Guy Harris <gharris@sonic.net> writes:
On Mar 5, 2024, at 12:56 PM, Russ Allbery via tz <tz@iana.org> wrote:
but for the record, PST8PDT was for support for very old commercial UNIXes where I believe that was the only recognized style of TZ setting, and I'm pretty dubious that the POSIX-introduced :PST8PDT syntax would work there.
That TZ syntax dates back at least to System III:
http://www.bitsavers.org/pdf/att/unix/System_III/UNIX_Users_Manual_Release_3...
(see CTIME(3C)), which did not support anything tzdb-related, and didn't even support the more elaborate POSIX TZ syntax to include rules.
I don't see any reference to the leading colon in that documentation. Am I just missing something? It seems to support what I said: PST8PDT was supported, but :PST8PDT was not. If an environment variable named TZ is present, asctime uses the contents of the variable to override the default time zone. The value of TZ must be a three-letter time zone name, followed by a number representing the difference between local time and Greenwich time in hours, followed by an optional three-letter name for a daylight time zone. For example, the setting for New Jersey would be EST5EDT. -- Russ Allbery (eagle@eyrie.org) <https://www.eyrie.org/~eagle/>