THE WORLD'S LARGEST WEB DEVELOPER SITE

PHP Tutorial

PHP HOME PHP Intro PHP Install PHP Syntax PHP Comments PHP Variables PHP Echo / Print PHP Data Types PHP Strings PHP Numbers PHP Constants PHP Operators PHP If...Else...Elseif PHP Switch PHP While Loops PHP For Loops PHP Functions PHP Arrays PHP Superglobals

PHP Forms

PHP Form Handling PHP Form Validation PHP Form Required PHP Form URL/E-mail PHP Form Complete

PHP Advanced

PHP Date and Time PHP Include PHP File Handling PHP File Open/Read PHP File Create/Write PHP File Upload PHP Cookies PHP Sessions PHP Filters PHP Filters Advanced PHP JSON

PHP OOP

PHP What is OOP PHP Classes/Objects PHP Constructor PHP Destructor PHP Access Modifiers PHP Inheritance PHP Constants PHP Abstract Classes PHP Traits PHP Static Methods PHP Static Properties

MySQL Database

MySQL Database MySQL Connect MySQL Create DB MySQL Create Table MySQL Insert Data MySQL Get Last ID MySQL Insert Multiple MySQL Prepared MySQL Select Data MySQL Delete Data MySQL Update Data MySQL Limit Data

PHP XML

PHP XML Parsers PHP SimpleXML Parser PHP SimpleXML - Get PHP XML Expat PHP XML DOM

PHP - AJAX

AJAX Intro AJAX PHP AJAX Database AJAX XML AJAX Live Search AJAX Poll

PHP Examples

PHP Examples PHP Quiz PHP Exercises PHP Certificate

PHP Reference

PHP Overview PHP Array PHP Calendar PHP Date PHP Directory PHP Error PHP Filesystem PHP Filter PHP FTP PHP JSON PHP Libxml PHP Mail PHP Math PHP Misc PHP MySQLi PHP Network PHP SimpleXML PHP Stream PHP String PHP XML Parser PHP Zip PHP Timezones

PHP headers_sent() Function

❮ PHP Network Reference

Example

If no headers are sent, send one:

<?php
if (!headers_sent()) {
  header("Location: https://www.w3schools.com/");
  exit;
}
?>

<html>
<body>

...
...


Definition and Usage

The headers_sent() function checks if/where headers have been sent.

Syntax

headers_sent(file,line)

Parameter Values

Parameter Description
file Optional. If the 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
line Optional. Specifies the line number where the output started


Technical Details

Return Value: TRUE if HTTP headers has been sent, FALSE otherwise
PHP Version: 4.0+
PHP Changelog: PHP 4.3: Added the optional file and line parameters

More Examples

Example

Using the optional file and line parameters:

<?php
// $file and $line are passed in for later use
// Do not assign them values beforehand
if (!headers_sent($file, $line))
  {
  header("Location: https://www.w3schools.com/");
  exit;
  // Trigger an error here
  }
else
  {
  echo "Headers sent in $file on line $line";
  exit;
  }
?>

<html>
<body>

...
...

❮ PHP Network Reference