[FFmpeg-devel] [PATCH 2/2] avformat/udp: Replace use of pthread_cancel.

[Nicolas George]

Replying for the completeness of the discussion.

Le tridi 13 frimaire, an CCXXV, Matt Oliver a écrit :
> Thats the trick, not to large that it results noticeable shutdown delays to
> the user but not to quick that it polls to often, on a modern machine id
> think something like 0.01s would be ok.

I would agree. Unfortunately, even not speaking of the deep-sleep states
I evoked earlier, FFmpeg also supports much smaller hardware than what
is required to run anything related to MSVC. On some supported hardware,
a 100 Hz poll would be too much.

> I was thinking of just using setsockopt to set a value for SO_RCVTIMEO only
> in circular_buffer_task_rx. That way recv will timeout at the specified
> interval which will then use the existing code that checks the recv return.
> In case of timeout that check will continue back to top of loop that will
> have the s->close_req check to terminate the thread if needed.
> something like:

Indeed, in theory that would work. I always forget about these options.
In my experience they do not work reliably, and I would argue against
their use in portable code. For example, starting there:
http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_socket.h.html
can you tell me the type of the arguments to SO_RCVTIMEO? I know Linux
man page tells us it is struct timeval, but that is not a portable
standard.

Also, these options are just a band aid to implement polling.

> Is anyone working on that as your right i definitely think an event system
> for all protocols is the best option. Its just that has a larger scope than
> i can handle so i was trying to get a simple shorter term fix for udp.

Working on it really, no, and not in the foreseeable future. But I have
some detailed ideas about how to proceed for when I will get to it. I
can share them if someone wants to do it.

Regards,

-- 
  Nicolas George
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