al_ustr_compare - Allegro 5 API

       This  function  compares  us1  and  us2  by  code point values.  Returns zero if the strings are equal, a
       positive number if us1 comes after us2, else a negative number.

       This does not take into account locale-specific sorting rules.  For that you will  need  to  use  another
       library.

       al_ustr_compare - Allegro 5 API

al_ustr_ncompare(3alleg5), al_ustr_equal(3alleg5)

Allegro reference manual                                                                al_ustr_compare(3alleg5)

              #include <allegro5/allegro.h>

              int al_ustr_compare(const ALLEGRO_USTR *us1, const ALLEGRO_USTR *us2)