Date: Mon, 18 Jul 2022 09:03:11 -0700 From: Paul Eggert via tz <tz@iana.org> Message-ID: <3c04acad-382b-66d2-e16a-97b69643d3dd@cs.ucla.edu> | Good point, and POSIX and the C standard are both wrong here. They're wrong. But not (as things stand) not there. The standards (at least POSIX) treat a timezone (TZ) as stdoffset[dst[offset][,start[/time],end[/time]]] (which does not represent well in plain ascii). At most two offsets, one for standard time, one for summer time. The same for all years, the only variation is which of the two applies now. The alternate form with a leading : is implementation defined, and so nothing more can be said about that. So, tm_isdst is all that is ever need to select one of those. The problem is that that is a hopelessly inept view of how a timezone really behaves - but that's at a whole other level than the specification of strftime("%z") which just follows from this definition. kre