PHP. Руководство по PHP. 2005
session_is_registered
session_is_registered
(PHP 4, PHP 5)session_is_registered -- Find out whether a global variable is registered in a session
Description
bool session_is_registered (string name)session_is_registered() returns TRUE if there is a global variable with the name name registered in the current session.
Замечание: If $_SESSION (or $HTTP_SESSION_VARS for PHP 4.0.6 or less) is used, use isset() to check a variable is registered in $_SESSION.
