[FFmpeg-user] build error at libavformat/udp.o

[Moritz Barsnick]

On Tue, Sep 01, 2020 at 10:57:33 +0000, Hyoung Kim via ffmpeg-user wrote:
>     Yes, older source works fine, but newer sources (4.1.6, 4.2.1, 4.3.1 and git head) has build problem. So I have compared the source of udp.c between 4.0.6 and 4.3.1. There is a difference, but even the 4.0.6 has same statements which caused syntax error. So there could be 3 possibilities.
> 1. Define difference between older source and newer source.2. The primitive type has been converted to struct or union in older source somewhere while newer source does not.3. The build environment could have been changed in newer source.
> Any idea about this?

As long as no one else can reproduce this issue, it's up to you to try.

To find out which specific change broke your build - yes, it could be
ffmpeg's build system config - you would use "git bisect".

You go to the git master branch, find a commit where it still works
(probably around 4.0.x time) and a commit when it no longer works
(probably around 4.1.x time, from your reports), and git will help you
iterate through commits to find the offending one, with least possible
iterations.

There are quite a few instructions around for this process. I would
need to look it up myself, as I have only seldomly used it.

Regards,
Moritz