[FFmpeg-devel] [PATCH V6 4/6] lavu: add side data AV_FRAME_DATA_BOUNDING_BOXES

[Hendrik Leppkes]

On Tue, Apr 6, 2021 at 6:45 PM Nicolas George <george at nsup.org> wrote:
>
> Guo, Yejun (12021-04-06):
> > compile error on ubuntu 18.04 with default setting:
> > error: ISO C90 forbids variable length array ‘boxes’ [-Werror=vla]
> >       AVBoundingBox boxes[nb_bboxes];
>
> This warning is explicitly added by configure it, we do not have to keep
> it if it hiders us.
>
> If people agree with my analysis that pointers to VLA used to compute
> sizes and offsets in an isolated function are not a problem, unlike
> actual VLAs on the stack, then we can just remove it. I do not think we
> are at risk of adding VLAs by mistake.
>

Unfortunately, this is not correct. I don't know about optimization
problems, but I do know that compilers we do support, which are C11
compliant (where VLAs are optional), do not implement them (just
confirmed this with a test, as well, to make sure).

- Hendrik