求助,如何获取某一个minor-mode 定义时所绑定的的 :variable?

一般来说,定义minor-mode时,默认的变量和mode是同一个名字,但是有的minor-mode不同,比如:

(define-minor-mode read-only-mode
  :variable buffer-read-only
  ;; We're saving this value here so that we can restore the
  ;; readedness state after reverting the buffer to the value that's
  ;; been explicitly set by the user.
  (setq-local read-only-mode--state buffer-read-only)
  (cond
   ((and (not buffer-read-only) view-mode)
    (View-exit-and-edit)
    (setq-local view-read-only t))		; Must leave view mode.
   ((and buffer-read-only view-read-only
         ;; If view-mode is already active, `view-mode-enter' is a nop.
         (not view-mode)
         (not (eq (get major-mode 'mode-class) 'special)))
    (view-mode-enter))))

read-only-mode 所定义的是 :variable buffer-read-only, 如何获取 任何一个minor mode相关绑定的这个变量呢?我好像没找到方法,不会真要到定义文件正则匹配吧?虽然本质上我想要确定某个minor mode 是否已经enable,有更好的方法吗?

多谢!我一直只会用variable来判定minor mode是否enable,manual 还是要细读呢。