What role does output buffering play in preventing "Headers already sent" errors when working with cookies and session variables in PHP, and how can it affect the functionality of code in different environments like XAMPP and online servers?

Output buffering in PHP can prevent "Headers already sent" errors by storing output in a buffer before sending it to the browser. This is important when working with cookies and session variables because headers must be sent before any output to the browser. Without output buffering, any whitespace or text sent before setting cookies or session variables can cause the "Headers already sent" error. Implementing output buffering ensures that headers are sent at the appropriate time, preventing these errors. 

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

// Set cookies or session variables here
setcookie("cookie_name", "cookie_value", time() + 3600);

// Send output to the browser
ob_end_flush();
?>

Keywords

output buffering Headers already sent cookies session variables XAMPP

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