YCMD layer

• YouCompleteMe based code-completion
• Integrations with company, flycheck, and eldoc

To use this configuration layer, add it to your ~/.spacemacs. You will need to add ycmd to the existing dotspacemacs-configuration-layers list in this file.

1. Install the ycm server. Installation instructions can be found here.

2. Set the ycmd-server-command variable to reflect the path to the installation:

   (setq ycmd-server-command '("python" "/path/to/YouCompleteMe/third_party/ycmd/ycmd"))
   

   Note that no filename expansions are done, so ~ -paths will not work out of the box. If you need expansions, you can use Emacs's file-truename like this:

   (setq ycmd-server-command (list "python" (file-truename "~/some/path")))
   

3. By default, spacemacs configures ycmd for getting the compilation flags from either a compile_{commands.json} or a .clang_complete file and get additionnal flags from a .ycm_extraflags file. If you do not like this behaviour, you can write your own .ycm_extraconf.py file. See Configuration for more details.

4. Whitelist the file by adding the following to .spacemacs:

   ;; In this example we whitelist everything in the Develop folder
   (setq ycmd-extra-conf-whitelist '("~/Develop/*"))
   

5. The completion is not going to work automatically until we actually force it:

   (setq ycmd-force-semantic-completion t)
   

This package requires the auto-completion layer in order to get actual completion. The syntax-checking layer is required for flycheck support.

By default this layer only activates ycmd for c++-mode and c-mode.

If you want ycmd support in other modes you might just want to add it for specific languages like:

(add-hook 'c++-mode-hook 'ycmd-mode)

Spacemacs uses its own ycmd global configuration file. If you prefer, you can write your own .ycm_extraconf.py.

Spacemacs will search for a compile_command.json or fall back to a .clang_complete file in all parent directories of the current translation unit. Spacemacs will try to make up for missing files in the compile_{commands.json} using heuristics described in global_conf.py.

The user can provide additionnal flags by writing a .ycm_extraflags in any parent directory of the current translation unit. This is particularly useful when cross-compiling.

Example .ycm_extraflags:

# Additionnal flags for ycmd
--sysroot="/path/to/your/toolchain/libc" # if you are cross-compiling

If your build system doesn't handle the creation of a compile_{commands.json}, you can use tools such as Bear or scan-build to generate it, which both work with almost any build system.