[xine-devel] metronome sync loop

[Giuseppe C. <co...@lu...>]

Hi all
I'm a newbie in xine development and absolutely ignorant in video stuff so I
can give only general advices...

1) metronom_sync_loop (metronom.c)
I suggest changing the sleep() call with nanosleep().
Reasons:

POSIX (and UNIX 98) absolutely require that sleep() function as specified
for the calling thread without any effect at all on other threads. However,
on implementations that don't/can't claim full POSIX conformance, sleep()
is one of the functions voted most likely to be broken because the 
traditional implementation relies on SIGALRM and won't work correctly with
threads. When such implementations support nanosleep(), that's more likely
to work correctly, though there are no guarantees. (Again, POSIX requires
that BOTH work correctly, and once someone's broken one rule, it makes
little sense to bet they've followed other related rules... at least, don't
bet very much.
(comp.programming.threads FAQ)

sleep() may be implemented using SIGALRM; mixing calls to alarm() and
sleep() is a bad idea.
(Linux manual)

Anyway, using signals and threads is not a simple matter. One of the better
strategies I've seen is to spawn a thread which waits for all the
interesting signals. For every one catched it posts a semaphore (sem_post is
signal safe). Other threads should wait on the semaphores.
But this is the theory, I don't know if applicable to xine.

2) is it possible to have a general description/diagram on how the various
xine threads are spawned/synchronized?

Thank you

--
	Giuseppe "Cowo" Corbelli ~\/~ My software: http://cowo.mascanc.net
		-<! $>cd /pub   $>more beer !>-