Clangd lsp with emacs : external library


I am using spacemacs (emacs distribution) and I activated the C/C++ layer with clangd as the backend for LSP.

I am currently doing a project with the gtkmm library and in one of my headers I include the library like this :

#include <gtkmm.h>

The library is installed on my system but clangd doesn’t recognize it and says :

'gtkmm.h' file not found [pp_file_not_found]

It really annoys me because now I have errors everywhere like so :

Capture d’écran de 2020-08-13 22-21-20

So is it possible to tell clangd where the external libraries are with lsp and emacs?

System :

  • OS : Pop!_OS 20.04
  • spacemacs : develop branch ca2cdd0fc
  • clangd : clangd version 10.0.0-4ubuntu1

(Btw : I created a topic on the emacs stack exchange but no answers yet… )

you need to tell clangd how to compile your project. you can find details in

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Thanks for pointing this out! :slight_smile: It works now, I should have check the documentation…

One thing is that I am using the meson build system so all the build files are located under a special build folder and this is where the compile_commands.json file is.

So is there a way to tell clangd to check the json file located in a specific folder?

after clangd-11, we’ll also be looking for directories named build to find compile_commands.json. but for a general solution, you can either:

  • create symlink in your project root, pointing at the compile_commands.json inside the build directory
  • provide --compile-commands-dir=<string> to clangd, pointing at the directory containing the compilation database.
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Thanks for your complete answer, have a great day! :slight_smile: