Cannot set cookie, and redirect (header already set)

Hi,

I have already read How do I solve the Headers already sent warning problem? and attempted that solution.

I am trying to detect these URLs (permalink?c=feed) to set a cookie, and redirect to permalink.

But I get an error saying headers already set by wp-include/link-template.php:3.

if ($_GET['c'] == "feed") {
$permal = the_permalink();
setcookie("feed", "read", time()+5400);
header("HTTP/1.1 301 Moved Permanently");
header("Location: $permal");
die; }