al_set_audio_stream_fragment - Allegro 5 API

       This  function  needs  to be called for every successful call of al_get_audio_stream_fragment(3alleg5) to
       indicate that the buffer (pointed to by val) is filled with new data.

       al_set_audio_stream_fragment - Allegro 5 API

al_get_audio_stream_fragment(3alleg5)

Allegro reference manual                                                   al_set_audio_stream_fragment(3alleg5)

              #include <allegro5/allegro_audio.h>

              bool al_set_audio_stream_fragment(ALLEGRO_AUDIO_STREAM *stream, void *val)