Tony, Tony Rutkowski wrote:
> At 09:14 AM 6/27/2007, Martin Burnicki wrote: >>So GMT-2 is correct for Athens. > > I'm simply suggesting it should be UTC-2 Neither of both is correct since the 3 letters before the number shall be an abbreviation of the time zone name when daylight saving is not in effect. However, we've just discussed about the sign of the number, as expected by the standard C library, and why it is different from what one might think. The old-style syntax for this used another 3 letters _after_ the number to indicate that daylight saving is in effect, and they would be used as the name for the time zone during daylight saving. E.g. TZ=UTC0 specifies local time = UTC, without offset TZ=CET-1 specified Central European Standard Time, i.e. UTC+1h TZ=CET-1CST specifies Central European Summer Time, i.e. UTC+2h AFAIK the abbreviations used for single time zones are not standardized, though some like UTC, CET/CST, PST/PDT are commonly used. > See ISO8601 or Markus Kuhn's useful summary > at http://www.cl.cam.ac.uk/~mgk25/iso-time.html I know that page, and I know the difference between GMT and UTC, but Markus' page it does not even mention GMT, or abbreviations to be used for the time zone names. On the contrary, Markus' page mentions that the sign of the UTC offset should be written using e.g. -0500 for U.S./Canadian Eastern Standard Time (EST), whereas the correct notation as expected by the standard C library is EST5 rather than EST-5. Hm, I've just read Darren's reply which mentions the POSIX syntax as also described in Darren's link http://lists.boost.org/boost-users/2006/10/23162.php While with the old syntax I mentioned above the TZ setting had to be changed at the beginning and end of DST, POSIX has introduced an extended syntax which lets the C library compute the beginning and end of DST automatically without having to change the TZ setting. Anyway, in most cases the Olson timezone library is used nowadays on Unix-like system, providing even more flexibility. Martin -- Martin Burnicki Meinberg Funkuhren Bad Pyrmont Germany _______________________________________________ questions mailing list [email protected] https://lists.ntp.isc.org/mailman/listinfo/questions
