3v4l.org

run code in 500+ PHP versions simultaneously
<?php class B { const A = 1; } $c = "b"; // can't use ??, it is a fatal error echo B::{$c} ?? ''; // can't use isset() because it is an expression if (isset(B::{$c})) { echo B::{$c}; } // Must use defined() as it is a constant // and then, use the string syntax if (defined("B::$c")) { echo B::{$c}; } // This still yields a fatal error, or will check the class constant content if (defined(B::{$c})) { echo B::{$c}; }

Here you find the average performance (time & memory) of each version. A grayed out version indicates it didn't complete successfully (based on exit-code).

VersionSystem time (s)User time (s)Memory (MiB)
8.5.30.0260.00416.41
8.3.50.0050.00416.79
preferences:
50.55 ms | 493 KiB | 4 Q