[hellofunk]

What package are you using for your Emacs back end for completion? I've tried several and never really found them stable or even working in some cases. I write a couple thousand lines of C++ every week in emacs and I've actually become very productive without auto completion, so perhaps I'm not missing it anymore at all.

[conistonwater]

I use irony-mode (with its flycheck and company support) on OSX, and I think it works really well. It uses libclang as the backend, so for completion it's about as precise as a compiler can be.

[accatyyc]

I code in C so can't speak for C++, but I imagine it works well for that too: irony-mode as a backend and company-mode as frontend. It pretty much gives the Xcode auto-complete experience, and I think it works great!

[lmitchell]

Seconded this, this is my setup on both Windows and Linux and works for me across multi-million-line C and C++ codebases. It's quite finicky to get set up on Windows at first (or at least, it was for me last time I tried), but once you have irony-mode working with libclang, you don't need to think about it ever again, except for changing a couple compiler flags here and there.

My one complaint is that clang's MSVC mode is imperfect, and sometimes suggests some strange things (or produces some false negative/positive in syntax checking). But they've been getting much better lately and it's never caused me much pain.

e: also, second what a sibling said - combo this with flycheck-mode and you have yourself a full-blown C++ IDE in emacs ;)

[jonwot]

This is a good basic setup for C. Throw in a little flycheck-mode and you've got yourself something really sweet.

[hellofunk]

I tried irony mode, but my autocomplete pop-ups would contain all kinds of nonsense, and I noticed at least two other issues on the irony mode github page that showed other people with the same experience as mine, on Mac. So I eventually gave up after not tracking down a resolution.