May 1998 - tz - lists.iana.org

Re: tz leap second bug encountered by sendmail 8.8.8 in Australia
by Bradley White 25 May '98

25 May '98

> The basic problem is that tz code looks at the system file > .../zoneinfo/GMT to decide what leap seconds to use when computing > GMT; this leads to bogus results if the user wants leap seconds and > the system file doesn't (or vice versa). Might I proffer that this is not a problem with the tz code, but a truthful representation of the situation presented to it. If "the user wants leap seconds and the system file doesn't (or vice versa)," the user is just kidding themselves. Either the system clock ticks leap seconds (a stationary epoch), or it doesn't. All tz files used on the system should reflect that reality. The suggested gmtoff() algorithm will always produce such varying results if localtime() and gmtime() cannot agree on minute boundaries, whether the discrepancy is a leapsecond artifact or not. Bradley

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Re: proposed tz changes for Davis Station, Palestine, etc.
by Paul Eggert 24 May '98

24 May '98

In my most recent proposed change I forgot to update zone.tab for Davis. Also, some URLs in tzselect.ksh are obsolescent. Here's a further patch. =================================================================== RCS file: RCS/tzselect.ksh,v retrieving revision 1997.9 retrieving revision 1997.9.1.1 diff -u -r1997.9 -r1997.9.1.1 --- tzselect.ksh 1997/12/29 14:53:41 1997.9 +++ tzselect.ksh 1998/05/24 19:15:13 1997.9.1.1 @@ -10,7 +10,7 @@ # If your host lacks the Korn shell, # you can use either of the following free programs instead: # -# <a href=ftp://ftp.gnu.ai.mit.edu/pub/gnu/> +# <a href=ftp://ftp.gnu.org/pub/gnu/> # Bourne-Again shell (bash) # </a> # @@ -22,7 +22,7 @@ # If your host lacks awk, or has an old awk that does not conform to Posix.2, # you can use either of the following free programs instead: # -# <a href=ftp://ftp.gnu.ai.mit.edu/pub/gnu/> +# <a href=ftp://ftp.gnu.org/pub/gnu/> # GNU awk (gawk) # </a> # =================================================================== RCS file: RCS/zone.tab,v retrieving revision 1.2.1.6 retrieving revision 1.2.1.7 diff -u -r1.2.1.6 -r1.2.1.7 --- zone.tab 1998/05/24 07:36:46 1.2.1.6 +++ zone.tab 1998/05/24 19:15:37 1.2.1.7 @@ -33,6 +33,7 @@ AQ -9000+00000 Antarctica/South_Pole Amundsen-Scott Station, South Pole AQ -6448-06406 Antarctica/Palmer Palmer Station, Anvers Island AQ -6736+06253 Antarctica/Mawson Mawson Station, Holme Bay +AQ -6835+07758 Antarctica/Davis Davis Station, Vestfold Hills AQ -6617+11031 Antarctica/Casey Casey Station, Bailey Peninsula AQ -6640+14001 Antarctica/DumontDUrville Dumont-d'Urville Base, Terre Adelie AR -3436-05827 America/Buenos_Aires E Argentina (BA, DF, SC, TF)

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FW: tz interface problems
by Olson, Arthur David 23 May '98

23 May '98

---------- 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 22 May '98

22 May '98

> 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 21 May '98

21 May '98

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 20 May '98

20 May '98

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 20 May '98

20 May '98

"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 19 May '98

19 May '98

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 14 May '98

14 May '98

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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