3v4l.org

run code in 300+ PHP versions simultaneously
<?php abstract class Singleton { protected function __construct() {} protected function __clone() {} public static function getInstance() { static $instance = null; if (!$instance) { $instance = new static; } return $instance; } } class B extends Singleton { public $var = 2; } class F extends Singleton { public $var = 6; } var_dump(B::getInstance()); var_dump(F::getInstance());

preferences:
38.32 ms | 402 KiB | 5 Q