What are the common causes of the "Cannot send session cache limiter - headers already sent" warning in PHP?

The "Cannot send session cache limiter - headers already sent" warning in PHP occurs when there is whitespace or output sent before session_start() function is called. To solve this issue, make sure that there is no whitespace before session_start() function in your PHP file and that no output is sent to the browser before starting a session. 

<?php
ob_start(); // Start output buffering
session_start(); // Start the session
?>

Keywords

PHP session cache limiter headers error

Related Questions