--TEST-- Overriding SplFixedArray::offsetGet() only --FILE-- <?php class MyArray extends SplFixedArray { public function offsetGet($key) { return "prefix_" . parent::offsetGet($key); } } $arr = new MyArray(1); var_dump(isset($arr[0])); $arr[0] = "abc"; var_dump(isset($arr[0])); var_dump($arr[0]); ?> --EXPECT-- bool(false) bool(true) string(10) "prefix_abc"