Re: ac-type-getgroups.patch

[Akim Demaille]

Pavel Roskin <address@hidden> writes:

> > Index: ChangeLog
> > from  Akim Demaille  <address@hidden>
> >
> >         * acspecific.m4 (AC_TYPE_GETGROUPS): Check for unistd.h, and
> >         include it to get getgroups' prototype.
> 
> Ok.
> "info libc" says that you must include unistd.h to have gid_t defined.
> 
> >  [/* Thanks to Mike Rendell for this test.  */
> >  #include <sys/types.h>
> > +#if HAVE_UNISTD_H
> > +# include <unistd.h>
> > +#endif
> 
> Maybe it's better to use AC_INCLUDES_DEFAULT here, but I don't really
> care.

Positive: we won't check for unistd.h if AC_INCLUDES_DEFAULT has
already been used.

Negative: more works for the compiler, hence longer.

Future: AC_CHECK_HEADERS should simply be AC_REQUIRED.

Robustness: I tend to think that with more headers, we are more likely
to catch errors (for instance problems in headers themselves), which
is a _good_ thing: if the Autoconf tests are `pure', the program's
headers are definitely not that pure, and many are included
altogether.

Future: precisely with this in mind, I think the future of
AC_INCLUDES_DEFAULT will be system.h from autosystem.h.

?