> > On AIX mktime(3) leaves tm_isdst at -1 if it does not have timezone
> > info for that particular year and returns -1.
> > The following code then makes savings time out of the -1.
> > tz = (tm->tm_isdst ? (timezone - 3600) : timezone);
>
> Hmm. That description is consistant with what I see in the Linux man
> page. So I should check for (tm->tm_isdst > 0) rather than
> checking for non-zero?
It is obviously not possible to determine tm_isdst with mktime for a
negative time_t. Thus with above fix PST works, but PDT is then busted :-(
localtime does convert a negative time_t correctly including dst.
Is there another way to determine tm_isdst ?
Andreas