Index: lib/libc/sys/sigwaitinfo.2
===================================================================
--- lib/libc/sys/sigwaitinfo.2
+++ lib/libc/sys/sigwaitinfo.2
@@ -27,7 +27,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd September 27, 2012
+.Dd April 20, 2022
 .Dt SIGTIMEDWAIT 2
 .Os
 .Sh NAME
@@ -70,7 +70,9 @@
 .Fa timeout
 is the
 .Dv NULL
-pointer, the behavior is unspecified.
+pointer,
+.Fn sigtimedwait
+blocks indefinitely.
 .Dv CLOCK_MONOTONIC
 clock is used to measure the time interval specified by the
 .Fa timeout