Subject: Re: bug#11281: DST has not effect on windows XP when system DST adjustment is disabled

From: Kazuhiro Ito <[email-masked]>
Date: Fri, 23 May 2025 17:32:15 +0900

> > (let ((time (encode-time '(0 0 12 20 5 2025 nil nil t))))
> >   ;; The result depends on whether DST is enabled on Windows timezone
> >   ;; setting at the time of evaluating `(setenv "TZ" nil)'.
> >   (setenv "TZ" nil)
> >   (decode-time time "est5edt"))
> > 
> > ;; The case that DST is disabled on Windows control panel.
> > -> (0 0 7 20 5 2025 2 t -18000)
> > 
> > ;; DST is enabled.
> > -> (0 0 8 20 5 2025 2 t -14400)
(snip)

> My suggestion therefore is not to try such tricks in Emacs on Windows,
> and not to expect that to produce results that are as accurate as on
> Posix platforms.

Thank you for the comment.
What do you mean by 'such tricks'?  Using traditional timezone name or
using string as a ZONE pamareter?  If the former, what is proper
string for ZONE on Windows?

-- 
Kazuhiro Ito