3v4l.org

run code in 500+ PHP versions simultaneously
<?php namespace { define('B\CONSTANT', 123); define('B\NULL', 456); define('GLOBAL_CONSTANT', 789); } namespace B { var_dump(NULL); var_dump(CONSTANT); var_dump(\B\NULL); var_dump(GLOBAL_CONSTANT); }
Output for 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
NULL int(123) int(456) int(789)

preferences:
72.29 ms | 976 KiB | 4 Q