pcm: more better documentation for snd_pcm_poll_descriptors

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
This commit is contained in:
Jaroslav Kysela 2009-04-21 14:36:29 +02:00
parent a987a692bf
commit 0de385109a

View file

@ -104,9 +104,13 @@ implementation can be found in the \ref alsa_pcm_rw section.
The poll or select functions (see 'man 2 poll' or 'man 2 select' for further The poll or select functions (see 'man 2 poll' or 'man 2 select' for further
details) allows to receive requests/events from the device while details) allows to receive requests/events from the device while
an application is waiting on events from other sources (like keyboard, screen, an application is waiting on events from other sources (like keyboard, screen,
network etc.), too. \ref snd_pcm_poll_descriptors can be used to get a file network etc.), too. \ref snd_pcm_poll_descriptors can be used to get file
descriptor to poll or select on. The implemented descriptors to poll or select on (note that wait direction might be diferent
transfer routines can be found in the \ref alsa_transfers section. than expected - do not use only returned file descriptors, but handle
events member as well - see \ref snd_pcm_poll_descriptors function
description for more details and \ref snd_pcm_poll_descriptors_revents for
events demangling). The implemented transfer routines can be found in
the \ref alsa_transfers section.
\subsection pcm_transfer_async Asynchronous notification \subsection pcm_transfer_async Asynchronous notification
@ -1405,7 +1409,9 @@ int snd_pcm_poll_descriptors_count(snd_pcm_t *pcm)
* does the right "demangling". * does the right "demangling".
* *
* You can use output from this function as arguments for the select() * You can use output from this function as arguments for the select()
* syscall, too. * syscall, too. Do not forget to translate POLLIN and POLLOUT events to
* corresponding FD_SET arrays and demangle events using
* \link ::snd_pcm_poll_descriptors_revents() \endlink .
*/ */
int snd_pcm_poll_descriptors(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int space) int snd_pcm_poll_descriptors(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int space)
{ {