Re: [Qemu-devel] [RFC] Enable Werrror by default

[Christoph Egger]

On Thursday 11 June 2009 15:14:46 Mark McLoughlin wrote:
> On Thu, 2009-06-11 at 13:35 +0100, Paul Brook wrote:
> > I'd like to enable Werror by default. I've been using --enable-werror
> > locally for a while now, and it's been extremely useful in picking up
> > dumb errors (like the recent stellaris_enet.c breakage).
> >
> > Any objections?
> >
> > You can of course configure with --disable-werror if you really want the
> > force things to build.
>
> Based on experiences with other projects:
>
>   1) Release tarballs should not ship with -Werror on by default - e.g.
>      new gcc comes along with new warnings and the tarball build fails
>      with no benefit to anyone
>
>   2) Anyone submitting patches should build with -Werror and make sure
>      they don't introduce new warnings

Newer gcc enable warnings by default older versions already have as well.

>   3) People with newer gcc are likely to be tripped up by warnings
>      introduced by others with older gcc[1]
>
>   4) It's debatable whether builds from git should default to -Werror -
>      on the plus side it helps ensure (2) happens, on the minus side if
>      a warning does sneak in, it makes life a pain for everyone until a
>      fix gets applied
>
> IMHO, we should enable it by default for git builds.
>
> Cheers,
> Mark.
>
> [1] e.g. with gcc-4.4.0, but not with gcc-4.3.2:
>
>   hw/virtio-blk.c:302: warning: ‘blkcfg.size_max’ is used uninitialized in
> this function

You should see the same warning with gcc 4.3.2  -Wuninitialized , too.

Christoph

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