tzdb 2022g: 5 time zone changes

Read the 5 time zone changes in IANA tzdb 2022g, released on November 29, 2022, with links to affected countries and time zones.

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Published: · Automatically generated from source data.

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Source: IANA

Briefly

  • The northern edge of Chihuahua changes to US timekeeping.
  • Much of Greenland stops changing clocks after March 2023.
  • Fix some pre-1996 timestamps in northern Canada.
  • C89 is now deprecated; please use C99 or later.
  • Portability fixes for AIX, libintl, MS-Windows, musl, z/OS
  • In C code, use more C23 features if available.
  • C23 timegm now supported by default
  • Fixes for unlikely integer overflows

Changes to future timestamps

  • In the Mexican state of Chihuahua, the border strip near the US will change to agree with nearby US locations on 2022-11-30. The strip's western part, represented by Ciudad Juárez, switches from -06 all year to -07/-06 with US DST rules, like El Paso, TX. The eastern part, represented by Ojinaga, will observe US DST next year, like Presidio, TX. (Thanks to Heitor David Pinto.) A new Zone America/Ciudad_Juarez splits from America/Ojinaga.
  • Much of Greenland, represented by America/Nuuk, stops observing winter time after March 2023, so its daylight saving time becomes standard time. (Thanks to Jonas Nyrup and Jürgen Appel.)

Changes to past timestamps

  • Changes for pre-1996 northern Canada (thanks to Chris Walton): Merge America/Iqaluit and America/Pangnirtung into the former, with a backward compatibility link for the latter name. There is no good evidence the two locations differ since 1970. This change affects pre-1996 America/Pangnirtung timestamps. Cambridge Bay, Inuvik, Iqaluit, Rankin Inlet, Resolute and Yellowknife did not observe DST in 1965, and did observe DST from 1972 through 1979. Whitehorse moved from -09 to -08 on 1966-02-27, not 1967-05-28.
  • Colombia's 1993 fallback was 02-06 24:00, not 04-04 00:00. (Thanks to Alois Treindl.)
  • Singapore's 1981-12-31 change was at 16:00 UTC (23:30 local time), not 24:00 local time. (Thanks to Geoff Clare via Robert Elz.)
Other notes in this release (code, build procedure, documentation)

Changes to code

  • Although tzcode still works with C89, bugs found in recent routine maintenance indicate that bitrot has set in and that in practice C89 is no longer used to build tzcode. As it is a maintenance burden, support for C89 is planned to be removed soon. Instead, please use compilers compatible with C99, C11, C17, or C23.
  • timegm, which tzcode implemented in 1989, will finally be standardized 34 years later as part of C23, so timegm is now supported even if STD_INSPIRED is not defined.
  • Fix bug in zdump's tzalloc emulation on hosts that lack tm_zone. (Problem reported by Đoàn Trần Công Danh.)
  • Fix bug in zic on hosts where malloc(0) yields NULL on success. (Problem reported by Tim McBrayer for AIX 6.1.)
  • Fix zic configuration to avoid linkage failures on some platforms. (Problems reported by Gilmore Davidson and Igor Ivanov.)
  • Work around MS-Windows nmake incompatibility with POSIX. (Problem reported by Manuela Friedrich.)
  • Port mktime and strftime to debugging platforms where accessing uninitialized data has undefined behavior (strftime problem reported by Robert Elz).
  • Check more carefully for unlikely integer overflows, preferring C23 <stdckdint.h> to overflow checking by hand, as the latter has had obscure bugs.

Changes to build procedure

  • New Makefile rule check_mild that skips checking whether Link lines are in the file 'backward'. (Inspired by a suggestion from Stephen Colebourne.)