March 2017 - tz - lists.iana.org

Regarding mktime issue
by Gopesh Kumar Chaudhary March 9, 2017

March 9, 2017

Hello Everyone, This is Gopesh Kumar Chaudhary from India. I have couple of queries regarding mktime function. e.g. TZ=Europe/Berlin (Olson) struct tm prnt_time; prnt_time.tm_wday = 0; prnt_time.tm_mon = 10 - 1; prnt_time.tm_mday = 30; prnt_time.tm_hour = 2; prnt_time.tm_min = 0; prnt_time.tm_sec = 0; prnt_time.tm_year = 116; prnt_time.tm_isdst = -1; Above tm structure represent 30th OCT 2:30 2016 for Europe/Berlin in Olson . For Europe/Berlin DST fallback will happen on 30th Oct at 3 , so clock will show 2 to 3 time period twice. I have set the dst flag to -1 , for mktime to decide whether the given time in tm structure is DST time or non DST time. Now coming to my query : 1) In above mentioned scenario does mktime has the intelligence to decide whether above mentioned time in tm structure is in DST or not as dst flag is set to -1 ? 2) I have a sample code Sample code :- ----------------------- # cat gops.c #include<stdio.h> #include<time.h> int main(int argc,char **argv){ struct tm *at; time_t when,now; now=atoi(argv[1]); at=localtime(&now); at->tm_isdst = -1; when=mktime(at); printf("now=%d when=%d\n",now,when); return 0; } OS: Linux (RHEL 7.2) Platform:x86 TZ:Europe/Berlin (Olson) # ./gops 1477787940 ==============>This epoch is for 2:39 30th Oct 2016 DST now=1477787940 when=1477791540 ====>Here mktime is giving me the epoch for 2:39 30th Oct 2016 non-DST # ./gops 1477791540 ==============>This epoch is for 2:39 30th Oct 2016 non DST now=1477791540 when=1477791540 ====>Here mktime is giving me the epoch for 2:39 30th Oct 2016 non-DST With the above example it can be seen that irrespective of the DST/non-DST window , it is always giving non DST epoch only ---- Is this standard behavior or is this bug in mktime ? Thanks. Regards, Gopesh Kumar Chaudhary

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USNO web site down
by Arthur David Olson March 9, 2017

March 9, 2017

Just in time for this weekend's winter forward in the US, as noted by Neal Augenstein on Twitter: "Hmph, wanna see when spring starts? US Naval Observatory site and master clock are down." https://twitter.com/AugensteinWTOP/status/839900149375774720 http://www.usno.navy.mil/USNO/time/display-clocks/simpletime @dashdashado

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Re: [tz] tz abbr too long in 2017a Africa/Monrovia [was: zic throws warning for 2007a]
by Brian Inglis March 3, 2017

March 3, 2017

On 2017-03-02 18:47, Jonathan Leffler wrote: > On Wed, Mar 1, 2017 at 2:16 PM, Brian Inglis wrote: >On 2017-03-01 14:48, Tim Parenti wrote: >> On 1 March 2017 at 16:42, Brian Inglis wrote: >> Looks like it stores the over long abbreviation. >> So should probably patch: >> --- tz/releases/tzdata2017a/africa 2017-02-23 00:37:19.000000000 -0700 >> +++ tz/releases/tzdata2017b/africa 2017-03-01 14:36:43.479882200 -0700 >> @@ -431,7 +431,7 @@ Link Africa/Nairobi Indian/Mayotte >> # Zone NAME GMTOFF RULES FORMAT [UNTIL] >> Zone Africa/Monrovia -0:43:08 - LMT 1882 >> -0:43:08 - MMT 1919 Mar # Monrovia Mean Time >> - -0:44:30 - -004430 1972 May >> + -0:44:30 - -0044 1972 May >> 0:00 - GMT >> The above patch would be incorrect, though. It would be more correct >> to increase the allowed max abbreviation length. (Even better, >> numerical "abbreviations" like this should just be exempted from the >> caps, since they can technically be of almost any length, even though >> this is the longest they'll be in practice.) >POSIX limit in limits.h: >http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag… >under TZ definition for std and dst (abbrs) >"The interpretation of these fields is unspecified if either field is >less than three bytes (except for the case when dst is missing), more >than {TZNAME_MAX} bytes, or if they contain characters other than those >specified." >http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/limits.h.html#tag_… >"{_POSIX_TZNAME_MAX} >Maximum number of bytes supported for the name of a timezone (not of >the TZ variable). >Value: 6" > Note that the spiel above the entry for {_POSIX_TZNAME_MAX} says: > The /<limits.h>/ header shall define the following symbolic constants > with the values shown. These are the most restrictive values for > certain features on an implementation conforming to this volume of > POSIX.1-2008. Related symbolic constants are defined elsewhere in > this volume of POSIX.1-2008 which reflect the actual implementation > and which need not be as restrictive. For each of these limits, a > conforming implementation shall provide a value at least this large > or shall have no limit. A strictly conforming application must not > require a larger value for correct operation. > Is the code in tzcode intended to be a strictly conforming > application? From: http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap02.html#tag… the application is not a Strictly Conforming POSIX Application as it does not #define _POSIX_C_SOURCE 200809L, and is not a Conforming POSIX Application as it does not include a "statement of conformance that documents all options and limit dependencies, and all other ISO or IEC standards used", although commentary indicates POSIX compliance where notable. AFAICT like many packages, it is intended to be POSIX compliant and provide POSIX compliant implementations, to be portable to POSIX compliant and some non-POSIX systems. -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

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Problem with historical Asia/Manila?
by Paul Goyette March 3, 2017

March 3, 2017

According to the asia file, the Philippines jumped 24 hours on May 11, 1899, from -15:56:00 to +8:04:00 (they moved the international date line?) # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Manila -15:56:00 - LMT 1844 Dec 31 8:04:00 - LMT 1899 May 11 8:00 Phil +08/+09 1942 May 9:00 - +09 1944 Nov 8:00 Phil +08/+09 Yet zdump shows only a 4-minute step in local time, rather than the expected 24-hour step: # zdump -c 1815,2018 -v Asia/Manila Asia/Manila -9223372036854775808 = NULL Asia/Manila -9223372036854689408 = NULL Asia/Manila Tue Dec 31 15:55:59 1844 UT = Mon Dec 30 23:59:59 1844 LMT isdst=0 gmtoff=-57360 Asia/Manila Tue Dec 31 15:56:00 1844 UT = Wed Jan 1 00:00:00 1845 LMT isdst=0 gmtoff=29040 Asia/Manila Wed May 10 15:55:59 1899 UT = Wed May 10 23:59:59 1899 LMT isdst=0 gmtoff=29040 Asia/Manila Wed May 10 15:56:00 1899 UT = Wed May 10 23:56:00 1899 +08 isdst=0 gmtoff=28800 Asia/Manila Sat Oct 31 15:59:59 1936 UT = Sat Oct 31 23:59:59 1936 +08 isdst=0 gmtoff=28800 ... Obviously a low-priority issue, since it's more than 100 years ago, but still would be nice to know why we have a problem. It's not totally out of the realm of probability that someone will move the dateline again, perhaps if the UTC+14 parts of Kiribati were to separate from the rest of the country? :) Data gathered on a NetBSD 7.99.64 system running on amd64 hardware, and using the 2017a tzdata. I think we're still running 2016i version of tzcode. So the question(s): * is zdump wrong? * is the compiled data file wrong? * (most likely) am I just misinterpreting the data? * is this something that has already been fixed in a more recent tzcode release? +------------------+--------------------------+------------------------+ | Paul Goyette | PGP Key fingerprint: | E-mail addresses: | | (Retired) | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com | | Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org | +------------------+--------------------------+------------------------+

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zic throws warning for 2007a
by Derick Rethans March 1, 2017

March 1, 2017

Hi, I've just updated the PHP version of the TZ database, and while compiling with the current zic, I see: warning: "standard input", line 434: time zone abbreviation has too many characters (-004430) This is because of: 24 #ifndef ZIC_MAX_ABBR_LEN_WO_WARN 25 #define ZIC_MAX_ABBR_LEN_WO_WARN 6 26 #endif /* !defined ZIC_MAX_ABBR_LEN_WO_WARN */ 3108 if (cp - string > ZIC_MAX_ABBR_LEN_WO_WARN) 3109 mp = _("time zone abbreviation has too many characters"); That check was introduced in 2012j as per NEWS: Release 2012j - 2012-11-12 18:34:49 -0800 ... zic -v now complains about abbreviations that are less than 3 or more than 6 characters, as per Posix. Formerly, it checked for abbreviations that were more than 3. 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

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