- tz - lists.iana.org

FW: tz interface problems
by Olson, Arthur David May 23, 1998

May 23, 1998

---------- From: D. J. Bernstein[SMTP:djb@cr.yp.to] Sent: Monday, May 18, 1998 3:32 AM To: arthur_david_olson(a)nih.gov; djb(a)cr.yp.to Subject: tz interface problems 1. Check out the dates produced by sendmail on one host: Mon, 18 May 1998 16:36:37 +0930 Mon, 18 May 1998 16:36:38 +0930 Mon, 18 May 1998 16:36:39 +0929 Mon, 18 May 1998 16:36:40 +0929 The problem, of course, is that sendmail is figuring out the offset by comparing the hours and minutes shown by localtime() and gmtime(). Mailers don't care about time zone names; they want the UTC offset. Do you have a routine that, given a time, returns the offset? (1-second offsets can't be expressed in mail, but that's a separate problem.) 2. I'm sure you're aware that BSD and Linux now include your routines. Unfortunately, they don't make it easy for typical users to regenerate the time-zone files. Users could download new files, but that's a megabyte of data. The practical effect is that many systems slipped by a second in 1997, and will probably slip by another second at the end of 1998. How difficult would it be for you to get leap-second data from another file? I've been working on the Y2038 problem, and I've put together an /etc/leapsecs.dat format for recording leap seconds. ---Dan

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Re: FW: tz interface problems
by Bradley White May 22, 1998

May 22, 1998

> The problem, of course, is that sendmail is figuring out the offset by > comparing the hours and minutes shown by localtime() and gmtime(). > > That method should be reliable, so long as you pass the same timestamp > to both localtime and gmtime. Can you give more details about the problem? > > Do you have a routine that, given a time, returns the offset? > > There's not one in the tz packages, but one is commonly included in GNU code. > I'll enclose a copy at the end of this message. Of course the Right Way > to do it is to use tm_gmtoff, but this isn't blessed by the standards. > /* Yield A - B, measured in seconds. */ > time_t > difftm (a, b) > struct tm const *a; > struct tm const *b; > { : > } > > /* Yield the number of seconds that local time is ahead of GMT at > time T, or 0 if this is not known. */ > long > gmtoff (t) > time_t t; > { : > return difftm (ltp, &gmt); > } If you only need gmtoff() [and not the full generality of difftm()], a more simple solution that utilizes the fact that localtime() and gmtime() are never more than one day apart is ... long gmtoff(time_t t) { struct tm lcl = *localtime(&t); struct tm utc = *gmtime(&t); if (lcl.tm_mday != utc.tm_mday) (((lcl.tm_mon == utc.tm_mon) == (lcl.tm_mday > utc.tm_mday)) ? &lcl : &utc)->tm_hour += 24; return ((lcl.tm_hour - utc.tm_hour) * 60) + (lcl.tm_min - utc.tm_min); } Bradley

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Re: Update of the CIA World Factbook : no more TZ map
by mathew＠ican.net May 21, 1998

May 21, 1998

Apparently, the CIA world time zone map is still available online from the University of Texas at Austin: http://www.lib.utexas.edu/Libs/PCL/Map_collection/world_maps.html It has the 1997 map in pdf (Adobe Acrobat) format (http://www.lib.utexas.edu/Libs/PCL/Map_collection/world_maps/Std_Time_Zones…) and the 1995 map as a JPEG (http://www.lib.utexas.edu/Libs/PCL/Map_collection/world_maps/Time_95.jpg) Also see the CIA publication catalogue (http://www.odci.gov/cia/publications/mapspub/222.html) Mathew Englander

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Time zone converter
by Dee Ann Abel May 20, 1998

May 20, 1998

I'd like to announce a time zone converter that I have available. The URL is: http://www.burbs.com/cgi-bin/tzconvert.pl Is there an archive or FAQ available for this list? Thanks :) Dee Ann Abel

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Re: FW: tz interface problems
by Ulrich Drepper May 20, 1998

May 20, 1998

"Olson, Arthur David" <OLSONA(a)dc37a.nci.nih.gov> writes: > 2. I'm sure you're aware that BSD and Linux now include your routines. Wrong. For Linux using glibc we have our own functions. > Unfortunately, they don't make it easy for typical users to regenerate > the time-zone files. Users could download new files, but that's a > megabyte of data. Also not true. We distribute the database in glibc and whoever wants to update her/his system manually can use the diffs generated for each new version of glibc. -- Uli ---------------. drepper at gnu.org ,-. 1325 Chesapeake Terrace Ulrich Drepper \ ,-------------------' \ Sunnyvale, CA 94089 USA Cygnus Solutions `--' drepper at cygnus.com `------------------------

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Update of the CIA World Factbook : no more TZ map
by Antoine Leca May 19, 1998

May 19, 1998

Hi all, While browsing the CIA World factbook, I noticed that they have upgraded to 1997 version, which is very nice IMHO. <http://www.odci.gov/cia/publications/factbook/index.html> However, from our point point of view, this is not *that* nice, because they removed completely (unless I missed something) the TZ map of the world (and TZ informations about the countries as well, except a note about Kiribati moving the intl' date line). So the file www.htm should be updated to remove completely the present links. I do not know if we should keep the reference to this work. Note there is another reference to this map in the `asia' file (about Mongolia), which should be removed too. Antoine

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tzcode1998d.tar.gz and tzdata1998d.tar.gz
by Olson, Arthur David May 14, 1998

May 14, 1998

The files ftp://elsie.nci.nih.gov/pub/tzcode1998d.tar.gz and ftp://elsie.nci.nih.gov/pub/tzdata1998d.tar.gz are now available. The only differences between these and the 1998c files are changes to comments (in particular, elimination of references to CIA maps). "Arts.htm", "WWW.htm", "asia", and "australasia" are the only places where changes occur. --ado

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Saudi Arabia does not observe DST
by Paul Eggert April 13, 1998

April 13, 1998

I Followed up on the recent report that Kingdom of Saudi Arabia observes daylight saving time by asking the Saudi Embassy to the United States about it. They replied that DST is not observed there. ------- Start of forwarded message ------- From: Saeed Alahmed <saa(a)embassy.saudi.net> To: Paul Eggert <eggert(a)twinsun.com> Subject: RE: Does Saudi Arabia observe daylight saving time? Date: Mon, 13 Apr 1998 12:30:24 -0400 Return-Receipt-To: Saeed Alahmed <saa(a)embassy.saudi.net> Dear Sir, Saudi Arabia does not observe the daylight saving time. The time difference is 8 hours ahead of the USA and during the first weekend of April you would use the daylight time saving. ------- End of forwarded message -------

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FW: Time Zone Database
by Paul Stewart April 9, 1998

April 9, 1998

Clarissa is not on the time zone mailing list, but would like to be added (how does one do that again?) ------- Forwarded Message From: "Clarissa Gammel" <cg(a)pc-plus.de> To: Stewart(a)networks.ecse.rpi.edu Date: Tue, 7 Apr 1998 09:59:44 PDT Subject: Time Zone Database Hi Paul, I do not succeed. Would you please forward the questions below to the people with the unreachable adress tz(a)elsie.nci.nih.gov. and have me subscribed? Thank you very much in advance Clarissa Hello, I have some questions to the Time Zone Database: How often are there changes to the time difference information (approximately)? How many countries are there with different time zones in one country? Who provides that information? Is it a governmental institution? (contact adress) When in general are the dates for those changes? Are they regular, or each year different? Are there any rules? Which countries do or don't have summer or winter time? Thanks for helping me Clarissa ------- End of Forwarded Message

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FW: Question of time :-)
by Olson, Arthur David April 8, 1998

April 8, 1998

Note that Guenther is not on the time zone mailing list. --ado ---------- From: Guenther Grau[SMTP:Guenther.Grau@bk.bosch.de] Sent: Tuesday, April 07, 1998 12:36 PM To: tz(a)elsie.nci.nih.gov Subject: Question of time :-) Hi, I don't know if this is correct address to send this to, but I hope you'll be able to redirect me in case it's not :-) In my application I need to know, the time difference between any given time in any given timezone, and UTC. Is this possible to do WITHOUT changing the TZ environment variable? I cannot do this, because this is in a multithreaded program, and changing TZ would affect other threads. I cannot fork another process, as this takes too much time and resources. I need a program, that does sth. like this: > echo $TZ MET > date Tue Apr 7 18:31:42 MET DST 1998 > calculateUtcDifference "1.2.1998 12:13 EST" 5 hours I would be great if you knew a portable solution (solaris/hp-ux). Thanx in advance Guenther

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