Re: [HACKERS] Need confirmation of "Posix time standard" on FreeBSD

Thomas Lockhart writes:
> Someone mentioned recently that a timezone style of "GMT+0800" was on
> their FreeBSD machine as an allowed time zone, that its behavior was
> the same as the usual ISO8601 timezone of "-0800", and that this
> conformed to some sort of Posix standard.
> 
> I had posted patches for this, and have just modified the patch to be
> cleaner and more robust.
> 
> Before committing this (or at least before completing our upcoming
> beta period), I'd like confirmation that this actually matches
> expected behavior for a machine implementing a "GMT+0800" (or similar)
> time zone, and that it is indeed a Posix standard? Anyone??

I can confirm that it is a POSIX standard. Section 8.1.1 "Extensions
to Time Functions" of POSIX 1003.1-1988 says TZ can be of the form   :characters
for implementation-defined behaviour or else   std offset [dst [offset][,start[/time],end[/time]]]
(spaces for readability only) where std is three or more bytes
designating the standard time zone (any characters except a leading
colon, digits, comma, minus, plus or NUL allowed) and offset is the
value one must add to the local time to arrive at Coordinated
Universal Time. offset is of the form hh[:mm[:ss]] with hh required
and may be a single digit. Followed by gory details about the rest of
the fields. Phew.

--Malcolm

-- 
Malcolm Beattie <mbeattie@sable.ox.ac.uk>
Unix Systems Programmer
Oxford University Computing Services