C Code for draft-newman-datetime-00.txt

Antoine Leca Antoine.Leca at renault.fr
Fri Jan 17 09:16:37 UTC 1997

Tom Peterson (USG) wrote:
<from Ken Pizzini>
> > A problematical situation on any implementation is distinguishing
> > between an error return from mktime() and mktime() returning a
> > legitimate -1 value. [...]
> An error code (or errno) would help here I think.  If errno were set to a
> particular value when mktime() really couldn't represent the value, we'd have
> a way to distinguish between a valid -1 and and error -1 return value.

I agree with you.

> Problem is, we'd have trouble getting the standards like X/Open to accept
> this, since they claim they don't support negative time_t's (ie: times before
> the Epoch).

Strictly speaking, mktime() is not a X/Open standard, but part of the standard
C library.  So IMHO, the solution lie more in the realm of ISO/JTC2/SC22/WG14
(the comittee in charge of C standardization) than in X/Open.

And BTW, ISO C doesn't put any restriction on the range of the value of
the time_t (which is only arithmetical, not necessary [un]signed long int);
and Epoch does take any sense as long as ISO C is concerned.

Best regards,


More information about the tz mailing list