code: function glk_exit() {
      /* For safety, this is fast and idempotent. */
      has_exited = true;
      ui_disabled = true;
      gli_selectref = null;
      if (option_exit_warning)
          GlkOte.warning(option_exit_warning);
      update('exit');
      return DidNotReturn;
  }
docs: /* The catalog of Glk API functions.