- tz - lists.iana.org

Re: Ukraine to abolish DST?
by Yuriy Novostavskiy Aug. 16, 2024

Aug. 16, 2024

+ CC On Fri, Aug 16, 2024 at 6:19 PM Yuriy Novostavskiy <yuriy(a)novostavskiy.kiev.ua> wrote: > > Hi Paul, > > This small update is just a heartbeat that has no updates so far, but > it's on my eye and I will update you when something changes. > > To fully clarify what the current status is and the expected next steps: > Parliament voted for https://itd.rada.gov.ua/billInfo/Bills/Card/4294 > and document reached required amount of votes, but to become a bill > this document should be signed by the President has not happened yet, > moreover, it has not even been signed by the Chairman of the Parlament > which is just a bureaucracy formality, but without that step, the > document will not be given to President for signature.It's quite an > unusual delay in the processing of bills. The whole story of that > document is quite long, it appeared back in 2020 and was just added to > the vote list in 2024. > > Another document that you mentioned > https://itd.rada.gov.ua/billInfo/Bills/Card/44572, it's a project of > the decision to reject the first one, but it's not even planned to > vote in the Parlament. > > So, stay tuned. > > On Thu, Jul 18, 2024 at 11:09 AM Yuriy Novostavskiy > <yuriy(a)novostavskiy.kiev.ua> wrote: > > > > I assumed that changes would technically take affects on March 30, > > 2025, when DST will not be introduced. Anyway, I propose to keep those > > changes in "work in progress" status until a new law is finally signed > > and published, and in the final text will have clear understanding of > > 'de jure' cut-off date. > > > > I will keep it tracked and will inform you. > > > > BR/Yurii > > > > On Wed, Jul 17, 2024 at 10:20 PM Paul Eggert <eggert(a)cs.ucla.edu> wrote: > > > > > > Thanks for the heads-up about the bill. I found a copy on the Rada > > > website[1]. Assuming the president signs it and it becomes law, we'll > > > need a change and a new TZDB release. > > > > > > The bill says that the law would take effect three months after > > > promulgation, so it'd be helpful to find out its promulgation date > > > whenever that happens to be. > > > > > > A further proposed resolution was introduced today[2] to annul > > > yesterday's decision and stick with the status quo, on the grounds that > > > yesterday's decision wasn't properly conducted. Not knowing Ukrainian > > > politics, I don't know how today's proposal will affect matters. > > > > > > I am attaching a draft TZDB patch but I haven't installed it into the > > > development version, because the effective date isn't known (I > > > approximated it as "2025" in the draft patch), the bill as it stands > > > might not become law, and the patch will need commentary. The > > > zonenow.tab part of the draft patch would be temporary and that file > > > would need to be updated further after 2024-10-27 as Ukraine would merge > > > with Libya and Kaliningrad for future timestamps. > > > > > > [1]: https://itd.rada.gov.ua/billInfo/Bills/Card/4294 > > > [2]: https://itd.rada.gov.ua/billInfo/Bills/Card/44572

1 0

netherland timezone UTC offset (0:19:32.13) history
by Eitan Adler Aug. 6, 2024

Aug. 6, 2024

(I am not currently subscribed, please keep me CCed) Hi all, I'm interested in some specific timezone history. Specifically I'm curious about the origin of 'STDOFF 0:19:32.13'. Does anyone have an authoritative source for where this is derived from? Below is what I found so far: 1. In "NEWS" there is this entry: === zic now accepts subsecond precision in expressions like 00:19:32.13, which is approximately the legal time of the Netherlands from 1835 to 1937... === 2. Wikipedia here https://en.wikipedia.org/wiki/UTC%2B00:20 says === The reason for the specific offset of +0h 19m 32.13s was that the time zone was centered on the mean solar time of the Westertoren (4° 53' 01.95" E Longitude), the tower of the Westerkerk church in Amsterdam. === but I can't find any reference to this specific offset in any of the sources listed on Wikipedia. It is possible I missed the reference though. https://articles.adsabs.harvard.edu/pdf/1909Obs....32..297. https://books.google.com/books?id=MbA-AQAAIAAJ&pg=PA75&printsec=frontcover&… 3. I've seen several references that cite *to* wikipedia or tzdata, but I haven't been able to find anything older. (if this is off topic for the mailing list I apologize, this is the best place I could find) -- Eitan Adler

4 4

[PROPOSED] Mention Internet RFC 9557
by Paul Eggert Aug. 1, 2024

Aug. 1, 2024

--- theory.html | 5 +++++ tz-link.html | 20 ++++++++++++-------- 2 files changed, 17 insertions(+), 8 deletions(-) diff --git a/theory.html b/theory.html index 10281af1..d3573ede 100644 --- a/theory.html +++ b/theory.html @@ -581,6 +581,11 @@ in decreasing order of importance: some sense undefined; this notation is derived from <a href="https://datatracker.ietf.org/doc/html/rfc3339">Internet <abbr title="Request For Comments">RFC</abbr> 3339</a>. + (The abbreviation 'Z' that + <a href="https://datatracker.ietf.org/doc/html/rfc9557">Internet + <abbr>RFC</abbr> 9557</a> uses for this concept + would violate the POSIX requirement + of at least three characters in an abbreviation.) </li> </ul> diff --git a/tz-link.html b/tz-link.html index 739d07af..4d883883 100644 --- a/tz-link.html +++ b/tz-link.html @@ -193,9 +193,10 @@ After obtaining the code and data files, see the <code>README</code> file for what to do next. The code lets you compile the <code><abbr>tz</abbr></code> source files into machine-readable binary files, one for each location. The binary files -are in a special timezone information format (<dfn><abbr>TZif</abbr></dfn>) -specified by <a href="https://datatracker.ietf.org/doc/html/8536">Internet -<abbr>RFC</abbr> 8536</a>. +are in a special format specified by +<a href="https://datatracker.ietf.org/doc/html/8536">The +Time Zone Information Format (<abbr>TZif</abbr>)</a> +(Internet <abbr title="Request For Comments">RFC</abbr> 8536). The code also lets you read a <abbr>TZif</abbr> file and interpret timestamps for that location.</p> @@ -262,8 +263,8 @@ Studio Code</a>. <p> For further information about updates, please see <a href="https://datatracker.ietf.org/doc/html/rfc6557">Procedures for -Maintaining the Time Zone Database</a> (Internet <abbr -title="Request For Comments">RFC</abbr> 6557). More detail can be +Maintaining the Time Zone Database</a> (Internet <abbr>RFC</abbr> 6557). +More detail can be found in <a href="theory.html">Theory and pragmatics of the <code><abbr>tz</abbr></code> code and data</a>. <a href="https://a0.github.io/a0-tzmigration/">A0 TimeZone Migration</a> @@ -1174,9 +1175,12 @@ headers.</li> <li> <a href="https://datatracker.ietf.org/doc/html/rfc3339">Date and Time on the Internet: Timestamps</a> (Internet <abbr>RFC</abbr> 3339) -specifies an <abbr>ISO</abbr> 8601 -profile for use in new Internet -protocols.</li> +specifies an <abbr>ISO</abbr> 8601 profile for use in new Internet protocols. +An extension, <a href="https://datatracker.ietf.org/doc/html/rfc9557">Date +and Time on the Internet: Timestamps with Additional Information</a> +(Internet <abbr>RFC</abbr> 9557) extends this profile +to let you specify the <code><abbr>tzdb</abbr></code> timezone of a timestamp +via suffixes like "<code>[Asia/Tokyo]</code>". <li> <a href="https://web.archive.org/web/20190130042457/https://www.hackcraft.net/web/da…">Date & Time Formats on the Web</a> surveys web- and Internet-oriented date and time -- 2.43.0

1 0

Fwd: Bulletin C number 68
by Tim Parenti July 30, 2024

July 30, 2024

No leap second 2024-12-31, per below. See attached patch. -- Tim Parenti ---------- Forwarded message --------- From: IERS EOP Product Center <iers.eoppc(a)obspm.fr> Date: Thu, 4 Jul 2024 at 10:57 Subject: Bulletin C number 68 To: <bulc.iers(a)obspm.fr> INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE DE L'IERS OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : +33 1 40 51 23 35 e-mail : services.iers(a)obspm.fr http://hpiers.obspm.fr/eop-pc Paris, 04 July 2024 Bulletin C 68 To authorities responsible for the measurement and distribution of time INFORMATION ON UTC - TAI NO leap second will be introduced at the end of December 2024. The difference between Coordinated Universal Time UTC and the International Atomic Time TAI is : from 2017 January 1, 0h UTC, until further notice : UTC-TAI = -37 s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC, or to confirm that there will be no time step at the next possible date. Christian BIZOUARD Director Earth Orientation Center of IERS Observatoire de Paris, France

2 1

Parts of Georgia and Ukraine observing Moscow time
by Heitor David Pinto July 22, 2024

July 22, 2024

Hello, Sources indicate that Abkhazia has observed Moscow time since at least 2010:https://web.archive.org/web/20100725215624/http://abkhazia.travel:80/a… It's possible that South Ossetia has done the same. Both regions definitely changed to UTC+3 along with Moscow in 2014, and have remained in that time zone since then:https://www.kavkaz-uzel.eu/articles/251354/ In Ukraine, the portions of Donetsk and Luhansk regions administered by separatists have observed Moscow time since 2014:https://tass.com/world/756540 In 2022, the portions of Donetsk, Luhansk, Zaporizhzhia and Kherson regions administered by Russia also changed to Moscow time:https://tass.com/society/1568025https://tass.com/society/1605439 I understand that these changes are controversial, but the database does show Crimea in Moscow time since 2014, even though it remains under country code UA in file zone.tab. So I suppose that these other regions should be added as well, under codes GE and UA but showing their time zones observed in practice. Regards,David

2 1

Ukraine canceled DST in autumn of 2024
by Yuriy Novostavskiy July 17, 2024

July 17, 2024

Parlament of Ukraine decided to cancel introducing DST, so, starting from spring 2025 DST will not be used for Kyiv time zone. That law was proposed in 2020, and accepted July 17, 2024. Info on the parlament site of Ukraine https:// w1.c1.rada.gov.ua/pls/zweb2/webproc4_1?pf3511=70150 BTW, that decision should be finally approved by President that is not happened yet

1 0

Contributions of core, mantle and climatological processes to Earth’s polar motion
by Brooks Harris July 16, 2024

July 16, 2024

Contributions of core, mantle and climatological processes to Earth’s polar motion https://www.nature.com/articles/s41561-024-01478-2

1 0

Re: [tz] Time for a Lunar time zone? -Brooks
by Paul Eggert July 11, 2024

July 11, 2024

On 3/2/23 09:51, Brooks Harris wrote: > Will we need DST on the Moon? :-) I hope not! The Moon's axis tilts only 1.5°, much less than the 23.5° of Earth's axis, so seasonal effects on sunlight duration are much less intense on the Moon and there should be less need for Earth-like DST. A more pressing issue is that the length of day (including daytime and nighttime) varies more on the Moon. Local Earth days vary by at most 0.008 hours from the mean of 24 hours (this variation is due to the eccentricity of the Earth orbit and the obliquity of the ecliptic). So people who think that every local Earth day is exactly 24 hours are not far off. Local lunar days, in contrast, are roughly 29.5 ± 0.25 Earth days (again, this includes both lunar daytime and lunar nighttime). That's more slop to deal with, relatively speaking, and dealing with varying-length days could be a bit of a problem for civil time on the Moon. Presumably ESA's boffins are on top of this.....

4 5

Earth's inner core has slowed so much it's moving backward
by Brian Inglis July 5, 2024

July 5, 2024

Newer info related to leap second distribution and occurrences. Earth’s core has slowed so much it’s moving backward, scientists confirm: https://www.cnn.com/2024/07/05/science/earth-inner-core-rotation-slowdown-c… Inner core backtracking by seismic waveform change reversals: https://www.nature.com/articles/s41586-024-07536-4 TL;DR: Seismologists confirm ~70 year inner core oscillation cycle. Inner core rotated eastward faster than the planet 2003-2008 and back ~ 2.5* more slowly westward 2008-2023 over the same path relative to the mantle. Mantle density anomalies and mantle and core boundary topography gravitational coupling could explain LoD Length of Day SYO 6 Year Oscillation. Slower core spin, speeds up the mantle, the planet rotates faster, and the LoD shortens by ms. Core rotation should speed up again in 5-10 years if model is confirmed. -- Take care. Thanks, Brian Inglis Calgary, Alberta, Canada La perfection est atteinte Perfection is achieved non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut -- Antoine de Saint-Exupéry

1 0

Request for Change of Time Zone Name from Asia/Ho_Chi_Minh to Asia/Ha_Noi
by viet le July 4, 2024

July 4, 2024

Dear Sir/Madam, I am writing to formally request a change in the naming of the time zone for Viet Nam in your database. Currently, the time zone is listed as "Asia/Ho_Chi_Minh." However, I would like to propose that this be updated to "Asia/Ha_Noi" to reflect the official and more widely recognized name of the time zone. Hà Nội, as the capital city of Viet Nam, is the administrative and political center of the country. It holds significant historical, cultural, and socio-economic importance. Consequently, using Hà Nội as the reference point for the country's time zone would be more appropriate and align with international standards and practices. The change from "Asia/Ho_Chi_Minh" to "Asia/Ha_Noi" would not only reflect the official naming conventions but also aid in reducing confusion among users and developers who rely on accurate and standardized time zone data. This adjustment would bring consistency and clarity to the representation of Viet Nam's time zone in global systems. I kindly ask that IANA consider this request and take the necessary steps to implement the change. Your attention to this matter and efforts to ensure accurate representation in the time zone database are greatly appreciated. Thank you for your time and consideration. I look forward to your favorable response. Sincerely, Viet Le

6 5

Mongolia
by Heitor David Pinto July 4, 2024

July 4, 2024

Hello, Sources about time zones in Mongolia seem to list one of two conflicting configurations. The first configuration, mentioned in a comment to the TZ database in 1999, citing a Mongolian government website, lists the provinces of Bayan-Ölgii, Khovd and Uvs in UTC+7, and the rest of the country in UTC+8. The second configuration, mentioned in a comment to the database in 2001, lists Bayan-Ölgii, Khovd, Uvs, Govi-Altai and Zavkhan in UTC+7, Dornod and Sükhbaatar in UTC+9, and the rest of the country in UTC+8. The first configuration is still mentioned by several Mongolian travel agencies: https://www.adventurerider.mn/en/page/about_mongolia http://www.naturetours.mn/nt/mongolia.php https://www.newjuulchin.mn/web/content/7506?unique=fa24a0f6e96e022a3578ee51… It also matches these flight schedules in 2013: http://web.archive.org/web/20130722023600/https://www.hunnuair.com/en/timet… The flight times imply that the airports of Uliastai (Zavkhan), Choibalsan (Dornod) and Altai (Govi-Altai) are in the same time zone as Ulaanbaatar, and Khovd is one hour behind. It also matches a Mongolian news article about the election in 2017: https://mongolia.gogo.mn/r/806d6 The second configuration was mentioned by an official of the Mongolian standards agency in an interview in 2014: https://ikon.mn/n/9v6 And it's still listed by the Mongolian aviation agency: https://ais.mn/files/aip/eAIP/2023-12-25/html/eSUP/ZM-eSUP-23-04-en-MN.html The TZ database used the first configuration until 2001, when it switched to the second configuration, under the assumption that its sources were more reliable. In 2008, based on sources indicating that Choibalsan actually used UTC+8, the database changed Dornod and Sükhbaatar to UTC+8, but only from 2008 on, and maintained Govi-Altai and Zavkhan in UTC+7. This resulted in a mix of the two configurations that is not supported as a whole by any source. Based on all the above sources, I believe that the first configuration is what is actually observed in Mongolia and has been so all along, at least since 1999. The second configuration closely matches the ideal time zone boundaries at 97.5°E and 112.5°E but it doesn't seem to be used in practice. So I suggest the following: 1. In zone.tab, remove Govi-Altai and Zavkhan from Asia/Ulaanbaatar, assuming that they have always used the same time as Ulaanbaatar, or create a new zone Asia/Uliastai showing Govi-Altai and Zavkhan in UTC+8 since at least 1999. 2. Remove the zone Asia/Choibalsan or make it an alias of Asia/Ulaanbaatar, assuming that it has always used the same time as Ulaanbaatar, or list its change from UTC+9 to UTC+8 since at least 1999 instead of 2008. Regards,Dave | | Virus-free.www.avg.com |

2 2

error Portugal 1980
by Alois Treindl July 2, 2024

July 2, 2024

I think there is an error in TZ, regarding begin of DST in Portugal in 1980. A user of my website pointed it out. file europe has > Rule Port 1978 only - Oct 1 0:00s 0 - > Rule Port 1979 1982 - Sep lastSun 1:00s 0 - > Rule Port 1980 only - Mar lastSun 0:00s 1:00 S > Rule Port 1981 1982 - Mar lastSun 1:00s 1:00 S > Rule Port 1983 only - Mar lastSun 2:00s 1:00 S But Observatório Astronómico de Lisboa http://oal.ul.pt/hora-legal/legislacao-sobre-a-hora-legal/ has in document Tabela com a definição anual da Hora Legal portuguesa desde 1911 https://oal.ul.pt/documentos/2018/01/hl1911a2018.pdf > 1980 Hora do meridiano de Greenwich até à 1 hora do dia 6 de Abril, > instante > em que foi adiantada de 60 minutos, tendo-se regressado à hiora do meri- > diano de Greenwich às 2 horas do dia 28 de Setembro (Portaria nº 69/80) > I attach a patch file

4 12

[PROPOSED] More documentation updates for POSIX.1-2024
by Paul Eggert June 16, 2024

June 16, 2024

Be more careful when documenting tm_zone, tm_gmtoff, tzname, etc., in the light of POSIX.1-2024 etc. --- Makefile | 8 ++++-- newctime.3 | 79 ++++++++++++++++++++++++--------------------------- newstrftime.3 | 14 ++++----- newtzset.3 | 55 +++++++++++++++++++++++++++++++---- 4 files changed, 100 insertions(+), 56 deletions(-) diff --git a/Makefile b/Makefile index 99f2f56b..d6d66a1f 100644 --- a/Makefile +++ b/Makefile @@ -358,7 +358,9 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \ # # -DHAVE_TZNAME=0 # do not support "tzname" # # -DHAVE_TZNAME=1 # support "tzname", which is defined by system library # # -DHAVE_TZNAME=2 # support and define "tzname" -# # to the "CFLAGS=" line. "tzname" is required by POSIX.1-1988 and later. +# # to the "CFLAGS=" line. Although "tzname" is required by POSIX.1-1988 +# # and later, its contents are unspecified if you use a geographical TZ +# # and the variable is planned to be removed in a future POSIX edition. # # If not defined, the code attempts to guess HAVE_TZNAME from other macros. # # Warning: unless time_tz is also defined, HAVE_TZNAME=1 can cause # # crashes when combined with some platforms' standard libraries, @@ -369,7 +371,9 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \ # # -DUSG_COMPAT=1 # support, and variables are defined by system library # # -DUSG_COMPAT=2 # support and define variables # # to the "CFLAGS=" line; "timezone" and "daylight" are inspired by Unix -# # Systems Group code and are required by POSIX.1-2008 and later (with XSI). +# # Systems Group code and are required by POSIX.1-2008 and later (with XSI), +# # although their contents are unspecified if you use a geographical TZ +# # and the variables are planned to be rmeoved in a future edition of POSIX. # # If not defined, the code attempts to guess USG_COMPAT from other macros. # # # # To support the external variable "altzone", add diff --git a/newctime.3 b/newctime.3 index ccc19748..d19fd25b 100644 --- a/newctime.3 +++ b/newctime.3 @@ -9,8 +9,6 @@ asctime, ctime, difftime, gmtime, localtime, mktime \- convert date and time .el .ds - \- .B #include <time.h> .PP -.BR "extern char *tzname[];" " /\(** (optional) \(**/" -.PP .B [[deprecated]] char *ctime(time_t const *clock); .PP /* Only in POSIX.1-2017 and earlier. */ @@ -114,17 +112,6 @@ The function corrects for the time zone and any time zone adjustments (such as Daylight Saving Time in the United States). -After filling in the -.q "tm" -structure, -.B localtime -sets the -.BR tm_isdst 'th -element of -.B tzname -to a pointer to a string that's the time zone abbreviation to be used with -.BR localtime 's -return value. .PP The .B gmtime @@ -294,21 +281,43 @@ from UT, with positive values indicating east of the Prime Meridian. The field's name is derived from Greenwich Mean Time, a precursor of UT. .PP -In +In platforms conforming to POSIX.1-2024 the .B "struct tm" the .B tm_zone and .B tm_gmtoff -fields exist, and are filled in, only if arrangements to do -so were made when the library containing these functions was -created. -Similarly, the -.B tzname -variable is optional; also, there is no guarantee that -.B tzname -will -continue to exist in this form in future releases of this code. +fields exist, and are filled in. +For +.B localtime_rz +and +.B mktime_rz +the storage lifetime of the strings addressed by +.B tm_zone +extends until the corresponding +.B timezone_t +object is freed via +.BR tzfree . +For the other functions the lifetime extends until the +.I TZ +environment variable changes state and +.B tzset +is then called. +.PP +As a side effect, the +.BR ctime , +.B localtime +and +.B mktime +functions also behave as if +.B tzset +were called. +The +.B ctime_r +and +.B localtime_r +functions might (or might not) also behave this way. +This is for compatibility with older platforms, as required by POSIX. .SH FILES .ta \w'/usr/share/zoneinfo/posixrules\0\0'u /etc/localtime local timezone file @@ -322,11 +331,11 @@ continue to exist in this form in future releases of this code. If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from /usr/share/zoneinfo/GMT0 if present. .SH SEE ALSO -getenv(3), -newstrftime(3), -newtzset(3), -time(2), -tzfile(5) +.BR getenv (3), +.BR newstrftime (3), +.BR newtzset (3), +.BR time (2), +.BR tzfile (5). .SH NOTES The return values of .BR asctime , @@ -336,20 +345,6 @@ and .B localtime point to static data overwritten by each call. -The -.B tzname -variable (once set) and the -.B tm_zone -field of a returned -.B "struct tm" -both point to an array of characters that -can be freed or overwritten by later calls to the functions -.BR localtime , -.BR tzfree , -and -.BR tzset , -if these functions affect the timezone information that specifies the -abbreviation in question. The remaining functions and data are thread-safe. .PP The diff --git a/newstrftime.3 b/newstrftime.3 index 11e37ae8..a9997a09 100644 --- a/newstrftime.3 +++ b/newstrftime.3 @@ -398,7 +398,7 @@ also behaves as if were called. This is for compatibility with older platforms, as required by POSIX; it is not needed for -.BR tzset 's +.BR strftime 's own use. .SH "RETURN VALUE" If the conversion is successful, @@ -428,11 +428,11 @@ conversion and the number of seconds since the Epoch cannot be represented in a .c time_t . .SH SEE ALSO -date(1), -getenv(3), -newctime(3), -newtzset(3), -time(2), -tzfile(5) +.BR date (1), +.BR getenv (3), +.BR newctime (3), +.BR newtzset (3), +.BR time (2), +.BR tzfile (5). .SH BUGS There is no conversion specification for the phase of the moon. diff --git a/newtzset.3 b/newtzset.3 index 4708106d..661fb25b 100644 --- a/newtzset.3 +++ b/newtzset.3 @@ -15,6 +15,14 @@ tzset \- initialize time conversion information .PP .B void tzset(void); .PP +/\(** Optional and obsolescent: \(**/ +.br +.B extern char *tzname[]; +.br +.B extern long timezone; +.br +.B extern int daylight; +.PP .B cc ... \*-ltz .fi .SH DESCRIPTION @@ -341,6 +349,22 @@ if the implied call to fails, .B tzset falls back on UT. +.PP +As a side effect, the +.B tzset +function sets some external variables if the platform defines them. +It sets +.BR tzname [0] +and +.BR tzname [1] +to pointers to strings that are time zone abbreviations to be used with +standard and daylight saving time, respectively. +It also sets +.B timezone +to be the number of seconds that standard time is west of the Prime Meridian, +and +.B daylight +to be zero if daylight saving time is never in effect, non-zero otherwise. .SH "RETURN VALUE" If successful, the .B tzalloc @@ -379,8 +403,29 @@ and If /usr/share/zoneinfo/GMT is absent, UTC leap seconds are loaded from /usr/share/zoneinfo/GMT0 if present. .SH SEE ALSO -getenv(3), -newctime(3), -newstrftime(3), -time(2), -tzfile(5) +.BR getenv (3), +.BR newctime (3), +.BR newstrftime (3), +.BR time (2), +.BR tzfile (5). +.SH NOTES +Portable code should not rely on the contents of the external variables +.BR tzname , +.B timezone +and +.B daylight +as their contents are unspecified (and do not make sense in general) +when a geographical TZ is used. +In multithreaded applications behavior is undefined if one thread accesses +one of these variables while another thread invokes +.BR tzset . +A future version of POSIX is planned to remove these variables; +callers can instead use the +.I tm_gmtoff +and +.I tm_zone +members of +.B struct tm, +or use +.B strftime +with "%z" or "%Z". -- 2.43.0

2 2

[PROPOSED 1/3] Fix typo when making .txt man pages
by Paul Eggert June 12, 2024

June 12, 2024

* Makefile (MANTXTS): Fix typo: missing ‘:’. --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Makefile b/Makefile index c00eb317..344bb8ed 100644 --- a/Makefile +++ b/Makefile @@ -1054,7 +1054,7 @@ zdump.8.txt: zdump.8 zic.8.txt: zic.8 $(MANTXTS): workman.sh - LC_ALL=C sh workman.sh $(@.txt=) >$@.out + LC_ALL=C sh workman.sh $(@:.txt=) >$@.out mv $@.out $@ # Set file timestamps deterministically if possible, -- 2.43.0

1 2

[PROPOSED] SUPPORT_C89 now defaults to 1, not 0
by Paul Eggert June 8, 2024

June 8, 2024

Although POSIX requires this, I didn’t notice it until today. * Makefile, NEWS, localtime.c: Mention this. * private.h (SUPPORT_C89): Default to 1, not 0. --- Makefile | 5 +++-- NEWS | 4 ++++ localtime.c | 5 +++-- private.h | 17 ++++++++++------- 4 files changed, 20 insertions(+), 11 deletions(-) diff --git a/Makefile b/Makefile index 97a88535..c00eb317 100644 --- a/Makefile +++ b/Makefile @@ -263,8 +263,9 @@ LDLIBS= # -DRESERVE_STD_EXT_IDS if your platform reserves standard identifiers # with external linkage, e.g., applications cannot define 'localtime'. # -Dssize_t=long on hosts like MS-Windows that lack ssize_t -# -DSUPPORT_C89 if the tzcode library should support C89 callers+ -# However, this might trigger latent bugs in C99-or-later callers. +# -DSUPPORT_C89=0 if the tzcode library should not support C89 callers +# Although -DSUPPORT_C89=0 might work around latent bugs in callers, +# it does not conform to POSIX. # -DSUPPORT_POSIX2008 if the library should support older POSIX callers+ # However, this might cause problems in POSIX.1-2024-or-later callers. # -DSUPPRESS_TZDIR to not prepend TZDIR to file names; this has diff --git a/NEWS b/NEWS index 6b71212c..5238cb9e 100644 --- a/NEWS +++ b/NEWS @@ -8,6 +8,7 @@ Unreleased, experimental changes 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. Improve historical data for Portugal and possessions. Changes to data @@ -60,6 +61,9 @@ Unreleased, experimental changes 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 assumes POSIX.2-1992 or later, as practical porting targets now all support this. Also, tzselect uses some features from POSIX.1-2024 if available. diff --git a/localtime.c b/localtime.c index c9f0d1a8..7e3fd149 100644 --- a/localtime.c +++ b/localtime.c @@ -182,8 +182,9 @@ static int lcl_is_set; ** objects: a broken-down time structure and an array of char. ** Thanks to Paul Eggert for noting this. ** -** This requirement was removed in C99, so support it only if requested, -** as support is more likely to lead to bugs in badly written programs. +** Although this requirement was removed in C99 it is still present in POSIX. +** Follow the requirement if SUPPORT_C89, even though this is more likely to +** trigger latent bugs in programs. */ #if SUPPORT_C89 diff --git a/private.h b/private.h index 0c91a252..19d7f7d6 100644 --- a/private.h +++ b/private.h @@ -19,19 +19,22 @@ /* PORT_TO_C89 means the code should work even if the underlying compiler and library support only C89 plus C99's 'long long' - and perhaps a few other extensions to C89. SUPPORT_C89 means the - tzcode library should support C89 callers in addition to the usual - support for C99-and-later callers; however, C89 support can trigger - latent bugs in C99-and-later callers. These macros are obsolescent, - and the plan is to remove them along with any code needed only when - they are nonzero. A good time to do that might be in the year 2029 + and perhaps a few other extensions to C89. + + This macro is obsolescent, and the plan is to remove it along with + associated code. A good time to do that might be in the year 2029 because RHEL 7 (whose GCC defaults to C89) extended life cycle support (ELS) is scheduled to end on 2028-06-30. */ #ifndef PORT_TO_C89 # define PORT_TO_C89 0 #endif + +/* SUPPORT_C89 means the tzcode library should support C89 callers + in addition to the usual support for C99-and-later callers. + This defaults to 1 as POSIX requires, even though that can trigger + latent bugs in callers. */ #ifndef SUPPORT_C89 -# define SUPPORT_C89 0 +# define SUPPORT_C89 1 #endif #ifndef __STDC_VERSION__ -- 2.43.0

2 1

[PROPOSED 00/12] Assume POSIX.2-1992
by Paul Eggert June 1, 2024

June 1, 2024

For many years we have maintained code in tzselect and Makefile intended to port to older platforms that predate POSIX.2-1992. The only remaining such platform that is still supported by its supplier is Solaris 10 (2005), which has a shell and related tools that are still pre-POSIX by default, although POSIX variants are available. However, I recently discovered that Solaris 10’s own copy of tzselect now uses POSIX.2-1992 features and is based on the POSIX variants. Now that even Oracle has abandoned its pre-POSIX environment for TZDB, it’s time for us to follow suit. This series of patches updates the Makefile and tzselect shell script to assume POSIX.2-1992 or later. This simplifies maintenance and speeds up the code a bit. Paul Eggert (12): Assume POSIX.2 and eschew ‘expr’ Prefer $(CMD) to `CMD` in Makefile Prefer $PWD to $(pwd) in Makefile Avoid subshells when possible Assume POSIX.2 command substitution * tzselect.ksh: Assume POSIX.2 $PWD. * tzselect.ksh: Assume POSIX.2 awk. Avoid some subshells in tzselect Avoid an awk invocation via $'...' Use ‘export VAR=VAL’ syntax Avoid crash in Solaris 10 /usr/xpg4/bin/make Port ! to Solaris make .gitignore | 4 +- Makefile | 343 +++++++++++++++++++++++++-------------------------- NEWS | 9 ++ checknow.awk | 2 +- tzselect.ksh | 112 +++++++---------- workman.sh | 3 +- 6 files changed, 231 insertions(+), 242 deletions(-) -- 2.45.1

1 12

[PROPOSED] difftime isn’t pure either
by Paul Eggert May 28, 2024

May 28, 2024

See <https://sourceware.org/bugzilla/show_bug.cgi?id=31808#c1>. * private.h (difftime): No longer pure. --- private.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/private.h b/private.h index cacbe444..0c91a252 100644 --- a/private.h +++ b/private.h @@ -702,7 +702,7 @@ DEPRECATED_IN_C23 char *ctime(time_t const *); char *asctime_r(struct tm const *restrict, char *restrict); char *ctime_r(time_t const *, char *); #endif -ATTRIBUTE_PURE double difftime(time_t, time_t); +double difftime(time_t, time_t); size_t strftime(char *restrict, size_t, char const *restrict, struct tm const *restrict); # if HAVE_STRFTIME_L -- 2.45.1

1 0

Unicode CLDR supplemental/windowsZones.xml update? -Brooks Harris
by Brooks Harris May 28, 2024

May 28, 2024

Does someone know if the Unicode CLDR ../supplemental/windowsZones.xml has been updated? Following the best links I know to find: Unicode CLDR Overview https://cldr.unicode.org/index/downloads/cldr-45 Downloads https://cldr.unicode.org/index/downloads GitHub Tag https://raw.githubusercontent.com/RobThree/TimeZoneMapper/master/TimeZoneMa… This file says it corresponds with TzDb 2021a. Yet other notes say Windows zone were updated to TzDb 2024a: CLDR 45 Release Note https://cldr.unicode.org/index/downloads/cldr-45 Timezones Deprecating timezones that are no longer in zone.tab (America/Nipigon, ...) New Windows timezone mappings Was this file not actually updated or am I looking in the wrong place? Thanks, -Brooks

4 6

[PROPOSED 1/4] More updates to GCC_DEBUG_FLAGS for GCC 14
by Paul Eggert May 27, 2024

May 27, 2024

* Makefile (GCC_DEBUG_FLAGS): Omit -fno-common, as it is now the default. Omit -Wuninitialized as it’s implied by -Wall. Omit -Wno-address and -Wno-type-limits as they don’t seem to be needed with GCC 14. --- Makefile | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/Makefile b/Makefile index 6b093013..4d2ac1cf 100644 --- a/Makefile +++ b/Makefile @@ -313,7 +313,7 @@ GCC_INSTRUMENT = \ -fsanitize=undefined -fsanitize-address-use-after-scope \ -fsanitize-undefined-trap-on-error -fstack-protector # Omit -fanalyzer from GCC_DEBUG_FLAGS, as it makes GCC too slow. -GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \ +GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 \ $(GCC_INSTRUMENT) \ -Wall -Wextra \ -Walloc-size-larger-than=100000 -Warray-bounds=2 \ @@ -332,10 +332,9 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \ -Wsuggest-attribute=const -Wsuggest-attribute=format \ -Wsuggest-attribute=malloc \ -Wsuggest-attribute=noreturn -Wsuggest-attribute=pure \ - -Wtrampolines -Wundef -Wuninitialized -Wunused-macros -Wuse-after-free=3 \ + -Wtrampolines -Wundef -Wunused-macros -Wuse-after-free=3 \ -Wvariadic-macros -Wvla -Wwrite-strings \ - -Wno-address -Wno-format-nonliteral -Wno-sign-compare \ - -Wno-type-limits + -Wno-format-nonliteral -Wno-sign-compare # # If your system has a "GMT offset" field in its "struct tm"s # (or if you decide to add such a field in your system's "time.h" file), -- 2.43.0

2 5

Re: [tz] Unicode CLDR supplemental/windowsZones.xml update? -Brooks Harris
by Paul Eggert May 27, 2024

May 27, 2024

On 2024-05-26 12:44, Brooks Harris wrote: > Hi Pail, > On 2024-05-26 03:37 PM, Paul Eggert wrote: >> On 2024-05-26 12:30, Brooks Harris via tz wrote: >>> What is the best procedure to obtain the latest windowsZones.xml? >> >> https://github.com/unicode-org/cldr/blob/main/common/supplemental/windowsZo… > > This file is identical to the old one I have and does not reflect the > commits you referred me to. That's not a file, it's a bunch of info about the file. The info includes the file contents and a bunch of other stuff. If you just want the file, click the Raw button. >>> Is there a record of earlier versions? >> https://github.com/unicode-org/cldr/commits/main/common/supplemental/window… >> >> These are reachable from the earlier URL I emailed. > > Right, but no version of windowsZones.xml I can find has those commits > applied. ? Those changes are visible to me via that URL. Anyway, try clicking the "Raw" button. It should give you this URL: https://raw.githubusercontent.com/unicode-org/cldr/main/common/supplemental… and I see the changes there too.

4 7

[PROPOSED 1/4] Update GCC_DEBUG_FLAGS for GCC 14
by Paul Eggert May 25, 2024

May 25, 2024

* Makefile (GCC_DEBUG_FLAGS): Add -Wflex-array-member-not-at-end, -Wmissing-variable-declarations. --- Makefile | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 3f550b3f..a72fb2ea 100644 --- a/Makefile +++ b/Makefile @@ -315,10 +315,11 @@ GCC_DEBUG_FLAGS = -DGCC_LINT -g3 -O3 -fno-common \ -Walloc-size-larger-than=100000 -Warray-bounds=2 \ -Wbad-function-cast -Wbidi-chars=any,ucn -Wcast-align=strict -Wdate-time \ -Wdeclaration-after-statement -Wdouble-promotion \ - -Wduplicated-branches -Wduplicated-cond \ + -Wduplicated-branches -Wduplicated-cond -Wflex-array-member-not-at-end \ -Wformat=2 -Wformat-overflow=2 -Wformat-signedness -Wformat-truncation \ -Wimplicit-fallthrough=5 -Winit-self -Wlogical-op \ - -Wmissing-declarations -Wmissing-prototypes -Wnested-externs \ + -Wmissing-declarations -Wmissing-prototypes \ + -Wmissing-variable-declarations -Wnested-externs \ -Wnull-dereference \ -Wold-style-definition -Woverlength-strings -Wpointer-arith \ -Wshadow -Wshift-overflow=2 -Wstrict-overflow \ -- 2.45.1

1 3

[PROPOSED] Sub-second history for Maputo and Zurich
by Paul Eggert May 25, 2024

May 25, 2024

* africa (Africa/Maputo), europe (Europe/Zurich): Add #STDOFF comments for two zones with well-sourced standard time that was not an integral number of seconds away from UT. This does not change the TZif output files. --- africa | 5 +++-- europe | 5 +++-- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/africa b/africa index 695d66ed..4f0d1e7b 100644 --- a/africa +++ b/africa @@ -1101,11 +1101,11 @@ Zone Africa/El_Aaiun -0:52:48 - LMT 1934 Jan # El Aaiún # Zambia # Zimbabwe # -# From Paul Eggert (2024-04-09): +# From Paul Eggert (2024-05-24): # The London Gazette, 1903-04-03, page 2245, says that # as of 1903-03-03 a time ball at the port of Lourenço Marques # (as Maputo was then called) was dropped daily at 13:00:00 LMT, -# corresponding to 22:49:41.7 GMT; round this to UT+2:10:18. +# corresponding to 22:49:41.7 GMT, so local time was +02:10:18.3. # Conversely, the newspaper South Africa, 1909-02-09, page 321, # says the port had just installed an apparatus that communicated # "from the controlling clock in the new Observatory at Reuben Point ... @@ -1116,6 +1116,7 @@ Zone Africa/El_Aaiun -0:52:48 - LMT 1934 Jan # El Aaiún # For lack of better info, list 1909 as the transition date. # # Zone NAME STDOFF RULES FORMAT [UNTIL] + #STDOFF 2:10:18.3 Zone Africa/Maputo 2:10:18 - LMT 1909 2:00 - CAT diff --git a/europe b/europe index 9ea14914..2f180e64 100644 --- a/europe +++ b/europe @@ -3486,8 +3486,8 @@ Zone Atlantic/Canary -1:01:36 - LMT 1922 Mar # Las Palmas de Gran C. # but if no one is present after 11 at night, could be postponed until one # hour before the beginning of service. -# From Paul Eggert (2013-09-11): -# Round BMT to the nearest even second, 0:29:46. +# From Paul Eggert (2024-05-24): +# Express BMT as 0:29:45.500, approximately the same precision 7° 26' 22.50". # # We can find no reliable source for Shanks's assertion that all of Switzerland # except Geneva switched to Bern Mean Time at 00:00 on 1848-09-12. This book: @@ -3526,6 +3526,7 @@ Rule Swiss 1941 1942 - May Mon>=1 1:00 1:00 S Rule Swiss 1941 1942 - Oct Mon>=1 2:00 0 - # Zone NAME STDOFF RULES FORMAT [UNTIL] Zone Europe/Zurich 0:34:08 - LMT 1853 Jul 16 # See above comment. + #STDOFF 0:29:45.500 0:29:46 - BMT 1894 Jun # Bern Mean Time 1:00 Swiss CE%sT 1981 1:00 EU CE%sT -- 2.43.0

2 2

Deprecating POSIX Zones to Links?
by Justin Grant May 23, 2024

May 23, 2024

Hi TZ friends - I'm one of the volunteers working on ECMAScript's time zone strategy. We had a question: of all the legacy Zone names in TZDB, why have a few of them like "WET" and "EST5EDT" been retained as Zones, while the rest of the legacy names like "GB-Eire" and "Jamaica" have all been turned into Links pointing to some other Zone? What was special about the Zones below that caused them to stay as Zones? EST MST HST EST5EDT CST6CDT MST7MDT PST8PDT WET CET MET EET Regardless of the history behind these 11 Zone names, would there be interest in accepting a PR that turns these Zones into Links? I'm asking because ECMAScript's time zone enumeration API is specified to only return Zone names, but ECMAScript implementations in Safari and Chrome have long omitted the Zones above from their enumeration API because they create redundant and confusing results for end users. We'd like to align the specification to web reality, and ideally make these changes upstream in TZDB (if that would be welcome). Here's the mappings that we're currently considering in ECMAScript. We used the TZ approach of preferring the largest city for each of the DST-using legacy Zones. Although any other mappings would be OK with us, so let me know if you think there are more appropriate mappings. EST => Etc/GMT+5 MST => Etc/GMT+7 HST => Etc/GMT+10 EST5EDT => America/New_York CST6CDT => America/Chicago MST7MDT => America/Denver PST8PDT => America/Los_Angeles WET => Europe/Lisbon CET => Europe/Berlin MET => Europe/Berlin EET => Europe/Kyiv Thanks, Justin Grant

3 7

[PROPOSED 1/2] Don’t be so sure about leap seconds going away
by Paul Eggert May 14, 2024

May 14, 2024

* NEWS, theory.html (Leap seconds): * tz-link.html (Precision timekeeping): Use less-sure wording about leap seconds discontinuance, since the situation is still murky. --- NEWS | 2 +- theory.html | 10 +++++----- tz-link.html | 1 + 3 files changed, 7 insertions(+), 6 deletions(-) diff --git a/NEWS b/NEWS index 5c2cd1e5..e5db26b4 100644 --- a/NEWS +++ b/NEWS @@ -322,7 +322,7 @@ 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 diff --git a/theory.html b/theory.html index 50e9ee4d..4cb293da 100644 --- a/theory.html +++ b/theory.html @@ -1278,11 +1278,11 @@ between now and the future time. <p> Leap seconds were introduced in 1972 to accommodate the difference between atomic time and the less regular rotation of the earth. -Unfortunately they caused so many problems with civil -timekeeping that they -are <a href="https://www.bipm.org/en/cgpm-2022/resolution-4">planned -to be discontinued by 2035</a>. -Despite their impending obsolescence, a record of leap seconds is still +Unfortunately they have caused so many problems with civil +timekeeping that there are +<a href="https://www.bipm.org/en/cgpm-2022/resolution-4">plans +to discontinue them by 2035</a>. +Even if these plans come to fruition, a record of leap seconds will still be needed to resolve timestamps from 1972 through 2035. </p> diff --git a/tz-link.html b/tz-link.html index c6d96101..aaab7555 100644 --- a/tz-link.html +++ b/tz-link.html @@ -1129,6 +1129,7 @@ discontinuous adjustments be made to UTC for at least a century. The World Radiocommunication Conference <a href="https://www.itu.int/dms_pub/itu-r/opb/act/R-ACT-WRC.15-2023-PDF-E.pdf">resolved in 2023</a> to cooperate with this process. +However, there is still no consensus on how exactly to get rid of them. </li> </ul> </section> -- 2.40.1

1 1

manual pages in tzdb
by Alejandro Colomar May 12, 2024

May 12, 2024

Hi Paul, I had in mind something: I would like to cherry-pick all tzdb's commits that affect manual pages into the Linux man-pages git repository, instead of just pasting here snapshots of your manual pages. For that to work, we'd need to agree on a path inside the repository (or I could manually --or with a script-- edit each commit, which would be combersome, and I'd rather avoid). What do you think of moving the pages in the tzdb repository into man/man*/ directories? I see your repository is perfectly flat, so I don't know if there are strong reasons for that, or if it's just innertia. To be explicit, this is what I'd do in tzdb.git: diff --git a/date.1 b/man/man1/date.1 similarity index 100% rename from date.1 rename to man/man1/date.1 diff --git a/newctime.3 b/man/man3/newctime.3 similarity index 100% rename from newctime.3 rename to man/man3/newctime.3 diff --git a/newstrftime.3 b/man/man3/newstrftime.3 similarity index 100% rename from newstrftime.3 rename to man/man3/newstrftime.3 diff --git a/newtzset.3 b/man/man3/newtzset.3 similarity index 100% rename from newtzset.3 rename to man/man3/newtzset.3 diff --git a/time2posix.3 b/man/man3/time2posix.3 similarity index 100% rename from time2posix.3 rename to man/man3/time2posix.3 diff --git a/tzfile.5 b/man/man5/tzfile.5 similarity index 100% rename from tzfile.5 rename to man/man5/tzfile.5 diff --git a/tzselect.8 b/man/man8/tzselect.8 similarity index 100% rename from tzselect.8 rename to man/man8/tzselect.8 diff --git a/zdump.8 b/man/man8/zdump.8 similarity index 100% rename from zdump.8 rename to man/man8/zdump.8 diff --git a/zic.8 b/man/man8/zic.8 similarity index 100% rename from zic.8 rename to man/man8/zic.8 If we do that, then my idea would be to do $ git remote add tzdb git@github.com:eggert/tz.git in my Linux man-pages local repo, and cherry-pick commits '-- man/' from time to time. Does that sound good to you? Have a lovely day! Alex -- <https://www.alejandro-colomar.es/> A client is hiring kernel driver, mm, and/or crypto developers; contact me if interested.

9 20