Description
bool 
session_destroy ( void  )
     session_destroy() destroys all of the data
     associated with the current session. It does not unset any of
     the global variables associated with the session, or unset the
     session cookie.
    
     In order to kill the session altogether, like to log the user out, the
     session id must also be unset. If a cookie is used to propagate the 
     session id (default behavior), then the session cookie must be deleted.  
     setcookie() may be used for that.
    
     如果成功则返回 TRUE,失败则返回 FALSE。
    
     
| 例子 1. Destroying a session with $_SESSION | 
<?php// Initialize the session.
 // If you are using session_name("something"), don't forget it now!
 session_start();
 
 // Unset all of the session variables.
 $_SESSION = array();
 
 // If it's desired to kill the session, also delete the session cookie.
 // Note: This will destroy the session, and not just the session data!
 if (isset($_COOKIE[session_name()])) {
 setcookie(session_name(), '', time()-42000, '/');
 }
 
 // Finally, destroy the session.
 session_destroy();
 ?>
 | 
 | 
    注: 
      Only use session_unset() for older deprecated code 
      that does not use $_SESSION.
     
     See also
     unset() and
     setcookie().