From 0ecc03111d8a45162e4b4a8482a3a7941f4f1f0e Mon Sep 17 00:00:00 2001 From: Jaroslav Kysela Date: Wed, 3 Mar 2004 12:54:01 +0000 Subject: [PATCH] Improved comments for poll_descriptors --- src/pcm/pcm.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/src/pcm/pcm.c b/src/pcm/pcm.c index deb0a605..9d1b06c9 100644 --- a/src/pcm/pcm.c +++ b/src/pcm/pcm.c @@ -1220,9 +1220,13 @@ int snd_pcm_poll_descriptors_count(snd_pcm_t *pcm) * PCM handle. The poll desctiptor array should have the size returned by * \link ::snd_pcm_poll_descriptors_count() \endlink function. * + * The result is intended for direct use with the poll() syscall. + * * For reading the returned events of poll descriptor after poll() system * call, use \link ::snd_pcm_poll_descriptors_revents() \endlink function. - * The field values in pollfd structs may be bogus. + * The field values in pollfd structs may be bogus regarding the stream + * direction from the application perspective (POLLIN might not imply read + * direction and POLLOUT might not imply write). */ int snd_pcm_poll_descriptors(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int space) { @@ -1243,6 +1247,9 @@ int snd_pcm_poll_descriptors(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int s * \param nfds count of poll descriptors * \param revents returned events * \return zero if success, otherwise a negative error code + * + * This function does "demangling" of the revents mask returned from + * the poll() syscall to correct semantics (POLLIN = read, POLLOUT = write). */ int snd_pcm_poll_descriptors_revents(snd_pcm_t *pcm, struct pollfd *pfds, unsigned int nfds, unsigned short *revents) { -- 2.47.1