SID constant defined dynamically!
var_dump(defined('SID')); // bool(false) - Not defined...
session_start();
var_dump(defined('SID')); // bool(true) - Defined now!
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)
SID constant defined dynamically!
var_dump(defined('SID')); // bool(false) - Not defined...
session_start();
var_dump(defined('SID')); // bool(true) - Defined now!
Check whether session started using Predefined Constants
if (session_status() == PHP_SESSION_NONE) {
session_start();
}