Returns the control code that was last sent to this service process.
When running as a service you should periodically check this to determine if
your service needs to stop running.
Return Values
Returns a control constant; one of WIN32_SERVICE_CONTROL_CONTINUE,
WIN32_SERVICE_CONTROL_INTERROGATE,
WIN32_SERVICE_CONTROL_PAUSE,
WIN32_SERVICE_CONTROL_STOP,
WIN32_SERVICE_CONTROL_HARDWAREPROFILECHANGE,
WIN32_SERVICE_CONTROL_POWEREVENT,
WIN32_SERVICE_CONTROL_SESSIONCHANGE.