+utf32_iterator utf32_iterator_new(const uint32_t *s, size_t ns);
+void utf32_iterator_destroy(utf32_iterator it);
+
+size_t utf32_iterator_where(utf32_iterator it);
+int utf32_iterator_set(utf32_iterator it, size_t n);
+int utf32_iterator_advance(utf32_iterator it, size_t n);
+uint32_t utf32_iterator_code(utf32_iterator it);
+int utf32_iterator_grapheme_boundary(utf32_iterator it);
+int utf32_iterator_word_boundary(utf32_iterator it);
+