al_ustr_get_next - Allegro 5 API

       Find the code point in us beginning at byte offset *pos, then advance to the next code point.

       On  success  return  the  code  point value.  If pos was out of bounds (e.g. past the end of the string),
       return -1.  On an error, such as an invalid byte sequence, return  -2.   As  with  al_ustr_next(3alleg5),
       invalid byte sequences may be skipped while advancing.

       al_ustr_get_next - Allegro 5 API

al_ustr_get(3alleg5), al_ustr_prev_get(3alleg5)

Allegro reference manual                                                               al_ustr_get_next(3alleg5)

              #include <allegro5/allegro.h>

              int32_t al_ustr_get_next(const ALLEGRO_USTR *us, int *pos)