al_get_path_basename man page
al_get_path_basename — Allegro 5 API
#include <allegro5/allegro.h> const char *al_get_path_basename(const ALLEGRO_PATH *path)
Return the basename, i.e. filename with the extension removed. If the filename doesn't have an extension, the whole filename is the basename. If there is no filename part then the empty string is returned.
The returned pointer is valid only until the filename part of the path is modified in any way, or until the path is destroyed.