Index: head/lib/libc/stdtime/time2posix.3 =================================================================== --- head/lib/libc/stdtime/time2posix.3 (revision 192889) +++ head/lib/libc/stdtime/time2posix.3 (revision 192890) @@ -1,123 +1,123 @@ .\" $FreeBSD$ .\" .Dd September 11, 2005 .Dt TIME2POSIX 3 .Os .Sh NAME .Nm time2posix , .Nm posix2time .Nd convert seconds since the Epoch .Sh LIBRARY .Lb libc .Sh SYNOPSIS .In time.h .Ft time_t .Fn time2posix "time_t t" .Ft time_t .Fn posix2time "time_t t" .Sh DESCRIPTION .St -p1003.1-88 legislates that a time_t value of 536457599 shall correspond to "Wed Dec 31 23:59:59 GMT 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. .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). 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 passed-to functions such as .Xr time 3 , .Xr localtime 3 , .Xr mktime 3 and .Xr difftime 3 . However, .St -p1003.1-88 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 .Fn time2posix and .Fn 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 The .Fn time2posix function is single-valued. That is, every local time_t corresponds to a single POSIX time_t. The .Fn 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 does not 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 time_t and its conversion to, and back from, the POSIX representation over the leap second inserted at the end of June, 1993. .Bl -column "93/06/30" "23:59:59" "A+0" "X=time2posix(T)" .It Sy "DATE TIME T X=time2posix(T) posix2time(X)" .It "93/06/30 23:59:59 A+0 B+0 A+0" .It "93/06/30 23:59:60 A+1 B+1 A+1 or A+2" .It "93/07/01 00:00:00 A+2 B+1 A+1 or A+2" .It "93/07/01 00:00:01 A+3 B+2 A+3" .El .Pp A leap second deletion would look like... .Bl -column "??/06/30" "23:59:58" "A+0" "X=time2posix(T)" .It Sy "DATE TIME T X=time2posix(T) posix2time(X)" .It "??/06/30 23:59:58 A+0 B+0 A+0" .It "??/07/01 00:00:00 A+1 B+2 A+1" .It "??/07/01 00:00:01 A+2 B+3 A+2" .El .Pp .D1 No "[Note: posix2time(B+1) => A+0 or A+1]" .Pp If leap-second support is not enabled, local time_t's and POSIX time_t's are equivalent, and both .Fn time2posix and .Fn posix2time degenerate to the identity function. .Sh "SEE ALSO" .Xr difftime 3 , .Xr localtime 3 , .Xr mktime 3 , .Xr time 3 -.\" @(#)time2posix.3 8.1 +.\" @(#)time2posix.3 8.2 .\" This file is in the public domain, so clarified as of .\" 1996-06-05 by Arthur David Olson. Index: head/usr.sbin/zic/README =================================================================== --- head/usr.sbin/zic/README (revision 192889) +++ head/usr.sbin/zic/README (revision 192890) @@ -1,85 +1,88 @@ -@(#)README 8.2 +@(#)README 8.3 +This file is in the public domain, so clarified as of +2009-05-17 by Arthur David Olson. + $FreeBSD$ "What time is it?" -- Richard Deacon as The King "Any time you want it to be." -- Frank Baxter as The Scientist (from the Bell System film "About Time") 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. 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 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 To use the new functions, use a "-ltz" option when compiling or linking. Historical local time information has been included here to: * provide a compendium of data about the history of civil time that is useful even if the data are 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; * provide a test of 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! Thanks to these Timezone 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. 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. Index: head/usr.sbin/zic/Theory =================================================================== --- head/usr.sbin/zic/Theory (revision 192889) +++ head/usr.sbin/zic/Theory (revision 192890) @@ -1,569 +1,570 @@ -@(#)Theory 8.2 +@(#)Theory 8.3 +This file is in the public domain, so clarified as of +2009-05-17 by Arthur David Olson. $FreeBSD$ ----- 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', `EET' (see the file `europe'), and `Factory' (see the file `factory'). ----- 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 Edward M. Reingold and Nachum Dershowitz, Calendrical Calculations: The Millennium Edition , Cambridge University Press (2001). 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. Index: head/usr.sbin/zic/zdump.8 =================================================================== --- head/usr.sbin/zic/zdump.8 (revision 192889) +++ head/usr.sbin/zic/zdump.8 (revision 192890) @@ -1,61 +1,63 @@ .\" -.\" @(#)zdump.8 7.3 +.\" @(#)zdump.8 8.2 +.\" This file is in the public domain, so clarified as of +.\" 2009-05-17 by Arthur David Olson. .\" $FreeBSD$ .\" .Dd June 20, 2004 .Dt ZDUMP 8 .Os .Sh NAME .Nm zdump .Nd timezone dumper .Sh SYNOPSIS .Nm .Op Fl -version .Op Fl v .Op Fl c Ar [loyear,]hiyear .Op Ar zonename ... .Sh DESCRIPTION The .Nm utility prints the current time in each .Ar zonename named on the command line. .Pp The following options are available: .Bl -tag -width indent .It Fl -version Output version information and exit. .It Fl v For each .Ar 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 .Em isdst=1 if the given time is Daylight Saving Time or .Em isdst=0 otherwise. .It Fl c Ar 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. .El .Sh LIMITATIONS The .Fl v option may not be used on systems with floating-point time_t values that are neither float nor double. .Pp 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. .Sh "SEE ALSO" .Xr ctime 3 , .Xr tzfile 5 , .Xr zic 8 Index: head/usr.sbin/zic/zdump.c =================================================================== --- head/usr.sbin/zic/zdump.c (revision 192889) +++ head/usr.sbin/zic/zdump.c (revision 192890) @@ -1,670 +1,675 @@ +/* +** This file is in the public domain, so clarified as of +** 2009-05-17 by Arthur David Olson. +*/ + #ifndef lint static const char rcsid[] = "$FreeBSD$"; -static char elsieid[] = "@(#)zdump.c 8.8"; +static char elsieid[] = "@(#)zdump.c 8.9"; #endif /* not lint */ /* ** 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. */ #include #include /* for stdout, stderr */ #include /* for exit, malloc, atoi */ #include /* for strcpy */ #include /* for time_t */ #include /* for struct tm */ #include #include /* for FLT_MAX and DBL_MAX */ #include /* for isalpha et al. */ #ifndef isascii #define isascii(x) 1 #endif /* !defined isascii */ #ifndef ZDUMP_LO_YEAR #define ZDUMP_LO_YEAR (-500) #endif /* !defined ZDUMP_LO_YEAR */ #ifndef ZDUMP_HI_YEAR #define ZDUMP_HI_YEAR 2500 #endif /* !defined ZDUMP_HI_YEAR */ #ifndef MAX_STRING_LENGTH #define MAX_STRING_LENGTH 1024 #endif /* !defined MAX_STRING_LENGTH */ #ifndef TRUE #define TRUE 1 #endif /* !defined TRUE */ #ifndef FALSE #define FALSE 0 #endif /* !defined FALSE */ #ifndef EXIT_SUCCESS #define EXIT_SUCCESS 0 #endif /* !defined EXIT_SUCCESS */ #ifndef EXIT_FAILURE #define EXIT_FAILURE 1 #endif /* !defined EXIT_FAILURE */ #ifndef SECSPERMIN #define SECSPERMIN 60 #endif /* !defined SECSPERMIN */ #ifndef MINSPERHOUR #define MINSPERHOUR 60 #endif /* !defined MINSPERHOUR */ #ifndef SECSPERHOUR #define SECSPERHOUR (SECSPERMIN * MINSPERHOUR) #endif /* !defined SECSPERHOUR */ #ifndef HOURSPERDAY #define HOURSPERDAY 24 #endif /* !defined HOURSPERDAY */ #ifndef EPOCH_YEAR #define EPOCH_YEAR 1970 #endif /* !defined EPOCH_YEAR */ #ifndef TM_YEAR_BASE #define TM_YEAR_BASE 1900 #endif /* !defined TM_YEAR_BASE */ #ifndef DAYSPERNYEAR #define DAYSPERNYEAR 365 #endif /* !defined DAYSPERNYEAR */ #ifndef isleap #define isleap(y) (((y) % 4) == 0 && (((y) % 100) != 0 || ((y) % 400) == 0)) #endif /* !defined isleap */ #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 */ #define SECSPERDAY ((long) SECSPERHOUR * HOURSPERDAY) #define SECSPERNYEAR (SECSPERDAY * DAYSPERNYEAR) #define SECSPERLYEAR (SECSPERNYEAR + SECSPERDAY) #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 */ /* ** 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. */ #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 */ extern char ** environ; extern char * tzname[2]; static time_t absolute_min_time; static time_t absolute_max_time; static size_t longest; static char * progname; static int warned; static void usage(const char *progname, FILE *stream, int status); 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); #ifndef TYPECHECK #define my_localtime localtime #else /* !defined TYPECHECK */ static struct tm * my_localtime(tp) time_t * tp; { register struct tm * tmp; tmp = localtime(tp); if (tp != NULL && tmp != NULL) { 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"); } } return tmp; } #endif /* !defined TYPECHECK */ static void abbrok(abbrp, zone) const char * const abbrp; const char * const zone; { register const char * cp; register char * wp; if (warned) return; cp = abbrp; wp = NULL; while (isascii((unsigned char) *cp) && isalpha((unsigned char) *cp)) ++cp; if (cp - abbrp == 0) wp = _("lacks alphabetic at start"); else if (cp - abbrp < 3) wp = _("has fewer than 3 alphabetics"); 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, _("%s: warning: zone \"%s\" abbreviation \"%s\" %s\n"), progname, zone, abbrp, wp); warned = TRUE; } int main(argc, argv) int argc; char * argv[]; { register int i; register int c; register int vflag; register char * cutarg; register long cutloyear = ZDUMP_LO_YEAR; register long cuthiyear = ZDUMP_HI_YEAR; 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; INITIALIZE(cutlotime); INITIALIZE(cuthitime); #if HAVE_GETTEXT (void) setlocale(LC_MESSAGES, ""); #ifdef TZ_DOMAINDIR (void) bindtextdomain(TZ_DOMAIN, TZ_DOMAINDIR); #endif /* TEXTDOMAINDIR */ (void) textdomain(TZ_DOMAIN); #endif /* HAVE_GETTEXT */ for (i = 1; i < argc; ++i) if (strcmp(argv[i], "--version") == 0) { errx(EXIT_SUCCESS, "%s", elsieid); } else if (strcmp(argv[i], "--help") == 0) { usage(progname, 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 != -1) || (optind == argc - 1 && strcmp(argv[optind], "=") == 0)) { usage(progname, stderr, EXIT_FAILURE); } if (vflag) { if (cutarg != NULL) { long lo; long hi; char dummy; if (sscanf(cutarg, "%ld%c", &hi, &dummy) == 1) { 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"), progname, cutarg); exit(EXIT_FAILURE); } } setabsolutes(); cutlotime = yeartot(cutloyear); cuthitime = yeartot(cuthiyear); } (void) time(&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((size_t) (longest + 4))) == NULL) errx(EXIT_FAILURE, _("malloc() failed")); 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) { static char buf[MAX_STRING_LENGTH]; (void) strcpy(&fakeenv[0][3], argv[i]); if (!vflag) { show(argv[i], now, FALSE); continue; } 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); } } 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)) errx(EXIT_FAILURE, _("error writing standard output")); 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); } } 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; } 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; } } static time_t yeartot(y) const long y; { register long myy; register long seconds; register time_t t; myy = EPOCH_YEAR; t = 0; while (myy != y) { if (myy < y) { seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR; ++myy; if (t > absolute_max_time - seconds) { t = absolute_max_time; break; } t += seconds; } else { --myy; seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR; if (t < absolute_min_time + seconds) { t = absolute_min_time; break; } t -= seconds; } } return t; } static void usage(const char *progname, FILE *stream, int status) { fprintf(stream, _("usage: %s [--version] [-v] [--help] [-c [loyear,]hiyear] zonename ...\n\ \n\ Report bugs to tz@elsie.nci.nih.gov.\n"), progname); exit(status); } static time_t hunt(char *name, time_t lot, time_t hit) { time_t t; long diff; 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); } for ( ; ; ) { diff = (long) (hit - lot); if (diff < 2) 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; } else hit = t; } show(name, lot, TRUE); show(name, hit, TRUE); return hit; } /* ** Thanks to Paul Eggert for logic used in delta. */ static long delta(newp, oldp) 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) 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 void show(char *zone, time_t t, int v) { register struct tm * tmp; (void) printf("%-*s ", (int) longest, zone); if (v) { tmp = gmtime(&t); if (tmp == NULL) { (void) printf(tformat(), t); } else { dumptime(tmp); (void) printf(" UTC"); } (void) printf(" = "); } tmp = my_localtime(&t); dumptime(tmp); if (tmp != NULL) { if (*abbr(tmp) != '\0') (void) 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 */ } } (void) printf("\n"); if (tmp != NULL && *abbr(tmp) != '\0') abbrok(abbr(tmp), zone); } static char * abbr(tmp) struct tm * tmp; { register char * result; static char nada; if (tmp->tm_isdst != 0 && tmp->tm_isdst != 1) return &nada; result = tzname[tmp->tm_isdst]; return (result == NULL) ? &nada : result; } /* ** The code below can fail on certain theoretical systems; ** it works on all known real-world systems as of 2004-12-30. */ static const char * tformat(void) { if (0.5 == (time_t) 0.5) { /* floating */ if (sizeof (time_t) > sizeof (double)) return "%Lg"; return "%g"; } if (0 > (time_t) -1) { /* signed */ if (sizeof (time_t) > sizeof (long)) return "%lld"; if (sizeof (time_t) > sizeof (int)) return "%ld"; return "%d"; } if (sizeof (time_t) > sizeof (unsigned long)) return "%llu"; if (sizeof (time_t) > sizeof (unsigned int)) return "%lu"; return "%u"; } static void dumptime(timeptr) register const struct tm * timeptr; { static const char wday_name[][3] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat" }; static const char mon_name[][3] = { "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; if (timeptr == NULL) { (void) printf("NULL"); return; } /* ** The packaged versions of localtime and gmtime 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, 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)); } Index: head/usr.sbin/zic/zic.8 =================================================================== --- head/usr.sbin/zic/zic.8 (revision 192889) +++ head/usr.sbin/zic/zic.8 (revision 192890) @@ -1,463 +1,465 @@ .\" $FreeBSD$ .Dd June 20, 2004 .Dt ZIC 8 .Os .Sh NAME .Nm zic .Nd timezone compiler .Sh SYNOPSIS .Nm .Op Fl -version .Op Fl Dsv .Op Fl d Ar directory .Op Fl g Ar group .Op Fl L Ar leapsecondfilename .Op Fl l Ar localtime .Op Fl m Ar mode .Op Fl p Ar posixrules .Op Fl u Ar user .Op Fl y Ar command .Op Ar filename ... .Sh DESCRIPTION The .Nm utility reads text from the file(s) named on the command line and creates the time conversion information files specified in this input. If a .Ar filename is .Em - , the standard input is read. .Pp The following options are available: .Bl -tag -width indent .It Fl -version Output version information and exit. .It Fl D Do not automatically create directories. If the input file(s) specify an output file in a directory which does not already exist, the default behavior is to attempt to create the directory. If .Fl D is specified, .Nm will instead error out immediately. .It Fl d Ar directory Create time conversion information files in the named directory rather than in the standard directory named below. .It Fl g Ar group After creating each output file, change its group ownership to the specified .Ar group (which can be either a name or a numeric group ID). .It Fl L Ar 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. .It Fl l Ar timezone Use the given .Ar time zone as local time. The .Nm utility will act as if the input contained a link line of the form .Pp .D1 No "Link timezone localtime" .Pp (Note that this action has no effect on .Fx , since the local time zone is specified in .Pa /etc/localtime and not .Pa /usr/share/zoneinfo/localtime . ) .It Fl m Ar mode After creating each output file, change its access mode to .Ar mode . Both numeric and alphabetic modes are accepted (see .Xr chmod 1 ) . .It Fl p Ar timezone Use the given .Ar "time zone" Ns 's rules when handling POSIX-format time zone environment variables. The .Nm utility will act as if the input contained a link line of the form .Pp .D1 No "Link timezone posixrules" .It Fl u Ar user After creating each output file, change its owner to .Ar user (which can be either a name or a numeric user ID). .It Fl v Complain if a year that appears in a data file is outside the range of years representable by .Xr time 3 values. .It Fl s Limit time values stored in output files to values that are the same whether they are taken to be signed or unsigned. You can use this option to generate SVVS-compatible files. .It Fl y Ar command Use the given .Ar command rather than .Em yearistype when checking year types (see below). .El .Pp 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 are 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. .Pp A rule line has the form: .Dl "Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S For example: .Dl "Rule US 1967 1973 \- Apr lastSun 2:00 1:00 D .Pp The fields that make up a rule line are: .Bl -tag -width "LETTER/S" -offset indent .It NAME Give the (arbitrary) name of the set of rules this rule is part of. .It FROM Give the first year in which the rule applies. Any integer year can be supplied; the Gregorian calendar is assumed. The word .Em minimum (or an abbreviation) means the minimum year representable as an integer. The word .Em 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. .It TO Give the final year in which the rule applies. In addition to .Em minimum and .Em maximum (as above), the word .Em only (or an abbreviation) may be used to repeat the value of the .Em FROM field. .It TYPE Give the type of year in which the rule applies. If .Em TYPE is .Em \- then the rule applies in all years between .Em FROM and .Em TO inclusive. If .Em TYPE is something else, then .Nm executes the command .Li yearistype Ar year Ar 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. .It IN Name the month in which the rule takes effect. Month names may be abbreviated. .It ON Give the day on which the rule takes effect. Recognized forms include: .Pp .Bl -tag -width lastSun -compact -offset indent .It \&5 the fifth of the month .It lastSun the last Sunday in the month .It lastMon the last Monday in the month .It Sun>=8 first Sunday on or after the eighth .It Sun<=25 last Sunday on or before the 25th .El .Pp Names of days of the week may be abbreviated or spelled out in full. Note that there must be no spaces within the .Em ON field. .It AT Give the time of day at which the rule takes effect. Recognized forms include: .Pp .Bl -tag -width "\&1:28:14" -offset indent -compact .It 2 time in hours .It 2:00 time in hours and minutes .It 15:00 24-hour format time (for times after noon) .It 1:28:14 time in hours, minutes, and seconds .El .Pp 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 .Sq Li w if the given time is local .Dq "wall clock" time, .Sq Li s if the given time is local .Dq standard time, or .Sq Li u (or .Sq Li g or .Sq Li z ) if the given time is universal time; in the absence of an indicator, wall clock time is assumed. .It SAVE Give 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 .Em AT field (although, of course, the .Sq Li w and .Sq Li s suffixes are not used). .It LETTER/S Give the .Dq "variable part" (for example, the .Dq S or .Dq D in .Dq EST or .Dq EDT ) of time zone abbreviations to be used when this rule is in effect. If this field is .Em \- , the variable part is null. .El .Pp A zone line has the form: .Dl "Zone NAME GMTOFF RULES/SAVE FORMAT [UNTILYEAR [MONTH [DAY [TIME]]]] For example: .Dl "Zone Australia/Adelaide 9:30 Aus CST 1971 Oct 31 2:00 The fields that make up a zone line are: .Bl -tag -width indent .It NAME The name of the time zone. This is the name used in creating the time conversion information file for the zone. .It GMTOFF The amount of time to add to UTC to get standard time in this zone. This field has the same format as the .Em AT and .Em SAVE fields of rule lines; begin the field with a minus sign if time must be subtracted from UTC. .It 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 .Em \- then standard time always applies in the time zone. .It FORMAT The format for time zone abbreviations in this time zone. The pair of characters .Em %s is used to show where the .Dq "variable part" of the time zone abbreviation goes. Alternately, a slash (/) separates standard and daylight abbreviations. .It 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. .Pp The next line must be a .Dq continuation line; this has the same form as a zone line except that the string .Dq Zone and the name are omitted, as the continuation line will place information starting at the time specified as the .Em until information in the previous line in the file used by the previous line. Continuation lines may contain .Em until information, just as zone lines do, indicating that the next line is a further continuation. .El .Pp A link line has the form .Dl "Link LINK-FROM LINK-TO For example: .Dl "Link Europe/Istanbul Asia/Istanbul The .Em LINK-FROM field should appear as the .Em NAME field in some zone line; the .Em LINK-TO field is used as an alternate name for that zone. .Pp Except for continuation lines, lines may appear in any order in the input. .Pp Lines in the file that describes leap seconds have the following form: .Dl "Leap YEAR MONTH DAY HH:MM:SS CORR R/S For example: .Dl "Leap 1974 Dec 31 23:59:60 + S The .Em YEAR , .Em MONTH , .Em DAY , and .Em HH:MM:SS fields tell when the leap second happened. The .Em CORR field should be .Dq + if a second was added or .Dq - 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 .Em R/S field should be (an abbreviation of) .Dq Stationary if the leap second time given by the other fields should be interpreted as UTC or (an abbreviation of) .Dq Rolling if the leap second time given by the other fields should be interpreted as local wall clock time. .Sh "EXTENDED EXAMPLE" Here is an extended example of .Nm 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 .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 .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 1:00 Swiss CE%sT 1981 1:00 EU CE%sT .sp Link Europe/Zurich Switzerland .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 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. 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 time. .Sh NOTES For areas with more than two types of local time, you may need to use local standard time in the .Em 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, 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, .Nm 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. .Sh FILES .Bl -tag -width /usr/share/zoneinfo -compact .It /usr/share/zoneinfo standard directory used for created files .El .Sh "SEE ALSO" .Xr ctime 3 , .Xr tzfile 5 , .Xr zdump 8 -.\" @(#)zic.8 8.4 +.\" @(#)zic.8 8.5 +.\" This file is in the public domain, so clarified as of +.\" 2009-05-17 by Arthur David Olson.