oss_mixerinfo
oss_mixerinfo mixer;
sndctl_mixerinfo(audio_client_t *c, oss_mixerinfo *mi)
rv = sndctl_mixerinfo(c, (oss_mixerinfo *)data);
rv = sndctl_mixerinfo(c, (oss_mixerinfo *)data);
#define SNDCTL_MIXERINFO __OSSIOWR('X', 10, oss_mixerinfo)