Online PHP editor | output for JoUVi

<?php function acquire_some_resource() { return new class { public function __construct() { echo "<locked>\n"; } public function __destruct() { echo "</locked>\n"; } }; } echo "acquire some_resource\n"; $some_resource = acquire_some_resource(); echo "create fn capturing some_resource by reference\n"; $fn = function () use (&$some_resource) { $some_resource = null; // this line has an effect }; echo "call fn\n"; $fn(); echo "unset fn\n"; $fn = null; echo "unset some_resource\n"; $some_resource = null; echo "DONE.\n";