3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = 1; $b = [&$a]; $c = $b; unset($a); // <-- $b[0] = 2; echo "$b[0] $c[0]"; // 2 1
Output for 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.26, 8.2.0 - 8.2.13, 8.3.0
2 1

preferences:
93.32 ms | 403 KiB | 143 Q