3v4l.org

run code in 300+ PHP versions simultaneously
<?php function f(){ $v=1; $a=function(){ echo "BT\n"; }; $a(); } f();
Output for 5.6.0 - 5.6.29, 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.6 - 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
BT
preferences:
202.24 ms | 403 KiB | 221 Q