al_remove_path_component - Allegro 5 API

       Delete  the i’th directory component.  If the index is negative then count from the right, i.e. -1 refers
       to the last path component.  It is an error to pass an index which is out of bounds.

       al_remove_path_component - Allegro 5 API

al_insert_path_component(3alleg5), al_replace_path_component(3alleg5), al_drop_path_tail(3alleg5)

Allegro reference manual                                                       al_remove_path_component(3alleg5)

              #include <allegro5/allegro.h>

              void al_remove_path_component(ALLEGRO_PATH *path, int i)