Cedet cannot complete C++ standard class

[augustinus]

Hi guys:
I get a problem when i use the built-in cedet to write C++ code. It is
that cedet can not complete the standard C++ class such as string and
vector ... But cedet can complete the classes defined by me.And there is
no data in the semanticdb directory about C++ standard headers, I think
it cases the problem but I don't know what to do to make it work!
Here is my cedet setting:

(require 'cedet)
(setq semantic-default-submodes '(global-semantic-idle-scheduler-mode
global-semanticdb-minor-mode
global-semantic-idle-summary-mode
global-semantic-mru-bookmark-mode))
(semantic-mode 1)

(global-semantic-decoration-mode)

(require 'semantic/bovine/gcc)
(require 'semantic/bovine/c)

(defconst cedet-user-include-dirs
(list ".." "../include" "../inc" "../common" "../public" "."
"../.." "../../include" "../../inc" "../../common" "../../public"))

(setq cedet-sys-include-dirs (list
"/usr/include"
"/usr/include/bits"
"/usr/include/gnu"
"/usr/local/include"))

(let ((include-dirs cedet-user-include-dirs))
(setq include-dirs (append include-dirs cedet-sys-include-dirs))
(mapc (lambda (dir)
(semantic-add-system-include dir 'c++-mode)
(semantic-add-system-include dir 'c-mode))
include-dirs))

(setq semantic-c-dependency-system-include-path "/usr/include/")

(setq semanticdb-default-save-directory
(expand-file-name "~/.emacs.d/semanticdb"))

(provide 'cedet-setting)

Is there anyone have ideas about this problem?
Thank you!!!