Re: [Qemu-devel] [PULL v4 06/23] QEMU_BUILD_BUG_ON: use __COUNTER__

[Eric Blake <eblake@redhat.com>]

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On 01/31/2017 12:43 PM, Michael S. Tsirkin wrote:
> Some headers use QEMU_BUILD_BUG_ON. This causes a problem
> if the C file including that header happens to have
> QEMU_BUILD_BUG_ON at the same line number.
> 
> Fix using a widely available extension: __COUNTER__.
> If unavailable, provide a stub.

Uhh, this isn't the right commit message.  What happened?

> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  include/qemu/compiler.h | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/include/qemu/compiler.h b/include/qemu/compiler.h
> index 057639a..e0ce9ff 100644
> --- a/include/qemu/compiler.h
> +++ b/include/qemu/compiler.h
> @@ -97,6 +97,9 @@
>  #define QEMU_BUILD_BUG_ON(x)
>  #endif
>  
> +#define QEMU_BUILD_BUG_ON_ZERO(x) (sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)) - \
> +                                   sizeof(QEMU_BUILD_BUG_ON_STRUCT(x)))
> +
>  #if defined __GNUC__
>  # if !QEMU_GNUC_PREREQ(4, 4)
>     /* gcc versions before 4.4.x don't support gnu_printf, so use printf. */
> 

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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