3v4l.org

run code in 300+ PHP versions simultaneously
<?php function foo(&$bar) { echo "callable is "; var_dump(is_callable($output)); var_dump($bar); } foo($bar);
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
callable is Warning: Undefined variable $output in /in/igLvF on line 7 bool(false) NULL
Output for 5.0.4 - 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, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.25, 7.2.0 - 7.2.33, 7.3.0 - 7.3.31, 7.4.0 - 7.4.33
callable is Notice: Undefined variable: output in /in/igLvF on line 7 bool(false) NULL
Output for 7.3.32 - 7.3.33
callable is bool(false) NULL
Output for 4.3.0 - 4.3.11, 4.4.0 - 4.4.9, 5.0.0 - 5.0.3
callable is Notice: Undefined variable: output in /in/igLvF on line 7 bool(false) NULL
preferences:
206.54 ms | 402 KiB | 327 Q