Emacs如何在CC模式下设置行数

linyin

想在边上设置个行数,增加易读性.
http://zhdotemacs.sourceforge.net/emacs/x459.html
参考了这篇文章,但出现了错误

(emacs test.c)
An error has occurred while loading `/home/linyin/.emacs':

Symbol's function definition is void: set-scroll-bar-mode

To ensure normal operation, you should investigate the cause
of the error in your initialization file and remove it. Start
Emacs with the `--debug-init' option to view a complete error
backtrace

错误的信息

.emacs的配置:
(add-to-list 'load-path "/home/linyin")
(set-scroll-bar-mode nil) ; no scroll bar, even in x-window system
(require 'wb-line-number)
(wb-line-number-enable)