Hey Eddy, Here's the response from my OSX 10.10.4 (Time Zone: Pacific Standard Time (PST) -0800 UTC UTC/GMT).
$ ./mktime Studying DST transitions in system default time-zone Testing spring forward Initial: Sun Mar 8 02:30:00 2015 Accepted: 1425810600 Ignorant of DST (-> 1): Sun Mar 8 03:30:00 2015 Accepted: 1425810600 Claiming no DST (-> 1): Sun Mar 8 03:30:00 2015 Accepted: 1425807000 Claiming DST (-> 0): Sun Mar 8 01:30:00 2015 Testing fall backward Initial: Sun Nov 1 01:30:00 2015 Accepted: 1446366600 Ignorant of DST (-> 1): Sun Nov 1 01:30:00 2015 Accepted: 1446367200 Ignorant of DST (-> 1): Sun Nov 1 01:40:00 2015 Accepted: 1446370860 Ignorant of DST (-> 0): Sun Nov 1 01:41:00 2015 Accepted: 1446370200 Claiming no DST (-> 0): Sun Nov 1 01:30:00 2015 Accepted: 1446366600 Claiming DST (-> 1): Sun Nov 1 01:30:00 2015 $ HTH, -mandeep On Fri, Nov 6, 2015 at 4:34 AM, Welbourne Edward <edward.welbou...@theqtcompany.com> wrote: >> If you're willing to compile and run the attached simple C program, >> please let me know its output and your platform's details - ideally >> off-list - I'll give a summary in a few days' time. > > Thanks to those who responded, I now know: > * that all the platforms below do the same thing if tm_isdst is 0 or 1 (Yay > !) > * with .tm_isdst = -1, there is diversity of handling. > > When tm_isdst is 0 or 1, in the fall back it gets preserved; > in the spring forward, it gets flipped and tm_hour is changed > in the way it usually would for such a flip. > > OSX 10.10, Xcode 6.02 > * varies within the hour (see below) > * at half past: handled as if you'd claimed tm_isdst = 0 (see above) > > MacBook, Darwin 15.0.0 > Ubuntu 12.04, glibc 2.15 > Debian/stretch, glibc 2.19 > * clear tm_isdst and move an hour earlier in spring > * set tm_isdst and preserve hour in autumn > > MinGW > MSVC 2015 > * set tm_isdst and move an hour later in spring > * clear tm_isdst and preserve hour in autumn. > > My initial test was, it turns out, naive. Apparently some platforms > vary handling of -1 across the hour. I also bit the bullet and worked > out how to auto-detect DST transitions. One response indicates > asctime_r() isn't portable. So I attach a new version of mktime.c, that > needs no manual configuration and is, I hope, a little more portable. I > note that setting the TZ environment variable (on platforms that honour > it, at least) can be used to discover what your O/S thinks happens in > other time-zones than your local one. > > As before, if anyone feels inclined to give this a whirl, I'd again > appreciate any responses, along with descriptions of the system they > come from (e.g. uname -a output). > > Eddy > _______________________________________________ > Development mailing list > Development@qt-project.org > http://lists.qt-project.org/mailman/listinfo/development > _______________________________________________ Development mailing list Development@qt-project.org http://lists.qt-project.org/mailman/listinfo/development