What is the common issue with the "Cannot modify header information" warning in PHP?

The common issue with the "Cannot modify header information" warning in PHP occurs when attempting to modify header information after it has already been sent to the browser. To solve this issue, make sure to call the header functions before any output is sent to the browser, such as HTML content or whitespace. 

<?php
ob_start(); // Start output buffering

// Your PHP code here

header("Location: example.php"); // Redirect to another page

ob_end_flush(); // Flush the output buffer
?>

Keywords

header information warning PHP modification

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