title: How can you check if a PHP session exists?
body: <p>Just wondering how to check if a PHP session exists... My understanding is that no matter what, if I am using sessions, I have to start my files with session_start() to even access the session, even if I know it already exists.</p>
  
  <p>I've read to user session_id() to find out if a session exists, but since I have to use session_start() before calling session_id(), and session_start() will create a new ID if there isn't a session, how can I possible check if a session exists?</p>