On 10/05/2018 14:47, Vlad Khorsun via Firebird-devel wrote: > > According to: > > https://www.timeanddate.com/time/time-zones.html > > --- > Daylight Saving Time Zones > > Regions that use Daylight Saving Time (DST) change the time zone name > and time during the DST period. The words “daylight” or “summer” are > then usually included in the time zone name. The areas that don't use > DST remain on standard time zone all year. > > For example, California uses Pacific Daylight Time (PDT) during the > DST period, but Pacific Standard Time (PST) during the rest of the year. > --- > > And when you read more this page, you understand that this scheme does not work for computers:
--- Local Time Zone Names Illustration image Mountain Standard Time or Mountain Daylight Time or just Mountain Time? PunchStock.com To confuse matters more, each time zone can have different local time zone names, usually linked to the geographical name of the country or region. The time zone names may be completely different, even though the UTC offset is the same. For instance in Miami, Florida, is 5 hours behind UTC (UTC-5) and the standard time zone is Eastern Standard Time (EST). In Havana, Cuba, the standard time zone is also UTC-5, but it's called Cuba Standard Time (CST). Identical Abbreviations Another point that can cause confusion is that some time zone's names in totally different places have exactly the same abbreviation. For example, India Standard Time (IST) and Israel Standard Time (IST) have the same abbreviation, but completely different UTC offsets of UTC+5:30 and UTC+2:00. In many parts of the world, especially in countries with only one time zone, time zone names are not commonly used at all. --- > >> A DST is nothing different than a "rule change" and another "rule >> change" every year. > > Nope. DST doesn't affect time zone. It affects what time zone is actual > at given region. Before 2011 it was MSK "at winter" and MSD "at > summer" at > Moscow area. > Brazil has various time zones but does not have various 3/4 letters abbreviations for them. But we can use then in computers (with ICU in this case) using the names: America/Sao_Paulo Brazil/Acre Brazil/DeNoronha ... ICU does not even define BRT/BRST. AFAIK these names are ambiguous. The name for Moskow is Europe/Moscow. See the list here: https://github.com/FirebirdSQL/firebird/blob/work/time-zone-support/src/common/TimeZones.h Adriano ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
