PHP | header_sent() Function

Hello folks! welcome back to a new edition of our tutorial on PHP. In this tutorial guide, we are going to be studying about the PHP header_sent() Function.

The PHP header_sent() function checks if or where headers have been sent.

Syntax

Following below is the syntax to use this function -

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

READ: PHP | header_remove() Function

Parameter Details

Sr.No	Parameters & Description
1	file It contains the information about file or line parameters
2	Line It contains the line number where output has started.

Return Value

This built-in PHP function TRUE if headers have already been sent, otherwise FALSE.

Example

Try out the following example below -

<?php
   if (!headers_sent()) {
      header('Location: http://www.webdesigntutorialz.com/');
      exit;
   }
   
   if (!headers_sent($filename, $linenum)) {
      header('Location: http://www.webdesigntutorialz.com/');
      exit;
   } else {
      echo "Headers already sent in $filename on line $linenum\n" .
         "Cannot redirect, for now please click this <a " .
         "href = \"http://www.webdesigntutorialz.com\">link</a> instead\n";
      exit;
   }
?>

Output

The following example above will check whether headers have been sent or not, if it has sent, it shows a message otherwise it will send headers.

READ: PHP | header_register_callback() Function

Alright guys! This is where we are going to be rounding up for this tutorial post. In our next tutorial, we are going to be discussing about the http_response_code() Function in PHP.

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