getting autocompletion in emacs

[nikki via Digitalmars-d-learn]

I want to learn SDL2 and learn D at the same time, for the SDL2 
part autocompletion would be very nice.

I've found DCD but can't get it working (not finding symbols or 
declarations) at the moment but I was wondering if there are any 
alternatives, it's hard to google for d things and emacs, cause 
of emacs.d :)