3v4l.org

run code in 300+ PHP versions simultaneously
<?php // plain variable $a = 42; // array containing a reference $b = [ 'a' => &$a ]; // capture the array by-value $f = function() use($b) { // update the reference from inside the closure $b['a'] = 69; }; // call it $f(); // observe that both the array and the plain variable now have the new value var_dump($a, $b);

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