[FFmpeg-devel] [PATCH] configure: Remove av_restrict

[Martin Storsjö]

On Sun, 10 Mar 2024, Andreas Rheinhardt wrote:

> All versions of MSVC that support C11 (namely >= v19.27)
> also support the restrict keyword, therefore av_restrict
> is no longer necessary since 75697836b1db3e0f0a3b7061be6be28d00c675a0.
>
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
> Untested except via godbolt.
> MSVC actually uses it for optimizations: https://godbolt.org/z/3EzPnff9T

This change looks good overall, thanks! Fate runs successfully both with 
an old version of MSVC targeting x86_64 and a new one targeting aarch64.

However, MSVC 19.27 (aka 2019 16.7) can't successfully build ffmpeg at the 
moment - it regressed in ec1b6e0cd404b2f7f4d202802b1c0a40d52fc9b0. Now 
building fails with this error:

src/libavcodec/ccaption_dec.c(186): error C2143: syntax error: missing ')' before 'sizeof'
src/libavcodec/ccaption_dec.c(186): error C2143: syntax error: missing '{' before 'sizeof'
src/libavcodec/ccaption_dec.c(186): error C2059: syntax error: 'sizeof'

This issue is not present with the following version, MSVC 2019 16.8 
(aka 19.28) though.

> Btw: The block about __declspec(restrict) was always unneeded
> for FFmpeg due to 17fad33f81c7e9787fcdc17934fc1eee6c6aa4bf.
> It came from Libav commit 17fad33f81c7e9787fcdc17934fc1eee6c6aa4bf.

This looks like a copypaste typo, I presume the latter should have been 
0cff125200ab53fa3ae70d85b4f614f269fe3426. (The code it changed originated 
in dfa559bcbd41397b3408c59d016631c7c65e320f in libav.)

// Martin