Why are PHP Cookies Not Immediately Available After `setcookie()`?

Understanding the Delayed Appearance of Cookie Values in $_COOKIE

When attempting to retrieve a cookie's value immediately after invoking the setcookie() function in PHP, you may encounter an issue where $_COOKIE['uname'] remains undefined. This happens because cookies are not instantiated until the HTTP response is transmitted to the client.

The reason for this delay is that PHP cookies rely on the Set-Cookie HTTP header, which is included in the response headers. When setcookie() is called, it adds the Set-Cookie header to the response, but the header is not actually sent to the client until the script has finished executing.

However, you can overcome this limitation by manually setting the $_COOKIE['uname'] value after calling setcookie():

By setting the $_COOKIE value manually, the cookie becomes available for use in your script immediately. This allows you to access the cookie's value without having to rely on the next request from the client.

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