IMPRESS dotted_line CONTACT dotted_line search dotted_line Kontakt dotted_line sitemap dotted_line print
176 PHP-Resource users online

Switch to another languags Deutsch aktuelle Sprache Englisch

PHP Manual


(PHP 4, PHP 5)

headers_sentChecks if or where headers have been sent


bool headers_sent ([ string &$file [, int &$line ]] )

Checks if or where headers have been sent.

You can't add any more header lines using the header() function once the header block has already been sent. Using this function you can at least prevent getting HTTP header related error messages. Another option is to use Output Buffering.



If the optional file and line parameters are set, headers_sent() will put the PHP source file name and line number where output started in the file and line variables.


The line number where the output started.

Return Values

headers_sent() will return FALSE if no HTTP headers have already been sent or TRUE otherwise.


Version Description
4.3.0 The optional file and line parameters were added.


Example #1 Examples using headers_sent()


// If no headers are sent, send one
if (!headers_sent()) {

// An example using the optional file and line parameters, as of PHP 4.3.0
// Note that $filename and $linenum are passed in for later use.
// Do not assign them values beforehand.
if (!headers_sent($filename$linenum)) {

// You would most likely trigger an error here.
} else {

"Headers already sent in $filename on line $linenum\n" .
"Cannot redirect, for now please click this <a " .
"href=\"\">link</a> instead\n";




Headers will only be accessible and output when a SAPI that supports them is in use.

See Also

  • ob_start() - Turn on output buffering
  • trigger_error() - Generates a user-level error/warning/notice message
  • headers_list() - Returns a list of response headers sent (or ready to send)
  • header() - Send a raw HTTP header for a more detailed discussion of the matters involved.

Comments to the PHP manual
Write new comment


New Tutorial entries

Migration einer PHP 5 App auf PHP 7

Dieses PHP 7 Tutorial zeigt dir, wie du dein PHP5 Script auf PHP7 umstellst.

Berni | Category: PHP
PHP 7 Virtual Machine

Dieser Artikel zielt darauf ab, einen Überblick über die Zend Virtual Machine, wie es in PHP 7 gefunden wird.

Berni | Category: PHP
plotting masters - a professional guide - Teil II

Grafische Interpolation und Bestapproximation von numerischen Wertepaaren: Wir wollen Punkte auf einer Zeichenebene über verschiedene Verfahren miteinander verbinden.

EVAMasters | Category: PHP