rv = mSecond->QueryInterface(nsIBidirectionalEnumerator::GetIID(), (void**)&be);
rv = mSecond->QueryInterface(NS_GET_IID(nsIBidirectionalEnumerator), (void**)&be);
nsConjoiningEnumerator::Last(void){  nsresult rv;  nsIBidirectionalEnumerator* be;  rv = mSecond->QueryInterface(nsIBidirectionalEnumerator::GetIID(), (void**)&be);  if (NS_FAILED(rv)) return rv;  mCurrent = mSecond;  rv = be->Last();  NS_RELEASE(be);  return rv;}