mktime() failure vs 31-DEC-1969 23:59:59 GMT

[tomp at zk3.dec.com]

Hi Roland,

Thanks very much for the response.

> The standard way in ANSI C to detect errors when the return value is
> ambiguous is using `errno':

Unfortunately, the standards say that "no errors are defined" for
mktime().  (ie - testing for errno is not dependable)  The standards
I'm looking at are XPG4 (issue 1) and XPG4 (issue 2) aka UNIX 95 or
Spec1170.  Each of these standards are supersets of ANSI C, so I
suspect ANSI C does not define errors for mktime() either.

- Tom