[tz] McMurdo/South Pole
lester at lsces.co.uk
Mon Sep 23 08:48:58 UTC 2013
Guy Harris wrote:
> 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.
DateTimeZone was added in PHP5.2 ... There were problems when it was introduced
since the original attempt trod on the toes of older tools which did things
differently. DateTimeZone was introduced using the TZ data as it's reference
source, but currently there is no warning that while DateTime transparently goes
back in time, and it REQUIRES that a timezone is set, the data returned prior to
1970 may not be appropriate. Obviously this is not a problem that TZ would
accept, but it demonstrates that end users - such as myself! - would have no
idea that there WAS a problem until we dug deeper. PHP's documentation needs an
update, but we still have the problem of plugging this hole going forward?
Lester Caine - G8HFL
Contact - http://lsces.co.uk/wiki/?page=contact
L.S.Caine Electronic Services - http://lsces.co.uk
EnquirySolve - http://enquirysolve.com/
Model Engineers Digital Workshop - http://medw.co.uk
Rainbow Digital Media - http://rainbowdigitalmedia.co.uk
More information about the tz