Re: [PATCH] fix some clang warnings

[Jeff King <peff@peff.net>]

On Wed, Jan 16, 2013 at 06:12:03PM +0000, John Keeping wrote:

> On Wed, Jan 16, 2013 at 10:00:42AM -0800, Jeff King wrote:
> > It is not about the macro itself, but rather the callsites that do not
> > return error, but call it for its printing side effect. It seems that
> > clang -Wunused-value is OK with unused values from functions being
> > discarded, but not with constants. So:
> > 
> >   int foo();
> >   void bar()
> >   {
> >     foo(); /* ok */
> >     1; /* not ok */
> >     (foo(), 1); /* not ok */
> >   }
> > 
> > The first one is OK (I think it would fall under -Wunused-result under
> > either compiler). The middle one is an obvious error, and caught by both
> > compilers. The last one is OK by gcc, but clang complains.
> 
> I wonder if this would be changed in clang - the change in [1] is
> superficially similar.
> 
> [1] http://llvm.org/bugs/show_bug.cgi?id=13747

Yeah, I think it is exactly the same issue, and the fix they mention
there would apply to us, too.

Is it worth applying this at all, then? Or should we apply it but limit
it with a clang version macro (they mention r163034, but I do not know
if it is in a released version yet, nor what macros are available to
inspect the version)?

-Peff