https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108409
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Jonathan Wakely from comment #4) > The current code doesn't work on Windows either. https://learn.microsoft.com/en-us/windows/win32/api/timezoneapi/nf-timezoneapi-gettimezoneinformation only gives us the abbreviated names of the standard and daylight zones, e.g. "EST" and "EDT". But those names are not unique and cannot be used to map to a time zone, as the C++ standard points out in [time.zone.info.sys] p6: "Abbreviations are not unique among the time_zones, and so one cannot reliably map abbreviations back to a time_zone and UTC offset."
