[Zope3-dev] The Date Time and TimeZone question

[Tim Peters]

[Lennart Regebro]
> ...
> The specs I have seen for timezone support on unix date back far beyond
> 1970.

UNIX != C, and even the 2001 revision of the POSIX/Single Unix Specification
standard (IEEE Std 1003.1-2001) leaves the meaning of a negative time_t
undefined, and specifically warns that time_t still needn't be able to
represent dates beyond 2038.  See

    http://www.opengroup.org/onlinepubs/007904975/functions/time.html

There are no functions for datetime arithmetic defined in C that don't
require going through time_t, so that kills any hope of using standard C
functions for years outside of 1970-2038.  Any specific implementation of C
may allow for more than that, but there's not even a standard way to
determine whether one does.