al_ustr_size - Allegro 5 API

       Return  the size of the string in bytes.  This is equal to the number of code points in the string if the
       string is empty or contains only 7-bit ASCII characters.

       al_ustr_size - Allegro 5 API

al_ustr_length(3alleg5)

Allegro reference manual                                                                   al_ustr_size(3alleg5)

              #include <allegro5/allegro.h>

              size_t al_ustr_size(const ALLEGRO_USTR *us)