Enable C++23 standard library module feature, a.k.a. import std (P2465R3) in your CMake (≥ 3.26) project.
It also supported in C++20 as compiler extension.
There are prerequisites for using this repository.
- Your compiler must support the standard library module feature.
- Clang ≥ 17 with custom module build: support for both C++20 and C++23. Ninja ≥ 1.11 is required.
- MSVC: support for C++23 (≥ 19.36), C++20 (≥ 19.38).
- You need CMake ≥ 3.26 for module support in CMake.
All prerequisites satisfied, your simplest program will be:
CMakeLists.txt
cmake_minimum_required(VERSION 3.28)
project(CppStandardLibraryModule)
# --------------------
# Enable C++20 module support in CMake.
# Below code must be uncommented when use CMake < 3.28.
# --------------------
#if (CMAKE_VERSION VERSION_LESS "3.28.0")
# if(CMAKE_VERSION VERSION_LESS "3.27.0")
# set(CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API "2182bf5c-ef0d-489a-91da-49dbc3090d2a")
# else()
# set(CMAKE_EXPERIMENTAL_CXX_MODULE_CMAKE_API "aa1f7df0-828a-4fcd-9afc-2dc80491aca7")
# endif()
# set(CMAKE_EXPERIMENTAL_CXX_MODULE_DYNDEP 1)
#else()
# cmake_policy(VERSION 3.28)
#endif()
# --------------------
# Include CMake scripts.
# --------------------
file(DOWNLOAD https://raw.githubusercontent.com/stripe2933/CppStandardLibraryModule/main/cmake/EnableStandardLibraryModule.cmake
${CMAKE_BINARY_DIR}/EnableStandardLibraryModule.cmake
)
include(${CMAKE_BINARY_DIR}/EnableStandardLibraryModule.cmake)
# --------------------
# Main executable.
# --------------------
add_executable(CppStandardLibraryModule main.cpp)main.cpp
import std;
// import std.compat also available.
int main(){
std::cout << "Hello, world!\n";
}Or simply, you can just clone this template repository.
Build Standard Library Module from LLVM repository.
git clone https://github.com/llvm/llvm-project.git
cd llvm-project
mkdir build
cmake -G Ninja -S runtimes -B build \
-DLLVM_ENABLE_RUNTIMES="libcxx;libcxxabi;libunwind"
ninja -C buildAfter that, specify the CMake variable LIBCXX_BUILD to your custom module build directory, explained at Libc++ website in detail.
cd <your-project-dir>
mkdir build
cmake -S . -B build -G Ninja \
-DCMAKE_CXX_STANDARD=20 \
-DLIBCXX_BUILD=<build-dir>
ninja -C build
# Your executable will be at /buildHere's the Clang CI for your insight.
Specify the CMake variable VCTOOLS_INSTALL_DIR, which can be directly fetched
via $env:VCToolsInstallDir in x86 Native Tools Command Prompt for VS, explained at Microsoft documentation
in detail.
cd <your-project-dir>
mkdir build
cmake -S . -B build -G "Visual Studio 17 2022" -T v143 `
-DCMAKE_CXX_STANDARD=20 `
-DVCTOOLS_INSTALL_DIR="$env:VCToolsInstallDir"
cmake --build build -j4
# Your executable will be at build\ReleaseHere's the MSVC CI for your insight.