You want to read the value of a cookie that you've previously set.
Look in the $_COOKIE auto-global array, as shown in Example 8-5.
Reading a cookie value
A cookie's value isn't available in $_COOKIE during the request in which the cookie is set. In other words, the setcookie( ) function doesn't alter the value of $_COOKIE. On subsequent requests, however, each cookie sent back to the server is stored in $_COOKIE. If register_globals is on, cookie values are also assigned to global variables.
When a browser sends a cookie back to the server, it sends only the value. You can't access the cookie's domain, path, expiration time, or secure status through $_COOKIE because the browser doesn't send that to the server.
To print the names and values of all cookies sent in a particular request, loop through the $_COOKIE array, as in Example 8-6.
Reading all cookie values
8.2.4. See Also
Recipe 8.1 shows how to set cookies; Recipe 8.3 shows how to delete cookies; Recipe 8.12 explains output buffering; Recipe 9.15 for information on register_globals.