From 0de385109a5edd257264ebdc431465c8e38c2402 Mon Sep 17 00:00:00 2001 From: Jaroslav Kysela Date: Tue, 21 Apr 2009 14:36:29 +0200 Subject: pcm: more better documentation for snd_pcm_poll_descriptors Signed-off-by: Jaroslav Kysela --- src/pcm/pcm.c | 14 ++++++++++---- 1 file changed, 10 insertions(+), 4 deletions(-) diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c index 209c5bb0..e63bbe9e 100644 --- a/src/pcm/pcm.c +++ b/src/pcm/pcm.c @@ -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 details) allows to receive requests/events from the device while 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 -descriptor to poll or select on. The implemented -transfer routines can be found in the \ref alsa_transfers section. +network etc.), too. \ref snd_pcm_poll_descriptors can be used to get file +descriptors to poll or select on (note that wait direction might be diferent +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 @@ -1405,7 +1409,9 @@ int snd_pcm_poll_descriptors_count(snd_pcm_t *pcm) * does the right "demangling". * * 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) { -- cgit v1.2.1