Example of Github action for C++ rpoject

cpp.yml

# This is a basic workflow to help you get started with Actions
# workflow - цепочка действий
# Имя процесса Билдится на всех типах 📦 🐍
name: CMake Build Matrix

# Controls when the action will run. Triggers the workflow on push
on: 
  push:
  pull_request:
  release:
    # tags:
    # - 'v*' # Push events to matching v*, i.e. v1.0, v20.15.10

# A workflow run is made up of one or more jobs that can run sequentially or in parallel
jobs:
  # This workflow contains a single job called "build"
  build:
    # The type of runner that the job will run on
    name: ${{ matrix.config.name }}
    runs-on: ${{ matrix.config.os }} # будет запускаться по очереди на всех типах машин
    strategy:
      fail-fast: false
      matrix:
        config: 
        - {
            name: "Windows Latest MSVC",
            os: windows-latest,
            artifact: "windows_msvc.7z",
            build_type: "Release",
            cc: "cl",
            cxx: "cl",
            environment_script: "C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Auxiliary/Build/vcvars64.bat",
            archiver: "7z a",
            generators: "Visual Studio 16 2019"
          }
        - {
            name: "Windows Latest MinGW",
            os: windows-latest,
            artifact: "windows_mingw.7z",
            build_type: "Release",
            cc: "gcc",
            cxx: "g++",
            archiver: "7z a",
            generators: "Ninja"
          }
        - {
            name: "Ubuntu_Latest_GCC",
            os: ubuntu-latest,
            artifact: "ubuntu_gcc.7z",
            build_type: "Release",
            cc: "gcc",
            cxx: "g++",
            archiver: "7z a",
            generators: "Ninja"
          }
        - {
            name: "Ubuntu_GCC_9",
            os: ubuntu-latest,
            artifact: "ubuntu_gcc9.7z",
            build_type: "Release",
            cc: "gcc",
            cxx: "g++",
            archiver: "7z a",
            generators: "Ninja"
          }
        - {
            name: "macOS Latest Clang",
            os: macos-latest,
            artifact: "macos_clang.7z",
            build_type: "Release",
            cc: "clang",
            cxx: "clang++",
            archiver: "7za a",
            generators: "Ninja"
          }

    steps:
      # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
      - uses: actions/checkout@v2

      - name: Print env
        run: |
          echo github.event.action: ${{ github.event.action }}
          echo github.event_name: ${{ github.event_name }}
      - name: Install dependencies on windows
        if: startsWith(matrix.config.os, 'windows')
        run: |
          choco install ninja cmake
          ninja --version
          cmake --version
        # cmd "${{ matrix.config.environment_script }}"

      - name: Install dependencies on ubuntu
        if: startsWith(matrix.config.name, 'Ubuntu_Latest_GCC')
        run: |
          sudo apt-get update
          sudo apt-get install ninja-build cmake
          ninja --version
          cmake --version
          gcc --version
      - name: Install dependencies on ubuntu9
        if: startsWith(matrix.config.name, 'Ubuntu_GCC_9')
        run: |
          echo Update gcc-9 =======================================================================
          echo gcc version before
          gcc --version
          sudo add-apt-repository ppa:ubuntu-toolchain-r/test
          sudo apt-get update
          sudo apt-get install ninja-build cmake gcc-9 g++-9
          sudo update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-9 90 --slave /usr/bin/g++ g++ /usr/bin/g++-9 --slave /usr/bin/gcov gcov /usr/bin/gcov-9
          echo gcc version after
          gcc --version
          echo Update ninja =======================================================================
          echo ninja version before
          ninja --version
          # wget https://github.com/ninja-build/ninja/releases/download/v1.10.0/ninja-linux.zip
          wget https://github.com/ninja-build/ninja/releases/latest/download/ninja-linux.zip
          sudo unzip ninja-linux.zip -d /usr/local/bin/
          sudo update-alternatives --install /usr/bin/ninja ninja /usr/local/bin/ninja 1 --force
          echo ninja version after
          ninja --version
          echo Update cmake =======================================================================
          echo cmake version before
          cmake --version
          # curl --silent "https://api.github.com/repos/Kitware/CMake/releases/latest" | sed -n 's/.*tag_name":\s"\(.*\)".*/\1/p' | head -2
          # wget https://github.com/Kitware/CMake/releases/latest/download/cmake-3.16.5-Linux-x86_64.sh
          cmake_version=$(curl --silent "https://api.github.com/repos/Kitware/CMake/releases/latest" | sed -n 's/.*tag_name":\s"\(.*\)".*/\1/p' | head -2 | cut -c 2-)
          echo cmake download latest v$cmake_version version
          wget https://github.com/Kitware/CMake/releases/download/v$cmake_version/cmake-$cmake_version-Linux-x86_64.sh
          chmod +x cmake-$cmake_version-Linux-x86_64.sh
          sudo mkdir /opt/cmake
          sudo ./cmake-$cmake_version-Linux-x86_64.sh --prefix=/opt/cmake --skip-license
          sudo update-alternatives --install /usr/bin/cmake cmake /opt/cmake/bin/cmake 1 --force
          echo cmake version after
          cmake --version
      - name: Install dependencies on macos
        if: startsWith(matrix.config.os, 'macos')
        run: |
          brew install p7zip cmake ninja
          ninja --version
          cmake --version
          
      - name: Configure
        shell: bash
        run: |
          mkdir build
          mkdir instdir
          cmake \
            -S . \
            -B . \
            -DCMAKE_BUILD_TYPE=${{ matrix.config.build_type }} \
            -G "${{ matrix.config.generators }}" \
            -DCMAKE_INSTALL_PREFIX:PATH=instdir
      - name: Build
        shell: bash
        run: cmake --build . --config ${{ matrix.config.build_type }}

      - name: Install Strip
        shell: bash
        run: cmake --install . --strip

      - name: Pack
        shell: bash
        working-directory: instdir
        run: |
          ls -laR
          ${{ matrix.config.archiver }} ../${{ matrix.config.artifact }} .
      - name: Upload
        uses: actions/upload-artifact@v1
        with:
          path: ./${{ matrix.config.artifact }}
          name: ${{ matrix.config.artifact }}

      - name: Upload release asset
        if: github.event_name == 'release' && (github.event.action == 'published' || github.event.action == 'created')
        uses: actions/upload-release-asset@v1
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
        with:
          upload_url: ${{ github.event.release.upload_url }}
          asset_path: ./${{ matrix.config.artifact }}
          asset_name: ${{ matrix.config.artifact }}.zip
          asset_content_type: application/zip

Hi @camielverdult,
what I know is that C++20 is not yet the default option for the compiler to I think that you should set the flag -std=HERE-SOME-VALUE. The value is different across compiler version for example for GCC:

• GCC 8: -std=c++20
• GCC 9: -std=c++2a

Sometimes if you set the standard in cmake it uses the default library that is not the C++20 library and you get errors. I'm not sure if this is the real problem.

Thanks, I let github generate the workflow for cmake. I appreciate the gist!

Jobs using the windows-latest runner label migrated from Windows Server 2019 to Windows Server 2022. See article.

Use updated environment_script and generators like shown below,

            name: "Windows Latest MSVC",
            environment_script: "C:/Program Files (x86)/Microsoft Visual Studio/2022/Enterprise/VC/Auxiliary/Build/vcvars64.bat",
            generators: "Visual Studio 17 2022"