[FFmpeg-devel] [PATCH 2/2] avutil/mem_internal: Don't include stdalign.h on MSVC

[Martin Storsjö]

On Tue, 17 Dec 2024, Hendrik Leppkes wrote:

> On Tue, Dec 17, 2024 at 2:44 PM Zhao Zhili
> <quinkblack-at-foxmail.com at ffmpeg.org> wrote:
>>
>>
>>
>> > On Dec 17, 2024, at 21:13, Martin Storsjö <martin at martin.st> wrote:
>> >
>> > It's currently actually not used in MSVC builds, since
>> > 6e49b8699657b808b7dc80033f2c3f2d0e029fa3.
>> >
>> > Older versions of MSVC (or, in particular, older versions of UCRT)
>> > don't have stdalign.h; it's available since WinSDK 10.0.22000.0,
>> > shipped along with MSVC 2022 17.4 and newer.
>> >
>> > With this change, ffmpeg can still be built with MSVC 2019.
>>
>> LGTM. I’m shocked that a not-so-outdated version of MSVC doesn’t have
>> stdalign.h.
>>
>
> According to the documentation I found, 2019 16.8 should have
> introduced support for C11/C17 and stdalign.h
> In fact I can confirm that the ucrt of 10.0.20348.0 contains it, which
> is the latest Windows 10 SDK, any newer ones are branded Windows 11.

Ah, right; I dind't happen to have a MSVC install with that particular 
SDK.

> Although a standard installation of 2019 might be using an older
> Windows SDK, I'm not sure what it installs by default these days.

A fresh default install of 2019 still seems to pick the 10.0.19041.0 SDK; 
the newer ones are available as optional choices too, but aren't chosen by 
default.

> In any case, no reason to include the header if its not used for the
> moment. So LGTM as well.

Thanks!

// Martin