al_set_audio_stream_gain
bool al_set_audio_stream_gain(ALLEGRO_AUDIO_STREAM *stream, float val)
Introduced in 5.0.0
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.
Examples: ex_synth
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