3v4l.org

run code in 200+ PHP versions simultaneously
<?php $argv[1] = "PDO,FETCH_CLASSTYPE"; ?> <?=constant(explode(',',$argv[1])[0]."::".explode(',',$argv[1])[1])==262144?"Hello, world ":a;
Output for 5.4.0 - 7.4.0
Hello, world
Output for 4.3.0 - 5.3.29
<?=constant(explode(',',$argv[1])[0]."::".explode(',',$argv[1])[1])==262144?"Hello, world ":a;