3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php function test() { return null; } if(!isset(test())) { echo 'false'; }
Output for 7.0.0 - 7.0.1
Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in /in/KM9dg on line 6
Process exited with code 255.
Output for 5.5.24 - 5.6.16
Fatal error: Cannot use isset() on the result of a function call (you can use "null !== func()" instead) in /in/KM9dg on line 6
Process exited with code 255.
Output for 5.3.21 - 5.4.45
Fatal error: Can't use function return value in write context in /in/KM9dg on line 6
Process exited with code 255.