Simple C++20 module support for CMake

Provides the add_module_library CMake function that is a wrapper around add_library with additional module-specific rules.

This module currently supports:

• Clang 15+
• GCC 11+
• MSVC 19.28+

This module can also fallback to a non-modular library for compatibility.

Projects using add_module_library:

• {fmt}: a modern formatting library

Example

hello.cc:

module;

#include <cstdio>

export module hello;

export void hello() { std::printf("Hello, modules!\n"); }

main.cc:

import hello;

int main() { hello(); }

CMakeLists.txt:

cmake_minimum_required(VERSION 3.11)
project(HELLO CXX)

include(modules.cmake)

add_module_library(hello hello.cc)

add_executable(main main.cc)
target_link_libraries(main hello)

Building with clang:

CXX=clang++ cmake .
make

Running:

$ ./main
Hello, modules!

License

The code is distributed under the permissive MIT license with an optional exception that allows distributing binary code without attribution.