+bool utf8_is_printable_newline(const char* str, size_t length, bool newline) _pure_;
+#define utf8_is_printable(str, length) utf8_is_printable_newline(str, length, true)
+
+char *utf8_escape_invalid(const char *s);
+char *utf8_escape_non_printable(const char *str);