rem: ACE_Unbounded_Queue<T>::get (T *&item, size_t index) const
add: ACE_Double_Linked_List<T>::get (T *&item, size_t index)
context: ACE_Unbounded_Queue<T>::get (T *&item, size_t index) const{//   ACE_TRACE ("ACE_Unbounded_Queue<T>::get");  ACE_Node<T> *curr = this->head_->next_;  size_t i;  for (i = 0; i < this->cur_size_; i++)    {      if (i == index)        break;      curr = curr->next_;    }  if (i < this->cur_size_)    {      item = &curr->item_;      return 0;    }  else    return -1;}