note 111716 added to function.headers-sent

It is noted here that: "Headers will only be accessible and output when a SAPI that supports them is in use." Perhaps someone can elaborate. I just ran into a problem with this being the case on one machine and not another (and the code base breaks on one and not the other...) I'm new, but I won't exactly ask what "a SAPI" is, but how can one determine if a SAPI that supports them is in use? ---- Server IP: 69.147.83.199 Probable Submitter: 24.34.115.129 ---- Manual Page -- http://php.net/manual/en/function.headers-sent.php Edit -- https://master.php.net/note/edit/111716 Del: integrated -- https://master.php.net/note/delete/111716/integrated Del: useless -- https://master.php.net/note/delete/111716/useless Del: bad code -- https://master.php.net/note/delete/111716/bad+code Del: spam -- https://master.php.net/note/delete/111716/spam Del: non-english -- https://master.php.net/note/delete/111716/non-english Del: in docs -- https://master.php.net/note/delete/111716/in+docs Del: other reasons-- https://master.php.net/note/delete/111716 Reject -- https://master.php.net/note/reject/111716 Search -- https://master.php.net/manage/user-notes.php