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Date: Tue, 05 Jul 2011 10:05:04 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 3/3] Avoid Wunsed-but-set warnings (or
 errors in case of Werror)
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To: Markus Armbruster <armbru@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, Raghavendra D Prabhu <rprabhu@wnohang.net>, qemu-devel@nongnu.org, Raghavendra D Prabhu <raghu.prabhu13@gmail.com>, kvm@vger.kernel.org

On 07/05/2011 09:49 AM, Markus Armbruster wrote:
> >  If 'ret' has been used to silence compiler warnings about functions
> >  which have been declared with attribute __warn_unused_result__
> >  (eg write() and various other libc functions) then "(void)write()"
> >  is insufficient -- gcc requires the variable.
>
> gcc being silly.  Oh well.

In this particular case I think that the return value should be checked. 
  It's good if something is printed in the log saying that the reset 
wasn't done for some reason---even if it is just defensive.

The really silly thing is in glibc, not gcc.  __warn_unused_result__ was 
added to fwrite, where you have no certainty that the write has been 
done, but not to either fclose or fflush.  Oh well...

Paolo