3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = [1, 2, 3]; function foo(&$a) { $b = $a; $a[] = count($a) + 1; return $b; } var_dump( foo($a), // return value is *before* $a // after );

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24.05 ms | 404 KiB | 5 Q