PHP headers_sent() Function
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>
...
...
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