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UK timezones
by pla＠sktb.demon.co.uk Jan. 20, 1999

Jan. 20, 1999

Since May 1994, one small part of mainland Britain has been running on a different timezone from the rest of the UK. The exception is Cheriton Terminal, the rail terminal at the UK end of the Channel Tunnel (run by the Eurotunnel Concession) at Cheriton, Folkestone, Kent. Cheriton Terminal runs on Concession Time (abbreviation CT) in winter and Concession Time (abbreviation CT) in summer. You might think the names and abbreviations are confusing and stupid, I couldn't possibly comment. CT is formally defined to be equivalent to French Civil Time. So at present, given the way the EU timezone rules operate and the fact that the French have not yet persuaded the EU to let them abandon daylight savings time, CT is one hour ahead of GMT in winter and one hour ahead of BST in summer. This information came via Clive Feather of Demon Internet who puzzled many Demon Internet users by asking which part of the UK was in a different timezone. It goes without saying that Clive is a rail enthusiast... --Paul

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tzcode1999a.tar.gz and tzdata1999a.tar.gz
by Olson, Arthur David (NCI) Jan. 19, 1999

Jan. 19, 1999

The files ftp://elsie.nci.nih.gov/pub/tzcode1999a.tar.gz and ftp://elsie.nci.nih.gov/pub/tzdata1999a.tar.gz are now available. These include error message internationalizations and corrections in zic.c and zdump.c (as suggested by Vladimir Michl, vladimir.michl(a)upol.cz, to whom thanks!) --ado

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Partially translated output in timezones utils
by Vladimir Michl Jan. 18, 1999

Jan. 18, 1999

>Submitter-Id: net >Originator: Vladimir Michl >Organization: >Confidential: no >Synopsis: Partially translated output >Severity: >Priority: >Category: libc >Class: >Release: libc-2.0.109 >Environment: Host type: i586-pc-linux-gnu System: Linux trpajzlik 2.0.36 #3 Út pec 8 19:21:57 CET 1998 i586 unknown Architecture: i586 Addons: crypt linuxthreads localedata Build CFLAGS: -g -O2 Build CC: gcc Build shared: yes Build profile: yes Build omitfp: no Stdio: libio >Description: In file timezone/zdump.c on line 266 is code: (void) fprintf(stderr, _("%s: Error writing standard output "), argv[0]); (void) perror(_("standard output")); (void) exit(EXIT_FAILURE); The result of this code will be: "xxxx: Error writing standard output standard output: xxxxx" I suggest this change: (void) fprintf(stderr, _("%s: Error writing "), argv[0]); (void) perror(_("standard output")); (void) exit(EXIT_FAILURE); On line 768 of timezone/zic.c is code: return (errnum > 0 && errnum <= sys_nerr) ? sys_errlist[errnum] : "Unknown system error"; Message "Unknown system error" is not marked for translation. Please mark it. In file timezone/zic.c on line 433 in function warning(string) is: cp = ecpyalloc("warning: "); If this function is called output may be: warning: tento soubor neexistuje It is translated partially. Please, mark this message for translation. Thank you Vladimir Michl -- ********************************************************************** * Name: Vladimir Michl Student of Palacky University * * E-mail: Vladimir.Michl(a)upol.cz, MichlV(a)risc.upol.cz * * Web: http://www.inf.upol.cz/~michlv * * Address: U nove skoly 292 * * Velky Tynec * * 783 72 * * Czech Republic * **********************************************************************

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changes for Nicaragua and Fiji
by Steffen Thorsen Dec. 29, 1998

Dec. 29, 1998

Dear Sirs, Nicaragua seems to be back at -6:00 but I have not been able to find when they changed from -5:00, so I have not included any patch for this change. (I got this information from a citizen in Managua. I've also tried telnet ibw.com.ni 13 which is located there, and it shows -6:00 to UTC) It seems like Fiji has started using DST now, but they provide information only for the change this year. I have tried to make a diff for australasia and had to make a new rule for "Fiji" because of the DST. Patch for Fiji is included at the end. Leo Brandewie <lbrand(a)earthlink.net> got this information from the Fiji Government: Forwarded: Here's what I got back from the Fijian Government. Note that it fails to provide general rules, and due to a nasty coincidence we cannot infer them without risk. Since Nov. 1 and Feb 28 are both Sundays, we can assume but not prove that it starts on the first Sun. in Nov. and ends on the last Sun. in Feb. Hope this helps, Leo [ Part 2: "Included Message" ] Date: Tue, 29 Dec 1998 14:20:20 +0000 From: Fiji Government <info(a)fiji.gov.fj> To: Leo Brandewie <lbrand(a)earthlink.net> Subject: Re: Daylight Savings Leo Below is a Government press release on the 5th of October on Daylight Savings. "The Minister for Labour and Industrial Relations, Mr Vincent Lobendahn declared Daylight Saving to commence on November 1st, 1998. This means that at 2am on Sunday 1 November, clocks will be put forward to 3am and at 3am on Sunday 28 February 1999, clocks will be put back to 2am. The concept of daylight saving means that extra daylight will be available at the end of each day during the daylight saving period. The advantages of of daylight saving include: more time for sport, family recreation, gardening and other outdoor activities, savings in respect of electricity, reduction in nightime road accidents, increase in economic activity, with longer daylight hours for productive work activities, benefits to tourism by making best use of available daylight. According to a spokesman from the Ministry of Labour and Industrial Relations, Sunday morning has been chosen to ensure the least disruption to work activities as only shift workers employed at that time will be affected. The spokesman said the people will have to put their clocks forward by one hour before they go to bed on Saturday 31 October, which will ensure their time is correct when they wake up on Sunday morning. The same will apply on Saturday, 27 February next year, except that people will need to put their clocks back by one hour before they go to bed. However, shift workers employed at the time that clocks are officially changed will be affected. This means that a shift worker working an eight hour night shift starting at 10pm on Saturday 31 October and finishing at 6am on Sunday, 1 November 1998 will start and finish at those times but will work only seven hours due to the change in time. However, the person will still be entitled to eight hours pay. And a person who works the same shift from 10pm on Saturday 27 February until 6am on Sunday 28 February 1999 will work nine hours due to the change in time. The person must be paid for the extra hour and if the contract of service provides for overtime to be paid after eight hours, he or she would be entitled to the overtime rate of pay for the ninth hour of work." -END- diff -u australasia.old australasia --- australasia.old Thu Sep 24 16:46:09 1998 +++ australasia Tue Dec 29 11:31:06 1998 @@ -197,9 +197,15 @@ Zone Indian/Cocos 6:30 - CCT # Cocos Islands Time # Fiji + +# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S +Rule Fiji 1998 only - Nov 1 2:00 1:00 - +Rule Fiji 1999 only - Feb 28 3:00 0:00 - + # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Pacific/Fiji 11:53:40 - LMT 1915 Oct 26 # Suva - 12:00 - FJT # Fiji Time + 12:00 - FJT 1998 Nov 1 + 12:00 Fiji FJT # Fiji Time # French Polynesia # Zone NAME GMTOFF RULES FORMAT [UNTIL]

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New labels in EOP IERS/CB solutions
by IERS/CB Dec. 28, 1998

Dec. 28, 1998

Subject : Change in the labelling of the IERS/BC EOP solutions on January 1 >From D. Gambis Dear Colleagues, Please note the following labelling changes in the EOP solutions of the IERS Central Bureau: In order to avoid confusion, starting from 1 JANUARY 1999, the LABELS of IERS/BC solutions EOP(IERS) 97 C 01, 02, 03, 04 will be changed to: EOP(IERS) C 01 EOP(IERS) C 02 EOP(IERS) C 03 EOP(IERS) C 04 I hope that this will not introduce any problem in your data handling. Best Wishes to all for 1999. D. Gambis

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Israel Timezone -- Dates for 1999
by Ephraim Silverberg Dec. 28, 1998

Dec. 28, 1998

Here are the dates for Israel for 1999. The main changes are starting in 1999, the Friday morning changeover to DST will take place at 2 a.m. instead of midnight and the change back will also be on a Friday morning at 2 a.m. instead of Saturday night at midnight. The following are context diffs for the file 'asia' extracted from ftp://elsie.nci.nih.gov/pub/tzdata1998i.tar.gz -----------------------------Begin Context Diff------------------------------ *** asia Thu Sep 24 16:46:09 1998 --- asia.new Mon Dec 28 12:26:31 1998 *************** *** 509,530 **** Rule Zion 1988 only - Sep 3 0:00 0 S # From Ephraim Silverberg <ephraim(a)cs.huji.ac.il> ! # (1997-03-04 and 1998-03-16): # According to the Office of the Secretary General of the Ministry of # Interior, there is NO set rule for Daylight-Savings/Standard time changes. ! # Each year they decide anew what havoc to wreak on the country. However, ! # there is a "supposed" set of rules which is subject to change depending ! # on the party the Minister of Interior, the size of the coalition ! # government, the phase of the moon and the direction of the wind. Hence, ! # changes may need to be made on a semi-annual basis. One thing is entrenched ! # in law, however: that there must be at least 150 days of daylight savings ! # time annually. Ever since 1993, the change to daylight savings time is ! # on a Thursday night from midnight IST to 1 a.m IDT. The change back to ! # standard time is on a Saturday night from midnight daylight savings time ! # to 11 p.m. standard time. 1996 is an exception to this rule where the ! # change back to standard time took place on Sunday night instead of Saturday ! # night to avoid conflicts with the Jewish New Year. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Zion 1989 only - Apr 30 0:00 1:00 D --- 509,529 ---- Rule Zion 1988 only - Sep 3 0:00 0 S # From Ephraim Silverberg <ephraim(a)cs.huji.ac.il> ! # (1997-03-04, 1998-03-16 and 1998-12-28): # According to the Office of the Secretary General of the Ministry of # Interior, there is NO set rule for Daylight-Savings/Standard time changes. ! # One thing is entrenched in law, however: that there must be at least 150 ! # days of daylight savings time annually. From 1993-1998, the change to ! # daylight savings time was on a Friday morning from midnight IST to ! # 1 a.m IDT; up until 1998, the change back to standard time was on a ! # Saturday night from midnight daylight savings time to 11 p.m. standard ! # time. 1996 is an exception to this rule where the change back to standard ! # time took place on Sunday night instead of Saturday night to avoid ! # conflicts with the Jewish New Year. Starting in 1999, the change to ! # daylight savings time will still be on a Friday morning but from ! # 2 a.m. IST to 3 a.m. IDT; furthermore, the change back to standard time ! # will now also be on a Friday morning from 2 a.m. IDT to 1 a.m. IST. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Zion 1989 only - Apr 30 0:00 1:00 D *************** *** 570,588 **** Rule Zion 1997 only - Sep 14 0:00 0 S Rule Zion 1998 only - Mar 20 0:00 1:00 D Rule Zion 1998 only - Sep 6 0:00 0 S ! # From Member of Knesset Avraham Poraz, as quoted in Ha'aretz (1998-09-02): ! # [The 1998-09-06 transition is to] serve the interests of a small minority ! # of ultra-Orthodox Sephardic Jews who, during the [Hebrew] month of Elul, ! # recite Slihot penitential prayers in the early morning hours ! # and thus find daylight time inconvenient. # From Paul Eggert (1998-01-12): ! # Here are guesses for rules after 1998. # They are probably wrong, but they are more likely than no DST at all. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S ! Rule Zion 1999 max - Mar Fri>=15 0:00 1:00 D ! Rule Zion 1999 max - Sep Sun>=1 0:00 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Jerusalem 2:20:56 - LMT 1880 --- 569,589 ---- Rule Zion 1997 only - Sep 14 0:00 0 S Rule Zion 1998 only - Mar 20 0:00 1:00 D Rule Zion 1998 only - Sep 6 0:00 0 S + Rule Zion 1999 only - Apr 2 2:00 1:00 D + Rule Zion 1999 only - Sep 3 2:00 0 S ! # Due to imminent elections in 1999, there are no dates for the year 2000 ! # and beyond. There was a move to legislate the DST rules in Israel, but ! # due to the government's fall, it most likely won't be brought to the Knesset ! # for first reading before the elections and will probably be altered by the ! # newly elected government. # From Paul Eggert (1998-01-12): ! # Here are guesses for rules after 1999. # They are probably wrong, but they are more likely than no DST at all. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S ! Rule Zion 2000 max - Mar Fri>=15 2:00 1:00 D ! Rule Zion 2000 max - Sep Fri>=1 2:00 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Asia/Jerusalem 2:20:56 - LMT 1880 ------------------------------End Context Diff------------------------------- ___________________________________________________________________________ Ephraim Silverberg, CS System Group, Phone number: 972-2-6585521 Hebrew University, Jerusalem, Israel. Fax number: 972-2-6585439 WWW: http://www.cs.huji.ac.il/~ephraim E-mail: ephraim(a)cs.huji.ac.il

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RE: Solaris mktime with multiple timezones
by Olson, Arthur David (NCI) Nov. 23, 1998

Nov. 23, 1998

I compiled the small program (bugtest.c) mentioned in the letter below using the latest elsie.nci.nih.gov source; the program ran okay. As Scott mentions, folks on the mailing list probably do need to be aware of the bug. --ado From: Scott Harrington [SMTP:seh4@ix.netcom.com] Sent: Friday, November 06, 1998 1:16 PM Subject: BUG: Solaris mktime with multiple timezones I have posted the attached message to comp.unix.solaris, so replies should probably be posted there. I wanted to notify this mailing list since the bug affects those who use multiple time zones in their programs... I have uncovered a bug in the mktime() routine found in libc.so.1 and libc.a on my SunOS 5.5.1 Generic_103640-12 sun4u sparc SUNW,Ultra-2 machine: -rw-r--r-- 1 bin bin 1155756 Jun 23 1997 /usr/lib/libc.a -rwxr-xr-x 1 bin bin 664760 Jun 23 1997 /usr/lib/libc.so.1 I have attached a small program which should determine if your system has the bug or not.

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FW: symlinks in zic
by Olson, Arthur David (NCI) Nov. 17, 1998

Nov. 17, 1998

-----Original Message----- From: Mani Varadarajan [SMTP:mani@be.com] Sent: Monday, November 16, 1998 9:04 PM To: eggert(a)twinsun.com; tz(a)elsie.nci.nih.gov Subject: symlinks in zic Dear Time Zone experts, I incorporated your timezone database into the BeOS last year. The BeOS file system does not support hard links, so I had to implement symbolic link support myself. Judging from the latest version of tzcode, which I just stumbled upon today, I notice that you have done the same. I suggest a few changes to your implementation, detailed in the attached diff. The problem with how it is right now is that if zic is invoked as follows: zic -d foodir <rules files> where foodir is a relative and not an absolute path, the symbolic links in the timezone database point to bogus places. (We use relative paths in our build environment at Be during our daily builds of the BeOS.) My proposed changes fix this problem. We have used my modified version of zic for over a year now in production without any problems. Please let me know what you think of the changes. I am not on this list so please keep me on the CC list. Thanks, Mani *** zic.c.old Mon Nov 16 17:48:18 1998 --- zic.c Mon Nov 16 16:47:55 1998 *************** *** 605,616 **** if (mkdirs(toname) != 0) (void) exit(EXIT_FAILURE); result = link(fromname, toname); #if (HAVE_SYMLINK - 0) if (result != 0) { ! result = symlink(fromname, toname); if (result == 0) warning(_("hard link failed, symbolic link used")); } #endif if (result != 0) { --- 605,624 ---- if (mkdirs(toname) != 0) (void) exit(EXIT_FAILURE); + result = link(fromname, toname); #if (HAVE_SYMLINK - 0) if (result != 0) { ! char *s = (char *) tofile; ! register char * symlinkcontents = NULL; ! while ((s = strchr(s+1, '/')) != NULL) ! symlinkcontents = ecatalloc(symlinkcontents, "../"); ! symlinkcontents = ecatalloc(symlinkcontents, fromfile); ! ! result = symlink(symlinkcontents, toname); if (result == 0) warning(_("hard link failed, symbolic link used")); + ifree(symlinkcontents); } #endif if (result != 0) {

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symlinks in zic
by Mani Varadarajan Nov. 17, 1998

Nov. 17, 1998

Dear Time Zone experts, I incorporated your timezone database into the BeOS last year. The BeOS file system does not support hard links, so I had to implement symbolic link support myself. Judging from the latest version of tzcode, which I just stumbled upon today, I notice that you have done the same. I suggest a few changes to your implementation, detailed in the attached diff. The problem with how it is right now is that if zic is invoked as follows: zic -d foodir <rules files> where foodir is a relative and not an absolute path, the symbolic links in the timezone database point to bogus places. (We use relative paths in our build environment at Be during our daily builds of the BeOS.) My proposed changes fix this problem. We have used my modified version of zic for over a year now in production without any problems. Please let me know what you think of the changes. I am not on this list so please keep me on the CC list. Thanks, Mani *** zic.c.old Mon Nov 16 17:48:18 1998 --- zic.c Mon Nov 16 16:47:55 1998 *************** *** 605,616 **** if (mkdirs(toname) != 0) (void) exit(EXIT_FAILURE); result = link(fromname, toname); #if (HAVE_SYMLINK - 0) if (result != 0) { ! result = symlink(fromname, toname); if (result == 0) warning(_("hard link failed, symbolic link used")); } #endif if (result != 0) { --- 605,624 ---- if (mkdirs(toname) != 0) (void) exit(EXIT_FAILURE); + result = link(fromname, toname); #if (HAVE_SYMLINK - 0) if (result != 0) { ! char *s = (char *) tofile; ! register char * symlinkcontents = NULL; ! while ((s = strchr(s+1, '/')) != NULL) ! symlinkcontents = ecatalloc(symlinkcontents, "../"); ! symlinkcontents = ecatalloc(symlinkcontents, fromfile); ! ! result = symlink(symlinkcontents, toname); if (result == 0) warning(_("hard link failed, symbolic link used")); + ifree(symlinkcontents); } #endif if (result != 0) {

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FW: Asia/Ishigaki?
by Olson, Arthur David (NCI) Nov. 16, 1998

Nov. 16, 1998

-----Original Message----- From: Hideyuki Suzuki [SMTP:hideyuki@sat.t.u-tokyo.ac.jp] Sent: Monday, November 09, 1998 6:50 AM To: tz(a)elsie.nci.nih.gov Subject: Re: Asia/Ishigaki? I also examined other data concerning Japan in tzdata1998i. The patch at the bottom of this mail fixes the following points. - Only one timezone JST is used everywhere in Japan. - In tzdata1998i, the location of 'Tokyo' (+3542+13946) seems to be around the University of Tokyo. However, 'Tokyo' usually stands for the former location of Tokyo Astronomical Observatory: E 139 44' 40".90 (9h 18m 58s.727), N 35 39' 16".0. This data is from 'Rika Nenpyou (Chronological Scientific Tables) 1996' edited by National Astronomical Observatory of Japan. - JST (Japan Standard Time) has been used since Jan. 1, 1888 0:00AM (JST). The law is enacted on July 7, 1886. I couldn't understand the comment 'There is no information for Marcus.' Does anyone know what 'Marcus' is? -- hideyuki diff -u tzdata1998i/asia tzdata/asia --- tzdata1998i/asia Thu Sep 24 23:46:09 1998 +++ tzdata/asia Mon Nov 9 20:12:24 1998 @@ -610,12 +610,9 @@ # We go with Shanks and omit daylight saving in those years for Asia/Tokyo. # Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Asia/Tokyo 9:19:04 - LMT 1896 +Zone Asia/Tokyo 9:18:59 - LMT 1887 9:00 - JST -Zone Asia/Ishigaki 8:16:36 - LMT 1896 - 8:00 - CST # There is no information for Marcus. -# Other Japanese possessions are probably like Asia/Tokyo. # Jordan # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S diff -u tzdata1998i/zone.tab tzdata/zone.tab --- tzdata1998i/zone.tab Thu Sep 24 23:46:11 1998 +++ tzdata/zone.tab Mon Nov 9 19:25:10 1998 @@ -188,8 +188,7 @@ IT +4154+01229 Europe/Rome JM +1800-07648 America/Jamaica JO +3157+03556 Asia/Amman -JP +3542+13946 Asia/Tokyo most locations -JP +2420+12409 Asia/Ishigaki south Ryukyu Islands +JP +3539+13944 Asia/Tokyo KE -0117+03649 Africa/Nairobi KG +4254+07436 Asia/Bishkek KH +1133+10455 Asia/Phnom_Penh

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FW: Asia/Ishigaki?
by gwil＠mindspring.com Nov. 10, 1998

Nov. 10, 1998

>From: Hideyuki Suzuki [SMTP:hideyuki@sat.t.u-tokyo.ac.jp] > [...] >I couldn't understand the comment 'There is no information for Marcus.' >Does anyone know what 'Marcus' is? Marcus Island is the name used by Americans for Minami-Tori-shima. It's located at about 24 deg. 18 min. N., 153 deg. 58 min. E., which I think makes it the easternmost, as well as one of the southernmost, of the Japanese islands. It was administered by the U.S. military from the end of World War II to 1968. This background should help to explain why it's referred to by its American name, and why it might be expected to lie in a different time zone. -- Gwillim Law

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FW: Asia/Ishigaki?
by Olson, Arthur David (NCI) Nov. 9, 1998

Nov. 9, 1998

-----Original Message----- From: Hideyuki Suzuki [SMTP:hideyuki@sat.t.u-tokyo.ac.jp] Sent: Saturday, November 07, 1998 11:54 AM To: tz(a)elsie.nci.nih.gov Subject: Asia/Ishigaki? In tzdata1998i.tar.gz, I found that two timezones are defined for Japan. This is somewhat strange to me, because only JST (+0900) is used everywhere in Japan including Ishigaki island. I want to suggest that Asia/Ishigaki (CST, +0800) zone should be removed. However, you may wonder why it was added to the database, and in tzarchive I found the following comment: Date: Tue, 3 Sep 1996 17:14:22 -0700 From: Paul Eggert <eggert(a)twinsun.com> Subject: proposed patch for selecting TZ, MET->CST, Sri Lanka, Antarctica,... > Asia/Ishigaki - uncomment it, since it seems to be right I don't know whether the zone was added at this time, but I suspect that it was added because of an ambiguous reason. So, I believe that it should be removed. I'm not on the tz list, so please leave my address in Cc: line when you reply. Thanks. -- hideyuki

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Asia/Ishigaki?
by Hideyuki Suzuki Nov. 9, 1998

Nov. 9, 1998

In tzdata1998i.tar.gz, I found that two timezones are defined for Japan. This is somewhat strange to me, because only JST (+0900) is used everywhere in Japan including Ishigaki island. I want to suggest that Asia/Ishigaki (CST, +0800) zone should be removed. However, you may wonder why it was added to the database, and in tzarchive I found the following comment: Date: Tue, 3 Sep 1996 17:14:22 -0700 From: Paul Eggert <eggert(a)twinsun.com> Subject: proposed patch for selecting TZ, MET->CST, Sri Lanka, Antarctica,... > Asia/Ishigaki - uncomment it, since it seems to be right I don't know whether the zone was added at this time, but I suspect that it was added because of an ambiguous reason. So, I believe that it should be removed. I'm not on the tz list, so please leave my address in Cc: line when you reply. Thanks. -- hideyuki

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BUG: Solaris mktime with multiple timezones
by Scott Harrington Nov. 6, 1998

Nov. 6, 1998

I have posted the attached message to comp.unix.solaris, so replies should probably be posted there. I wanted to notify this mailing list since the bug affects those who use multiple time zones in their programs. -------- Original Message -------- Subject: BUG: Solaris mktime with multiple timezones Date: Fri, 06 Nov 1998 18:09:17 +0000 From: Scott Harrington <seh4(a)ix.netcom.com> Newsgroups: comp.unix.solaris I have uncovered a bug in the mktime() routine found in libc.so.1 and libc.a on my SunOS 5.5.1 Generic_103640-12 sun4u sparc SUNW,Ultra-2 machine: -rw-r--r-- 1 bin bin 1155756 Jun 23 1997 /usr/lib/libc.a -rwxr-xr-x 1 bin bin 664760 Jun 23 1997 /usr/lib/libc.so.1 The error is that mktime() returns WRONG values when you're switching between multiple time zones in a single program. I have attached a small program which should determine if your system has the bug or not. I make a mktime call in GB timezone, and then in GMT timezone. The second lookup returns incorrect values. If you have the bug, your output will be: TZ=GB 892162800 0 0 0 10 3 98 5 99 1 should be TZ=GB 892162800 0 0 0 10 3 98 5 99 1 TZ=GMT 892162800 0 0 23 9 3 98 4 98 0 should be TZ=GMT 892166400 0 0 0 10 3 98 5 99 0 On systems which implement mktime correctly, the output will be: TZ=GB 892162800 0 0 0 10 3 98 5 99 1 should be TZ=GB 892162800 0 0 0 10 3 98 5 99 1 TZ=GMT 892166400 0 0 0 10 3 98 5 99 0 should be TZ=GMT 892166400 0 0 0 10 3 98 5 99 0 I am curious to find out on which systems this bug exists. (2.6? /opt/SUNWspro/lib/libc.so.1?) The public Sunsolve patch list apropos 'libc' only led me to patch 103612-46 (I already had 103612-30) and applying this patch did not fix the problem. I have a crude LD_PRELOAD workaround (using the implementation of mktime from GNU glibc-2.0.7) for existing executables, if anyone is interested let me know and I will mail it or post it to this newsgroup. #include <time.h> #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { time_t t; { struct tm tmBuf = {0, 0, 0, 10, 3, 98, 0, 0, -1}; putenv("TZ=GB"); t = mktime(&tmBuf); printf("TZ=GB %ld %d %d %d %d %d %d %d %d %d", t, tmBuf.tm_sec, tmBuf.tm_min, tmBuf.tm_hour, tmBuf.tm_mday, tmBuf.tm_mon, tmBuf.tm_year, tmBuf.tm_wday, tmBuf.tm_yday, tmBuf.tm_isdst); printf(" should be\n"); printf("TZ=GB 892162800 0 0 0 10 3 98 5 99 1\n"); } printf("\n"); { struct tm tmBuf = {0, 0, 0, 10, 3, 98, 0, 0, -1}; putenv("TZ=GMT"); t = mktime(&tmBuf); printf("TZ=GMT %ld %d %d %d %d %d %d %d %d %d", t, tmBuf.tm_sec, tmBuf.tm_min, tmBuf.tm_hour, tmBuf.tm_mday, tmBuf.tm_mon, tmBuf.tm_year, tmBuf.tm_wday, tmBuf.tm_yday, tmBuf.tm_isdst); printf(" should be\n"); printf("TZ=GMT 892166400 0 0 0 10 3 98 5 99 0\n"); } exit(0); }

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Re: new time conversion interface
by Nathan Myers Nov. 5, 1998

Nov. 5, 1998

Paul Hill wrote: > Nathan Myers wrote: > > > We're dealing with _humans_, here. It's a reasonable goal to try to > > increase the reliability of time entries by noting likely errors. > > ... > > A note that the time changed recently is *extremely* helpful when > > getting confirmation of a time entry, but most programmers are not > > equipped or inclined to root about in a transition database, > > Why would a programmer want to? To minimize mistakes. Any relevant information the system has that the user doesn't is a lost opportunity. People are not (uniformly) stupid, and can respond usefully to a notification that an entered time is dubious. Likewise, a logged timestamp annotated with reasons to doubt it may be more useful than a bare timestamp. The conversion function has discovered the information, the calling program is equipped to decide if it's useful. > The programmer asked to please > convert the fields into a timestamp given the TZ provided. I don't > see how going to look for other transition rules has anything to > do with it. There is still a list of possible interpretations > given just one possible fully accurate TZ definition. Current conversion functions don't report a list of possible interpretations, they report just one. That's what I'd like to fix in this interface. > Going looking > in a transition DB only provides more entries for the list returned > (An additional entry might capture a possible alternate based on > the possibility that the programmer really did not pass the library > the right TZ, because the library code can see that the given rules > did not apply on the date provided in the time struct.) The point is that the conversion function has just looked up all the relevant entries. It can discard any additional information it has gathered, or report it. The caller is equipped to choose which of the additional information is useful, but only if it's reported. > > I agree that the two examples are too similar. Originally I had > > #0 as the canonical "certain" time, and then realized that (as > > you noted) that condition is rare. At some point the likelihood > > of an error due to a transition becomes smaller than that of a > > simple typo, which can only be determined empirically. > > So how are you going to put that fuzzy set in the library code so > that sometimes you can return a "doubtful subsitution" and sometimes > you can return a "possible unofficial time"? Maybe instead of a "doubtful/possible" flag it just reports how long before the reported time the last transition occurred, and what the conversion would be if that one was missed. > > > Speaking of ambiguity, could you explain what your are really trying > > > to capture in #1 and #2, because your descriptions are of the same > > > circumstance. > > > > Er, that's a typo. ... > > > > The intended entry for #2 was 03:30. This is a valid "official" > > time, unlike 02:30. However, it is very likely to be wrong. > > But that makes the #2 entry jibberish, if I rewrite it as [gibberish] > Maybe it should be: > 2. Spring ambiguity, enter 03:30, but that is so close to the > change time it is suspicious. > > It would seem you could do the discussion of favor and repost a > complete list of possible combinations and what kind of rules you > are going to use to put your tags on all of the different > interpretations. That might not be the best description of the goal. The goal is a way for the conversion function to report the circumstances of the conversion in a form that is easily interpreted for different purposes. In my posting I was too specific about what are still unresolved design issues. > > Cases that are identical as far as the program is concerned > > (time is an hour off because of a clock not reset) are quite > > different in how the user experiences them. > > "identical as far as the program is concerned", but you are trying > to return two different values from the "alternative" time. > ... > One has to ask: since you have 16 possible return flag combinations, > could you please explain why only 5 of them are covered in your > list (and I see only 2), and what is right or wrong about the other > 11, i.e. "doubtful ... unofficial" etc. If you only have 5, just > have one enum that lists them and not imply states that don't exist. It may be that one enum with five values, or with four values and a field for when the last time change happened, would be appropriate. Again, you have identified a danger of being too specific. What I posted was an (unfortunately confusing) example meant to lend some concreteness to the discussion. Can we agree that it's useful for the conversion function to report (also) the circumstances of the conversion? Then we can proceed to explore how to report those circumstances. Nathan Myers ncm(a)cantrip.org

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new time conversion interface
by ncm＠cantrip.org Nov. 5, 1998

Nov. 5, 1998

Apologies for following up my own posting, but I don't want to lose the thread here. I have edited the quoted text below for clarity. > > Nathan Myers wrote: > > > The problem with the mktime model is that conversions between civil > > > time and timestamps can result in 2, 1, or <1 valid conversions ... > > ... it's a rare wall clock, legal document, train schedule or > airline ticket that indicates UTC offset, and when it does it's > likely to be wrong, especially during the "interesting" times. > ... > The problem that normally arises is that someone enters a date/time > and I want a numeric real-time value. I distinguish the following > troublesome cases: > > 1. It's in spring and they enter 02:30, and that time doesn't exist, > but there's a good guess (e.g. equiv. to 03:30) for what > they probably meant. (There's a corresponding case for leap > seconds.) > 2. In spring they enter 03:30, which might be correct, but they might > well have meant 04:30 because they failed to reset their clock. > 3. In autumn, they enter 01:30; did they mean the first time it > happened that day or the second? Either is equally valid. > 4. (Also in autumn) If they enter 02:30, did they mean officially > 02:30, or did they mean the second 01:30? I believe that conversions should yield a struct containing a reference timestamp, followed by up to four offsets tagged with official wall-clock offset, interpretation, and confidence values. For example, in the cases above, and ignoring leap seconds for the moment, we would get 0. Unambiguous time, e.g. 04:30 morning of a time change t0=123456789 offset 0: 0 sec; wall-clock offset: -3600 sec; interpretation: unambiguous; confidence: certain offset 0: -3600 sec; wall-clock offset: -3600 sec. interpretation: suggested substitute; confidence: doubtful 1. Spring ambiguity, enter 02:30 when it doesn't exist because civil time proceeded 01:59:59 -> 03:00:00. (Or 02:00:00 to 03:00:01? I don't know.) t0=123456789 offset 0: 0 sec; wall-clock offset: -3600 sec. interpretation: suggested substitute; confidence: doubtful 2. Spring ambiguity, enter 02:30 when it doesn't exist because civil time proceeded 01:59:59 -> 03:00:00 (or whatever). t0=123456789 offset 0: 0 sec; wall-clock offset: 0 sec. interpretation: official choice; confidence: Nominally unambiguous offset 1: -3600 sec; wall-clock offset: 0 sec. interpretation: suggested substitute; confidence: doubtful 3. Autumn ambiguity, enter 01:30 on morning when civil time proceeds from 01:59:59 to 01:00; is it the first or second 01:30 event? t0=123456789 offset 0: 0 sec; wall-clock offset: 3600 sec. interpretation: ambiguous choice; confidence: equal alternative offset 1: 3600 sec; wall-clock offset: 0 sec. interpretation: ambiguous choice; confidence: equal alternative 4. Autumn, enter 02:30, same morning as above; did they mean the official 02:30, or did they mean the second 01:30 because they failed to reset their clock? t0=123456789 offset 0: 0 sec; wall-clock offset: 0 sec. interpretation: official choice; confidence: Nominally unambiguous offset 1: 3600 sec; wall-clock offset: 0 sec. interpretation: unofficial choice; confidence: Possible alternative For each case above one might have up to two more entries corresponding to leap-second ambiguities. The detailed semantics of all the possible "interpretation" and "confidence" tags must be nailed down. This might end up looking sort of like the following C struct layout, using deliberately unsatisfactory names for exposition: typedef ... time_stamp; /* something more-or-less numeric */ typedef enum { official, unofficial, ambiguous, suggested } time_meaning; typedef enum { nominal, alternative, possible, doubtful } time_confidence; struct time_interpretation { int offset; /* limited to +/- 3601 */ long wall_offset; /* limited to +/- 43200 */ time_meaning meaning; time_confidence confidence; }; struct time_from_civil { time_stamp reference_time; int interpretation_count; /* range 0-4 */ time_interpretation interpretation[4]; }; (I've neglected leap-second ambiguity interpretations because they would reduce the clarity of the exposition.) The conversion function might look like: int time_convert(const struct tm *, const time_zone *, time_from_civil *); I think an interface like this would encapsulate knowledge about time conversion issues, exposing a high-level view of the possible real-time values implied by wall-clock time records. I think it would lead to better, more robust interfaces for conversions, and reduce programmer errors. Comments? Nathan Myers ncm(a)cantrip.org

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news from Estonia
by peter＠aldie.co.uk Nov. 4, 1998

Nov. 4, 1998

My relative in Estonia reports a rather confused picture. The law is clear enough: this year they changed to the EU rule time of 01:00 UTC from their previous midnight UTC. This is a change from 04:00 -> 03:00 local time. The newspapers didn't catch up though. They were still saying it was a change from 03:00 -> 02:00 local time. They can perhaps be forgiven for this as the new law was only dated 22 September. This spring in the UK the Times (a supposed `newspaper of record') printed a picture of a clock showing it going from 02:00 to 03:00. We haven't done that since 1980. The Estonian law can be found at: http://trip.rk.ee/cgi-bin/thw?${BASE}=akt&${OOHTML}=rtd&TA=1998&TO=1&AN=1390 Knowing my poor grasp of Estonian he offers the following free translation: According to the association agreement between the EU and the Republic of Estonia ratified by the Estonian law (RT II 1995, 22--27, 120) and in accordance with the 8th directive of EU 22. July 1997, 97/44/EU (EUT L 206, 1.08.1997, pp 62--63) the Government of Estonia decides to change to Summer Time as follows 1) start 3.00 by the zone time (1.00 GMT) on last sunday of March changing to 4.00; 2) end 4.00 by the zone time (1.00 GMT) on last sunday of October changing to 3.00) I also asked him whether they use any standard abbreviation for their standard and summer times. He says no, they use "suveaeg" (summer time) and "talveaeg" (winter time). He says there is still some discussion about whether they should continue fiddling with the clocks but didn't provide any specifics. Most Estonian newspapers have web pages linked from http://www.ee/www/Media/Journalism/Newspapers/welcome.html. The papers' pages are nearly all in Estonian only so I can't offer any more clues. Finally, this just confirms the existing data. No change is needed to the europe file. Peter Ilieve peter(a)aldie.co.uk

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Re: new time conversion interface
by Ian Tragen Nov. 3, 1998

Nov. 3, 1998

> long wall_offset; /* limited to +/- 43200 */ > Re. the above - I may have missed something here but if you restrict the offset to +/-12 hours, you would run into difficulties with New Zealand DST which is UTC+13h. Ian Tragen -- World Clock Page:- http://www.page-1.com/time

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Time Zone Converter
by Carroll, Nancy Oct. 30, 1998

Oct. 30, 1998

To Whom it May Concern, I am writing on behalf of Manitoba Trade with respect to your database of information used to operate a time zone converter. I am working on reconstruction of our website and in particular the method of constructing a time zone converter. Do you have any sort of licensing arrangement with respect to the use of your database? Do you allow your database to be used by outside sources? Could you please forward details of the nature of your operations and whether there is any way that we might be able to draw on your database of information for our time zone utility? Thank you very much for considering my inquiry. Sincerely, Nancy Carroll Manitoba Trade

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timezone database
by Roy Valdehueza Oct. 27, 1998

Oct. 27, 1998

Dear TZ, i'm glad you guys are around. If you don't mind though i'd like to ask which file on your ftp site am i going to download if i need a timezone database? And what database format is this? How is it used (or at least you can give me which file will give me the mechanics or algorithm to use this database)? Thanx a lot and advance merry Christmas! Gratefully yours, roy valdehueza

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new C time interface
by Nathan Myers Oct. 24, 1998

Oct. 24, 1998

[apologies if this has been seen before.] Part of the problem with struct tm/time_t is that it works ok for inode times but not for other equally-important uses. The problem with the mktime model is that conversions between civil time and timestamps can result in 2, 1, or <1 valid conversions, and neither the user (before the conversion) nor the library is equipped to favor one result over another, or deal properly with nonexistent times. mktime offers no interface for the algorithm to report what it finds, so it must falsify its results. I hope that any interface offered to improve on mktime will expose the information needed to write reliable code. If it is also "nice" for the common ranges where there actually is a one-to-one mapping, that's a bonus, but correctness should come first. Nathan Myers ncm(a)cantrip.org http://www.cantrip.org/

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Re: new C time interface
by INFOMAN Inc. Oct. 23, 1998

Oct. 23, 1998

I tend to agree with Nathan's remarks on for new C time interface. The issue, i.e. need for, correctness in conversions and linkages between (local) civil times and timestamps is one that is also raised in the context of e-commerce and e-business and needs to be resolved. Jake Knoppers <mpereira(a)istar.ca>

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Re: Proposal for new ISO C 9x time API
by Markus Kuhn Oct. 16, 1998

Oct. 16, 1998

Dear Timezone Gurus, I have now revised my proposal for a new <time.h> for C, which you can find on http://www.cl.cam.ac.uk/~mgk25/c-time/ When you have some time, please let me know what you think about it. Ideally we might manage to make this the basis for a proposal for ISO C9X. In case it is already too late for that, we might at least consider implementing it in the Olsen library and publish it independently (say via IETF as an RFC, or via the POSIX project). I have also added to the end of this page a pretty comprehensive list of links to online resources relevant to the topic, and a few more will come as soon as I have access to our scanner again. Markus -- Markus G. Kuhn, Security Group, Computer Lab, Cambridge University, UK email: mkuhn at acm.org, home page: <http://www.cl.cam.ac.uk/~mgk25/>

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Re: Proleptic Gregorian and "Proleptik Julian xtime"
by INFOMAN Inc. Oct. 16, 1998

Oct. 16, 1998

The attached file "prolep.doc" is the extract from the entry in the Oxford English Dictionary (Second Edition) on Compact Disc. It may interest you all to know that Oxford records "proleptik" in use in Medieval times as meaning "predictive, prognostic" or "of the nature of a pre-assumption; pre-conceived; apriori; axiomatic"...etc. Nathan Myers is right when he states "proleptic" refers to the future not the past. The question is how far into the future to predict as can be noted in the following quotation in Oxford of pre-POSIX xtime calendar standardization efforts to determine the date at which God created the earth. Usher (1658) "Having placed therefore our heads of this Period in the Kalends of January, in that proleptik year, the first of our Christian vulgar account must be reckoned the 4717 of the Julian Period". This having been noted it is interesting that as we approach the 2nd millenium , we again have a "proleptic" debate. Jake Knoppers

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Re: Proleptic Gregorian (was Re: Functions add/diff/cmp for xtime)
by Rich Wales Oct. 15, 1998

Oct. 15, 1998

Antoine Leca wrote: . . . TIME_TAI *or* TIME_UTC (as defined by Markus, with the added point that the calendar should be the proleptic Gregorian). Markus Kuhn replied: Question: What precisely does "proleptic" mean and where is it defined? . . . (I suspect it means "extended before the time it was defined", but would like to get a confirmation and reference.) Short answer: My understanding agrees with Markus's suspicion. Longer answer: I looked up the word in two respected American English dictionaries: the Webster's Ninth New Collegiate Dictionary (1985), and the American Heritage Dictionary (New College Edition, 1976). Webster's New Collegiate defines "prolepsis" (a noun) as "the represen- tation or assumption of a future act or development as if presently existing or accomplished", or "the application of an adjective to a noun in anticipation of the result of the action of the verb". "Proleptic" is listed as the corresponding adjective. The American Heritage defines "prolepsis" as "the anticipation and answering of an objection or argument before one's opponent has put it forward", or "the use of a descriptive word in anticipation of the act or circumstances that would make it applicable". It lists both "pro- leptic" and "proleptical" as adjective forms. Both dictionaries say the word is derived from Greek "prolambanein" (to take beforehand) < "pro-" (before) + "lambanein" (to take). Webster's New Collegiate says the first recorded use of the word in English was in 1578. So, the "proleptic Gregorian" calendar would be the result of extending the Gregorian calendar back into the past, before it came into use in a given location, or even before it was invented. My sense (as an educated native speaker of American English) is that "proleptic" and "prolepsis" are not commonly known or used by the aver- age English-speaking person. English is, of course, replete with such words, known primarily by authors, orators, and Scrabble players. Rich Wales richw(a)webcom.com http://www.webcom.com/richw/

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