3v4l.org

run code in 300+ PHP versions simultaneously
<?php function foo($bar) { return $bar * 2; } $x = 'foo'; echo ( true === is_callable($x) ? 'T' : 'F' ); echo ( 4 == $x(2) ? 'T' : 'F' );
Output for 7.3.0 - 7.3.33, 7.4.0 - 7.4.29, 8.0.0 - 8.0.19, 8.1.0 - 8.1.6
TT

preferences:
41.81 ms | 409 KiB | 5 Q