3v4l.org

run code in 300+ PHP versions simultaneously
<?php namespace Wat; if(!defined('foo')) { define('Wat\\foo', 'bar'); } var_dump(defined('Wat\\foo')); var_dump(defined('Wat\\foox')); echo foo;
Output for 5.6.38, 7.1.0 - 7.1.23, 7.2.0 - 7.2.33, 7.3.16 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
bool(true) bool(false) bar

preferences:
72.9 ms | 1446 KiB | 4 Q