On Thursday 20 November 2025 09:47:27 Martin Storsjö wrote:
> On Wed, 19 Nov 2025, Pali Rohár wrote:
>
> > On Monday 17 November 2025 17:43:41 Pali Rohár wrote:
> > > On Monday 17 November 2025 16:18:14 Martin Storsjö wrote:
> > > > On Sat, 25 Oct 2025, Pali Rohár wrote:
> > > >
> > > > > ---
> > > > > mingw-w64-crt/testcases/t_time.c | 96 ++++++++++++++++++++++++++++++--
> > > > > 1 file changed, 92 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/mingw-w64-crt/testcases/t_time.c
> > > > > b/mingw-w64-crt/testcases/t_time.c
> > > > > index 50b07d0083a7..75a15d816d31 100644
> > > > > --- a/mingw-w64-crt/testcases/t_time.c
> > > > > +++ b/mingw-w64-crt/testcases/t_time.c
> > > > > @@ -10,14 +10,17 @@ int __cdecl ftime64(struct __timeb64 *tb64);
> > > > >
> > > > > int main()
> > > > > {
> > > > > - time_t t;
> > > > > - __time32_t t32;
> > > > > - __time64_t t64;
> > > > > + time_t t, t_;
> > > > > + __time32_t t32, t32_;
> > > > > + __time64_t t64, t64_;
> > > > > struct timeb tb;
> > > > > struct _timeb tb_;
> > > > > struct __timeb32 tb32;
> > > > > struct __timeb64 tb64;
> > > > > struct tm *htm;
> > > > > + struct tm tm1;
> > > > > + struct tm tm2;
> > > > > + struct tm tm3;
> > > > > int ret1, ret2, ret3;
> > > > > const char *str;
> > > > > const wchar_t *wstr;
> > > > > @@ -95,7 +98,49 @@ int main()
> > > > > assert (htm->tm_yday == 74);
> > > > > assert (htm->tm_isdst == 0);
> > > > >
> > > > > - /* ctime returns time string in local timezone, so set local
> > > > > timezone to UTC to have test timezone independent */
> > > > > + time_t times[] = {
> > > > > + 1700000000 /* Tue Nov 14 22:13:20 UTC 2023 */,
> > > > > + 1600000000 /* Sun Sep 13 12:26:40 UTC 2020 */,
> > > > > + };
> > > > > + for (size_t i = 0; i < sizeof(times)/sizeof(*times); i++) {
> > > > > + t = times[i];
> > > > > + htm = localtime (&t);
> > > > > + tm1 = *htm;
> > > > > + printf ("localtime(%lld): sec=%d min=%d hour=%d mday=%d
> > > > > mon=%d year=%d wday=%d yday=%d isdst=%d\n",
> > > > > + (long long)t, htm->tm_sec, htm->tm_min, htm->tm_hour,
> > > > > htm->tm_mday, htm->tm_mon, htm->tm_year, htm->tm_wday, htm->tm_yday,
> > > > > htm->tm_isdst);
> > > > > + t_ = mktime (htm);
> > > > > + printf ("mktime(): %lld sec=%d min=%d hour=%d mday=%d
> > > > > mon=%d year=%d wday=%d yday=%d isdst=%d\n",
> > > > > + (long long)t_, htm->tm_sec, htm->tm_min, htm->tm_hour,
> > > > > htm->tm_mday, htm->tm_mon, htm->tm_year, htm->tm_wday, htm->tm_yday,
> > > > > htm->tm_isdst);
> > > > > + assert (t_ == t);
> > > > > + assert (memcmp (htm, &tm1, sizeof(tm1)) == 0);
> > > > > +
> > > > > + t32 = t;
> > > > > + htm = _localtime32 (&t32);
> > > > > + tm2 = *htm;
> > > > > + printf ("_localtime32(%d): sec=%d min=%d hour=%d mday=%d mon=%d
> > > > > year=%d wday=%d yday=%d isdst=%d\n",
> > > > > + t32, htm->tm_sec, htm->tm_min, htm->tm_hour, htm->tm_mday,
> > > > > htm->tm_mon, htm->tm_year, htm->tm_wday, htm->tm_yday, htm->tm_isdst);
> > > > > + t32_ = _mktime32 (htm);
> > > > > + printf ("_mktime32(): %d sec=%d min=%d hour=%d mday=%d mon=%d
> > > > > year=%d wday=%d yday=%d isdst=%d\n",
> > > > > + t32_, htm->tm_sec, htm->tm_min, htm->tm_hour, htm->tm_mday,
> > > > > htm->tm_mon, htm->tm_year, htm->tm_wday, htm->tm_yday, htm->tm_isdst);
> > > > > + assert (t32_ == t32);
> > > > > + assert (memcmp (htm, &tm2, sizeof(tm2)) == 0);
> > > > > +
> > > > > + t64 = t;
> > > > > + htm = _localtime64 (&t64);
> > > > > + tm3 = *htm;
> > > > > + printf ("_localtime64(%lld): sec=%d min=%d hour=%d mday=%d
> > > > > mon=%d year=%d wday=%d yday=%d isdst=%d\n",
> > > > > + t64, htm->tm_sec, htm->tm_min, htm->tm_hour, htm->tm_mday,
> > > > > htm->tm_mon, htm->tm_year, htm->tm_wday, htm->tm_yday, htm->tm_isdst);
> > > > > + t64_ = _mktime64 (htm);
> > > > > + printf ("_mktime64(): %lld sec=%d min=%d hour=%d mday=%d
> > > > > mon=%d year=%d wday=%d yday=%d isdst=%d\n",
> > > > > + t64_, htm->tm_sec, htm->tm_min, htm->tm_hour, htm->tm_mday,
> > > > > htm->tm_mon, htm->tm_year, htm->tm_wday, htm->tm_yday, htm->tm_isdst);
> > > > > + assert (t64_ == t64);
> > > > > + assert (memcmp (htm, &tm3, sizeof(tm3)) == 0);
> > > > > +
> > > > > + assert (memcmp (&tm1, &tm2, sizeof(tm1)) == 0);
> > > > > + assert (memcmp (&tm2, &tm3, sizeof(tm2)) == 0);
> > > > > + }
> > > > > +
> > > > > + /* ctime, localtime and mktime returns time string in local
> > > > > timezone, so set local timezone to UTC to have test timezone
> > > > > independent */
> > > > > putenv ("TZ=UTC");
> > > >
> > > > In addition to setting TZ=UTC here, is it possible to set some other
> > > > well-known timezone that would be available everywhere, which we could
> > > > use
> > > > for some testcases for cases closer to the DST switchover time? We
> > > > could do
> > > > that for both mktime and localtime IMO.
> > >
> > > I could try to add, but I'm not sure if CRT libraries would be able to
> > > process DST support for non-system timezone. Because Windows system and
> > > WinAPI has just one fixed timezone, which provides bunch of timezone and
> > > DST related functions. And CRT library allows to define any timeshift,
> > > so then there can be a mix of WinAPI timezone, CRT timezone, WinAPI DST
> > > and CRT DST... That is why I wrote test below the quoted part in UTC as
> > > it does not have any DST and no offset.
> > >
> > > > In itself, these test additions probably are fine though - the above
> > > > would
> > > > be nice extras. But given that corner case handling close to DST
> > > > switchovers, I think it would be good to actually check such a case.
> > > >
> > > > So this patchset in itself looks ok, except for the one issue I found in
> > > > 2/7.
> > > >
> > > > // Martin
> >
> > Here is diff for this 7/7 change which adds those tests which can uncover
> > localtime DST issue:
> >
> > I chose year 2005 because it seems that forced PST8PDT timezone uses
> > hardcoded DST settings and older libraries do not have 2006 pacific zone
> > changes. So tests for year 2005 can be run also against older CRT libs.
>
> Yes, that sounds reasonable to test an old date.
>
> Can you resend this patchset, rebased on latest master, with the fix for
> _localtime64 and the updated test? This large diff is messy to extract from
> being pasted inline in a mail.
>
> // Martin
Sure, I will resend it.
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