- var_dump: documentation ( source)
- ob_start: documentation ( source)
- headers_sent: documentation ( source)
- ob_end_clean: documentation ( source)
<?php
ob_start();
$sent_a = headers_sent();
ob_end_clean(); // or ob_clean(); etc..
$sent_b = headers_sent();
var_dump($sent_a);
var_dump($sent_b);
exit;