# File lib/rbreadline.rb, line 8314
  def rl_exchange_point_and_mark(count, key)
    if (@rl_mark > @rl_end)
      @rl_mark = -1
    end
    if (@rl_mark == -1)
      rl_ding()
      return -1
    else
      @rl_point, @rl_mark = @rl_mark, @rl_point
    end
    0
  end