al_attach_mixer_to_voice - Allegro 5 API

       Attaches  a  mixer  to a voice.  It must have the same frequency and channel configuration, but the depth
       may be different.

       Returns true on success, false on failure.

       al_attach_mixer_to_voice - Allegro 5 API

al_detach_voice(3alleg5), al_voice_has_attachments(3alleg5)

Allegro reference manual                                                       al_attach_mixer_to_voice(3alleg5)

              #include <allegro5/allegro_audio.h>

              bool al_attach_mixer_to_voice(ALLEGRO_MIXER *mixer, ALLEGRO_VOICE *voice)