al_lock_sample_id - Allegro 5 API

       Locks  a  ALLEGRO_SAMPLE_ID(3alleg5),  returning  the  underlying ALLEGRO_SAMPLE_INSTANCE(3alleg5).  This
       allows you to adjust the various properties of the instance (such as volume, pan, etc) while the sound is
       playing.

       This function will return NULL if the sound corresponding to the id is no longer playing.

       While locked, ALLEGRO_SAMPLE_ID will be unavailable to additional calls to al_play_sample(3alleg5),  even
       if the sound stops while locked.  To put the ALLEGRO_SAMPLE_ID back into the pool for reuse, make sure to
       call al_unlock_sample_id when you’re done with the instance.

       al_lock_sample_id - Allegro 5 API

al_play_sample(3alleg5), al_unlock_sample_id(3alleg5)

       5.2.3

              [UnstableAPI]: New API.

Allegro reference manual                                                              al_lock_sample_id(3alleg5)

              #include <allegro5/allegro_audio.h>

              ALLEGRO_SAMPLE_INSTANCE* al_lock_sample_id(ALLEGRO_SAMPLE_ID *spl_id)