I am using Emacs with auto-complete package. I know that Emacs can auto-detect the language. I would like it to automatically add keywords of the detected language to the completion list, in order to allow me to complete such keywords, even if I just open an empty file.
For example, if launch Emacs with a brand new file
$ emacs main.c
I would like to be able to auto-complete to
#include if I write