Re: avoiding obsolete macros like AC_TRY_RUN

[Ralf Wildenhues]

Hello Bruno,

* Bruno Haible wrote on Tue, Jul 20, 2010 at 02:40:06AM CEST:
> Coming back to our discussion of AC_TRY_RUN etc. in
> [1] <http://lists.gnu.org/archive/html/bug-gnulib/2009-09/msg00042.html>
> [2] <http://lists.gnu.org/archive/html/bug-gnulib/2009-09/msg00056.html>
> 
> I now realized that "autoconf -Wall" is giving warnings because of
> gettext.m4, intl.m4, and similar, which are shared between gettext and
> gnulib.

Well yeah, that's why the discussion in [1] came up in the first place.

> I'm considering to replace the uses of AC_TRY_RUN etc. for this reason.

Good.

> But I have to come back to the drawbacks of AC_*_IFELSE (item 1 in [1]).

Most of which have been refuted in the discussion following [1].

> > I agree on the less-than-ideal naming of the AC_*_IFELSE macros.
> 
> Good. Do you have any plans to achieve a better naming?

No.  I don't think we should, either.  New users don't seem to have a
problem with the current names.  Old users will never have no problem
with new names, no matter how much better they are.

> > >      - Pitfall: It's easy to forget the invocation of AC_LANG_SOURCE, and 
> > > then
> > >        autoconf generates code which will fail on many but not all 
> > > platforms.
> > 
> > We should think about what we can do to address this, thanks for the
> > suggestion.
> 
> Have you or the other Autoconf developers found a way to address this?

No.  This is the only remaining point we should consider looking at
IMHO.  And we should be very careful not to warn about valid macro
uses, so it's likely that good documentation is the best way.  Most
of our AC_LANG_SOURCE and AC_LANG_PROGRAM examples in the manual are
already double-quoted, and the "Quotation Rule Of Thumb" essentially
contains the rule of thumb I stated in [a].  IOW, if you get used to
double-quoting literal content, then this just falls into place
naturally.

> > Users of your macros have to live with the constant set of warnings
> > about obsolete macro usage
> 
> The attached patches will fix this.

I'm glad you're doing this change, even if now you've now reinvested
the time.

Cheers,
Ralf

[a] http://lists.gnu.org/archive/html/bug-gnulib/2009-09/msg00056.html