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TZ database format specification
by Sean B. Durkin Jan. 25, 2007

Jan. 25, 2007

Hello, Where can I find the specification for the format of the files within the TZ database? I am developing a Delphi (pascal) program to do time zone conversions, using the TZ database. Faithfully, Sean B. Durkin

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Mexico DST news
by Jesper Norgaard Welen Jan. 23, 2007

Jan. 23, 2007

I have not found any single news item that any political decision has been taken whether to follow in Mexico the new US DST rule (that is a month longer than the old one). After the legal fight between former president Vicente Fox and former Mexico City mayor Manuel Lopez Obrador it was clarified in supreme court that DST issues remain with the Congress. On the page of the Energy Saving Trust of Mexico http://www.fide.org.mx/servicios/verano.html it says that DST (spanish: horario de verano) will start in 2007 Sunday 1.st. of April, and end Sunday 28.th. of October (old US-style DST). In the following page http://www.cenam.mx/HoraExacta.asp there is an explanation of that USA will change their schedule to be from Second Sunday of March at 2:00 until First Sunday of November at 2:00 while Mexico will continue with the old DST that is from First Sunday of April at 2:00 to Last Sunday of October at 2:00. However, I'm willing to bet a dinner on that Mexico will follow US from one of these two scenarios: (a) A hasty just-in-time decision puts Mexico on US DST just before 11.th. of March 2007. (b) Next year, a decision is made to put Mexico on the new US style DST, e.g. starting 9.th. of March 2008. Of course at the moment it looks like Mexico is in good company since Cuba, Haiti and Turks & Caicos Islands will also follow old-style US DST. But that is also a reason to keep a close eye on these countries, which might possibly change to keep it simpler to do business with the US (essentially the argument for Canada to change). I found the page http://www.cddhcu.gob.mx/bibliot/publica/inveyana/polisoc/horver/capitulo5.h tm which belongs to the Mexican Congrees (Camara de Diputados) that mentions the different timezone rules in Mexico since 1921. A fair amount of it corresponds well with the tz database (and therefore with Shanks, I presume) but there are differences. If everything is taken literally, there are at least a need to introduce new timezones for the states Campeche, Tamaulipas, Tabasco+CHS, Baja California Sur, Durango, Veracruz+Oaxaca, and Coahuila. Before I go too far with deciphering this, I would like to hear the general opinion about if this is an authoritative source or not - after all the Congress only recently got authority over timezone issues in Mexico (formally), and this list might have some goofed up details from extracting from old documents by "new" people. It does seem odd that there is no activity between 1948 and 1981. But perhaps we should just rely on Shanks for that period. Particularly I would like Paul Eggert's/David Olson's opinion on this. Regards, - Jesper Jesper Nørgaard Welen Email: jnorgard(a)Prodigy.Net.mx Project Leader (Líder de Proyecto) Software CIMMYT - Centro Internacional de Mejoramiento de Maíz y Trigo Dirección: CIMMYT Int. c/o Jesper Nørgaard Km. 45, Carretera México-Veracruz El Batán Texcoco, Edo. de México CP 56130 MEXICO Tel.: +52 (55) 58-04-20-04 ext. 1374 Fax: +52 (55) 58-04-75-58 Tel. Casa: 53-10-05-95 ó 53-10-97-78 Download the shareware program World Time Explorer, I made: http://www.worldtimeexplorer.com/index.html

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Comparing updates
by Dillard, Tom Jan. 22, 2007

Jan. 22, 2007

Hi, I am hoping someone can direct me to what I hope is an easy question. I would like to compare the TZ differences between 2006m down to 2006p. What changes went in between those versions? Thanks, Tom Dillard | 972-461-4116 | tom.dillard(a)tekelec.com

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variations on GMT-8:00
by Curtis Doty Jan. 19, 2007

Jan. 19, 2007

Hi, this is just historical curiosity. I notice that "Rule CA" is applied to Zone America/Los_Angeles (and therefore US/Pacific and US/Pacific-New). But Zone PST8PDT does not have these same (California?) rules. Is there a political precedence for this? I see the bulk of the differences are the period from 1948 until the Uniform Time Act. But it's also curious that America/Los_Angeles references the US rule that defines PST from 1983 to 1918; whereas PST8PDT does not. Why this discrepancy between PST8PDT and the equivalent geographically named zones that use PST? If there is an online explanation for this kind of thing, I'd happily go RTFW. ../C

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(no subject)
by Jha, Vikash Kumar Jan. 18, 2007

Jan. 18, 2007

Hi, I am using RedHat linux 2.4.18 ....For updating for new DST rules .. What are the things I should do...? Please let me know. Regars Vikash

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FW: Cross building tzcode
by Olson, Arthur David (NIH/NCI) [E] Jan. 11, 2007

Jan. 11, 2007

Let's see if we can include the attachment this time, yes? --ado -----Original Message----- From: John Faith [mailto:jfaith@freescale.com] Sent: Thursday, January 11, 2007 1:39 PM To: tz(a)lecserver.nci.nih.gov Subject: Cross building tzcode Hello, In the hope that this might be useful to someone else, attached is a patch to the main tzcode Makefile that we use to cross build. The reason for the patch is that in a cross-compiling environment, generating the data files requires a zic which runs on the host and the target requires the cross-built binary, so the Makefile generates both. I have tested this with ARM targets. We build using a rpm .spec file with something like: make HOST_CC=<path_to_the_host_cc> TOPDIR=%{__prefix} TZDIR=%{_prefix}/share/zoneinfo ETCDIR=%{_prefix}/usr/bin By the way, you can probably ignore the parts about "nawk"->"awk" (I did not have nawk installed), and the bit about "ksh"->"bash" (I didn't have ksh). Thanks! , John Faith Freescale Semiconductor --- timezone-2006n/Makefile.orig 2006-10-02 12:32:16.000000000 -0700 +++ timezone-2006n/Makefile 2006-10-19 10:25:23.000000000 -0700 @@ -218,9 +218,11 @@ CFLAGS= zic= ./zic ZIC= $(zic) $(ZFLAGS) +zic-host= ./zic-host +ZIC-HOST= $(zic-host) $(ZFLAGS) # The name of a Posix-compliant `awk' on your system. -AWK= nawk +AWK= awk # The path where SGML DTDs are kept. SGML_SEARCH_PATH= $(TOPDIR)/share/doc/sgml-lib/REC-html401-19991224/ @@ -244,8 +246,15 @@ VALIDATE_ENV = \ cc= cc CC= $(cc) -DTZDIR=\"$(TZDIR)\" +# Get host compiler for cross environment. If HOST_CC is not defined, +# assume non-cross build. +ifndef HOST_CC + HOST_CC=$(CC) +endif + TZCSRCS= zic.c localtime.c asctime.c scheck.c ialloc.c TZCOBJS= zic.o localtime.o asctime.o scheck.o ialloc.o +TZCOBJS-HOST= zic-host.o localtime-host.o asctime-host.o scheck-host.o ialloc-host.o TZDSRCS= zdump.c localtime.c ialloc.c TZDOBJS= zdump.o localtime.o ialloc.o DATESRCS= date.c localtime.c logwtmp.c strftime.c asctime.c @@ -278,12 +287,12 @@ ENCHILADA= $(DOCS) $(SOURCES) $(DATA) $( SHELL= /bin/sh -all: tzselect zic zdump $(LIBOBJS) +all: tzselect zic zic-host zdump $(LIBOBJS) ALL: all date install: all $(DATA) $(REDO) $(TZLIB) $(MANS) $(TABDATA) - $(ZIC) -y $(YEARISTYPE) \ + $(ZIC-HOST) -y $(YEARISTYPE) \ -d $(TZDIR) -l $(LOCALTIME) -p $(POSIXRULES) -rm -f $(TZDIR)/iso3166.tab $(TZDIR)/zone.tab cp iso3166.tab zone.tab $(TZDIR)/. @@ -314,15 +323,18 @@ zdump: $(TZDOBJS) zic: $(TZCOBJS) yearistype $(CC) $(CFLAGS) $(LFLAGS) $(TZCOBJS) $(LDLIBS) -o $@ +zic-host: $(TZCOBJS-HOST) yearistype + $(HOST_CC) $(CFLAGS) $(LFLAGS) $(TZCOBJS-HOST) $(LDLIBS) -o $@ + yearistype: yearistype.sh cp yearistype.sh yearistype chmod +x yearistype -posix_only: zic $(TDATA) - $(ZIC) -y $(YEARISTYPE) -d $(TZDIR) -L /dev/null $(TDATA) +posix_only: zic-host $(TDATA) + $(ZIC-HOST) -y $(YEARISTYPE) -d $(TZDIR) -L /dev/null $(TDATA) -right_only: zic leapseconds $(TDATA) - $(ZIC) -y $(YEARISTYPE) -d $(TZDIR) -L leapseconds $(TDATA) +right_only: zic-host leapseconds $(TDATA) + $(ZIC-HOST) -y $(YEARISTYPE) -d $(TZDIR) -L leapseconds $(TDATA) # In earlier versions of this makefile, the other two directories were # subdirectories of $(TZDIR). However, this led to configuration errors. @@ -333,9 +345,9 @@ right_only: zic leapseconds $(TDATA) # Therefore, the other two directories are now siblings of $(TZDIR). # You must replace all of $(TZDIR) to switch from not using leap seconds # to using them, or vice versa. -other_two: zic leapseconds $(TDATA) - $(ZIC) -y $(YEARISTYPE) -d $(TZDIR)-posix -L /dev/null $(TDATA) - $(ZIC) -y $(YEARISTYPE) \ +other_two: zic-host leapseconds $(TDATA) + $(ZIC-HOST) -y $(YEARISTYPE) -d $(TZDIR)-posix -L /dev/null $(TDATA) + $(ZIC-HOST) -y $(YEARISTYPE) \ -d $(TZDIR)-leaps -L leapseconds $(TDATA) posix_right: posix_only other_two @@ -364,6 +376,7 @@ tzselect: tzselect.ksh sed \ -e 's|AWK=[^}]*|AWK=$(AWK)|g' \ -e 's|TZDIR=[^}]*|TZDIR=$(TZDIR)|' \ + -e 's|/bin/ksh|/bin/bash|g' \ <$? >$@ chmod +x $@ @@ -423,4 +436,8 @@ scheck.o: private.h strftime.o: tzfile.h zic.o: private.h tzfile.h +# Rules for host objects +%-host.o: %.c + $(HOST_CC) $(CFLAGS) -c $< -o $@ + .KEEP_STATE:

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Cross building tzcode
by John Faith Jan. 11, 2007

Jan. 11, 2007

Hello, In the hope that this might be useful to someone else, attached is a patch to the main tzcode Makefile that we use to cross build. The reason for the patch is that in a cross-compiling environment, generating the data files requires a zic which runs on the host and the target requires the cross-built binary, so the Makefile generates both. I have tested this with ARM targets. We build using a rpm .spec file with something like: make HOST_CC=<path_to_the_host_cc> TOPDIR=%{__prefix} TZDIR=%{_prefix}/share/zoneinfo ETCDIR=%{_prefix}/usr/bin By the way, you can probably ignore the parts about "nawk"->"awk" (I did not have nawk installed), and the bit about "ksh"->"bash" (I didn't have ksh). Thanks! , John Faith Freescale Semiconductor --- timezone-2006n/Makefile.orig 2006-10-02 12:32:16.000000000 -0700 +++ timezone-2006n/Makefile 2006-10-19 10:25:23.000000000 -0700 @@ -218,9 +218,11 @@ CFLAGS= zic= ./zic ZIC= $(zic) $(ZFLAGS) +zic-host= ./zic-host +ZIC-HOST= $(zic-host) $(ZFLAGS) # The name of a Posix-compliant `awk' on your system. -AWK= nawk +AWK= awk # The path where SGML DTDs are kept. SGML_SEARCH_PATH= $(TOPDIR)/share/doc/sgml-lib/REC-html401-19991224/ @@ -244,8 +246,15 @@ VALIDATE_ENV = \ cc= cc CC= $(cc) -DTZDIR=\"$(TZDIR)\" +# Get host compiler for cross environment. If HOST_CC is not defined, +# assume non-cross build. +ifndef HOST_CC + HOST_CC=$(CC) +endif + TZCSRCS= zic.c localtime.c asctime.c scheck.c ialloc.c TZCOBJS= zic.o localtime.o asctime.o scheck.o ialloc.o +TZCOBJS-HOST= zic-host.o localtime-host.o asctime-host.o scheck-host.o ialloc-host.o TZDSRCS= zdump.c localtime.c ialloc.c TZDOBJS= zdump.o localtime.o ialloc.o DATESRCS= date.c localtime.c logwtmp.c strftime.c asctime.c @@ -278,12 +287,12 @@ ENCHILADA= $(DOCS) $(SOURCES) $(DATA) $( SHELL= /bin/sh -all: tzselect zic zdump $(LIBOBJS) +all: tzselect zic zic-host zdump $(LIBOBJS) ALL: all date install: all $(DATA) $(REDO) $(TZLIB) $(MANS) $(TABDATA) - $(ZIC) -y $(YEARISTYPE) \ + $(ZIC-HOST) -y $(YEARISTYPE) \ -d $(TZDIR) -l $(LOCALTIME) -p $(POSIXRULES) -rm -f $(TZDIR)/iso3166.tab $(TZDIR)/zone.tab cp iso3166.tab zone.tab $(TZDIR)/. @@ -314,15 +323,18 @@ zdump: $(TZDOBJS) zic: $(TZCOBJS) yearistype $(CC) $(CFLAGS) $(LFLAGS) $(TZCOBJS) $(LDLIBS) -o $@ +zic-host: $(TZCOBJS-HOST) yearistype + $(HOST_CC) $(CFLAGS) $(LFLAGS) $(TZCOBJS-HOST) $(LDLIBS) -o $@ + yearistype: yearistype.sh cp yearistype.sh yearistype chmod +x yearistype -posix_only: zic $(TDATA) - $(ZIC) -y $(YEARISTYPE) -d $(TZDIR) -L /dev/null $(TDATA) +posix_only: zic-host $(TDATA) + $(ZIC-HOST) -y $(YEARISTYPE) -d $(TZDIR) -L /dev/null $(TDATA) -right_only: zic leapseconds $(TDATA) - $(ZIC) -y $(YEARISTYPE) -d $(TZDIR) -L leapseconds $(TDATA) +right_only: zic-host leapseconds $(TDATA) + $(ZIC-HOST) -y $(YEARISTYPE) -d $(TZDIR) -L leapseconds $(TDATA) # In earlier versions of this makefile, the other two directories were # subdirectories of $(TZDIR). However, this led to configuration errors. @@ -333,9 +345,9 @@ right_only: zic leapseconds $(TDATA) # Therefore, the other two directories are now siblings of $(TZDIR). # You must replace all of $(TZDIR) to switch from not using leap seconds # to using them, or vice versa. -other_two: zic leapseconds $(TDATA) - $(ZIC) -y $(YEARISTYPE) -d $(TZDIR)-posix -L /dev/null $(TDATA) - $(ZIC) -y $(YEARISTYPE) \ +other_two: zic-host leapseconds $(TDATA) + $(ZIC-HOST) -y $(YEARISTYPE) -d $(TZDIR)-posix -L /dev/null $(TDATA) + $(ZIC-HOST) -y $(YEARISTYPE) \ -d $(TZDIR)-leaps -L leapseconds $(TDATA) posix_right: posix_only other_two @@ -364,6 +376,7 @@ tzselect: tzselect.ksh sed \ -e 's|AWK=[^}]*|AWK=$(AWK)|g' \ -e 's|TZDIR=[^}]*|TZDIR=$(TZDIR)|' \ + -e 's|/bin/ksh|/bin/bash|g' \ <$? >$@ chmod +x $@ @@ -423,4 +436,8 @@ scheck.o: private.h strftime.o: tzfile.h zic.o: private.h tzfile.h +# Rules for host objects +%-host.o: %.c + $(HOST_CC) $(CFLAGS) -c $< -o $@ + .KEEP_STATE:

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Canada DST Rules for 2007
by Johan Lindfors Jan. 10, 2007

Jan. 10, 2007

Hi, I'm verifying Canada DST in 2007 Rules and there seems to be conflict with documentation in these pages and in the source page. (Also I may be the conflict ;-)) But please could you verify this: These two pages: http://home.tiscali.nl/~t876506/TZworld.html#nam http://home.tiscali.nl/~t876506/Multizones.html#ca Versus source pages: http://inms-ienm.nrc-cnrc.gc.ca/time_services/daylight_saving_e.html http://inms-ienm.nrc-cnrc.gc.ca/faq_time_e.html#5 Possible conflicts: 1. Can not found explanation from source page why DST should end Last Sun of October in following Cities instead of First Sunday in November(Canada)? Canada >=2007 on Mar Sun>=8 2:00 1:00 Canada >=2007 off Nov Sun>=1 2:00 0 Winn on Apr Sun>=1 2:00 1:00 Winn off Oct lastSun 2:00s 0 Edm on Apr Sun>=1 2:00 1:00 Edm off Oct lastSun 2:00 0 Vanc on Apr Sun>=1 2:00 1:00 Vanc off Oct lastSun 2:00 0 NT_YK on Apr Sun>=1 2:00 1:00 NT_YK off Oct lastSun 2:00 0 2. In the source page there are defined that Manitoba that is same as Winnipeg DST ends 3:00 instead of 2:00. Winn on Apr Sun>=1 2:00 1:00 Winn off Oct lastSun 2:00s 0 Br Johan Lindfors

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Re: FW: suggestion for simplified represention of timezone rules
by Paul Eggert Jan. 9, 2007

Jan. 9, 2007

Robert Hodge <roberth(a)sisconet.com> writes: > It's not a source code issue. I have been able to compile it on windows. > The problem is that the resultant files don't work correctly. They > don't reflect the rules that are defined in the zoneinfo source files. In what sense do the files not work, exactly? For example, does your zic's output match the output generated by zic on GNU/Linux or Unix machines? If so, then the problem is not with the way you built zic; it lies somewhere else. If not, then exactly how does the output differ? > It appears that the existing zoneinfo 'compilers' are misinterpreting > the text data and are building binary zone files incorrectly. zic should be quite reliable on GNU/Linux and Unix platforms, as its output is used in a lot of places. Occasionally we get bug reports, and we do fix any specific bugs that are reported. It is certainly quite possible that there is a portability bug when zic is run on non-POSIXish platforms. However, your report did not contain enough details for us to know what the bug is, or how to reproduce it.

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suggestion for simplified represention of timezone rules
by Robert Hodge Jan. 8, 2007

Jan. 8, 2007

Hello, I have been doing extensive work with the tz database, and while the data is quite useful, it is not in the most accessible format. I have had little success using the zic compiler or any of the source code, and have been forced to do my own parsing and analysis of the data. One aspect of the representation of rules I find awkward is the notation for the day on which a rule takes effect. There are rules such as "lastSun" or "Sun>=8", etc. While descriptive, they are are hard to process. I would like to suggest a better approach. It takes the form "d op nn", where 'd' is the day-of-week, 0=Sun to 6=Sat 'op' is a comparison code of '<', '=' or '>', and 'nn' is a 2-digit day number (may be 00 or 32) The comparision code works as follows: '=' nn is an exact value '<' rule describes the last day less than nn '>' rule describes the first day greater than nn Examples: 0>07 first Sun > 7 (same as first Sun >= 8) 0<32 last Sun < 32 (same as "lastSun") 0=27 Sun the 27th of the month When a range of years are involved in a rule, there is no exact day-of-week, and in such cases, '9' may be used as a place-holder: 9=01 the first day of the month, regardless of what day-of-week it is There is little need to use a day-of-week with >, since the value would always be the same. Example: 9>07 means: first day of the month (regardless of day of week) that is > 7 is always 8. It is conceivable that 9<nn could be used, but the only case where it would have any merit is in February: 9<32 last day of the month For months other than Feb, the value is a constant for a given month, and for Feb it depends on the leap-year status. Since no one (that I know of) does anthing about DST in Feb, we can safely eliminate the 9<nn form as well as the 9>nn form. The conversion from existing rules to this format is pretty straightforward: lastSun 0<32 '32' is constant for 'last' Sun>=8 0>07 subtract 1 from the tz rule value Sun<=21 0<22 add 1 to the tz rule value May 1 9=01 for May 1 of any year May 1 1980 4=01 May 1 1980 is a Thursday Hope you find this interesting. Regards, Robert Hodge

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