-/* Return 1 if two yx_uint16 coordinates a and b are equal, else 0. */
-extern char yx_uint16_cmp(struct yx_uint16 a, struct yx_uint16 b);
+/* Return 1 if two yx_uint16 coordinates at "a" and "b" are equal, else 0. */
+extern uint8_t yx_uint16_cmp(struct yx_uint16 * a, struct yx_uint16 * b);