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tz database
by Zhang, Heather Sept. 24, 2014

Sept. 24, 2014

Hi, I downloaded most recent tz data from http://www.iana.org/time-zones, Time Zone Data v. 2014g (Released 2014-08-28) tzdata2014g.tar.gz<http://www.iana.org/time-zones/repository/releases/tzdata2014g.tar.gz> (278.2kb) Time Zone Code v. 2014g (Released 2014-08-28) tzcode2014g.tar.gz<http://www.iana.org/time-zones/repository/releases/tzcode2014g.tar.gz> (174.0kb) After reading the README file and other document, I understand that the gz is for compiling into unix commands that provide various timezone functions, am I correct? If I m correct, does IANA provide a csv/xls download of tz with daylight saving time info for all cities in the world and delta download periodically? Thanks & Regards, Heather Zhang | Sabre | W: 682.605.2968 | B1 Flex

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[PROPOSED_PATCH] * localtime.c (localtime_tzset): Coalesce two identical flag args.
by Paul Eggert Sept. 23, 2014

Sept. 23, 2014

All callers changed. --- localtime.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/localtime.c b/localtime.c index 30b5fbc..e692513 100644 --- a/localtime.c +++ b/localtime.c @@ -1389,14 +1389,14 @@ localtime_rz(struct state *sp, time_t const *timep, struct tm *tmp) #endif static struct tm * -localtime_tzset(time_t const *timep, struct tm *tmp, bool settz, bool setname) +localtime_tzset(time_t const *timep, struct tm *tmp, bool setname) { int err = lock(); if (err) { errno = err; return NULL; } - if (settz || !lcl_is_set) + if (setname || !lcl_is_set) tzset_unlocked(); tmp = localsub(lclptr, timep, setname, tmp); unlock(); @@ -1406,13 +1406,13 @@ localtime_tzset(time_t const *timep, struct tm *tmp, bool settz, bool setname) struct tm * localtime(const time_t *const timep) { - return localtime_tzset(timep, &tm, true, true); + return localtime_tzset(timep, &tm, true); } struct tm * localtime_r(const time_t *const timep, struct tm *tmp) { - return localtime_tzset(timep, tmp, false, false); + return localtime_tzset(timep, tmp, false); } /* -- 1.9.1

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[PROPOSED PATCH] * northamerica (America/Jamaica): 1974 sprang forward on Jan. 6,
by Paul Eggert Sept. 23, 2014

Sept. 23, 2014

not Apr. 28. * NEWS: Document this. --- NEWS | 2 ++ northamerica | 13 ++++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/NEWS b/NEWS index 06e7094..8562fae 100644 --- a/NEWS +++ b/NEWS @@ -4,6 +4,8 @@ Unreleased, experimental changes Changes affecting past time stamps + America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28. + Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01, not 1920-01-06. The old entry was based on a misinterpretation of Shanks. diff --git a/northamerica b/northamerica index 0f5ed3c..3d72505 100644 --- a/northamerica +++ b/northamerica @@ -2991,10 +2991,21 @@ Zone America/Tegucigalpa -5:48:52 - LMT 1921 Apr # Shanks & Pottenger give -5:07:12, but Milne records -5:07:10.41 from an # unspecified official document, and says "This time is used throughout the # island". Go with Milne. Round to the nearest second as required by zic. +# +# Shanks & Pottenger give April 28 for the 1974 spring-forward transition, but +# Lance Neita writes that Prime Minister Michael Manley decreed it January 5. +# Assume Neita meant Jan 6 02:00, the same as the US. Neita also writes that +# Manley's supporters associated this act with Manley's nickname "Joshua" +# (recall that in the Bible the sun stood still at Joshua's request), +# and with the Rod of Correction which Manley said he had received from +# Haile Selassie, Emperor of Ethiopia. See: +# Neita L. The politician in all of us. Jamaica Observer 2014-09-20 +# http://www.jamaicaobserver.com/columns/The-politician-in-all-of-us_17573647 +# # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone America/Jamaica -5:07:11 - LMT 1890 # Kingston -5:07:11 - KMT 1912 Feb # Kingston Mean Time - -5:00 - EST 1974 Apr 28 2:00 + -5:00 - EST 1974 -5:00 US E%sT 1984 -5:00 - EST -- 1.9.3

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Chile 2014 changes
by DONATELLA SABELLICO Sept. 22, 2014

Sept. 22, 2014

Hi, in which "Time Zone Data " are contained the Chile 2014 changes? See http://www.minenergia.cl/ministerio/noticias/generales/ministerio-de-energi… Donatella Sabellico. "One Life. One Love. To love each other" Visit IBM TWA Forum! https://ibm.biz/BdxJFs TWA NewsLetter! http://ibm.biz/Bdxij4 Join SMC Connect community! https://www.ibm.com/developerworks/servicemanagement/ IBM Italia S.p.A. Sede Legale: Circonvallazione Idroscalo - 20090 Segrate (MI) Cap. Soc. euro 347.256.998,80 C. F. e Reg. Imprese MI 01442240030 - Partita IVA 10914660153 Società con unico azionista Società soggetta all?attività di direzione e coordinamento di International Business Machines Corporation (Salvo che sia diversamente indicato sopra / Unless stated otherwise above)

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[PROPOSED PATCH 1/4] Have zdump output gmtoff= even on platforms lacking TM_GMTOFF.
by Paul Eggert Sept. 22, 2014

Sept. 22, 2014

* zdump.c (adjusted_yday, gmtoff): New functions. (show): Use new function gmtoff to output gmtoff= even on platforms that do not define TM_GMTOFF. * NEWS: Document this. --- NEWS | 3 +++ zdump.c | 49 ++++++++++++++++++++++++++++++++++++++++++------- 2 files changed, 45 insertions(+), 7 deletions(-) diff --git a/NEWS b/NEWS index 21e85a7..618ddb7 100644 --- a/NEWS +++ b/NEWS @@ -17,6 +17,9 @@ Unreleased, experimental changes Changes affecting code + zdump -V and -v now output gmtoff= values on all platforms, + not merely on platforms defining TM_GMTOFF. + The tz library's localtime and mktime functions now set tzname to a value appropriate for the requested time stamp, and zdump now uses this on platforms not defining TM_ZONE, fixing a 2014g regression. diff --git a/zdump.c b/zdump.c index 0aa94fc..92dd3c1 100644 --- a/zdump.c +++ b/zdump.c @@ -851,19 +851,54 @@ delta(struct tm * newp, struct tm *oldp) return result; } +/* Return A->tm_yday, adjusted to compare it fairly to B->tm_yday. + Assume A and B differ by at most one year. */ +static int +adjusted_yday(struct tm const *a, struct tm const *b) +{ + int yday = a->tm_yday; + if (b->tm_year < a->tm_year) + yday += 365 + isleap_sum(b->tm_year, TM_YEAR_BASE); + return yday; +} + +/* If A is the broken-down local time and B the broken-down UTC for + the same instant, return A's UTC offset in seconds, where positive + offsets are east of Greenwich. On failure, return LONG_MIN. */ +static long +gmtoff(struct tm const *a, struct tm const *b) +{ +#ifdef TM_GMTOFF + return a->TM_GMTOFF; +#else + if (! b) + return LONG_MIN; + else { + int ayday = adjusted_yday(a, b); + int byday = adjusted_yday(b, a); + int days = ayday - byday; + long hours = a->tm_hour - b->tm_hour + 24 * days; + long minutes = a->tm_min - b->tm_min + 60 * hours; + long seconds = a->tm_sec - b->tm_sec + 60 * minutes; + return seconds; + } +#endif +} + static void show(timezone_t tz, char *zone, time_t t, bool v) { register struct tm * tmp; - struct tm tm; + register struct tm * gmtmp; + struct tm tm, gmtm; printf("%-*s ", longest, zone); if (v) { - tmp = my_gmtime_r(&t, &tm); - if (tmp == NULL) { + gmtmp = my_gmtime_r(&t, &gmtm); + if (gmtmp == NULL) { printf(tformat(), t); } else { - dumptime(tmp); + dumptime(gmtmp); printf(" UT"); } printf(" = "); @@ -874,10 +909,10 @@ show(timezone_t tz, char *zone, time_t t, bool v) if (*abbr(tmp) != '\0') printf(" %s", abbr(tmp)); if (v) { + long off = gmtoff(tmp, gmtmp); printf(" isdst=%d", tmp->tm_isdst); -#ifdef TM_GMTOFF - printf(" gmtoff=%ld", tmp->TM_GMTOFF); -#endif /* defined TM_GMTOFF */ + if (off != LONG_MIN) + printf(" gmtoff=%ld", off); } } printf("\n"); -- 1.9.3

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Thread Safety Notes
by Andy Heninger Sept. 22, 2014

Sept. 22, 2014

I've been looking over the thread safe additions to localtime.c, and have a few comments. 1. Use of C's 'volatile' declaration is not sufficient to implement fully thread-safe double-checked locking. The complications are confusing and subtle. Here is a paper that goes into the question in depth: http://www.aristeia.com/Papers/DDJ_Jul_Aug_2004_revised.pdf The bottom line is that doing it right needs memory barrier operations - a read acquire and write release or equivalent for the flag variable being tested. Volatile does not guarantee these. C11 has the necessary functions, but is not yet widely available. [ http://www.open-std.org/jtc1/sc22/WG14/www/docs/n1570.pdf ] Compilers mostly have non-standard extensions available that will do the job, often modeled after those in gcc. 2. The function gmtcheck() needs to recheck the gmt_is_set flag after acquiring the lock. As it stands, multiple threads could replicate the initialization, overwriting a previously set gmtptr in the process. This is unrelated to the volatile question. 3. The volatile variable lcl_is_set is referenced while not holding the lock in only one place, in localtime_r(). And from there the function localtime_tzset() is unconditionally called, which unconditionally acquires the lock. With minor refactoring, all access to lcl_is_set could be from code that is holding the lock, which would allow lcl_is_set to be an ordinary variable with no special thread safety considerations. If it were up to me, I would probably remove use of the double-checked idiom, and rely on solely lock(). Slightly slower, but simple, portable and safe. The alternative is to #define some compiler-dependent atomic operations. Thanks, -- Andy Heninger

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Europe/London Sat Oct 26 23:00:00 1968 UT
by "" Sept. 15, 2014

Sept. 15, 2014

Looks like isdst should be 1 on Europe/London Sat Oct 26 23:00:00 1968 and Europe/London Sun Oct 31 01:59:59 1971 zdump -v -c 1968,1973 Europe/London Europe/London -9223372036854775808 = NULL Europe/London -9223372036854689408 = NULL Europe/London Sun Feb 18 01:59:59 1968 UT = Sun Feb 18 01:59:59 1968 GMT isdst=0 gmtoff=0 Europe/London Sun Feb 18 02:00:00 1968 UT = Sun Feb 18 03:00:00 1968 BST isdst=1 gmtoff=3600 Europe/London Sat Oct 26 22:59:59 1968 UT = Sat Oct 26 23:59:59 1968 BST isdst=1 gmtoff=3600 Europe/London Sat Oct 26 23:00:00 1968 UT = Sun Oct 27 00:00:00 1968 BST isdst=0 gmtoff=3600 Europe/London Sun Oct 31 01:59:59 1971 UT = Sun Oct 31 02:59:59 1971 BST isdst=0 gmtoff=3600 Europe/London Sun Oct 31 02:00:00 1971 UT = Sun Oct 31 02:00:00 1971 GMT isdst=0 gmtoff=0 Europe/London Sun Mar 19 01:59:59 1972 UT = Sun Mar 19 01:59:59 1972 GMT isdst=0 gmtoff=0 Europe/London Sun Mar 19 02:00:00 1972 UT = Sun Mar 19 03:00:00 1972 BST isdst=1 gmtoff=3600 Europe/London Sun Oct 29 01:59:59 1972 UT = Sun Oct 29 02:59:59 1972 BST isdst=1 gmtoff=3600 Europe/London Sun Oct 29 02:00:00 1972 UT = Sun Oct 29 02:00:00 1972 GMT isdst=0 gmtoff=0 Europe/London 9223372036854689407 = NULL Europe/London 9223372036854775807 = NULL

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Typo in africa timezone file
by Marcel Telka Sept. 11, 2014

Sept. 11, 2014

In https://www.ietf.org/timezones/data/africa I found the following lines: # From Gunther Vermier (2015-05-13): # our Egypt office confirms that the change will be at 15 May "midnight" (24:00) I think the timestamp (2015-05-13) is not correct there. Should it say 2014-05-13 instead? -- +-------------------------------------------+ | Marcel Telka e-mail: marcel(a)telka.sk | | homepage: http://telka.sk/ | | jabber: marcel(a)jabber.sk | +-------------------------------------------+

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Regarding Russian Time zone change
by Peddi, Radhika (Radhika) Sept. 9, 2014

Sept. 9, 2014

Hi, I have taken latest tzdata tar and replaced Europe time zone in my joda. However I didn't find any changes in October 26 UTC Off string. Can you please tell me whether the changes are included in tzdata or not? Thanks & Regards, Radhika Peddi|Avaya India Pvt. Ltd.| Wing 'A', Level -5, Tower-11, Cybercity, Magarpatta City, Hadapsar | Pune, 411028|India Voice +91 20 4101 8311| Email: rpeddi<mailto:rpeddi@avaya.com>@avaya.com [Please consider the environment before printing this email]|7 Switch off POWER |[cid:image008.jpg@01CD293C.65903AA0] Save Water |q RECYCLE |P PRESERVE trees |

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valgrind errors loading UTC
by Richter, Jörg Sept. 8, 2014

Sept. 8, 2014

When loading ‚UTC‘ the function tzload seems to use an uninitialized value here: localtime.c:574: for (i = 0; i < sp->typecnt; ++i) if (sp->types[i] == 0) // <- sp->types[0] is uninitialized (sp->typecnt is 1) break; It might be a user error on my side. But I am unable to spot it. Note that the UTC file was generated with an older version. This is with tzcode2014g - Jörg

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