May 1999 - tz - lists.iana.org

FW: UK Timezone info
by Olson, Arthur David (NCI) May 12, 1999

May 12, 1999

Note that Robert Brady is not on the time zone mailing list. --ado -----Original Message----- From: Robert Brady [SMTP:rwb197@ecs.soton.ac.uk] Sent: Wednesday, May 12, 1999 12:11 PM To: tz(a)elsie.nci.nih.gov Subject: UK Timezone info You'll like this : the power to set time-zone in the UK might be devolved to the Scottish Parliamant and Welsh Assembly. See : http://www.parliament.the-stationery-office.co.uk/pa/ld199899/ldbills/047/1… 7.htm -- Robert.

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UK Timezone info
by Robert Brady May 12, 1999

May 12, 1999

You'll like this : the power to set time-zone in the UK might be devolved to the Scottish Parliamant and Welsh Assembly. See : http://www.parliament.the-stationery-office.co.uk/pa/ld199899/ldbills/047/1… -- Robert.

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FW: FW: Australian Timezone issues.
by Olson, Arthur David (NCI) May 11, 1999

May 11, 1999

-----Original Message----- From: Chris Bitmead [SMTP:chris.bitmead@bigfoot.com] Sent: Tuesday, May 11, 1999 4:30 AM To: 'tz' Cc: Robert Elz Subject: Re: FW: Australian Timezone issues. Robert Elz wrote: > | Has any thought been given to having the Australian EST timezone renamed > | to AEST? > > No. Or at least, I certainly hope it has not. why? > | For example, when a database dumps a time 'Sun May 9 11:07:06 > | EST 1999 in Australia, and then the database reads the time back in, it > | assumes that EST is New York time and everything gets screwed up. > > Any code that does that is simply broken. Time zone names > are a hint to humans. They simply aren't unambiguous. The > two Aust zone abbreviations that are the same as their US > equivalents (EST and CST) aren't the only ambiguous ones > around (and then there are all the places that have no real > concept of a timezone name at all - and the tz database > just invents one for them - most of the countries in South > East Asia are given "ICT", which seems to be "Indo China > Time" which, as a label, means nothing locally > at all). Well I'll report that to the database developers. If that is the official way it is, and it's not just Australia in this boat, then I guess things have to change in how people write code. This is a quote from the POSTGRESQL database documentation... "If the compiler option USE_AUSTRALIAN_RULES is set then EST refers to Australia Eastern Std Time, which has an offset of +10:00 hours from UTC. Australian time zones and their naming variants account for fully one quarter of all time zones in the Postgres time zone lookup table." > | reports when TZ=EST. > > You give ambiguous input, you can expect to get ambiguous ouput. > If you want to specify Australian time, use > TZ=Australia/Sydney or whatever, and for North American, > use TZ=America/New_York. But there doesn't seem to be a portable way to find out the string "Australia/Sydney" on your computer. Everything would be fine and dandy if strftime() returned the zone as "Australia/Sydney", but that's not what it does, it returns the mnumonic EST buried inside the zone file. If the mnumonic was "Australia/Sydney" then fine, but it's not. > You need to > be more precise than just "eastern" anyway to represent > historical times accurately. Well, current times would be a start. > Alternatively, convince the whole world that time zone > names ought always have a country, or region prefix - > perhaps we could have "American Eastern Standard Time" (not > US, as it applies in Canada, and perhaps parts of > Mexico and other parts of Central America as well) and > Australian Eastern Standard Time, and both could be AEST Do we have to convince the world, or merely UNIX operating system vendors? After all, as you say zone names are ambiguous now, so nobody can be relying on them for other than (potentially inaccurate) information. So making them unique could only improve things no? > Time zone names are just an inherantly local phenomenon - > anything, anywhere, which intends to write, and then parse, > a date string needs to be sure that the string contains the > numeric zone offset. Even humans which don't carry time offsets and summer time rules around in their heads?

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FW: Australian Timezone issues.
by Olson, Arthur David (NCI) May 11, 1999

May 11, 1999

Note that Chris is not on the time zone mailing list; be sure that any replies are directed to Chris. --ado -----Original Message----- From: Chris Bitmead [SMTP:chris.bitmead@bigfoot.com] Sent: Sunday, May 09, 1999 11:12 AM To: tz(a)elsie.nci.nih.gov Subject: Australian Timezone issues. I understand this is the appropriate email address for addressing issues with the standard UNIX timezone files. Has any thought been given to having the Australian EST timezone renamed to AEST? The conflicting name with the American EST has caused too much grief for too long. AEST is the proper abbreviation anyway in an international context and is reported on international radio broadcasts that refer to Australian timezones. The current practice of using plain EST simply breaks everything. For example, when a database dumps a time 'Sun May 9 11:07:06 EST 1999 in Australia, and then the database reads the time back in, it assumes that EST is New York time and everything gets screwed up. Another example, typing date in Australia's EST zone gives Sun May 9 11:07:06 EST 1999 But typing TZ=EST date Sat May 8 20:07:06 EST 1999 Inconsistent or what? As far as I know it is only Australian zones which suffer from this stupidity. It basicly renders timezones partly useless in Australia, because the timezone abbreviation of EST is ambiguous, and whenever interpreted, it's always done wrongly as NY time. This means that a lot of UNIX software simply doesn't work properly in Australia. Frankly I count the standard UNIX date program amoungst the many because the time it reports as EST is different to the date it reports when TZ=EST. What would have to be done to get this changed in the zoneinfo files? -- Chris Bitmead http://www.bigfoot.com/~chris.bitmead mailto:chris.bitmead@bigfoot.com

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When Citizens Disagree on Even the Time of Day
by Paul Eggert May 10, 1999

May 10, 1999

On today's op-ed page of the LA Times, Jorge G. Castan~eda, a political scientest and writer in Mexico City, used time zones as a metaphor for the political fragmentation and social dissolution of today's Mexico. Among other things, he writes: One example involves the time zones in the country and the absurd debate that took place in March as to who would adopt daylight saving time. Some states have adopted the hour change, others have not. Some are on U.S. Central time, some on Mountain time and some on Pacific time, while the one that used to go by Eastern time--Quintana Roo, where Cancun is located--decided to go back to Central time. While Mexico City Mayor Cuauhtemoc Cardenas wisely desisted from heeding his rank and file and accepted the federal government's decision to move clocks forward on April 1, it was touch and go for several days. The country cannot even agree, literally, on the time of day. I assume that the ``April 1'' here was the date of Cardenas's decision, not the date the clocks actually moved (which was presumably April 4 as usual in North America these days). We know about Quintana Roo and have some idea of states that fall into all the categories mentioned above, but it perhaps some states have changed since last year, and it would be useful to know exactly what happened in Mexico this spring. Reference: http://www.latimes.com/HOME/NEWS/COMMENT/t000041976.1.html

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Australian Timezone issues.
by Chris Bitmead May 9, 1999

May 9, 1999

I understand this is the appropriate email address for addressing issues with the standard UNIX timezone files. Has any thought been given to having the Australian EST timezone renamed to AEST? The conflicting name with the American EST has caused too much grief for too long. AEST is the proper abbreviation anyway in an international context and is reported on international radio broadcasts that refer to Australian timezones. The current practice of using plain EST simply breaks everything. For example, when a database dumps a time 'Sun May 9 11:07:06 EST 1999 in Australia, and then the database reads the time back in, it assumes that EST is New York time and everything gets screwed up. Another example, typing date in Australia's EST zone gives Sun May 9 11:07:06 EST 1999 But typing TZ=EST date Sat May 8 20:07:06 EST 1999 Inconsistent or what? As far as I know it is only Australian zones which suffer from this stupidity. It basicly renders timezones partly useless in Australia, because the timezone abbreviation of EST is ambiguous, and whenever interpreted, it's always done wrongly as NY time. This means that a lot of UNIX software simply doesn't work properly in Australia. Frankly I count the standard UNIX date program amoungst the many because the time it reports as EST is different to the date it reports when TZ=EST. What would have to be done to get this changed in the zoneinfo files? -- Chris Bitmead http://www.bigfoot.com/~chris.bitmead mailto:chris.bitmead@bigfoot.com

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Re: FW: POSIX-TZ without rules
by Guido Flohr May 5, 1999

May 5, 1999

On Thu, Apr 29, 1999 at 04:39:29PM -0700, Paul Eggert wrote: > From: Guido Flohr [SMTP:gufl0000@stud.uni-sb.de] > Sent: Monday, April 26, 1999 9:46 PM > > for testing purposes I set the envariable TZ to "CET-1CEST-2", > i. e. a valid POSIX-style string but without explicit rules. > I also uninstalled the database for that test. > > Under these circumstances tzparse() in localtime.c will return an error > because it fails to open a default rules file. From what I remember I > would say that POSIX demands that the US rules should be applied instead. > > POSIX.1 is not US-centric here; it says that the behavior in this case > is implementation-defined. The rationale (POSIX 1003.1-1996 section > B.8.1.1 page 493 lines 5609-5612) says ``An implementation may provide > those rules [i.e. the DST rules not explicitly specified by the user] OK, I'll never use the word POSIX again. ;-) My information is only second hand. > Anyway, "CET-1CEST-2" is perfectly POSIX-compliant and the library should > not return an error then. > > Yes. My reading of POSIX.1 is that the implementation is allowed to > guess the DST rules, but it's not allowed to fail. I agree. A popular German Unix guide recommends "CET-1CEST-2" as the default TZ setting for Germany, German HP-UX distributions use it to (well, with "MET" instead of "CET"). > The GNU libc handles this case by assuming an implicit rule of > "M4.1.0,M10.5.0" (commented as "US Federal Law"). My solution is somewhat > different: I generated a header "new_york.h" > > Both solutions have problems. The first mishandles old dates; the > second assumes the New York City DST rules, whereas it'd be better to > assume only the US rules. Implementing the plain US rules (back to > 1918) would be better; can you do this? Do you mean writing a rules file for that case (which could be compiled and hardcoded into the library)? Actually I even have problems with that solution. I think we had better leave DST alone if no rules are available. Guessing rules always means to do exactly the wrong thing for half of the world, assuming rules that are suitable for the northern hemisphere means to discriminate the southern hemisphere. Correct me if I'm wrong, but isn't it possible to explicitely mark that question as undecidable by setting tm->tm_isdst resp. the variable daylight to -1? Collecting back data which will most probably provide wrong results looks a little ridiculous to me. What should we do when time_t grows 64 bits big? Guess if Alexander arrived one hour early at Issos because the Greek had DST and the Persians hadn't? > > In zic.c, the analysis of the return value of > system("yearistype ...") assumes a certain structure of that return value. > > That's clearly a portability bug; here's a patch. Fine. > +#if HAVE_SYS_WAIT_H - 0 > +#include <sys/wait.h> /* for WIFEXITED and WEXITSTATUS */ > +#endif /* HAVE_SYS_WAIT_H - 0 */ > + > +#ifndef WIFEXITED > +#define WIFEXITED(status) (((status) & 0xff) == 0) > +#endif /* !defined WIFEXITED */ > +#ifndef WEXITSTATUS > +#define WEXITSTATUS(status) (((status) >> 8) & 0xff) > +#endif /* !defined WEXITSTATUS */ Will that work on BSD systems with a union wait? system() returns int, so what does BSD recommend to get the status bits? Sorry, I don't know, I just want to point out a possible problem. Ciao Guido -- http://stud.uni-sb.de/~gufl0000 mailto:gufl0000@stud.uni-sb.de

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