Standard library missing when using CMake to generate compile_commands.json

[beckettloose]

Hello! I'm in the process of migrating a project over from old mbed (with PlatformIO) to mbed-ce. So far things are going well, and I am able to build and flash the project just fine with ninja. I use neovim with clangd as my "IDE", which requires a compile_commands.json file to instruct clangd how to build the project. I used the cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=ON option, which gets me most of the way there. Everything from mbed-os itself is detected fine now, but it would appear that some standard library functionality is still errored out. Here is a list of everything that throws an error so far

• cstddef
• std::vector
• chrono
• printf()
• memcpy()
• strlen()

I had a similar issue before when using PlatformIO, but they have an environment variable called COMPILATIONDB_INCLUDE_TOOLCHAIN that fixed it. I think the culprit is that cmake is not including the mbed c library or minimal printf library when creating compile_commands.json, but I'm not sure how to go about fixing it. Any help with this would be greatly appreciated.

[JohnK1987]

Hello,

I remember the MbedStudio and KeilStudio cloud has similar/same issue. Developers said the issue is directly in the clangd, and they were not able to do something with this for 3years.

@multiplemonomials any suggestion?

BR, Jan

[multiplemonomials]

Afraid not, I only use CLion and VS Code myself. But perhaps it's not including the arm-none-eabi-gcc toolchain include dirs where the atandard library lives?

[beckettloose]

Looks like the root cause of my issue was clangd (the language server itself) not using gcc-arm's include directories. The solution was manually specifying the gcc-arm include directories in my .clangd file like this:

CompileFlags:
  Add:
    - -I/usr/local/gcc-arm/arm-none-eabi/include/c++/14.3.1
    - -I/usr/local/gcc-arm/arm-none-eabi/include/c++/14.3.1/arm-none-eabi
    - -I/usr/local/gcc-arm/arm-none-eabi/include