3v4l.org

run code in 300+ PHP versions simultaneously
<?php $foo = $_GET['bar'] ?? 'hello'; echo $foo; $_GET['bar'] = 'good bye'; $foo = $_GET['bar'] ?? 'hello'; echo $foo;
Output for 7.0.0 - 7.0.33, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
hellogood bye
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.40
Parse error: syntax error, unexpected '?' in /in/NKmSK on line 2
Process exited with code 255.
preferences:
270.26 ms | 402 KiB | 330 Q