This is a vim plugin derived from cppman for opening cppreference documentation in a new vertical split inside vim. Press <Leader>c (\c for me) with the cursor over the identifier you want to look up.
mkdir -p ~/.vim/pack/mattkretz/start
cd ~/.vim/pack/mattkretz/start
git clone https://github.com/mattkretz/vim-cppman
Copyright © Matthias Kretz. Distributed under GPLv3 or later.