3v4l.org

run code in 300+ PHP versions simultaneously
<?php class A { private static self $singleton; public function __construct() { if(!isset(self::$singleton)) { self::$singleton = $this; } return self::$singleton; } } $a = new A; $b = new A; $c = new A; var_dump($a); var_dump($b); var_dump($c);
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.19, 8.3.0 - 8.3.7
object(A)#1 (0) { } object(A)#2 (0) { } object(A)#3 (0) { }
preferences:
68.65 ms | 402 KiB | 123 Q