Provided by: allegro5-doc_5.0.11-2_all 

NAME
al_set_audio_stream_gain - Allegro 5 API
SYNOPSIS
#include <allegro5/allegro_audio.h>
bool al_set_audio_stream_gain(ALLEGRO_AUDIO_STREAM *stream, float val)
DESCRIPTION
Set the playback gain.
Returns true on success, false on failure. Will fail if the sample instance is attached directly to a
voice.
SEE ALSO
al_get_audio_stream_gain(3alleg5).
al_set_audio_stream_gain(... Allegro reference manual()