3v4l.org

run code in 300+ PHP versions simultaneously
<?php $a = "foo"; $b = str_repeat("a", 3); echo "Static Var\n"; testCopy($a); echo "Dynamic Var\n"; testCopy($b); function testCopy($var) { echo memory_get_usage() . "\n"; $var = (string) $var; echo memory_get_usage() . "\n"; }

preferences:
34.45 ms | 402 KiB | 5 Q