[tz] McMurdo/South Pole

Guy Harris guy at alum.mit.edu
Mon Sep 23 05:38:08 UTC 2013

On Sep 22, 2013, at 9:57 PM, Lester Caine <lester at lsces.co.uk> wrote:

> A similar situation has now been created in the PHP API, which has also been switched to using TZ as the 'bible' when it comes to DST information. So the above statement applies ... except that the TZ data needs to return 'invalid' when a request is made that it can not process.

Such as any request for information given a date/time prior to the establishment of some form of standard time in the specified tzdb zone.

> So that we can then revert to an alternate lookup.

There do not appear to be any APIs in


that take a longitude (and perhaps latitude) as an argument, so there's nothing those APIs can do to convert times prior to the establishment of standard time.

I think it's a good idea for the tzdb to, if possible, contain the date of the initial establishment of standard time (which I'd define as a time scheme, specified in law, that applies to *all* of the tzdb zone in question, so this rules out, among other things, "use local mean time at the specific location" as a scheme) for each tzdb zone.  Anybody who wants to handle times prior to that time is on their own, at least with respect to the tzdb.

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