snd_mixer_routes()
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 number of routes that are currently valid in proutes. Read only.
- routes_over
- The number of routes that could not be retrieved due to the size constraints of the proutes local storage. Read only.
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 |
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