FW: Problem in DST fall back procedure

Paul Eggert eggert at CS.UCLA.EDU
Mon Nov 13 18:59:34 UTC 2006


"Olson, Arthur David \(NIH/NCI\) [E]" <olsona at dc37a.nci.nih.gov> writes:

> We cahnged time to 01:55 , 4 Nov 2007. 
> The time advances normally from 02:00hrs on and "does not fall back to
> 01:00hrs as desired".

My guess is that you set the time to the _second_ 01:55 on that date.
So the clock _should_ advance normally through 02:00.  If you want to
observe a jump, you have to set the time to the _first_ 01:55 on that
date.

> # date
> Sun Nov  4 02:01:23 EST 2007

So far so good; that's a valid time stamp.

> # zdump -v US/Alaska | grep 2007
> US/Alaska  Sat Nov  3 23:05:42 2007 AKDT
> US/Alaska  Sun Mar 11 10:59:59 2007 GMT = Sun Mar 11 01:59:59 2007 AKST isdst=0 gmtoff=-32400
> US/Alaska  Sun Mar 11 11:00:00 2007 GMT = Sun Mar 11 03:00:00 2007 AKDT isdst=1 gmtoff=-28800
> US/Alaska  Sun Nov  4 09:59:59 2007 GMT = Sun Nov  4 01:59:59 2007 AKDT isdst=1 gmtoff=-28800
> US/Alaska  Sun Nov  4 10:00:00 2007 GMT = Sun Nov  4 01:00:00 2007 AKST isdst=0 gmtoff=-32400

This is also valid behavior; the clock jumps backward just before
02:00 on 2007-11-04.  Your example for Yukon was similar.

So far, I don't see a bug.



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