3v4l.org

run code in 200+ php & hhvm versions
Bugs & Features
<?php ob_start(); header("X-WTFIDONTEVEN: true"); if (headers_sent()) { echo "sent"; } else { echo "not sent"; } ob_end_flush();
Output for 5.2.3 - 7.1.7
not sent
Output for 4.3.0 - 5.2.2
sent