Provided by: allegro5-doc_5.2.9.1+dfsg-1.1build4_all 

NAME
al_create_mutex - Allegro 5 API
SYNOPSIS
#include <allegro5/allegro.h> ALLEGRO_MUTEX *al_create_mutex(void)
DESCRIPTION
Create the mutex object (a mutual exclusion device). The mutex may or may not support “recursive” lock‐ ing. Returns the mutex on success or NULL on error.
SEE ALSO
al_create_mutex_recursive(3alleg5). Allegro reference manual al_create_mutex(3alleg5)