"Olson, Arthur David \(NIH/NCI\) [E]" <olsona@dc37a.nci.nih.gov> writes:
From: Zefram [mailto:zefram@fysh.org] Sent: Friday, May 19, 2006 12:30 PM
there's no rigorous treatment of what base time scale to apply the offset to.
In the current implementation, the base time scale is always UTC, usually with leap seconds skipped, but leap second support is there if you want it. Hence UK times are de facto (modulo leap seconds), not de jure. I suppose there might be more-advanced applications where most Unix processes wants to use a UTC-based time scale, but one process wants to use a GMT-based one (or UT1, or Mars solar time, etc.). But that sounds pretty specialized. It shouldn't be needed for civil times anywhere on the planet, so it'd probably be an astronomical application or something like that. If someone wanted to do that, I'd like to see their implementation before worrying about adding support for it to the tz code or database. There's a similar issue for support for other calendars, e.g., the Persian calendar in widespread use in Iran.