3v4l.org

run code in 300+ PHP versions simultaneously
<?php $r = &$a[]; var_dump($a, $r); $r = 2; var_dump($a, $r);
Output for 8.1.0 - 8.1.33, 8.2.0 - 8.2.29, 8.3.0 - 8.3.26, 8.4.1 - 8.4.14
array(1) { [0]=> &NULL } NULL array(1) { [0]=> &int(2) } int(2)
preferences:
74.3 ms | 406 KiB | 5 Q