diff options
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | manual/time.texi | 27 |
2 files changed, 30 insertions, 2 deletions
@@ -1,5 +1,10 @@ 2013-12-17 Paul Eggert <eggert@cs.ucla.edu> + Document TZ transition times >= 25:00:00. + * manual/time.texi (TZ Variable): Document transition times from + 25:00:00 through 167:59:59. These are already supported, and this + support will help with version-3 tz-format files. + * manual/time.texi (TZ Variable): Modernize North America example to reflect current (i.e., 2007-and-later) daylight saving rules. diff --git a/manual/time.texi b/manual/time.texi index 60dff77e0a..c65a73e29f 100644 --- a/manual/time.texi +++ b/manual/time.texi @@ -2086,9 +2086,11 @@ between @code{1} and @code{12}. The @var{time} fields specify when, in the local time currently in effect, the change to the other time occurs. If omitted, the default is -@code{02:00:00}. +@code{02:00:00}. The hours part of the time fields can range from +0 through 167; this is an extension to POSIX.1, which allows +only the range 0 through 24. -Here is an example @code{TZ} value, including the appropriate +Here are some example @code{TZ} values, including the appropriate Daylight Saving Time and its dates of applicability. In North American Eastern Standard Time (EST) and Eastern Daylight Time (EDT), the normal offset from UTC is 5 hours; since this is @@ -2100,6 +2102,27 @@ at 2:00am. EST+5EDT,M3.2.0/2,M11.1.0/2 @end smallexample +Israel Standard Time (IST) and Israel Daylight Time (IDT) are 2 hours +ahead of the prime meridian in winter, springing forward an hour on +March's fourth Tuesday 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. + +@smallexample +IST-2IDT,M3.4.4/26,M10.5.0 +@end smallexample + +Western Argentina Summer Time (WARST) is 3 hours behind the prime +meridian all year. 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 @code{WART} +is a placeholder. + +@smallexample +WART4WARST,J1/0,J365/25 +@end smallexample + The schedule of Daylight Saving Time in any particular jurisdiction has changed over the years. To be strictly correct, the conversion of dates and times in the past should be based on the schedule that was in effect |