This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: -Wunused-macros
On 23-Jul-2002, Neil Booth <neil@daikokuya.co.uk> wrote:
>
> > One question: will we get warnings for cases where
> > a macro is only used in a conditionally compiled piece of
> > code for which the condition is false?
> > E.g.
> >
> > #define FOO ...
> >
> > #ifndef __GNUC__
> > ... FOO ...
> > #endif
>
> This macro will be reported as unused. I actually think that's a
> good idea - it encourages making the definition conditional along
> with the code that uses it. Do you agree?
Not really. I'm not convinced that making the definition conditional
is always an improvement. Especially for cases like this,
#define FOO ...
#ifdef BAR1
...
#ifdef BAR2
... FOO ...
#endif
...
#endif
#ifdef BAR3
... FOO ...
#endif
where the definition of FOO would need to be wrapped inside a
complex conditional,
#if (defined(BAR1) && defined(BAR2)) || defined (BAR3)
#define FOO
#endif
this just seems like it would add additional maintenance work
whenever the condition changes.
But I think the warning is still useful even if it gives a few
false positives in cases like this.
--
Fergus Henderson <fjh@cs.mu.oz.au> | "I have always known that the pursuit
The University of Melbourne | of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.