Re: Testing for unknown flags in different compilers

[Julien ÉLIE]

Hi Bob,

> > I have been working on a changes whereby an autoconf user can invoke a
> > macro like
> >
> > AC_WARN_ADD([-Wextra])
> >
> > to add user-specified flags to the compiler/linker invocations.
>
> I don't think that it is a particularly good idea to enable any warning
> options by default in a package unless the warnings are likely to
> indicate that the code the developer should have already perfected is
> somehow faulty (e.g. unexpected interface definition or missing
> prototype) on the system it is being built on.
>
> Usually only the developers of a package are interested in seeing and
> fixing warnings.  Warnings are only a cause for concern (usually undue
> concern) for others.

I believe the suggested macro could be worthwhile (from the standpoint 
of a developer) in the case of building a software on various OSes on 
different platforms (for instance the GCC C Farm servers).
One could then have a WARNINGS variable in his Makefile with the 
recognized flags on the platform (thanks to checks done by several calls 
to the suggested AC_WARN_ADD macro, that incidentally should have a 
second variable to tell which variable to populate -- for instance here, 
the WARNINGS variable).

Then, for automatic builds on several OSes, I would only have to run 
"make warnings" that I would have told to run the compiler with 
$WARNINGS appended.
This way, no need to worry about the set of flags available on the 
platform.  It would be found out automatically.
Of course, apart from automatic builds, it could be useful for manual 
builds (by developers running "make warnings").


Though I agree that it is not a good idea to add these flags by default 
to the end user, the feature could be useful for other people.

--
Julien ÉLIE

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