diff options
Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 124 |
1 files changed, 122 insertions, 2 deletions
@@ -1,5 +1,125 @@ News for the tz database +Release 2024b - 2024-09-04 12:27:47 -0700 + + Briefly: + Improve historical data for Mexico, Mongolia, and Portugal. + System V names are now obsolescent. + The main data form now uses %z. + The code now conforms to RFC 8536 for early timestamps. + Support POSIX.1-2024, which removes asctime_r and ctime_r. + Assume POSIX.2-1992 or later for shell scripts. + SUPPORT_C89 now defaults to 1. + + Changes to past timestamps + + Asia/Choibalsan is now an alias for Asia/Ulaanbaatar rather than + being a separate Zone with differing behavior before April 2008. + This seems better given our wildly conflicting information about + Mongolia's time zone history. (Thanks to Heitor David Pinto.) + + Historical transitions for Mexico have been updated based on + official Mexican decrees. The affected timestamps occur during + the years 1921-1927, 1931, 1945, 1949-1970, and 1981-1997. + The affected zones are America/Bahia_Banderas, America/Cancun, + America/Chihuahua, America/Ciudad_Juarez, America/Hermosillo, + America/Mazatlan, America/Merida, America/Mexico_City, + America/Monterrey, America/Ojinaga, and America/Tijuana. + (Thanks to Heitor David Pinto.) + + Historical transitions for Portugal, represented by Europe/Lisbon, + Atlantic/Azores, and Atlantic/Madeira, have been updated based on a + close reading of old Portuguese legislation, replacing previous data + mainly originating from Whitman and Shanks & Pottenger. These + changes affect a few transitions in 1917-1921, 1924, and 1940 + throughout these regions by a few hours or days, and various + timestamps between 1977 and 1993 depending on the region. In + particular, the Azores and Madeira did not observe DST from 1977 to + 1981. Additionally, the adoption of standard zonal time in former + Portuguese colonies have been adjusted: Africa/Maputo in 1909, and + Asia/Dili by 22 minutes at the start of 1912. + (Thanks to Tim Parenti.) + + Changes to past tm_isdst flags + + The period from 1966-04-03 through 1966-10-02 in Portugal is now + modeled as DST, to more closely reflect how contemporaneous changes + in law entered into force. + + Changes to data + + Names present only for compatibility with UNIX System V + (last released in the 1990s) have been moved to 'backward'. + These names, which for post-1970 timestamps mostly just duplicate + data of geographical names, were confusing downstream uses. + Names moved to 'backward' are now links to geographical names. + This affects behavior for TZ='EET' for some pre-1981 timestamps, + for TZ='CET' for some pre-1947 timestamps, and for TZ='WET' for + some pre-1996 timestamps. Also, TZ='MET' now behaves like + TZ='CET' and so uses the abbreviation "CET" rather than "MET". + Those needing the previous TZDB behavior, which does not match any + real-world clocks, can find the old entries in 'backzone'. + (Problem reported by Justin Grant.) + + The main source files' time zone abbreviations now use %z, + supported by zic since release 2015f and used in vanguard form + since release 2022b. For example, America/Sao_Paulo now contains + the zone continuation line "-3:00 Brazil %z", which is less error + prone than the old "-3:00 Brazil -03/-02". This does not change + the represented data: the generated TZif files are unchanged. + Rearguard form still avoids %z, to support obsolescent parsers. + + Asia/Almaty has been removed from zonenow.tab as it now agrees + with Asia/Tashkent for future timestamps, due to Kazakhstan's + 2024-02-29 time zone change. Similarly, America/Scoresbysund + has been removed, as it now agrees with America/Nuuk due to + its 2024-03-31 time zone change. + + Changes to code + + localtime.c now always uses a TZif file's time type 0 to handle + timestamps before the file's first transition. Formerly, + localtime.c sometimes inferred a different time type, in order to + handle problematic data generated by zic 2018e or earlier. As it + is now safe to assume more recent versions of zic, there is no + longer a pressing need to fail to conform RFC 8536 section 3.2, + which requires using time type 0 in this situation. This change + does not affect behavior when reading TZif files generated by zic + 2018f and later. + + POSIX.1-2024 removes asctime_r and ctime_r and does not let + libraries define them, so remove them except when needed to + conform to earlier POSIX. These functions are dangerous as they + can overrun user buffers. If you still need them, add + -DSUPPORT_POSIX2008 to CFLAGS. + + The SUPPORT_C89 option now defaults to 1 instead of 0, fixing a + POSIX-conformance bug introduced in 2023a. + + tzselect now supports POSIX.1-2024 proleptic TZ strings. Also, it + assumes POSIX.2-1992 or later, as practical porting targets now + all support that, and it uses some features from POSIX.1-2024 if + available. + + Changes to build procedure + + 'make check' no longer requires curl and Internet access. + + The build procedure now assumes POSIX.2-1992 or later, to simplify + maintenance. To build on Solaris 10, the only extant system still + defaulting to pre-POSIX, prepend /usr/xpg4/bin to PATH. + + Changes to documentation + + The documentation now reflects POSIX.1-2024. + + Changes to commentary + + Commentary about historical transitions in Portugal and her former + colonies has been expanded with links to many relevant legislation. + (Thanks to Tim Parenti.) + + Release 2024a - 2024-02-01 09:28:56 -0800 Briefly: @@ -161,7 +281,7 @@ Release 2023d - 2023-12-21 20:02:24 -0800 * It uses the special .POSIX target. * It quotes special characters more carefully. * It no longer mishandles builds in an ISO 8859 locale. - Due to the CC changes, TZDIR is now #defined in a file tzfile.h + Due to the CC changes, TZDIR is now #defined in a file tzdir.h built by 'make', not in a $(CC) -D option. Also, TZDEFAULT is now treated like TZDIR as they have similar roles. @@ -283,7 +403,7 @@ Release 2023a - 2023-03-22 12:39:33 -0700 To improve tzselect diagnostics, zone1970.tab's comments column is now limited to countries that have multiple timezones. - Note that leap seconds are planned to be discontinued by 2035. + Note that there are plans to discontinue leap seconds by 2035. Release 2022g - 2022-11-29 08:58:31 -0800 |