1. 拷贝配置文件
cp ~/.vim/bundle/YouCompleteMe/cpp/ycm/.ycm_extra_conf.py ~/.vim/.ycm_extra_conf.py
2. 修改配置文件~/.vim/.ycm_extra_conf.py
添加：
‘-isystem‘,
‘/usr/include‘,
‘-isystem‘,
‘/usr/local/include‘
3. 修改~/.vimrc
let g:ycm_global_ycm_extra_conf=‘~/.vim/.ycm_extra_conf.py‘
let g:ycm_seed_identifiers_with_syntax = 1 "C/C++关键字自动补全
原文：http://www.cnblogs.com/chenzc/p/5504354.html