Re: AC_*/AM_* macros for options

[Paul Eggert]

On 10/30/2013 02:36 AM, Jeffrey Walton wrote:

> time_t is supposed to be an integer or real
> (http://pubs.opengroup.org/onlinepubs/009696699/basedefs/sys/types.h.html).

Unsigned integers are integers, so an unsigned time_t
conforms to POSIX, and some POSIXish systems use unsigned
time_t (QNX is one example).  There's nothing wrong with the code in
<http://lists.gnu.org/archive/html/autoconf/2013-10/msg00030.html>
even if time_t is unsigned, GCC's warning in that case is bogus,
and the only realistic workaround is to not ask GCC to
generate the warning.

By the way, you should switch to the latest POSIX version;
time_t is no longer allowed to be floating-point.

> the Linux kernel guys don't feel the C language rules apply to them.

That's a separate issue, surely.  They don't use Autoconf, and this is
the Autoconf mailing list.

> I was able to write 15 or so negative test cases
> that broke that parser based on that one warning.

Sure, *sometimes* the warning is useful, just as even a
clock that's stopped is right twice a day.  But in the code
I deal with, the warning is a false alarm more often than
not.  Requiring it for an entire project would often be the
wrong thing to do.  Having Autoconf make it the default for
all projects sounds like it'd be a mistake.