3v4l.org

run code in 300+ PHP versions simultaneously
<?php $foo = $_GET['bar'] ?? 'hello'; echo $foo . "\n"; $_GET['bar'] = 'good bye'; $foo = $_GET['bar'] ?? 'hello'; echo $foo;
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.20, 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 - 8.1.30, 8.2.0 - 8.2.25, 8.3.0 - 8.3.13
hello good bye
Output for 5.5.0 - 5.5.38, 5.6.0 - 5.6.28
Parse error: syntax error, unexpected '?' in /in/0CfbE on line 2
Process exited with code 255.
preferences:
73.9 ms | 407 KiB | 5 Q