snd_mixer_read()

Read pending mixer events

Synopsis:

#include <sys/asoundlib.h>

int snd_mixer_read(
       snd_mixer_t *handle, 
       snd_mixer_callbacks_t *callbacks );

Arguments:

handle

The handle for the mixer device. This must have been created by snd_mixer_open().

callbacks

A pointer to a snd_mixer_callbacks_t structure that defines the list of callbacks.

Library:

libasound.so

Description:

The snd_mixer_read() function reads pending mixer events from the mixer handle. As each event is read, the list of callbacks is checked for a handler for this event. If a match is found, the callback is invoked. This function is usually called when the select() library call indicates that there is data to be read on the mixer's file descriptor.

Returns:

The number of events read from the handle, or a negative value on error.

Errors:

-EBADF

Invalid file descriptor. Your handle may be corrupt.

-EINTR

The read operation was interrupted by a signal, and either no data was transferred, or the resource manager responsible for that file doesn't report partial transfers.

-EIO

An event I/O error occurred.

Classification:

QNX Neutrino

See also:

snd_mixer_callbacks_t, snd_mixer_eid_t, snd_mixer_file_descriptor(), snd_mixer_get_filter(), snd_mixer_set_filter()