How can headers already sent errors be avoided when setting cookies in PHP?

Headers already sent errors in PHP can be avoided when setting cookies by ensuring that no output is sent to the browser before calling the `setcookie()` function. This error occurs when PHP tries to set a cookie after headers have already been sent to the browser, which can happen if there is any whitespace or HTML content before the `setcookie()` function is called. 

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

// Set cookie after ensuring no output has been sent
setcookie("cookie_name", "cookie_value", time() + 3600, "/");

ob_end_flush(); // Flush output buffer
?>

Keywords

headers_sent ob_start setcookie output buffering error_reporting

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