if (NS_FAILED(cN->ChildAt(--numChildren,*getter_AddRefs(cLastChild))))
if (NS_FAILED(cN->ChildAt(--numChildren, getter_AddRefs(cLastChild))))
nsresult nsGeneratedContentIterator::PrevNode(nsCOMPtr<nsIContent> *ioNextNode){  if (!ioNextNode)    return NS_ERROR_NULL_POINTER;     nsCOMPtr<nsIContent> cN = *ioNextNode;  nsCOMPtr<nsIContent> cLastChild;  PRInt32 numChildren;    cN->ChildCount(numChildren);    // if it has children then prev node is last child  if (numChildren)  {    if (NS_FAILED(cN->ChildAt(--numChildren,*getter_AddRefs(cLastChild))))      return NS_ERROR_FAILURE;    if (!cLastChild)      return NS_ERROR_FAILURE;    *ioNextNode = cLastChild;    return NS_OK;  }    // else prev sibling is previous  return GetPrevSibling(cN, ioNextNode);}