Get the number of routes in the mixer and their IDs
Synopsis:
#include <sys/asoundlib.h>
int snd_mixer_routes( snd_mixer_t *handle,
snd_mixer_routes_t *routes );
Arguments:
- handle
- The handle for the mixer device.
This must have been created by
snd_mixer_open().
- routes
- A pointer to a
snd_mixer_routes_t
structure that snd_mixer_routes() fills in with information
about the routes.
Library:
libasound.so
Use the -l asound option with
qcc
to link against this library.
Description:
The snd_mixer_routes() function fills the given
snd_mixer_routes_t structure with the number of routes in the
mixer that the handle was opened on.
It also fills in the array of route IDs pointed to by proutes
to a limit of routes_size.
Note:
We recommend that you work with mixer groups instead of manipulating the elements directly.
Before calling snd_mixer_routes(), set the members of this structure as follows:
- proutes
- This pointer must be NULL, or point to a valid storage
location for the routes (i.e., an array of
snd_mixer_eid_t
structures).
- routes_size
- The size of this storage location in
sizeof( snd_mixer_eid_t ) units (i.e., the number of entries
in the proutes array).
On a successful return, the function sets these members:
- routes
- The total number of routes in the mixer.
- routes_over
- The number of routes that couldn't be copied to the storage location.
- proutes
- The list of routes.
Returns:
Zero on success, or a negative value on error.
Errors:
- -EINVAL
- Invalid handle.
Classification:
QNX Neutrino
| Safety: |
|
|---|
| Cancellation point |
No |
| Interrupt handler |
No |
| Signal handler |
Yes |
| Thread |
Yes |