December 2017 - tz - lists.iana.org

proposed time zone package changes (Samoa, Factory, et al.)
by Arthur David Olson Aug. 28, 2019

Aug. 28, 2019

Below find proposed time zone package changes; the executive summary: * Makefile Change LOCALTIME default from "Factory" to "GMT"; do not compile "factory" file (but keep it in the distribution). * Theory Remove reference to "Factory" zone. * australasia Change end of DST in Samoa in 2011 from 2011-04-03 0:00 to 2011-04-03 1:00 (thanks to Raymond Hughes for a reference). * localtime.c Initialize ttinfo structures filled by tzparse (thanks to Ravindra for reporting a valgrind warning). * zic.c Fix generation of POSIX strings for zones with rules using "weekday<=n" forms of dates (thanks to Lei Liu for finding the problem). Also, limit output for non-POSIX-specificable zones defined to follow the same rules every year. (Note that no zones of either of the above types appear in the distribution; these changes cater to add-on zones). If no problems are found, 2010n will appear on 2010-10-25. --ado diff -r -c old/Makefile new/Makefile *** old/Makefile Mon Sep 27 09:24:25 2010 --- new/Makefile Tue Oct 12 12:36:50 2010 *************** *** 1,5 **** # <pre> ! # @(#)Makefile 8.8 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)Makefile 8.9 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 12,18 **** # make zonenames # to get a list of the values you can use for LOCALTIME. ! LOCALTIME= Factory # If you want something other than Eastern United States time as a template # for handling POSIX-style time zone environment variables, --- 12,18 ---- # make zonenames # to get a list of the values you can use for LOCALTIME. ! LOCALTIME= GMT # If you want something other than Eastern United States time as a template # for handling POSIX-style time zone environment variables, *************** *** 262,269 **** DOCS= README Theory $(MANS) date.1 Makefile PRIMARY_YDATA= africa antarctica asia australasia \ europe northamerica southamerica ! YDATA= $(PRIMARY_YDATA) pacificnew etcetera factory backward ! NDATA= systemv SDATA= solar87 solar88 solar89 TDATA= $(YDATA) $(NDATA) $(SDATA) TABDATA= iso3166.tab zone.tab --- 262,269 ---- DOCS= README Theory $(MANS) date.1 Makefile PRIMARY_YDATA= africa antarctica asia australasia \ europe northamerica southamerica ! YDATA= $(PRIMARY_YDATA) pacificnew etcetera backward ! NDATA= systemv factory SDATA= solar87 solar88 solar89 TDATA= $(YDATA) $(NDATA) $(SDATA) TABDATA= iso3166.tab zone.tab diff -r -c old/Theory new/Theory *** old/Theory Mon Sep 27 09:24:25 2010 --- new/Theory Tue Oct 12 12:36:50 2010 *************** *** 1,4 **** ! @(#)Theory 8.4 This file is in the public domain, so clarified as of 2009-05-17 by Arthur David Olson. --- 1,4 ---- ! @(#)Theory 8.5 This file is in the public domain, so clarified as of 2009-05-17 by Arthur David Olson. *************** *** 287,294 **** See the file `backward' for most of these older names (e.g. `US/Eastern' instead of `America/New_York'). The other old-fashioned names still supported are ! `WET', `CET', `MET', `EET' (see the file `europe'), ! and `Factory' (see the file `factory'). ----- Time zone abbreviations ----- --- 287,293 ---- See the file `backward' for most of these older names (e.g. `US/Eastern' instead of `America/New_York'). The other old-fashioned names still supported are ! `WET', `CET', `MET', and `EET' (see the file `europe'). ----- Time zone abbreviations ----- diff -r -c old/australasia new/australasia *** old/australasia Mon Sep 27 09:24:27 2010 --- new/australasia Tue Oct 12 13:14:56 2010 *************** *** 1,5 **** # <pre> ! # @(#)australasia 8.18 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. --- 1,5 ---- # <pre> ! # @(#)australasia 8.19 # This file is in the public domain, so clarified as of # 2009-05-17 by Arthur David Olson. *************** *** 487,497 **** # http://www.parliament.gov.ws/documents/acts/Daylight%20Saving%20Act%20%2020… # </a> Zone Pacific/Apia 12:33:04 - LMT 1879 Jul 5 -11:26:56 - LMT 1911 -11:30 - SAMT 1950 # Samoa Time -11:00 - WST 2010 Sep 26 ! -11:00 1:00 WSDT 2011 Apr 3 -11:00 - WST # Solomon Is --- 487,507 ---- # http://www.parliament.gov.ws/documents/acts/Daylight%20Saving%20Act%20%2020… # </a> + # From Raymond Hughes (2010-10-07): + # Please see + # <a href="http://www.mcil.gov.ws"> + # http://www.mcil.gov.ws + # </a>, + # the Ministry of Commerce, Industry and Labour (sideframe) "Last Sunday + # September 2010 (26/09/10) - adjust clocks forward from 12:00 midnight + # to 01:00am and First Sunday April 2011 (03/04/11) - adjust clocks + # backwards from 1:00am to 12:00am" + Zone Pacific/Apia 12:33:04 - LMT 1879 Jul 5 -11:26:56 - LMT 1911 -11:30 - SAMT 1950 # Samoa Time -11:00 - WST 2010 Sep 26 ! -11:00 1:00 WSDT 2011 Apr 3 1:00 -11:00 - WST # Solomon Is diff -r -c old/localtime.c new/localtime.c *** old/localtime.c Mon Sep 27 09:24:26 2010 --- new/localtime.c Tue Oct 12 12:36:51 2010 *************** *** 5,11 **** #ifndef lint #ifndef NOID ! static char elsieid[] = "@(#)localtime.c 8.14"; #endif /* !defined NOID */ #endif /* !defined lint */ --- 5,11 ---- #ifndef lint #ifndef NOID ! static char elsieid[] = "@(#)localtime.c 8.15"; #endif /* !defined NOID */ #endif /* !defined lint */ *************** *** 914,919 **** --- 914,920 ---- register unsigned char * typep; register char * cp; register int load_result; + static struct ttinfo zttinfo; INITIALIZE(dstname); stdname = name; *************** *** 986,991 **** --- 987,993 ---- /* ** Two transitions per year, from EPOCH_YEAR forward. */ + sp->ttis[0] = sp->ttis[1] = zttinfo; sp->ttis[0].tt_gmtoff = -dstoffset; sp->ttis[0].tt_isdst = 1; sp->ttis[0].tt_abbrind = stdlen + 1; *************** *** 1099,1106 **** } /* ** Finally, fill in ttis. - ** ttisstd and ttisgmt need not be handled. */ sp->ttis[0].tt_gmtoff = -stdoffset; sp->ttis[0].tt_isdst = FALSE; sp->ttis[0].tt_abbrind = 0; --- 1101,1108 ---- } /* ** Finally, fill in ttis. */ + sp->ttis[0] = sp->ttis[1] = zttinfo; sp->ttis[0].tt_gmtoff = -stdoffset; sp->ttis[0].tt_isdst = FALSE; sp->ttis[0].tt_abbrind = 0; *************** *** 1113,1118 **** --- 1115,1121 ---- dstlen = 0; sp->typecnt = 1; /* only standard time */ sp->timecnt = 0; + sp->ttis[0] = zttinfo; sp->ttis[0].tt_gmtoff = -stdoffset; sp->ttis[0].tt_isdst = 0; sp->ttis[0].tt_abbrind = 0; diff -r -c old/zic.c new/zic.c *** old/zic.c Mon Sep 27 09:24:26 2010 --- new/zic.c Tue Oct 12 13:37:29 2010 *************** *** 3,9 **** ** 2006-07-17 by Arthur David Olson. */ ! static char elsieid[] = "@(#)zic.c 8.22"; #include "private.h" #include "locale.h" --- 3,9 ---- ** 2006-07-17 by Arthur David Olson. */ ! static char elsieid[] = "@(#)zic.c 8.24"; #include "private.h" #include "locale.h" *************** *** 1881,1896 **** register int week; if (rp->r_dycode == DC_DOWGEQ) { ! week = 1 + rp->r_dayofmonth / DAYSPERWEEK; ! if ((week - 1) * DAYSPERWEEK + 1 != rp->r_dayofmonth) return -1; } else if (rp->r_dycode == DC_DOWLEQ) { if (rp->r_dayofmonth == len_months[1][rp->r_month]) week = 5; else { ! week = 1 + rp->r_dayofmonth / DAYSPERWEEK; ! if (week * DAYSPERWEEK - 1 != rp->r_dayofmonth) return -1; } } else return -1; /* "cannot happen" */ (void) sprintf(result, "M%d.%d.%d", --- 1881,1896 ---- register int week; if (rp->r_dycode == DC_DOWGEQ) { ! if ((rp->r_dayofmonth % DAYSPERWEEK) != 1) return -1; + week = 1 + rp->r_dayofmonth / DAYSPERWEEK; } else if (rp->r_dycode == DC_DOWLEQ) { if (rp->r_dayofmonth == len_months[1][rp->r_month]) week = 5; else { ! if ((rp->r_dayofmonth % DAYSPERWEEK) != 0) return -1; + week = rp->r_dayofmonth / DAYSPERWEEK; } } else return -1; /* "cannot happen" */ (void) sprintf(result, "M%d.%d.%d", *************** *** 2018,2023 **** --- 2018,2024 ---- register char * envvar; register int max_abbr_len; register int max_envvar_len; + register int prodstic; /* all rules are min to max */ max_abbr_len = 2 + max_format_len + max_abbrvar_len; max_envvar_len = 2 * max_abbr_len + 5 * 9; *************** *** 2032,2037 **** --- 2033,2039 ---- timecnt = 0; typecnt = 0; charcnt = 0; + prodstic = zonecount == 1; /* ** Thanks to Earl Chew ** for noting the need to unconditionally initialize startttisstd. *************** *** 2053,2058 **** --- 2055,2062 ---- updateminmax(rp->r_loyear); if (rp->r_hiwasnum) updateminmax(rp->r_hiyear); + if (rp->r_lowasnum || rp->r_hiwasnum) + prodstic = FALSE; } } /* *************** *** 2075,2080 **** --- 2079,2094 ---- if (max_year <= INT_MAX - YEARSPERREPEAT) max_year += YEARSPERREPEAT; else max_year = INT_MAX; + /* + ** Regardless of any of the above, + ** for a "proDSTic" zone which specifies that its rules + ** always have and always will be in effect, + ** we only need one cycle to define the zone. + */ + if (prodstic) { + min_year = 1900; + max_year = min_year + YEARSPERREPEAT; + } } /* ** For the benefit of older systems,

5 6

Brazilian state of Goiás may abolish DST
by World Time Zone April 27, 2019

April 27, 2019

According to some news Brazilian state of Goiás may abolish DST: "The Energy and Mines Commission of the House of Representatives approved a Legislative Decree that suspends daylight saving time in Goiás." http://www.infomoney.com.br/minhas-financas/consumo/noticia/7061178/comissa… Also, ".... this year the federal government even considered not implementing daylight saving time, but left the decision to 2018." Alexander Krivenyshev https://www.WorldTimeZone.com

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Re: [tz] [IANA #985615] Sudan Time Zone change
by ahmed.atyya＠ntc.gov.sd June 25, 2018

June 25, 2018

Dear Sir/ Madam we would like to inform you that the Republic of Sudan is going to change the time zone from (GMT + 3:00) to (GMT+ 2:00) starting from Wednesday 1 November 2017. this is for your information and action if required. Best Regards Dear Mr. Paul We would like to inform you as TZ coordinator that the Republic of Sudan is planning to change its time zone from GMT+ 3:00 to GMT +2:00 ( The original time zone ) starting from 1 November 2017 Please if you can update time zone data base Or you you can tell us what action is needed from Sudan government Best Regards Ahmed Atyya Head of Numbering Section National Telecomm. Corporation – Sudan Phone: +249123499988 Email: ahmed.atyya@ ----- Original Message ----- From: Sabrina Tanamal via RT <iana-questions(a)iana.org> To: ahmed atyya <ahmed.atyya(a)ntc.gov.sd> Sent: Tue, 17 Oct 2017 01:33:06 +0300 (EAT) Subject: [IANA #985615] Sudan Time Zone change Dear Ahmed, Thank you for contacting us. We host the Time Zone Database, but updates are made by the Time Zone Coordinator in consultation with the Time Zone mailing list, in accordance with RFC 6557. Questions about the contents of the database should be sent to the mailing list. For mailing list archives and subscription information, please see http://www.iana.org/time-zones Best regards, Sabrina Tanamal IANA Services Specialist On Mon Oct 16 09:55:06 2017, ahmed.atyya(a)ntc.gov.sd wrote: > Dear Sir/ Madam > > > > > > we would like to inform you that the Republic of Sudan is going to > change the time zone from (GMT + 3:00) to (GMT+ 2:00) starting from > Wednesday 1 November 2017. > > > this is for your information and action if required. > > > > > > Best Regards > > > > > > Ahmed Atyya > > > Head of Numbering Section > > National Telecomm. Corporation – Sudan > > Phone: +249123499988 > > Email: ahmed.atyya(a)ntc.gov.sd

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Reason for removal of several TZ
by Thomas M Steenholdt Jan. 23, 2018

Jan. 23, 2018

Hi guys, Almost a year ago, commit 2999bb5bee719acbba8b9dd50fb9fb00c7788623 removed several TZ abbreviations and I'm trying to understand this. For my own use, what I'm after is WGT/WGST which are now "simply -03". WGT/WGST has been in tzdata for a long time, so the removal causes certain things to go belly up. The change was only implemented in Ubuntu recently, which is why this only turned into a problem for me now. WGT/WGST seems to be a widely accepted abbreviation for the West Greenland Time zone. So can someone explain to me the reason behind the removal and what would needed to get it re-implemented? Thanks. /Thomas

40 174

broken compression in archive
by Zefram Jan. 18, 2018

Jan. 18, 2018

I'm doing some work on how to access historical tzdb versions, and I noticed that tz{code,data}94d.tar.Z are, despite their names, uncompressed tar files. To be precise, I refer to the files with these SHA-512 hashes: 9872b757ee3a8bf0ed3de1f0875f878b977b34bd2b60440b23a8c7308a7514d12a5d5d283387973e61b75e1a8eebd27009aab78eee4e12f1f1a5593f71941328 tzcode94d.tar.Z e1524951a5c261cc8eef1f3adadf5ebf8143293745fda9411a0090d6bb6e19f899dd7a6e55fe2f8f490a167a3da392020e49b369984bc1f5cbed87d664eb58de tzdata94d.tar.Z They're unique, in the present archive <ftp://ftp.iana.org/tz/releases/>, in having a mismatch between format and filename suffix. I think these files should be replaced, in the archive, with actual compressed (with compress(1)) versions of these tars, under the same name, so that the names are no longer misleading and they are in the same format as the surrounding files. The other way to make the names no longer misleading is to rename these files, dropping the ".Z" suffix, but this approach has the problem that these files would (still) have a different format from all the other tarballs. Note that this mismatch is not a mistake made in the original release of 94d, and the replacement that I'm proposing would not erase a record of the original release files. The original 94d release was of *gzipped* tar files, which are not in the present archive. Actual releases switched from .Z to .gz at 93g, but the archive files switch at tzdata95c and tzcode95d. Obviously someone recompressed the intervening tarballs somewhere along the chain of custody that led to the present archive, and it appears that the failure to (re)compress 94d happened in that process. -zefram

4 6

Brazil moves DST start to November
by Steffen Thorsen Jan. 17, 2018

Jan. 17, 2018

According to many media sources, next year's DST start in Brazil will move to the first Sunday of November, and it will stay like that for the years after. Some examples in Portugese: https://noticias.r7.com/economia/por-eleicao-temer-reduz-periodo-de-horario… https://exame.abril.com.br/brasil/por-eleicao-temer-reduz-periodo-de-horari… We have made a brief English summary: https://www.timeanddate.com/news/time/brazil-delays-dst-2018.html Best regards, Steffen Thorsen - timeanddate.com

4 7

Canada/East-Saskatchewan
by Derick Rethans Jan. 16, 2018

Jan. 16, 2018

Hi, I saw that the PHP build with the new timezone database (2017.3) failed due to Canada/East-Saskatchewan suddenly being gone. What's up with that? https://travis-ci.org/php/php-src/jobs/291636544#L1280 cheers, Derick -- https://derickrethans.nl | https://xdebug.org | https://dram.io Like Xdebug? Consider a donation: https://xdebug.org/donate.php twitter: @derickr and @xdebug

6 9

Three time zones meeting at one location
by Paul Eggert Dec. 29, 2017

Dec. 29, 2017

In yesterday's My Modern Met, Jessica Stewart says that in over 20 locations in the world, three different time zones converge. Surveyor Generals Corner in Australia and Treriksrøysa (for the point where Finland, Norway, and Russia meet) are two examples. For time zone hounds it may be an amusing read, if only to spot the mistakes. Stewart J. Places around the world where three time zones meet in the same spot. My Modern Met. 2017-12-28. https://mymodernmet.com/three-different-time-zones-facts/

1 0

Lithuania calls on EU to stop adjusting clocks for daylight savings
by Lord Buddha Dec. 23, 2017

Dec. 23, 2017

https://www.theguardian.com/world/2017/dec/22/lithuania-calls-on-eu-to-stop…

1 0

Transitions after those included in zoneinfo binaries?
by Paul G Dec. 21, 2017

Dec. 21, 2017

I recently noticed a discrepancy between the python-dateutil and pytz libraries when calculating offsets for dates after the last included transition in the zonefile binaries. What it boils down to is that when it runs out of transitions, python-dateutil selects the "standard" offset and pytz assumes that after the last transition the value "holds". In the southern hemisphere, this produces two different behaviors. Obviously there's no "right" answer here, since these are predictions about what time zones will be applied 20 years in the future (and even if the rules stayed the same, the "end date" is entirely artificial). Still, I wonder if it might be worth a bit of discussion and possibly a note in the Theory file? Barring a representation of the data that exposes the rules directly (in which case no such artificial limitation would be necessary), I think either fallback is defensible. Best, Paul

7 10

Complexities of time rendered graphically
by Steve Jones Dec. 19, 2017

Dec. 19, 2017

Folks: Today's XKCD comic is amusing: https://xkcd.com/1930/ Steve Jones [image: Emacs!]

3 5

default value of TZDEFAULT
by scs＠eskimo.com Dec. 18, 2017

Dec. 18, 2017

[This is a tzcode issue, not tzdata. Your regular discussion of zone definition and naming issues will resume shortly. :-) ] Consider this simple little program: #include <stdio.h> #include <time.h> int main() { time_t t = time(NULL); struct tm *tmp = localtime(&t); puts(asctime(tmp)); return 0; } There's nothing special about this program (that's the point). But suppose I download tzcode or tzdb and then compile the little program (call it lt.c) along with a just-built localtime(), like this: make localtime.o cc -o lt lt.c localtime.o But if I then run 'lt', it is likely not to work -- there's a pretty good chance it will print the current time in UTC, not my local time zone. If it fails, one reason is that it didn't successfully find my system's already-installed tz files. (That is, I made no attempt to build or install any new tz files.) The reason it didn't find them is obvious enough, and the Makefile contains all the hints I need: TOPDIR= /usr/local # "Compiled" time zone information is placed in the "TZDIR" directory # (and subdirectories). # Use an absolute path name for TZDIR unless you're just testing the software. # TZDIR_BASENAME should not contain "/" and should not be ".", ".." or empty. TZDIR_BASENAME= zoneinfo TZDIR= $(TOPDIR)/etc/$(TZDIR_BASENAME) And, sure enough, on my system, the already-installed tz files are not in /usr/local, they're in /usr/share. So it looks like if I change TOPDIR to /usr/share, or TZDIR to /usr/share/zoneinfo, I should be able to fix it. But no! It still doesn't work, and the reason is, my user environment doesn't have the TZ environment variable set; I'm assuming that the system's default time zone will be used. And, out of the box, the tzcode distribution assumes that the local time zone is defined by a file 'localtime' *in TZDIR*; that is, it essentially assumes that TZDEFAULT is $TZDIR/localtime. But some (perhaps even many) systems put it in /etc/localtime. That's where my (MacOS) system puts it, and a lot of Linux systems put it there, too. The upshot is that on such a system, if you compile and use localtime.c straight out of the tzcode distribution, it won't find your localtime file, and will end up falling back to UTC unless TZ is set. Since the Makefile already lets you set your own version of TZDIR (overriding the setting in tzfile.h), I think it makes sense to do the same thing for TZDEFAULT. Patch attached. With this patch in place, and with the Makefile edited to say TZDEFAULT = "/etc/localtime" fresh compiles of localtime.o correctly find my system's localtime file, and the lt program finally prints local time, as expected. (This tweak to TZDEFAULT's usage helps the extraction case -- that is, when the code tries to fetch the default zone, but not necessarily the tz file building case. I'm not sure whether 'make install' will do the right thing when TZDEFAULT is set, but it definitely doesn't do the right thing if DESTDIR and TZDEFAULT are both set. Is using DESTDIR supported? The Makefile should probably document it if so.) Diagnosing problems involving misconfigured TZDIR and TZDEFAULT variables can be surprisingly difficult. The localtime code doesn't have any way of telling you it's having trouble finding tz files in general, or the localtime file in particular. I'll address that issue in a separate thread. Steve Summit scs(a)eskimo.com

4 10

setting TZ and calling localtime_r
by scs＠eskimo.com Dec. 18, 2017

Dec. 18, 2017

There's code in tzcode (and, I suspect not coincidentally, glibc's localtime implementation as well) to not call the internal version of tzset on calls to localtime_r, but rather only on calls to localtime. The justification is that Posix says localtime_r doesn't need to update the global tzname variable. I don't have a copy of the Posix spec handy, so I can't check: does Posix also say that localtime_r doesn't need to check for and make use of a possibly-changed value of TZ? As implemented (both in tzcode and glibc), it doesn't. If a program calls localtime, then calls setenv to set a new value of TZ, then calls localtime again, it works as expected, but if it calls localtime_r, setenv, localtime_r, it doesn't. (The workaround, of course, is to call localtime_r, setenv, tzset, localtime_r.)

5 4

Kyiv
by gocdoms gocdoms Dec. 18, 2017

Dec. 18, 2017

Hello! City Kyiv is not Kiev. The *founder* of Kyiv is *Kyi*. Not Kie! Please see attached picture.

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Asia/Shanghai (was: Re: Kyiv)
by Phake Nick Dec. 15, 2017

Dec. 15, 2017

Speaking of which, after reading naming convention of zones, wouldn't it still be better to rename the zone to Asia/Beijing mowadays? As almost all users are referring to the zone as "Beijing Time", if in any case there are different time standard emerge that caused Beijing and Shamghai to use different tome standard instead, then it would be more likely for the zone's user to think the Beijing time is a time being continued while Shanghai time would be another new time. In order to reflect the line of thinking and thus when future communication or ammendment easier when things really do change, would such renaming make sense? 2017年12月16日 03:20 於 "Garrett Wollman" <wollman(a)csail.mit.edu> 寫道： > > Contrast the case (which thankfully we do not have to deal with) of > the capital city of the People's Republic of China. In English, it > used to be called "Peking", and in fact in the name of the university > and of the duck dish it still is. The PRC government made a concerted > campaign to change the name used by English speakers to be "Beijing", > which is a phonetic representation of the name of the city in Mandarin > (putonghua). This has to a very large extent worked, and now most > English texts say "Beijing" and not "Peking" (although many people > still don't pronounce it "correctly" because the letters in hanyu > pinyin don't have the same sound values as they do in English). > However, in many languages *other than English*, the name of the city > has not changed -- AFAIK it's still "Pékin" in French, for example.

3 2

tzdata gpg key
by Zura Kutchava Dec. 8, 2017

Dec. 8, 2017

Dear Friends, On https://data.iana.org/time-zones/releases/ I found packages and signatures, but cannot find gpg key to veryfing them. Can you be so kind to tell me where is gpg key for verifying? I am building linux from scratch and writing script for downloading and verifying main packages, so your help will be very important. Thanks beforehand, Regards.

2 1

Europe/Kiev
by Bohdan Vovchuk Dec. 7, 2017

Dec. 7, 2017

Hello. Please change timezone *Europe/Kiev* to *Europe/Kyiv* because first variation is wrong. Ukrainian timezone should be changed to Europe/Kyiv. Kyiv - is a one and only correct international transliteration. -- *Regards, Bohdan Vovchuk*

2 1

Filling the gaps ...
by Lester Caine Dec. 5, 2017

Dec. 5, 2017

The main problem that everybody seems to be skirting around is that the tz database has NO interest in exactly where someone is located and there is no remit TO manage that. Even tzdist which was the latest attempt to plug a major distribution hole has no remit on supplying the correct data for a particular location! Both are simply managing the set of rules that anybody can use where ever they are. Importantly allowing third parts to work out a local time for some elsewhere in the world. Some other data source is really needed to serve up the CURRENT set of rules for a location, and that is probably only currently possible using geonames.org which uses the current timezone_id and it's own simplified timeZone.txt table! What is missing is any historic (or ongoing) changes to that information, such as a location that was using one tz rule set but moved to another. In addition any pre-1970 material can not be identified. tzdist has the remit and tools to fill one of the holes that tz on it's own can not and that is historic changes TO the rule sets. My interest in the tz database came from a major problem with material that had been normalised to UTC time but there was no record as to what rules had been used TO normalise the data, so one could not verify if the CURRENT tz rules were appropriate for establishing the then local times. As Paul has quite rightly pointed out, much historic data was invented, so CORRECTING the data when more accurate information is established is perfectly correct, but one needs to be able to also establish just which rules have changed and one can then adjust the material that is now suspect ( - IF APPROPRIATE ;) ) The whole point of tzdist was to sort current day problems, so if a mobile device with a stored calendar lands in a new location where there has been an 'unscheduled' change of tz rules that change CAN be propagated quickly without needing a full tz update but that will only work if someone is actually running the primary tzdist source. Moving forward, that primary tzdist source needs to maintain a full historic record prior to 1970 since it also provides the base from which rules for historic data normalization can be managed. It allows for the tz timezone_id's to be used to identify the base rule sets, but allows new rule sets to be created ... just without any rules on just how THAT is managed :( Potentially any geonameid could have it's own individual tzdist dataset and track the history of changes as a location moves from one political jurisdiction to another and show it's simple solar time as appropriate. Something that neither tzdist or tz is actually mandated to supply? Merging geonames.org with openstreetmap.org one gets graphic displays of the area that timezones CURRENTLY cover, but one can not establish if the same offsets applied back in the 1960's when DST local times are well documented. And both databases throw away the historic data to those mappings along with a whole load of other historic material. While the vast majority of users probably could not care less, the annoyance here is that the material existed so it's not as if we are asking for extra work, just a mechanism that remembers that say in 2014 the Crimea moved from one set of tz rules to another. Once the mechanism is in place, then as new historic material comes to light, the historic record can be corrected and tzdist has the mechanism for that in relation to timezone rules. So as a start ... what has happened to tzdist. The full historic record of tz changes can provide a complete set of data that has been used over the last 20 years and as new changes are logged in now they can be pushed to tzdist while also maintaining tz distribution for off-line population systems. -- Lester Caine - G8HFL ----------------------------- Contact - http://lsces.co.uk/wiki/?page=contact L.S.Caine Electronic Services - http://lsces.co.uk EnquirySolve - http://enquirysolve.com/ Model Engineers Digital Workshop - http://medw.co.uk Rainbow Digital Media - http://rainbowdigitalmedia.co.uk

3 3

[PROPOSED] Pacify GCC 7.2.1 x86-64 -Wmaybe-uninitialized
by Paul Eggert Dec. 4, 2017

Dec. 4, 2017

* zdump.c (main): Add an INITIALIZE to pacify gcc 7.2.1 20170915 (Red Hat 7.2.1-2) on x86-64 with -Wmaybe-uninitialized, which otherwise incorrectly warns that ‘ab’ might be used uninitialized. Clarify the expression that confused GCC (though the clarification is evidently not enough). --- zdump.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/zdump.c b/zdump.c index 3cd4f42..60a027e 100644 --- a/zdump.c +++ b/zdump.c @@ -552,6 +552,7 @@ main(int argc, char *argv[]) } if (t < cutlotime) t = cutlotime; + INITIALIZE (ab); tm_ok = my_localtime_rz(tz, &t, &tm) != NULL; if (tm_ok) { ab = saveabbr(&abbrev, &abbrevsize, &tm); @@ -567,11 +568,10 @@ main(int argc, char *argv[]) : cuthitime); struct tm *newtmp = localtime_rz(tz, &newt, &newtm); bool newtm_ok = newtmp != NULL; - if (! (tm_ok & newtm_ok - ? (delta(&newtm, &tm) == newt - t - && newtm.tm_isdst == tm.tm_isdst - && strcmp(abbr(&newtm), ab) == 0) - : tm_ok == newtm_ok)) { + if (tm_ok != newtm_ok + || (tm_ok && (delta(&newtm, &tm) != newt - t + || newtm.tm_isdst != tm.tm_isdst + || strcmp(abbr(&newtm), ab) != 0))) { newt = hunt(tz, argv[i], t, newt); newtmp = localtime_rz(tz, &newt, &newtm); newtm_ok = newtmp != NULL; -- 2.14.3

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Very cool app that uses yout TZ Database
by Anton Skorniakov Dec. 4, 2017

Dec. 4, 2017

Hello! First of all, I want to thank you very much for such cool time zones database, we are using it in our product. I want to suggest adding one more cool and simple free web based time zone converter app https://timezoneconverterapp.com/ to this page https://data.iana.org/time-zones/tz-link.html (“Web sites using recent versions of the tz database” section). I am one of the creators of this app and of course, it uses IANA TZ Database. Thank you! _________________ Anton

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