Session Name & ID

string session_name ([ string $name ] )
session_name() returns the name of the current session.
The session name is reset to the default value stored in session.name at request startup time.

string session_id ([ string $id ] )
session_id() is used to get or set the session id for the current session.
The constant SID can also be used to retrieve the current name and session id as a string suitable for adding to URLs.

bool session_regenerate_id ([ bool $delete_old_session ] )
session_regenerate_id() will replace the current session id with a new one, and keep the current session information.