Get the number of groups in the mixer and their group IDs
Synopsis:
#include <sys/asoundlib.h>
int snd_mixer_groups( snd_mixer_t *handle,
snd_mixer_groups_t *groups );
Arguments:
- handle
- The handle for the mixer device.
This must have been created by
snd_mixer_open().
- groups
- A pointer to a
snd_mixer_groups_t
structure that
snd_mixer_groups() fills in with information about the groups.
Library:
libasound.so
Use the -l asound option with
qcc
to link against this library.
Description:
The snd_mixer_groups() function
fills the given snd_mixer_groups_t structure with the number of
groups in the mixer that the handle was opened on.
It also fills in the array of group IDs pointed to by pgroups to
a limit of groups_size.
Before calling snd_mixer_groups(), set the members of the
snd_mixer_groups_t as follows:
- pgroups
- This pointer must be NULL or point to a valid storage
location for the groups (i.e., an array of
snd_mixer_gid_t
structures).
- groups_size
- The size of the pgroups storage location in
sizeof(snd_mixer_gid_t) units (i.e., the number of entries in the array).
On a successful return, snd_mixer_groups() fills in these members:
- groups
- The total groups in the mixer.
- groups_over
- The number of groups that couldn't be copied to the storage location.
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 |