C

C support is available natively in Zed.

• Tree Sitter: tree-sitter/tree-sitter-c
• Language Server: clangd/clangd

Clangd: Force detect as C

Clangd out of the box assumes mixed C++/C projects. If you have a C-only project you may wish to instruct clangd to all files as C using the -xc flag. To do this, create a .clangd file in the root of your project with the following:

CompileFlags:
  Add: [-xc]

By default clang and gcc by will recognize *.C and *.H (uppercase extensions) as C++ and not C and so Zed too follows this convention. If you are working with a C-only project (perhaps one with legacy uppercase pathing like FILENAME.C) you can override this behavior by adding this to your settings:

{
  "file_types": {
    "C": ["C", "H"]
  }
}

Formatting

By default Zed will use the clangd language server for formatting C code. The Clangd is the same as the clang-format CLI tool. To configure this you can add a .clang-format file. For example:

---
BasedOnStyle: GNU
IndentWidth: 2
---

See Clang-Format Style Options for a complete list of options.

You can trigger formatting via cmd-shift-i|ctrl-shift-i or the editor: format action from the command palette or by adding format_on_save to your Zed settings:

  "languages": {
    "C": {
      "format_on_save": "on",
      "tab_size": 2
    }
  }

See Clang-Format Style Options for a complete list of options.

Compile Commands

For some projects Clangd requires a compile_commands.json file to properly analyze your project. This file contains the compilation database that tells clangd how your project should be built.

CMake Compile Commands

With CMake, you can generate compile_commands.json automatically by adding the following line to your CMakeLists.txt:

set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

After building your project, CMake will generate the compile_commands.json file in the build directory and clangd will automatically pick it up.