database

Network protocols for tz data

Other tz compilers

Other TZif readers

Other tz-based time zone software

Other time zone databases

Maps

Time zone boundaries

Civil time concepts and history

National histories of legal time

Costs and benefits of time shifts

Precision timekeeping

Time notation

See also

Theory and pragmatics of the `tz` code and data

Scope of the `tz` database

Accuracy of the `tz` database

Extensions to POSIX in the +`tz` code

The `tz` database

Web pages using recent versions of the `tz` database

Other `tz` compilers

Other `tz` binary file readers

Other `tz`-based time zone software

The `tz` database

Downloading the `tz` database

Changes to the `tz` database

Commentary on the `tz` database

Web sites using recent versions of the +`tz` database

Network protocols for `tz` data

Other `tz` compilers

Other `tz`-based time zone software