Re: Should -Wjump-misses-init be in -Wall?

[Paolo Bonzini <bonzini at gnu dot org>]

Gabriel Dos Reis wrote:
> On Tue, Jun 23, 2009 at 11:12 AM, Joe Buck<Joe.Buck@synopsys.com> wrote:
> > On Tue, Jun 23, 2009 at 12:43 AM, Alan Modra<amodra@bigpond.net.au> wrote:
> > > > ..., but I think this warning should be in -Wc++-compat, not -Wall
> > > > or even -Wextra.  Why?  I'd argue the warning is useless for C code,
> > > > unless you care about C++ style.
> > On Tue, Jun 23, 2009 at 12:35:48AM -0700, Gabriel Dos Reis wrote:
> > > I do not think it is useless for C99 codes because C99 allows
> > > C++ style declarations/initialization in the middle of a block.
> > But if the initialization is skipped and the variable is then used,
> > won't we get an uninitialized-variable warning?
>
> Did we get any in the cases Ian reported?

No, because they were all like this:

  goto fail;

 ...
  int a = ...;
  if (a)
    {
     fail:
      // does not use a
      return;
    }

  ...

This is a bit ugly, but it's valid C code.

The only dubious one in my opinion was a missing bracket around switch, 
which was also harmless but warrants a warning.  This however could be 
implemented as a separate warning going into -Wextra.

I don't think this warning can report anything that -Wuninitialized 
cannot report, so it should go in -Wc++-compat only.

Paolo