Allegro 5 api
#include <allegro5/allegro_audio.h> double al_get_audio_stream_length_secs(ALLEGRO_AUDIO_STREAM *stream)
Return the length of the stream in seconds, if known. Otherwise returns zero.
Currently this can only be called on streams created with al_load_audio_stream(3alleg5), al_load_audio_stream_f(3alleg5) and the format-specific functions underlying those functions.
al_get_audio_stream_position_secs(3alleg5)