al_join_paths - Allegro 5 API

       Concatenate  two  path structures.  The first path structure is modified.  If `tail' is an absolute path,
       this function does nothing.

       If `tail' is a relative path, all of its  directory  components  will  be  appended  to  `path'.   tail’s
       filename will also overwrite path’s filename, even if it is just the empty string.

       Tail’s drive is ignored.

       Returns true if `tail' was a relative path and so concatenated to `path', otherwise returns false.

       al_join_paths - Allegro 5 API

al_rebase_path(3alleg5)

Allegro reference manual                                                                  al_join_paths(3alleg5)

              #include <allegro5/allegro.h>

              bool al_join_paths(ALLEGRO_PATH *path, const ALLEGRO_PATH *tail)