Ubuntu 14.10系统，通过emacs package system安装了模块auto-complete-clang

然后进入.emacs.d/init.el中如下配置：

;; auto complete 
(require 'auto-complete)
(add-to-list 'ac-dictionary-directories "~/.emacs.d/elpa/auto-complete-20150408.1132/ac-dict/")
(add-to-list 'ac-user-dictionary-files "~/.emacs.d/elpa/auto-complete-20150408.1132/ac-dict//dean.dict")
(require 'auto-complete-config)
;; end

;; auto-complete-clang  
(require 'auto-complete-clang)
;;(setq ac-clang-auto-save t)
;; 设置不自动启动  
(setq ac-auto-start nil)
;; 设置响应时间 0.5  
(setq ac-quick-help-delay 0.5)
;;(ac-set-trigger-key "TAB")    
;;(define-key ac-mode-map  [(control tab)] 'auto-complete)    
;; 提示快捷键为 M-/  
(define-key ac-mode-map  (kbd "M-/") 'auto-complete)
(defun my-ac-config ()    
  (setq ac-clang-flags    
        (mapcar(lambda (item)(concat "-I" item))    
               (split-string    
                " /usr/include/c++/4.9  /usr/include/c++/4.9/backward /usr/include")))
  (setq-default ac-sources '(ac-source-abbrev ac-source-dictionary ac-source-words-in-same-mode-buffers))
  (add-hook 'emacs-lisp-mode-hook 'ac-emacs-lisp-mode-setup)
  (add-hook 'c-mode-common-hook 'ac-cc-mode-setup)
  (add-hook 'ruby-mode-hook 'ac-ruby-mode-setup)
  (add-hook 'css-mode-hook 'ac-css-mode-setup)
  (add-hook 'auto-complete-mode-hook 'ac-common-setup)
  (global-auto-complete-mode t))
(defun my-ac-cc-mode-setup ()
  (setq ac-sources (append '(ac-source-clang ac-source-yasnippet) ac-sources)))
(add-hook 'c-mode-common-hook 'my-ac-cc-mode-setup)
;; ac-source-gtags
(my-ac-config)
(ac-config-default)
;; end

现在打开代码，在vector对象v后面输入v.pu

然后用M-/ 后等待，会自动显示push_back。

有时候不显示的原因是之前没有键入代码，不过没有关系，会逐渐学习。

现在还有个问题, auto-complete-clang貌似没有真正工作，因为提示过于简陋。还需要继续研究。