3v4l.org

run code in 300+ PHP versions simultaneously
<?php error_reporting(E_ALL); function out(&$x) { $x = 1; } out($c = NULL); echo "c = $c";
Output for 8.3.0 - 8.3.4
Fatal error: Uncaught Error: out(): Argument #1 ($x) could not be passed by reference in /in/VETGk:4 Stack trace: #0 {main} thrown in /in/VETGk on line 4
Process exited with code 255.
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.27, 8.2.0 - 8.2.17
Fatal error: Uncaught Error: out(): Argument #1 ($x) cannot be passed by reference in /in/VETGk:4 Stack trace: #0 {main} thrown in /in/VETGk on line 4
Process exited with code 255.
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.12 - 7.3.33, 7.4.0 - 7.4.33
Notice: Only variables should be passed by reference in /in/VETGk on line 4 c =
Output for 5.4.0 - 5.4.45, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28
Strict Standards: Only variables should be passed by reference in /in/VETGk on line 4 c =
Output for 5.1.2 - 5.1.6, 5.2.0 - 5.2.17, 5.3.0 - 5.3.29
c =
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.5, 5.1.0 - 5.1.1
c = 1

preferences:
198.89 ms | 402 KiB | 310 Q