April 2021 - tz - lists.iana.org

Re: [tz] Morocco : Ramdan Time Change 2021
by Paul Eggert March 15, 2023

March 15, 2023

On 3/19/21 3:15 AM, Semlali Naoufal wrote: > At the moment, we have no official government announcement to this effect. But, logically, the change to the GMT schedule should be made on the night of April 10-11, 2021 (last weekend before Ramadan). Yes, that's been the tzdb prediction too, ever since tzdb version 2018h (2018-12-23). For the record, here are tzdb's current predictions Morocco transitions during the next five years. Sun Apr 11 01:59:59 2021 UT = Sun Apr 11 02:59:59 2021 +01 Sun Apr 11 02:00:00 2021 UT = Sun Apr 11 02:00:00 2021 +00 Sun May 16 01:59:59 2021 UT = Sun May 16 01:59:59 2021 +00 Sun May 16 02:00:00 2021 UT = Sun May 16 03:00:00 2021 +01 Sun Mar 27 01:59:59 2022 UT = Sun Mar 27 02:59:59 2022 +01 Sun Mar 27 02:00:00 2022 UT = Sun Mar 27 02:00:00 2022 +00 Sun May 8 01:59:59 2022 UT = Sun May 8 01:59:59 2022 +00 Sun May 8 02:00:00 2022 UT = Sun May 8 03:00:00 2022 +01 Sun Mar 19 01:59:59 2023 UT = Sun Mar 19 02:59:59 2023 +01 Sun Mar 19 02:00:00 2023 UT = Sun Mar 19 02:00:00 2023 +00 Sun Apr 30 01:59:59 2023 UT = Sun Apr 30 01:59:59 2023 +00 Sun Apr 30 02:00:00 2023 UT = Sun Apr 30 03:00:00 2023 +01 Sun Mar 10 01:59:59 2024 UT = Sun Mar 10 02:59:59 2024 +01 Sun Mar 10 02:00:00 2024 UT = Sun Mar 10 02:00:00 2024 +00 Sun Apr 14 01:59:59 2024 UT = Sun Apr 14 01:59:59 2024 +00 Sun Apr 14 02:00:00 2024 UT = Sun Apr 14 03:00:00 2024 +01 Sun Feb 23 01:59:59 2025 UT = Sun Feb 23 02:59:59 2025 +01 Sun Feb 23 02:00:00 2025 UT = Sun Feb 23 02:00:00 2025 +00 Sun Apr 6 01:59:59 2025 UT = Sun Apr 6 01:59:59 2025 +00 Sun Apr 6 02:00:00 2025 UT = Sun Apr 6 03:00:00 2025 +01 Sun Feb 15 01:59:59 2026 UT = Sun Feb 15 02:59:59 2026 +01 Sun Feb 15 02:00:00 2026 UT = Sun Feb 15 02:00:00 2026 +00 Sun Mar 22 01:59:59 2026 UT = Sun Mar 22 01:59:59 2026 +00 Sun Mar 22 02:00:00 2026 UT = Sun Mar 22 03:00:00 2026 +01 Sun Feb 7 01:59:59 2027 UT = Sun Feb 7 02:59:59 2027 +01 Sun Feb 7 02:00:00 2027 UT = Sun Feb 7 02:00:00 2027 +00 Sun Mar 14 01:59:59 2027 UT = Sun Mar 14 01:59:59 2027 +00 Sun Mar 14 02:00:00 2027 UT = Sun Mar 14 03:00:00 2027 +01 Sun Jan 23 01:59:59 2028 UT = Sun Jan 23 02:59:59 2028 +01 Sun Jan 23 02:00:00 2028 UT = Sun Jan 23 02:00:00 2028 +00 Sun Mar 5 01:59:59 2028 UT = Sun Mar 5 01:59:59 2028 +00 Sun Mar 5 02:00:00 2028 UT = Sun Mar 5 03:00:00 2028 +01 Sun Jan 14 01:59:59 2029 UT = Sun Jan 14 02:59:59 2029 +01 Sun Jan 14 02:00:00 2029 UT = Sun Jan 14 02:00:00 2029 +00 Sun Feb 18 01:59:59 2029 UT = Sun Feb 18 01:59:59 2029 +00 Sun Feb 18 02:00:00 2029 UT = Sun Feb 18 03:00:00 2029 +01 Sun Dec 30 01:59:59 2029 UT = Sun Dec 30 02:59:59 2029 +01 Sun Dec 30 02:00:00 2029 UT = Sun Dec 30 02:00:00 2029 +00 Sun Feb 10 01:59:59 2030 UT = Sun Feb 10 01:59:59 2030 +00 Sun Feb 10 02:00:00 2030 UT = Sun Feb 10 03:00:00 2030 +01 Sun Dec 22 01:59:59 2030 UT = Sun Dec 22 02:59:59 2030 +01 Sun Dec 22 02:00:00 2030 UT = Sun Dec 22 02:00:00 2030 +00

3 9

United States Senate reintroduced Sunshine Protection Act, enabling Permanent DST
by Phake Nick Nov. 14, 2022

Nov. 14, 2022

I don't quite understand the legal text of the bill itself [2], but according to my reading, it seems like the bill will end DST across the entire US by shifting the standard time forward an hour, except in states/territories/area that currently doesn't enact DST, which they can choose to follow the new standard time or old standard time? 1: https://www.rubio.senate.gov/public/index.cfm/2021/3/rubio-colleagues-reint… 2: https://www.rubio.senate.gov/public/_cache/files/d34c77c0-acea-4074-bc57-14…

18 26

Re: [tz] iana build failures on Windows
by Paul Eggert Nov. 2, 2022

Nov. 2, 2022

On 4/19/21 7:09 AM, Manuela Friedrich wrote: > I had to include signal.h in zic.c to prevent the following error: > > zic.c(610): error C2061: syntax error: identifier 'got_signal' This is a portability bug recently introduced to zic.c. I installed the first attached patch to fix it. > The I needed to resolved error > > zic.obj : error LNK2019: unresolved external symbol tz_time referenced in function random_dirent This appears to be another recent portability bug. It's related to a portability problem you reported on MS-Windows in response to which in 2018d I committed a patch that introduced RESERVE_STD_EXT_IDS: https://github.com/eggert/tz/commit/24b45243c5210b4196987fdd06e6c288c358a268 When I recently added the randomish filename code to the development version, I neglected to deal with RESERVE_STD_EXT_IDS. The second attached patch should fix this issue. Please give the two patches a try, as I don't use MS-Windows and can't easily test these patches on that platform. > a test run of zdump -v produced way more output than in the last release, the Linux output seems to have become longer too, but maybe this is still under development. That change is intentional, and was caused by this: https://github.com/eggert/tz/commit/ac07b446a3afaa4cb1ae11a91785a201c91f6351 along with some neighboring commits. Thanks for reporting the problems, and I hope the current development version of tzdb addresses the issues you mentioned.

5 23

Re: [tz] Change Request: Europe/Kiev to Europe/Kyiv
by John Hawkinson March 18, 2022

March 18, 2022

I do not think we have handled this well; we have not given Victor Perov a good answer. Indeed, to some extent we've made it a "runaround." We can do better. We should take the time to write up a good lengthy explanation of the issues ("boilerplate"), because this a really important issue of concern to many people in the world and the project has indeed thought about it pretty carefully. Dismissing the inquiries because they are repetitive makes it seem like we haven't, and that unnecessarily upsets peopl. Victor Perev: I don't have time for a full write-up right now, but please consult the archives of the tz list (http://mm.icann.org/pipermail/tz/ or perhaps https://www.google.com/search?q=site%3Amm.icann.org%2Fpipermail%2Ftz%2F+kyiv which returns 203 results). The tz project is very conservative in its judgment for when the predominant English spelling of a city has changed, and so far the project has judged that Kiev is still preferred. We discussed it when major English newspapers and style guides changed from Kiev to Kyiv last year (prompted by the US presidential impeachment, which lead to a lot of discussion about Kyiv in America), and we will probably continue to discuss it as time goes on. But we've thought about it and discussed it a lot. The answers you got don't explain that, and that means we have not done a good a job as we should have. Sorry about that. In particular, I think Brian Inglis's answer was actually incorrect in a way that really matters ("Kiev is the correct English spelling"). There are multiple correct English spellings. It used to be that Kiev was the only one, but Kyiv is gaining popularity more and more. Paul Eggert <eggert(a)cs.ucla.edu> wrote on Sat, 15 Aug 2020 at 18:19:08 EDT in <cefc7f01-a3e9-f2a4-9ab9-5288147f994a(a)cs.ucla.edu>: > Thanks for bringing that to the mailing list (if I could shut off GitHub > pull requests I would). Although you cannot do so, we can handle them a little bit better. Please see https://docs.github.com/en/github/building-a-strong-community/creating-a-pu… You can create a template that explains to a would-be pull request submitter than pull requests will be closed and the project uses the mailing list for development discussions. ("I understand that the tz project does not use pull requests on github, and that if I enter a pull request here, it will be closed and I will be directed to send email to tz(a)iana.org.") For the particular case of regular, recurring issues, it may be worth while to keep one of #15, #26, and #27 open and mark the others as a duplicate of it, so that it is easier for newcomers to understand that this issue has been carefully considered and is not a simple oversight. https://github.com/eggert/tz/pulls?q=kiev Also, not to pick on Brian (again), but if the project policy is not to use github pull requests, it's not great to respond to pull requests on their substance, because it bifurcates the discussion and makes it seem like we actually do use pull requests ("except when we don't"). So what seems like a helpful thing may not be. -- jhawk(a)alum.mit.edu John Hawkinson

10 13

Italy April 1944 discrepancy between comment and data
by Alois Treindl Oct. 5, 2021

Oct. 5, 2021

For Italy in 1944 zone Europe/Rome there is a discrepancy between the comment and the data. comment: # From Paul Eggert (2016-10-27): # Go with INRiM for DST rules, except as corrected by Inglis for 1944 # for the Kingdom of Italy. This is consistent with Renzo Baldini. # Model Rome's occupation by using C-Eur rules from 1943-09-10 # to 1944-06-04; although Rome was an open city during this period, it # was effectively controlled by Germany. Data for Italy is Rule Italy 1944 only - Apr 2 2:00s 1:00 S Data for C-Eur is: Rule C-Eur 1944 1945 - Apr Mon>=1 2:00s 1:00 S where Mon>=1 in 1944 is April 3. So Rome is NOT following C-Eur. I think the rule for Itay is right, only the comment is misleading.

4 9

Historical fix for Tonga
by Tim Parenti Sept. 14, 2021

Sept. 14, 2021

First, a quick clerical patch: 0001, attached, fixes the placement of a comment which got shuffled around in the lead-up to publishing the changes for South Sudan in 2021a. Patch 0003 relates to Tonga, and comes from some of the links P Chan shared to 1957–1963 editions of The Air Almanac: https://mm.icann.org/pipermail/tz/2021-February/029866.html On Thu, 25 Feb 2021 at 03:43, P Chan <legco(a)outlook.com> wrote: > 1960 Nov (1962.1-4) > https://books.google.com/books?id=bVgtWM6kPZUC&pg=SL1-PA20 > 1961 Mar (1962.5-8) > https://books.google.com/books?id=W2nItAul4g0C&pg=SL1-PA20 When looking around at how this data was presented for other regions, I noticed on the preceding pages (listing "Places Fast on GMT", i.e., east of Greenwich) in some of the earlier editions provided that Tonga was listed at GMT+12:20. The peculiar offset stuck out, and I quickly noticed that some of the later editions of the same tables had it at GMT+13. A quick bisection puts the changeover, as far as The Air Almanac contemporaneously reckoned it, between November 1960 and March 1961. Previously, our data had Tonga transitioning to UT+13 in 1941 based on a quotation from a 1997 news article. Although this differs from what the Almanac suggests by some 20 years, the article does mention a change coincident with the New Year, and that Tāufaʻāhau Tupou IV was Crown Prince at the time. As his predecessor and mother, Queen Sālote Tupou III, reigned from 1918-04-05 to 1965-12-16, a possible transition of 1961-01-01 still jives with the gist of the article, even if the specific year was perhaps wrong or just misprinted. For what it's worth, our commentary already noted that Shanks & Pottenger had put the transition even later, at 1968-10-01. Although of course we don't know how they arrived at that date, given that they did, 1961 seems rather less out-of-place than it otherwise might. The attached patch 0003 makes this adjustment, while more fully documenting and comparing the conflicting sources. Thanks again to P Chan for pointing us to these resources. I wasn't expecting to get a "bonus" correction out of it, but one never knows quite what will catch the eye… -- Tim Parenti

3 3

[PATCH 1/8] * tzfile.5: Fix prefix/suffix typo (thanks to Ian Abbott).
by Paul Eggert Sept. 14, 2021

Sept. 14, 2021

--- tzfile.5 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tzfile.5 b/tzfile.5 index b4952d5..ec78689 100644 --- a/tzfile.5 +++ b/tzfile.5 @@ -134,7 +134,7 @@ bytes that represent time zone designations, which are null-terminated byte strings, each indexed by the .B tt_desigidx values mentioned above. -The byte strings can overlap if one is a prefix of the other. +The byte strings can overlap if one is a suffix of the other. The encoding of these strings is not specified. .IP * .B tzh_leapcnt -- 2.27.0

2 8

JavaScript IANA date/time library, now with support for leap seconds, TAI, TDT
by Kerry Shetline April 29, 2021

April 29, 2021

About two months ago I released the first major version of @tubular/time, a JavaScript/TypeScript npm package for date/time handling, with solid support for IANA timezones, including dealing with weird edge cases like 47-hour days and negative DST and such. I’ve just finished up adding a feature I’ve always wanted to have in a date/time package, and that’s the ability to properly handle and represent leap seconds. Along with that comes conversion to and from TAI (International Atomic Time) and astronomical time systems. https://www.npmjs.com/package/@tubular/time One interesting issue was how to handle a broad range of years (thousands of years forward and backward in time) in a way that was nicely integrated with Universal Coordinated Time. The idea for UTC got something of a wobbly start around 1960, and wasn’t implemented in its current form until 1972. Going forward in time, UTC is only strictly defined for up to six months beyond the next announced leap second, or next announced lack of any leap second on the way. I settled on the following scheme for resolving these issues, and I’m curious what others might think about it: * For all dates prior to 1957, estimated UT1 is in effect. This is most accurate back to 1600, for which there is sufficient astronomical data for reasonable approximate conversions from UT1 to TAI and dynamical time. Further back in time less accurate approximations are in effect. * From 1957-1958, using a sliding weighted average, UT1 transitions to proleptic UTC. * From 1958-1972 proleptic UTC, as proposed by Tony Finch (https://fanf.livejournal.com/69586.html) is used, with the first non-official leap second occurring at 1959-06-30 23:59:60. * From 1972 up until the latest updates provided by the International Bureau of Weights and Measures, well-defined UTC prevails, with the first official leap second occurring at 1972-06-30 23:59:60. * For a year to 18 months after the current time, or after the last defined leap second (whichever is later), a presumed leap-second-free span of UTC is projected to occur. * A sliding weighted average transition from UTC to estimated UT1 follows for the next 365 days. * Formulaic predicted UT1 is used for all later dates and times thereafter. Another project I’ve been working on (which isn’t quite ready for prime time because it’s utterly without documentation) is a new JavaScript timezone compiler. This has replaced an old Java project I used for generating the timezone data used by @tubular/time: https://github.com/kshetline/tubular_time_tzdb

7 16

Re: [tz] JavaScript IANA date/time library, now with support for leap seconds, TAI, TDT
by Kerry Shetline April 27, 2021

April 27, 2021

On Mon, 26 Apr 2021 16:03:59 -0400, John_Sauter via tz wrote: > Based on the way the Earth has been rotating recently, the next leap > second will be around the end of this decade, and it will be a negative > leap second. What kind of hopeless nerd does it make me that I find this an exciting prospect? I’ve taken negative leap seconds to be a nearly completely hypothetical idea, even though I have nevertheless coded diligently to account for the possibility.

2 1

Re: [tz] JavaScript IANA date/time library, now with support for leap seconds, TAI, TDT
by Kerry Shetline April 27, 2021

April 27, 2021

On Mon, 26 Apr 2021 15:06:12 -0600, Paul Gilmartin <PaulGBoulder(a)aim.com> wrote: >> POSIX time is really just UTC without the leap seconds, isn?t it? >> > More precisely, POSIX time counts non-leap seconds since 1972-01-01t00:00:00 UTC. That would be 1970-01-01T00:00:00 UTC. 1972 is, however, the year that the first official leap second (for POSIX not to count) occurred.

1 1

Re: [tz] JavaScript IANA date/time library, now with support for leap seconds, TAI, TDT
by Steve Allen April 26, 2021

April 26, 2021

On Mon 2021-04-26T17:17:13+0100 Tony Finch via tz hath writ: > My aim back then was to sketch what might be a reasonable way to bridge > between pre-atomic time and UTC, for code that can only support an integer > offset between UTC and TAI. If your code supports rubber seconds then it > should probably use the USNO table that records the rate and phase offsets > between 1962 and 1972. (I don't know another source of that table, nor > where you can get a copy while maia.usno.navy.mil is down.) Keep in mind that the USNO numbers only apply to time signals broadcast in the US, and before 1968 they ignore the many microseconds of offset between NBS and USNO. Germany did not start to broadcast the old UTC until the late 1960s, until 1974-01-01 broadcast both old UTC and SAT, and stopped providing old UTC as of 1970-04-01 because it had been deemed illegal. Soviet and Chinese time signals never used the old UTC. Sussing out the particulars for individual cases of national time signals needs finding remnants of the high-acid paper that each national time service used for bulletins issued to its users, and/or diving through the BIH Bulletin Horaire and Circular D to pull out the received timing of each official broadcast. It is much simpler to ignore the 50 to 200 ms jumps that were put into old UTC and say that before 1972 all available sources of civil time provided UT (nevermind the particular flavor, nobody set their clock that accurately) and after 1972 UTC with leap seconds. For civil time I do not see any advantage in a model with greater complexity than just plain UT as the basis time scale before 1972-01-01. This is adequate for any IANA tz library. For precise time no general model applies. Each precise timestamp must be meticulously referenced to the particulars of the clocks that were used to obtain it. No available clocks were using TAI before 1972-01-01, and this does not belong in any IANA tz library. Constructing a model that supposes it is possible to do better is akin to writing The Silmarillion. Look at the BIH plots of the accuracy of clocks https://www.ucolick.org/~sla/leapsecs/BHsHn05p142.html millisecond agreement between different national authorities was not achieved until 1960 during the UK/US experiment that became old UTC. > * TAI is a retrospective timescale; it isn't defined in the future. TAI also cannot be defined prior to mid 1955, and it was not generally availble for use by any system until 1972-01-01 when broadcast time signals began to be based on TAI. The BIPM will never tolerate TAI becoming part of an international agreement. The best that can be hoped for in a new international agreement on time is one (or more) new TAI-like uniform scale which will be offset by some integer number of seconds from TAI. The reason we use UTC is because it is what is in the current international agreement. Everybody involved in the technical aspects eschewed the use of UTC for their systems from before 1972-01-01. Look at the ATSC agreement for a technically-competent time scale. They chose GPS time because it is practically available. ATSC was not bound by international bureaucratic requirements, so they could make that choice. Because it is ultimately controlled by USNO GPS system time will never become part of an international agreement. On Mon 2021-04-26T12:42:19-0400 John Sauter via tz hath writ: > In looking at historical estimates of the rotation of the Earth based > on astronomical observations of occulations and eclipses, I found that > the values of UT1 are reliabe only since 1825. (Nevertheless, my table > of proleptic leap seconds goes back to the year -2000.) Morrison, L. V.; Stephenson, F. R.; Hohenkerk, C. Y.; Zawilski, M. DOI: 10.1098/rspa.2020.0776 Bibliographic Code: 2021RSPSA.47700776M Proceedings of the Royal Society A, Volume 477, Issue 2246, id.20200776 all tabulated at http://astro.ukho.gov.uk/nao/lvm/ That is the place to look, and it will continue to be so for the lifetime of the authors. But what is it mean to ask reliable? That is very much the question given that prior to "reliable" everybody's clock was set to local apparent time. What exactly is the question that is trying to be answered by an algorithm like this? Ultimately it is necessary to model two kinds of time: 1) earth rotation time (which before the 20th century differed by a second or more depending on who was setting the clock) because that is a subdivision of internationally agreed calendar days 2) uniform time (which becomes possible to interpret as atomic time beginning in 1955). -- Steve Allen <sla(a)ucolick.org> WGS-84 (GPS) UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m

3 3

[PROPOSED] Do not assume bytes have 8 bits
by Paul Eggert April 26, 2021

April 26, 2021

* zic.c (convert, convert64): Mask bytes with 0xff before storing them, for portability to machines where bytes have more than 8 bits. Although this is surely only of theoretical interest, we might as well be portable. --- zic.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/zic.c b/zic.c index 88b1531..77a5698 100644 --- a/zic.c +++ b/zic.c @@ -1927,7 +1927,7 @@ convert(uint_fast32_t val, char *buf) unsigned char *const b = (unsigned char *) buf; for (i = 0, shift = 24; i < 4; ++i, shift -= 8) - b[i] = val >> shift; + b[i] = (val >> shift) & 0xff; } static void @@ -1938,7 +1938,7 @@ convert64(uint_fast64_t val, char *buf) unsigned char *const b = (unsigned char *) buf; for (i = 0, shift = 56; i < 8; ++i, shift -= 8) - b[i] = val >> shift; + b[i] = (val >> shift) & 0xff; } static void -- 2.27.0

4 5

[PATCH] Fix potential integer overflow in differ_by_repeat
by Paul Eggert April 26, 2021

April 26, 2021

* localtime.c (differ_by_repeat): Remove, since the subtraction t1 - t0 could in theory overflow in 64-bit TZif data. (tzloadbody): Redo to avoid integer overflow. * private.h (SECSPERREPEAT_BITS): Remove; no longer used. --- localtime.c | 30 ++++++++++++++---------------- private.h | 3 +-- 2 files changed, 15 insertions(+), 18 deletions(-) diff --git a/localtime.c b/localtime.c index 9dd496d..9840b89 100644 --- a/localtime.c +++ b/localtime.c @@ -334,14 +334,6 @@ scrub_abbrs(struct state *sp) } } -static bool -differ_by_repeat(const time_t t1, const time_t t0) -{ - if (TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS) - return 0; - return t1 - t0 == SECSPERREPEAT; -} - /* Input buffer for data read from a compiled tz file. */ union input_buffer { /* The first part of the buffer, interpreted as a header. */ @@ -660,20 +652,26 @@ tzloadbody(char const *name, struct state *sp, bool doextend, if (sp->typecnt == 0) return EINVAL; if (sp->timecnt > 1) { + if (sp->ats[0] <= TIME_T_MAX - SECSPERREPEAT) { + time_t repeatat = sp->ats[0] + SECSPERREPEAT; + int repeattype = sp->types[0]; for (i = 1; i < sp->timecnt; ++i) - if (typesequiv(sp, sp->types[i], sp->types[0]) && - differ_by_repeat(sp->ats[i], sp->ats[0])) { + if (sp->ats[i] == repeatat + && typesequiv(sp, sp->types[i], repeattype)) { sp->goback = true; break; - } + } + } + if (TIME_T_MIN + SECSPERREPEAT <= sp->ats[sp->timecnt - 1]) { + time_t repeatat = sp->ats[sp->timecnt - 1] - SECSPERREPEAT; + int repeattype = sp->types[sp->timecnt - 1]; for (i = sp->timecnt - 2; i >= 0; --i) - if (typesequiv(sp, sp->types[sp->timecnt - 1], - sp->types[i]) && - differ_by_repeat(sp->ats[sp->timecnt - 1], - sp->ats[i])) { + if (sp->ats[i] == repeatat + && typesequiv(sp, sp->types[i], repeattype)) { sp->goahead = true; break; - } + } + } } /* Infer sp->defaulttype from the data. Although this default diff --git a/private.h b/private.h index cee3b11..340a354 100644 --- a/private.h +++ b/private.h @@ -642,7 +642,7 @@ time_t time2posix_z(timezone_t, time_t) ATTRIBUTE_PURE; #define TIME_T_MAX_NO_PADDING MAXVAL(time_t, TYPE_BIT(time_t)) /* The extreme time values. These are macros, not constants, so that - any portability problem occur only when compiling .c files that use + any portability problems occur only when compiling .c files that use the macros, which is safer for applications that need only zdump and zic. This implementation assumes no padding if time_t is signed and either the compiler lacks support for _Generic or time_t is not one @@ -727,7 +727,6 @@ char *ctime_r(time_t const *, char *); #define YEARSPERREPEAT 400 /* years before a Gregorian repeat */ #define DAYSPERREPEAT ((int_fast32_t) 400 * 365 + 100 - 4 + 1) #define SECSPERREPEAT ((int_fast64_t) DAYSPERREPEAT * SECSPERDAY) -#define SECSPERREPEAT_BITS 34 /* ceil(log2(SECSPERREPEAT)) */ #define AVGSECSPERYEAR (SECSPERREPEAT / YEARSPERREPEAT) #define TM_SUNDAY 0 -- 2.27.0

1 0

[PROPOSED 1/2] Do not assume unsigned->signed conversion style
by Paul Eggert April 23, 2021

April 23, 2021

* localtime.c (detzcode64): Use int_fast64_t, not uint_fast64_t, for local variable, to avoid an implementation-defined conversion when the variable’s value is returned. --- localtime.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/localtime.c b/localtime.c index 6c88b6e..9dd496d 100644 --- a/localtime.c +++ b/localtime.c @@ -237,7 +237,7 @@ detzcode(const char *const codep) static int_fast64_t detzcode64(const char *const codep) { - register uint_fast64_t result; + register int_fast64_t result; register int i; int_fast64_t one = 1; int_fast64_t halfmaxval = one << (64 - 2); -- 2.27.0

1 1

[PROPOSED 1/2] * SECURITY: New file.
by Paul Eggert April 20, 2021

April 20, 2021

--- SECURITY | 15 +++++++++++++++ 1 file changed, 15 insertions(+) create mode 100644 SECURITY diff --git a/SECURITY b/SECURITY new file mode 100644 index 0000000..40128bc --- /dev/null +++ b/SECURITY @@ -0,0 +1,15 @@ +Please report any sensitive security-related bugs via email to the +tzdb designated coordinators, currently Paul Eggert +<eggert(a)cs.ucla.edu> and Tim Parenti <tim(a)timtimeonline.com>. +Put "tzdb security" at the start of your email's subject line. +We prefer communications to be in English. + +You should receive a response within a week. If not, please follow up +via email to make sure we received your original message. + +If we confirm the bug, we plan to notify affected third-party services +or software that we know about, prepare an advisory, commit fixes to +the main development branch as quickly as is practical, and finally +publish the advisory on tz(a)iana.org. As with all tzdb contributions, +we give credit to security contributors unless they wish to remain +anonymous. -- 2.27.0

1 1

Wisconsin daylight savings 1957
by TJ April 17, 2021

April 17, 2021

Hey everyone, I was doing some digging and found the following referendum in 1957 for Wisconsin. - https://ballotpedia.org/Wisconsin_Daylight_Saving_Time,_Question_1_(April_1… The text of the measure that passed was: "Shall section 175.095 (2) of the statutes, which proposes a statewide daylight saving time of one hour per day from the last Sunday in April to the last Sunday in September in each year be law beginning with the last Sunday in April 1957?" However, the 1947 ballot to use daylight savings was defeated: https://ballotpedia.org/Wisconsin_Daylight_Saving_Time_Referendum,_Question… In the tz db for North America, it looks like Wisconsin is using America/Chicago which has a few rules for the time period in question: Rule Chicago 1922 1954 - Sep lastSun 2:00 0 S Rule Chicago 1955 1966 - Oct lastSun 2:00 0 S It appears to me that Wisconsin might need some modification? Is this the correct mailing list for this discussion? Thanks, TJ

3 3

Ref: What time is it: managing time in the internet
by Brian Inglis April 17, 2021

April 17, 2021

"What time is it: managing time in the internet", p37–44, July 2019, "Proceedings of the Applied Networking Research Workshop" https://dl.acm.org/doi/10.1145/3340301.3341125 "investigation of how current local time is reported accurately by devices connected to the internet", analysis of tzdb and updates, "proposals for enhancing TZDB management and reducing vulnerabilities in the system." -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised. [Data in binary units and prefixes, physical quantities in SI.]

2 2

Terminology: “Central European Summer Time” vs “Europe/Berlin”
by Michael[tm] Smith April 15, 2021

April 15, 2021

In the time zone taxonomy, if the term for “Europe/Berlin” is clearly “time zone”, and “GMT+2” is precisely a “timezone offset”, is there a term (other than “time zone”) for what “Central European Summer Time” is — either an authoritative/ normative term, or else at least a best-practice term that’s commonly used? The context is, I’m updating some of the MDN documentation related to JavaScript methods and properties for dealing with dates, including these articles: * https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/… * https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/… And in particular, I’m working on trying to describe the timeZoneName property, in the context of the following behavior: Consider the following code: TZ=Europe/Berlin node -e "console.log(new Intl.DateTimeFormat('en-us', \ { timeZoneName: 'short' }).formatToParts())" When you run that, what you get back is this: [ { type: 'month', value: '4' }, { type: 'literal', value: '/' }, { type: 'day', value: '13' }, { type: 'literal', value: '/' }, { type: 'year', value: '2021' }, { type: 'literal', value: ', ' }, { type: 'timeZoneName', value: 'GMT+2' } ] So part of what I want to explain in the MDN articles is: When you specify “timeZoneName: 'short'”, what you get back as the value for the 'timeZoneName' field in the output is actually a time zone *offset* — not a time zone. But along with that, I need to deal with describing this case: TZ=Europe/Berlin node -e "console.log(new Intl.DateTimeFormat('en-us', { timeZoneName: 'long' }).formatToParts())" When you run that, what you get back is this: [ { type: 'month', value: '4' }, { type: 'literal', value: '/' }, { type: 'day', value: '13' }, { type: 'literal', value: '/' }, { type: 'year', value: '2021' }, { type: 'literal', value: ', ' }, { type: 'timeZoneName', value: 'Central European Summer Time' } ] That’s the particular thing I’m struggling with — that is, when you specify “timeZoneName: 'long'”, what do I call the 'Central European Summer Time' that you get back in the output? Something like “a localized long name for the associated time zone offset” is the best I’ve been able to come up with. But I’ve been hoping there might be some authoritative term for it that I’ve not managed to find yet. And I realize there’s no “Central European Summer Time” in the zoneinfo data itself — and so implementations get that by doing some kind of lookup against (I guess) CLDR. So I guess it’s expected that the documentation for the IANA timezone database itself doesn’t have a term for it. And I guess it’s also unsurprising that CLDR seems to just use the term “time zone” to refer to it — since CLDR doesn’t need to bee more precise and since because CLDR doesn’t need to do anything with the actual canonical time zone names such as Europe/Berlin, it doesn’t have the problem of distinguishing between what a time zone is and what time zone offset is. But from what I’ve seen in issues and questions reported by developers at MDN and Stack Overflow, probably the single biggest source of chronic frustration that developers have when dealing with date-related methods and properties in programming languages comes down to a fundamental misunderstanding of what a time zone is, and how it differs from time zone offset. So I’ve admired what Matt Johnson-Pint has done at Stack Overflow in answering many questions — and in putting the https://stackoverflow.com/tags/timezone/info and https://stackoverflow.com/tags/timezone-offset/info pages together — to provide developers with the kind of clarity they need to solve their problems. And so what I’m hoping to do with my MDN changes is to bring similar clarity to developers through MDN. And so also that’s why it seems important to get the terminology right at MDN when explaining to developers exactly what “Central European Summer Time” is. –Mike -- Michael[tm] Smith https://people.w3.org/mike

6 10

FW: [Ext] The TZ Coordination
by Naela Sarras April 2, 2021

April 2, 2021

Dear Paul, Please see the note below from our colleagues in Morocco regarding the upcoming timezone change for Morocco. Best regards, Naela Naela Sarras Director, IANA Operations ICANN From: EL MAAYATI Afaf <afaf(a)anrt.ma> Date: Wednesday, May 27, 2020 at 12:01 PM To: Naela Sarras <naela.sarras(a)iana.org> Cc: BENLEMLIH Hamida <benlemlih(a)anrt.ma> Subject: [Ext] The TZ Coordination Dear Naela, I hope this email finds you well, safe and healthy. Actually, I have a request concerning the configuration of the Time-Zone for Morocco. In the Database file: ftp://ftp.iana.org/tz/tzdb-2020a/africa, it’s mentionned that a program will be running to implement the transition dates: [cid:image001.jpg@01D6342E.01C70B10] Currently we are implementing GMT and we will move to GMT+1 next Sunday, May 31. So, if possible, would you please help to get in touch with Mr. Paul Eggert, in order to have the procedure to notify IANA officially, from a governmental source, with the changes of TZ in Morocco. Thank you in advance for your feedback and for your habitual support. Best Regards, Afaf ________________________________ Ce message, son contenu et toutes les pièces jointes sont adressés à l'attention exclusive de leur (s) destinataire (s) et sont strictement confidentiels : ils relèvent de la correspondance privée. Toute publication, utilisation ou diffusion, même partielle, par des personnes autres que les destinataires est interdite et doit être autorisée par l'Agence Nationale de Règlementation des Télécommunications (ANRT, Royaume du Maroc). Si vous recevez ce message par erreur, nous vous prions de le détruire après en avoir informé son expéditeur sans délai. L’ANRT décline toute responsabilité pour toute altération, déformation ou falsification subi par le message et ses pièces jointes au cours de leur transmission. Retrouvez toutes les informations de l’ANRT sur son site Web à l’adresse suivante : http://www.anrt.ma. ________________________________ This message, its content and its attachments are intended for the exclusive use of the named addressee (s) and are strictly confidential. Any copy or other use of this information by persons or entities other than the intended recipient is prohibited and should be authorized by the National Agency of Telecommunications Regulation (ANRT, Morocco). If you have received this communication in error, please delete the material and notify the sender. The ANRT accepts no liability for any alteration, distortion or falsification that may occur during the transmission of this message. All information about ANRT can be found on our website at the following address http://www.anrt.ma. ________________________________ إن هذه الرسالة ومحتواها ومرفقاتها موجهة خصيصا للشخص المرسل إليه وتعتبر سرية وتصنف ضمن خانة المراسلات ذات طبيعة شخصية. ويمنع منعا كليا نشر أو استعمال أو بث، ولو بطريقة جزئية، لهذه الرسالة من طرف أشخاص غير المرسل إليهم ما لم يتم الترخيص بذلك من طرف الوكالة الوطنية لتقنين المواصلات (المملكة المغربية. في حالة ما إذا توصلتم هذه الرسالة عن طريق الخطأ، يرجى منكم العمل على إتلافها فورا بعد إخبار الشخص المرسل إليه بذلك. ولا تتحمل الوكالة الوطنية لتقنين المواصلات أي مسؤولية عن أي تحريف أو تغيير أو تزييف قد يلحق بمحتوى الرسالة أو بمرفقاتها خلال عملية الإرسال. للمزيد من المعلومات، يرجى الاطلاع على الموقع الإلكتروني للوكالة الوطنية لتقنين المواصلات : http://www.anrt.ma.

9 16

News article about EU DST
by Matt Johnson-Pint April 1, 2021

April 1, 2021

Good article from Bloomberg about how the pandemic has put the EU's plans to stop daylight saving time on hold. https://www.bloomberg.com/news/articles/2021-03-11/will-daylight-saving-tim… (It covers a bit about the recent US bill as well.) It also links to a humorous bit about time in Iceland from 2009 that may be worthy of our tz-art.html page: https://www.youtube.com/watch?v=q5q77MQzU2Q Cheers! -Matt

1 0