al_unlock_sample_id - Allegro 5 API

       Unlocks  a  ALLEGRO_SAMPLE_ID(3alleg5),  allowing  future calls to al_play_sample(3alleg5) to reuse it if
       possible.  Note that after the id is unlocked, the ALLEGRO_SAMPLE_INSTANCE(3alleg5) that  was  previously
       returned by al_lock_sample_id(3alleg5) will possibly be playing a different sound, so you should only use
       it after locking the id again.

       al_unlock_sample_id - Allegro 5 API

al_play_sample(3alleg5), al_lock_sample_id(3alleg5)

       5.2.3

              [UnstableAPI]: New API.

Allegro reference manual                                                            al_unlock_sample_id(3alleg5)

              #include <allegro5/allegro_audio.h>

              void al_unlock_sample_id(ALLEGRO_SAMPLE_ID *spl_id)