3v4l.org

run code in 300+ PHP versions simultaneously
<?php function &f(&$x){return $x;} f($x) =& $y;
Output for 5.3.0 - 5.3.28, 5.4.0 - 5.4.25
Fatal error: Can't use function return value in write context in /in/4BZQf on line 3
Process exited with code 255.
preferences:
182.7 ms | 1395 KiB | 62 Q