3v4l.org

run code in 300+ PHP versions simultaneously
<?php $x = 0; $a = array(&$x); // [&0] $b = $a; // [&0] $x = 2; // a=[&2], b=[&2] //unset($x); // //$b[1]++; $b[0]++; echo $a[0], ' ', $b[0];
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29, 5.4.0 - 5.4.45, 5.5.0 - 5.5.38, 5.6.0 - 5.6.40, 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17, 8.3.0 - 8.3.4
3 3

preferences:
314.05 ms | 405 KiB | 454 Q