auto-complete-mode turns off when I start typing

Question

I do not remember changing any thing in my auto-complete package settings beside hooking it with html-mode. The mode starts as expected, when I run some C or C++ code but after typing any thing the mode turns off. I get no errors or warnings.

Here is the related code:

(require 'auto-complete)
(require 'auto-complete-config)
(ac-config-default)

;; initialize auto-complete-c-headers and gets called for c/c++ hooks
(defun my:ac-c-header-init ()
  (require 'auto-complete-c-headers)
  (add-to-list 'ac-sources 'ac-source-c-headers)
  (add-to-list 'ac-sources `ac-source-c))
;; fuction call from c/c++ hooks
(add-hook 'c++-mode-hook 'my:ac-c-header-init)
(add-hook 'c-mode-hook 'my:ac-c-header-init)
(add-hook 'html-mode 'auto-complete-mode)

Answer 1

I find this line to be failing: (add-to-list 'ac-sourcesac-source-c))`

The correct code looks like:

(require 'auto-complete)
(require 'auto-complete-config)
(ac-config-default)

;; initialize auto-complete-c-headers and gets called for c/c++ hooks
(defun my:ac-c-header-init ()
  (require 'auto-complete-c-headers)
  (add-to-list 'ac-sources 'ac-source-c-headers))
;; fuction call from c/c++ hooks
(add-hook 'c++-mode-hook 'my:ac-c-header-init)
(add-hook 'c-mode-hook 'my:ac-c-header-init)
(add-hook 'html-mode 'auto-complete-mode)