3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php if (@readfile('/foo') === false) { echo "foo"; } header('HTTP/1.1 404 Not Found');
based on TkECJ
Output for 5.2.3 - 7.2.0
foo Warning: Cannot modify header information - headers already sent by (output started at /in/3B28W:4) in /in/3B28W on line 6
Output for 4.3.0 - 5.2.2
foo