Lines Matching +full:center +full:- +full:spread
5 <meta charset="UTF-8">
7 pre {margin-left: 2em; white-space: pre-wrap;}
34 href="https://www.iana.org/time-zones"><code><abbr>tz</abbr></code>
37 It organizes <a href="tz-link.html">time zone and daylight saving time
42 (1970-01-01 00:00:00 <a
45 Although 1970 is a somewhat-arbitrary cutoff, there are significant
61 <code>America/Denver</code> which observes US-style daylight saving
72 Clock transitions before 1970 are recorded for location-based timezones,
74 misbehave if data entries were omitted for pre-1970 transitions.
78 details of pre-1970 civil timekeeping.
91 href="https://en.wikipedia.org/wiki/Unix">UNIX</a>-like systems.
92 As of this writing, the current edition of POSIX is POSIX.1-2024,
94 Unlike its predecessor POSIX.1-2017 (<a
96 Group Base Specifications Issue 7</a>, IEEE Std 1003.1-2017, 2018
97 Edition), POSIX.1-2024 requires support for the
100 standard and daylight saving times required by POSIX.1-2017.
130 locale-dependent strings like "Prague", "Praha", "Прага", and "布拉格".
191 '<code>.</code>', '<code>-</code>' and '<code>_</code>'.
196 '<code>-</code>'.
209 Although the reference implementation is case-sensitive, some
231 as a near-duplicate or alias of <code>Asia/Dubai</code>
274 Among locations with similar populations, pick the best-known
314 a location's consensus English-language spelling changes; for example,
316 due to long-time widespread use of the new city name instead of the old.
332 The other old-fashioned names still supported are
344 '<code>Etc/GMT0</code>', '<code>Etc/GMT-0</code>', '<code>Etc/GMT+0</code>',
345 '<code>GMT0</code>', '<code>GMT-0</code>' and '<code>GMT+0</code>',
354 href="https://en.wikipedia.org/wiki/ISO_3166-1"><abbr
356 3166-1</a> officially assigned two-letter code for an inhabited
374 The backward-compatibility file <code>zone.tab</code> is similar
375 but conforms to the older-version guidelines related to <abbr>ISO</abbr> 3166-1;
395 like <code><+08>-8</code>;
418 '<code>+</code>' or '<code>-</code>'.
427 Previous editions of this guideline required upper-case letters, but the
430 Standard Time</a> preferred "ChST", so lower-case letters are now
432 Also, POSIX from 2001 on relaxed the rule to allow '<code>-</code>',
436 '<code>-</code>' are safe in all locales.
440 expression <code>[-+[:alnum:]]{3,6}</code> should match the
447 Use abbreviations that are in common use among English-speakers,
458 AHST/AHDT Alaska-Hawaii,
479 MET/MEST Middle European (a backward-compatibility alias for
508 Typically, numeric abbreviations (e.g., '<code>-</code>004430' for
521 FFMT Fort-de-France;
534 PPMT Port-au-Prince;
566 <code>-</code>05 and <code>+</code>0530 that are generated
575 English, and the database uses 'CET' even for circa-1910
589 (<abbr>UT</abbr>) (with time zone abbreviation '<code>-</code>00') for
591 The leading '<code>-</code>' is a flag that the <abbr>UT</abbr> offset is in
593 from <a href="https://www.rfc-editor.org/rfc/rfc3339">Internet
596 <a href="https://www.rfc-editor.org/rfc/rfc9557">Internet
609 '<code>-</code>0600' instead of time zone abbreviations like 'CST'.
638 The pre-1970 entries in this database cover only a tiny sliver of how
658 href="https://www.dissentmagazine.org/blog/booked-a-global-history-of-time-vanessa-ogle">Booked:
659 A Global History of Time</a>. <cite>Dissent</cite> 2015-12-17.
662 Most of the pre-1970 data entries come from unreliable sources, often
672 years of first-class work done by
674 "<a href="https://www.polyomino.org.uk/british-time/">History of
683 agree with each other), church-clock time was used for birth
696 database stands for the containing region, its pre-1970 data
699 Kingdom, but its pre-1847 times are valid only for locations that
710 but the date of standardization (1880-08-02) is not in the
726 database were often spread out over hours, days, or even decades.
739 However, on 1911-03-11 at 00:00, some public-facing French clocks
778 Gregorian calendar</a> with days containing 24 equal-length hours
780 Pre-standard time is modeled as local mean time.
786 timekeeping</a> had twelve varying-length daytime hours with a
787 non-hour-based system at night.
789 calendar with 24-hour days. These divergences range from
791 wee hours of the morning, to more-significant differences such as <a
792 …href="https://theworld.org/stories/2015-01-30/if-you-have-meeting-ethiopia-you-better-double-check…
800 like <code><-03>3</code> or <code>America/Cayenne</code> starts
821 and since pre-1972 <abbr>UTC</abbr> seconds varied in length,
833 to more than about one-hour accuracy.
865 database's pre-1970 and future timestamps are either wrong or
885 <a href="tz-link.html#tzdb">part of many platforms</a>, where the
886 primary use of this package is to update obsolete time-related files.
901 like <code>CET-1CEST,M3.5.0,M10.5.0/3</code> uses a complex
915 <h3 id="POSIX.1-2017">POSIX.1-2017 properties and limitations</h3>
917 Some platforms support only the features required by POSIX.1-2017,
918 and have not yet upgraded to POSIX.1-2024.
925 POSIX.1-2017 does not require support for geographical <code>TZ</code>,
934 which is all that POSIX.1-2017 requires,
935 has a format that is hard to describe and is error-prone in practice.
958 Starting with POSIX.1-2001, <var>std</var> and <var>dst</var>
960 this allows "<code>+</code>" and "<code>-</code>" in the names.
982 leading '<code>+</code>' or '<code>-</code>' is not allowed.
988 origin-1 day number not counting February 29
991 origin-0 day number counting February 29 if present
1018 <pre><code>TZ='NZST-12NZDT,M9.5.0,M4.1.0/3'</code></pre>
1031 POSIX.1-2017 also has the limitations of POSIX.1-2024,
1035 <h3 id="POSIX.1-2024">POSIX.1-2024 properties and limitations</h3>
1037 POSIX.1-2024 extends POSIX.1-2017 in the following significant ways:
1041 POSIX.1-2024 requires support for geographical <code>TZ</code>.
1045 POSIX.1-2024 requires <code>struct tm</code>
1054 like <code>"<-02>2<-01>,M3.5.0/-1,M10.5.0/0"</code>
1059 However POSIX.1-2024, like earlier POSIX editions, has some limitations:
1062 The <code>TZ</code> environment variable is process-global, which
1063 makes it hard to write efficient, thread-safe applications that
1067 In POSIX, there is no tamper-proof way for a process to learn the
1076 limit phone calls to off-peak hours.
1097 <h3 id="POSIX-extensions">Extensions to POSIX in the
1110 since 1970-01-01 00:00:00 <abbr>UTC</abbr>, ignoring leap seconds.
1111 In practice, <code>time_t</code> is usually a signed 64- or 32-bit
1112 integer; 32-bit signed <code>time_t</code> values stop working after
1113 2038-01-19 03:14:07 <abbr>UTC</abbr>, so new implementations these
1114 days typically use a signed 64-bit integer.
1115 Unsigned 32-bit integers are used on one or two platforms, and 36-bit
1116 and 40-bit integers are also used occasionally.
1118 floating-point type, this was not supported by any practical system,
1119 and POSIX.1-2013+ and the <code><abbr>tz</abbr></code> code both
1126 the name of a file from which time-related information is read.
1129 <a href="https://www.rfc-editor.org/rfc/9636">Internet
1153 assume pre-POSIX <code>TZ</code> values.
1159 more-efficient thread-safe applications that need to use multiple
1183 they are not needed, and are relics of a too-simple model that does
1184 not suffice to handle many real-world timestamps.
1228 <h3 id="other-portability">Other portability notes</h3>
1238 may now examine <code>localtime(&clock)->tm_zone</code>
1254 In <abbr>SVR2</abbr>, time conversion fails for near-minimum or
1255 near-maximum <code>time_t</code> values when doing conversions
1332 <a href="tz-link.html#download">Downloading
1363 <a href="https://www.bipm.org/en/cgpm-2022/resolution-4">plans
1378 <a href="tz-link.html#precision">Precision timekeeping</a>,
1383 However, kernel-clock twiddling approximates UTC only roughly,
1400 calls to <code>gmtime</code>-like functions
1416 If the POSIX-compatible <abbr>TZif</abbr> file set is installed
1418 leap-second-aware file set is by default installed in a separate
1419 directory <samp>zoneinfo-leaps</samp>.
1422 processes being leap-second aware while other processes are
1423 POSIX-compatible; the leap-second choice is system-wide.
1425 discard <samp>zoneinfo</samp> and rename <samp>zoneinfo-leaps</samp>
1441 …e.org/fr/academic/subjects/computer-science/computing-general-interest/calendrical-calculations-ul…
1459 href='https://www.whitehouse.gov/wp-content/uploads/2024/04/Celestial-Time-Standardization-Policy.p…
1486 It is divided into a conventional 24-hour clock, so each Mars second
1494 meridian</a> of Mars goes through the center of the crater
1495 <a href="https://en.wikipedia.org/wiki/Airy-0">Airy-0</a>, named in
1519 sequential count of Mars solar days elapsed since about 1873-12-29
1526 On other planets, Sun-based time and calendars would work quite
1559 (2020-03-08).
1563 <em><a href="https://mitpress.mit.edu/books/making-time-mars">Making
1564 Time on Mars</a></em>, MIT Press (March 2020), ISBN 978-0262043854.
1567 Jia-Rui Chong,
1568 … "<a href="https://www.latimes.com/archives/la-xpm-2004-jan-14-sci-marstime14-story.html">Workdays
1570 (2004-01-14), pp A1, A20–A21.
1574 …"<a href="https://www.theatlantic.com/technology/archive/2015/02/jet-lag-is-worse-on-mars/386033/"…
1575 Lag Is Worse on Mars</a>", <cite>The Atlantic</cite> (2015-02-26)
1579 "<a href="https://www.universetoday.com/37481/days-of-the-planets/">How
1581 (2016-01-20).
1588 This file is in the public domain, so clarified as of 2009-05-17 by