Suppress "old style definition" warning
@@ -1263,7 +1263,7 @@ static VALUE parser_new(int argc, VALUE *argv, VALUE self) {
// from this function. A delegate must be added before the parser can be
// used. Optionally oj_parser_set_options can be called if the options are not
// set directly.
-VALUE oj_parser_new() {
+VALUE oj_parser_new(void) {
ojParser p = ALLOC(struct _ojParser);
#if HAVE_RB_EXT_RACTOR_SAFE
