Php – Check if PHP session has already started


I have a PHP file that is sometimes called from a page that has started a session and sometimes from a page that doesn't have session started. Therefore when I have session_start() on this script I sometimes get the error message for "session already started". For that I've put these lines:


but this time I got this warning message:

Notice: Undefined variable: _SESSION

Is there a better way to check if session has already started?

If I use @session_start will it make things work properly and just shut up the warnings?

Best Solution

Recommended way for versions of PHP >= 5.4.0 , PHP 7

if (session_status() === PHP_SESSION_NONE) {


For versions of PHP < 5.4.0

if(session_id() == '') {