Re: Wshadow: Better name for 'optarg'?

[Daniel P . Berrangé]

On Thu, Oct 05, 2023 at 07:17:17AM +0200, Markus Armbruster wrote:
> Philippe Mathieu-Daudé <philmd@linaro.org> writes:
> 
> > On 4/10/23 19:35, Thomas Huth wrote:
> >> On 04/10/2023 19.23, Richard Henderson wrote:
> >>> On 10/4/23 03:05, Philippe Mathieu-Daudé wrote:
> >>>> Hi,
> >>>>
> >>>> I'm getting a bunch of errors for 'optarg' declared in <unistd.h>:
> >>>
> >>> I thought things like this is why we were trying -Wshadow=local.
> >>>
> >>> I think it's unlikely that we'll be able to prevent all such cases.
> >> Given the broad range of operating systems and libraries that we support 
> >> in QEMU, I agree with Richard - it will likely be impossible to enable 
> >> that option without =local by default without risking that compilation 
> >> breaks on some exotic systems or new versions of various libraries.
> >
> > -Wshadow=local doesn't seem to work here which is why I switched
> > to -Wshadow. I probably misunderstood something from Markus cover
> > letter. My setup is:
> >
> > C compiler for the host machine: clang (clang 14.0.3 "Apple clang version 
> > 14.0.3 (clang-1403.0.22.14.1)")
> >
> > I suppose we'll figure that out when eventually enabling -Wshadow=local
> > on CI. Meanwhile I already cleaned the 'optarg' warnings that were
> > bugging me, see:
> > 20231004120019.93101-1-philmd@linaro.org/">https://lore.kernel.org/qemu-devel/20231004120019.93101-1-philmd@linaro.org/
> > I'll try to get -Wshadow=local, but the other series still seems a
> > good cleanup, as I used more meaningful variable names.
> 
> I'm aiming just for -Wshadow=local now.  If somebody else gets us all
> the way to -Wshadow, I'll clap from the sidelines.
> 
> I'm mildly skeptical about -Wshadow without =local when targeting a wide
> range of toolchains over a long time.

We don't need to claim that QEMU will build warning-free on all possible
toolchains, only our CI covered platforms get that expectation. If users
see warnings on untested toolchains they can either send further patches,
or turn off -Werror, and/or contribute to CI coverage.

With regards,
Daniel
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