wrong emacs configuration when trying to setup ggtags and flycheck with prelude

I am trying to fine-tune the setup for emacs with emacs prelude included. I want to have as the default checker cppcheck for flycheck and activate ggtags by default for GNU Global. I am coding mainly c++. It used to work before for ggtags-mode variable but now it seems not to work anymore.

(load "/home/user/.emacs.d/init.el")


(defun my-c-mode-common-hook ()
  "Hook for all c derived modes."
  (c-add-style "my-style"
           '("stroustrup"
             (c-offsets-alist
              (innamespace . [0])
              (inline-open . 0)
              (inher-cont . c-lineup-multi-inher)
              (arglist-cont-nonempty . +)
              (template-args-cont . +))))
(setq c-default-style "my-style")
(when (derived-mode-p 'c-mode 'c++-mode)
(ggtags-mode 1)
(flycheck-select-checker "c/c++-cppcheck"))
)


 (add-hook 'c-mode-common-hook
      (my-c-mode-common-hook))

I have a warning that says the following functions are not known to be defined: ggtags-mode, flycheck-select-checker. But when loading the .emacs file is loaded, there are no errors.

Can anyone help me with the right way to make these 2 minor modes work correctly configured? For me it seems the right way to do it, but obviously I am missing something.

Solution

You use add-hook wrongly: It takes a function as 2nd argument but you call your function there and so pass the value of (flycheck-select-checker ..) as the function. You will likely see an error in a C (C/Java/C++/AWK/...) mode.

What you need to do is (add-hook 'c-mode-common-hook 'my-c-mode-common-hook).

Also this code will never be executed:

(when (derived-mode-p 'c-mode 'c++-mode)
  (ggtags-mode 1)
  (flycheck-select-checker "c/c++-cppcheck"))

because 'c-mode is not derived of 'c++-mode, I guess you want to check if the current major-mode is derived of c++-mode:

(when (derived-mode-p major-mode 'c++-mode)
  (ggtags-mode 1)
  (flycheck-select-checker "c/c++-cppcheck"))