From accb3871668201a1d7b9c54713b94b814c879271 Mon Sep 17 00:00:00 2001 From: Eli Zaretskii Date: Fri, 24 Mar 2023 14:10:30 +0300 Subject: Fix system time sampling on MS-Windows * src/timefns.c (emacs_localtime_rz) [WINDOWSNT]: Unconditionally call tzset to make sure we pick up all the changes of time zone, working around the MS CRT caching. --- src/timefns.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'src') diff --git a/src/timefns.c b/src/timefns.c index b3132e7bc34..87971cf4563 100644 --- a/src/timefns.c +++ b/src/timefns.c @@ -180,6 +180,15 @@ static timezone_t const utc_tz = 0; static struct tm * emacs_localtime_rz (timezone_t tz, time_t const *t, struct tm *tm) { +#ifdef WINDOWSNT + /* The Windows CRT functions are "optimized for speed", so they don't + check for timezone and DST changes if they were last called less + than 1 minute ago (see http://support.microsoft.com/kb/821231). + So all Emacs features that repeatedly call time functions (e.g., + display-time) are in real danger of missing timezone and DST + changes. Calling tzset before each localtime call fixes that. */ + tzset (); +#endif tm = localtime_rz (tz, t, tm); if (!tm && errno == ENOMEM) memory_full (SIZE_MAX); -- cgit v1.2.3