al_get_current_directory man page
al_get_current_directory — Allegro 5 API
#include <allegro5/allegro.h> char *al_get_current_directory(void)
Returns the path to the current working directory, or NULL on failure. The returned path is dynamically allocated and must be destroyed with al_free(3).
Allegro's errno is filled in to indicate the error if there is a failure. This function may not be implemented on some (virtual) filesystems.