al_create_mutex - Allegro 5 API

       Create  the  mutex  object  (a  mutual  exclusion  device).  The mutex may or may not support “recursive”
       locking.

       Returns the mutex on success or NULL on error.

       al_create_mutex - Allegro 5 API

al_create_mutex_recursive(3alleg5).

Allegro reference manual                                                                al_create_mutex(3alleg5)

              #include <allegro5/allegro.h>

              ALLEGRO_MUTEX *al_create_mutex(void)