[FFmpeg-devel] [PATCH] avutil/mem: Fix invalid use of av_alloc_size

Michael Niedermayer michael at niedermayer.cc
Tue Nov 27 00:40:57 EET 2018


On Sun, Nov 25, 2018 at 05:55:37PM -0800, Mark Harris wrote:
> On 2018-11-25 17:29, James Almer wrote:
> > On 11/25/2018 10:01 PM, Michael Niedermayer wrote:
> >> On Sat, Nov 24, 2018 at 01:02:02PM -0800, Mark Harris wrote:
> >>> The alloc_size attribute is valid only on functions that return a
> >>> pointer.  GCC 9 (not yet released) warns about invalid usage:
> >>>
> >>> ./libavutil/mem.h:342:1: warning: 'alloc_size' attribute ignored on a function returning int' [-Wattributes]
> >>>   342 | av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);
> >>>       | ^~~~~~~~~~~~~
> >>
> >> Is the attribute also useless on all other compilers ?
> > 
> > The attribute is only used when __GNUC__ is defined, so it should for
> > any such compiler (GCC and Clang).
> > 
> > https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html
> > 
> 
> The Clang documentation does note a minor difference from GCC, but both
> GCC and Clang agree that it applies to functions that return a pointer.
>  The size is the number of bytes allocated at that pointer.  It doesn't
> support an indirect reference to the allocated memory; if it did it
> would likely need an additional parameter to indicate which argument was
> the indirect reference.

ok, will apply

thx


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Never trust a computer, one day, it may think you are the virus. -- Compn
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