3v4l.org

run code in 300+ PHP versions simultaneously
<?php function getVarName(&$var) { $var = serialize($var); $name = array_search($var, $GLOBALS, true); $var = unserialize($var); return $name; } function foo(&$yoba) { echo getVarName($yoba); } $peka = true; foo($peka);
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
peka

preferences:
104.29 ms | 402 KiB | 121 Q