3v4l.org

run code in 300+ PHP versions simultaneously
<?php error_reporting(E_ALL); function setDefault(&$variable, $default) { if (!isset($variable)) { $variable = $default; } } $foo = array( 'foo' => 'oof' ); setDefault($foo['bar']['uuu'], 'rab'); print_r($foo); ?>
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, 5.5.0 - 5.5.37, 5.6.0 - 5.6.28, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
Array ( [foo] => oof [bar] => Array ( [uuu] => rab ) )

preferences:
283.43 ms | 406 KiB | 380 Q