It seems to me there is some ambiguity during the transition between Daylight time to Standard time for example in the US at 2:00 AM DT on 11/1 Daylight time ended and Standard time began the time now being 1:00 AM ST. This means that a time of 1:30 is meaningless unless it is qualified as ST or DT. So, how can TzSpecificLocalTimeToSystemTime convert this time?
A:
It can guess, at best. Since SYSTEMTIME structure lacks DST bit, there are indeed inherently ambiguous periods.
Tuure Laurinolli
2009-11-07 13:21:08
A:
Raymond Chen wrote about this topic, hopefully that post will clear things up.
Michael Dunn
2009-11-07 19:10:22
So it is better to give an ambiguous possibly wrong answer that is symmetrical with SystemTimeToTzSpecificLocalTime than to provide a function which does the job right? Seems pretty weird to me.
Mike D
2009-11-11 14:04:27