al_init man page
al_init — Allegro 5 API
#include <allegro5/allegro.h> #define al_init() (al_install_system(ALLEGRO_VERSION_INT, atexit))
Like al_install_system(3), but automatically passes in the version and uses the atexit function visible in the current binary.
Note: It is typically wrong to call al_init anywhere except the final game binary. In particular, do not call it inside a shared library unless you know what you're doing. In those cases, it is better to call al_install_system either with a
NULL atexit_ptr, or with a pointer to atexit provided by the user of this shared library.
al_get_cpu_count(3), al_get_ram_size(3), al_install_system(3), al_set_app_name(3), al_set_org_name(3).