TIL

Symlink compile_commands.json for LSP Support

CMake generates compile_commands.json in the build directory, but LSP tools like clangd look for it in the project root. Create a symlink:

ln -sf build-linux/compile_commands.json /path/to/project/compile_commands.json

Important: If you’re cross-compiling for multiple platforms, link to your native build’s compile_commands.json, not the cross-compilation target:

# Good - LSP runs natively, needs native include paths
ln -sf build-linux/compile_commands.json compile_commands.json

# Bad - MinGW headers won't work for native LSP analysis
ln -sf build-windows/compile_commands.json compile_commands.json

Enable generation in CMakeLists.txt:

set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

This gives your editor/LSP full knowledge of:

• Include paths
• Compiler flags
• Preprocessor definitions
• Compilation units

Most LSP errors like “cannot find header” disappear once compile_commands.json is properly linked.