Re: Testing for unknown flags in different compilers

[David A. Wheeler]

David A. Wheeler wrote:
> > I*AM*  advocating a*basic*  warning level by default.
> > I interpret that on gcc to be "-Wall" or some variant.

Paul Eggert:
> -Wall generates too many false positives in practice.  Perhaps some 
> variant would be better, but we'd have to see the details.

I get the impression that even if "-Wall" has too many false positives,
there are one or two options that can be added to address that
when using gcc (per previous discussion on autoconf mailing lists).
So the default for gcc could be dialed to "-Wall -_whatever_".

> I doubt whether all developers will agree about this, so it'll be useful 
> to have an option that can be set in configure.ac. Packages whose 
> developers like the commonly-used './configure --enable-gcc-warnings' 
> approach could specify in configure.ac that warnings are off by 
> default.  Packages whose developers like basic warnings (whatever they 
> are) enabled by default could do that too.

I agree.  I think it's *important* that warnings should be enabled by default,
as I noted earlier, but also I agree that making warnings the default
will *only* be acceptable if developers can easily disable or tweak
the warning flags for their specific project.

Adding mechanisms to do this, regardless of the compiler in use, would
be a big step forward.

--- David A. Wheeler