Information about all elements in a mixer
typedef struct snd_mixer_elements_s
{
    int32_t     elements, elements_size, elements_over;
    uint8_t     zero[4];            /* alignment -- zero fill */
    snd_mixer_eid_t *pelements;
    void        *pzero;             /* align pointers on 64-bits;
                                       point to NULL */
    uint8_t     reserved[128];      /* must be filled with zeroes */
}       snd_mixer_elements_t;
The snd_mixer_elements_t structure describes all the elements in a mixer. You can fill in this structure by calling snd_mixer_elements().
The members of the snd_mixer_elements_t structure include:
If pelements isn't NULL, snd_mixer_elements() stores the mixer element IDs in the array.
QNX Neutrino