# File lib/linecache.rb, line 186
  def getline(filename, line_number, reload_on_change=true)
    filename = unmap_file(filename)
    filename, line_number = unmap_file_line(filename, line_number)
    lines = getlines(filename, reload_on_change)
    if lines and (1..lines.size) === line_number
        return lines[line_number-1]
    else
        return nil
    end
  end