   """
   @spec rootname(t) :: binary
   def rootname(path) do
-    FN.rootname(IO.chardata_to_string(path))
+    :filename.rootname(IO.chardata_to_string(path))
   end
 
   @doc """

  """
  @spec dirname(t) :: binary
  def dirname(path) do
    FN.dirname(IO.chardata_to_string(path))
  end

  @doc """

  that require it (like `wildcard/2` and `expand/1`).
  """

  @type t :: :unicode.chardata()

  @doc """
