al_run_detached_thread man page
al_run_detached_thread — Allegro 5 API Runs the passed function in its own thread, with
void al_run_detached_thread(void *(*proc)(void *arg), void *arg)
arg passed to it as only parameter. This is similar to calling al_create_thread(3), al_start_thread(3) and (after the thread has finished) al_destroy_thread(3) - but you don't have the possibility of ever calling al_join_thread(3) on the thread.
Runs the passed function in its own thread, with