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
relative_to = DirectoryOfThisScript()修改为：
relative_to = ‘/usr/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/CharType/p/3512705.html