The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
SID
(string) "name=ID"
or empty string if session ID was set in an appropriate session cookie. This is the same id as the one returned by session_id(). PHP_SESSION_DISABLED
(int) PHP_SESSION_NONE
(int) PHP_SESSION_ACTIVE
(int)