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From: Avi Kivity <avi@redhat.com>
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Subject: Re: [Qemu-devel] [5466] Only use __builtin_* with GCC >= 3.4
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To: qemu-devel@nongnu.org

Jamie Lokier wrote:
> Glibc uses "#if __GNUC_PREREQ (3,4)" which is quite neat.
> Do "grep -R GNUC_PREREQ /usr/include".
>
> I use (and define if not already defined) the same macro in my
> programs, on the assumption that the macro's meaning is unlikely to
> ever change or be different elsewhere.
>   

It's illegal to define or use an identifier beginning with two 
underscores, unless it's documented by the implementation.  What if 
glibc adds a third argument?  All your apps wil break.

You should define your own macros for this, with a non-__ name.

-- 
error compiling committee.c: too many arguments to function