73c5c3b1_rol_Message_Constants___Manual_vice_Control_Message_Constants_Description
[Constant] WIN32_SERVICE_CONTROL_PRESHUTDOWN [Value] 0x0000000F [Description] 
Notifies a service that the system will be shutting down. A service that handles this notification blocks system shutdown until the service stops or the preshutdown time-out interval expires. This value is not supported by Windows Server 2003 and Windows XP/2000.
PHP: Win32Service Service Control Message Constants - Manual
Description