audio__setgain
audio__setgain((F), (V), AUDIO__PLAY|AUDIO__GAIN)
audio__setgain((F), (V), AUDIO__RECORD|AUDIO__GAIN)
audio__setgain((F), (V), AUDIO__MONGAIN)
audio__setgain((F), (V), AUDIO__SET|AUDIO__PLAY|AUDIO__GAIN)
audio__setgain((F), (V), AUDIO__SET|AUDIO__RECORD|AUDIO__GAIN)
audio__setgain((F), (V), AUDIO__SET|AUDIO__MONGAIN)
EXTERN_FUNCTION(int audio__setgain, (int, double *, unsigned));