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snd_ctl_read()

Read pending control events

Synopsis:

#include <sys/asoundlib.h>

int snd_ctl_read( snd_ctl_t * handle, 
                  snd_ctl_callbacks_t * callbacks );

Library:

libasound.so

Description:

The snd_ctl_read() function reads pending control events from the control 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 on the return of the select() library call.

Returns:

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

Errors:

-EBADF
Invalid file descriptor, filedes, open for reading.
-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:

ALSA

Safety:
Cancellation point No
Interrupt handler No
Signal handler Yes
Thread Yes

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