Garrett Wollman wrote, on 04 Nov 2022: > > <<On Fri, 4 Nov 2022 09:36:25 +0000, "Austin Group Bug Tracker via > austin-group-l at The Open Group" <austin-group-l@opengroup.org> said: > > > As I understand it, this requires that if mktime() determines that DST is > > in effect, it returns the same result as it would for tm_isdst=1, otherwise > > it returns the same result as it would for tm_isdst=0. That is how all > > certified UNIX and POSIX systems behave. Until now I thought it was how all > > mktime() implementations behave, but I see that the C DR that you cite > > mentions "Arthur David Olson's popular ``tz'' time zone software" as > > returning -1. That was back in 1994, so I wonder if it still does or if it > > has changed to behave like other implementations. > > As a practical matter, although now maintained by Paul Eggert and > under the auspices of IANA, this Reference Implementation, known as > "tzcode", is used by many if not most platforms, and has been for many > many years.
If it returns -1 for times "in the gap" then it isn't being used by any certified UNIX or POSIX system, nor by Debian GNU/Linux (or any other Linux distro, I assume, but that's the one I tested). -- Geoff Clare <g.cl...@opengroup.org> The Open Group, Apex Plaza, Forbury Road, Reading, RG1 1AX, England
