3v4l.org

run code in 300+ PHP versions simultaneously
<?php function foo(&$arg) { echo "hi\n"; var_dump($arg); } $a = 'bar'; $b =& $a; call_user_func('foo', $b); call_user_func('foo', $a);
Output for 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Warning: foo(): Argument #1 ($arg) must be passed by reference, value given in /in/M2Sfq on line 11 hi string(3) "bar" Warning: foo(): Argument #1 ($arg) must be passed by reference, value given in /in/M2Sfq on line 13 hi string(3) "bar"
Output for 7.1.0 - 7.1.20, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33
Warning: Parameter 1 to foo() expected to be a reference, value given in /in/M2Sfq on line 11 hi string(3) "bar" Warning: Parameter 1 to foo() expected to be a reference, value given in /in/M2Sfq on line 13 hi string(3) "bar"
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, 5.5.24 - 5.5.35, 5.6.8 - 5.6.28, 7.0.0 - 7.0.20
hi string(3) "bar" hi string(3) "bar"
preferences:
294.94 ms | 404 KiB | 311 Q