I have a question about how to make semantic parse c language files which don't have .c suffix. Our project make us must use other suffix like cin, cdt for C header etc. I can open these files using c-mode with following sentence: (add-to-list 'auto-mode-alist '("\\.cin\\'" . c-mode)).
  But how to make semantic parse these files and let it work in auto complete?

 Looking forward to your kind reply.