通过 Github Actions 构建时如何使用 clang-10 或 gcc-10？

Question

我正在用 C++ 编写一个库，它实现了一些不同的协程原语，该库针对的是新发布的 C++20。因此，它还利用了诸如在 C++20 中添加到语言中的概念之类的东西。

我想使用 github 操作来构建库，但构建失败，因为ubuntu-latest使用 GCC 9 和 CLang 9，但我的库至少需要 GCC 10 或 Clang 10 才能构建。

我尝试通过设置来配置构建操作-DCMAKE_CXX_COMPILER=g++-10，但该操作在配置 CMake 阶段失败，因为在系统上找不到 g++-10。

有什么方法可以指定 github 操作应该使用 GCC 10 还是 Clang 10？

这是我尝试运行的最新工作流文件：

name: CMake

on: [push]

env:
  # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
  BUILD_TYPE: Release

jobs:
  build:
    # The CMake configure and build commands are platform agnostic and should work equally
    # well on Windows or Mac.  You can convert this to a matrix build if you need
    # cross-platform coverage.
    # See: https://docs.github.com/en/actions/configuring-and-managing-workflows/configuring-a-workflow#configuring-a-build-matrix
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v2

    - name: Create Build Environment
      # Some projects don't allow in-source building, so create a separate build directory
      # We'll use this as our working directory for all subsequent commands
      run: cmake -E make_directory ${{runner.workspace}}/build

    - name: Configure CMake
      # Use a bash shell so we can use the same syntax for environment variable
      # access regardless of the host operating system
      shell: bash
      working-directory: ${{runner.workspace}}/build
      # Note the current convention is to use the -S and -B options here to specify source 
      # and build directories, but this is only available with CMake 3.13 and higher.  
      # The CMake binaries on the Github Actions machines are (as of this writing) 3.12
      run: cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DCMAKE_CXX_COMPILER=g++-10

    - name: Build
      working-directory: ${{runner.workspace}}/build
      shell: bash
      # Execute the build.  You can specify a specific target with "--target <NAME>"
      run: cmake --build . --config $BUILD_TYPE

    - name: Test
      working-directory: ${{runner.workspace}}/build
      shell: bash
      # Execute tests defined by the CMake configuration.  
      # See https://cmake.org/cmake/help/latest/manual/ctest.1.html for more detail
      run: ctest -C $BUILD_TYPE

这就是它失败的地方：

Run cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DCMAKE_CXX_COMPILER=g++-10
-- The CXX compiler identification is unknown
CMake Error at CMakeLists.txt:2 (project):
  The CMAKE_CXX_COMPILER:

    g++-10

  is not a full path and was not found in the PATH.

  Tell CMake where to find the compiler by setting either the environment
  variable "CXX" or the CMake cache entry CMAKE_CXX_COMPILER to the full path
  to the compiler, or to the compiler name if it is in the PATH.


-- Configuring incomplete, errors occurred!
See also "/home/runner/work/conduit/build/CMakeFiles/CMakeOutput.log".
See also "/home/runner/work/conduit/build/CMakeFiles/CMakeError.log".
##[error]Process completed with exit code 1.

Answer 1

正如一些程序员所提到的，从 apt 安装 g++ 是可行的方法（除非它是默认安装的）；为构建增加一两分钟。然后你可以通过在配置步骤中传递CC和CXX变量来告诉 cmake 它应该使用哪个编译器：

- run:   |
         sudo apt update
         sudo apt install gcc-10 g++-10
  shell: bash

# ... #

- run:   cmake $GITHUB_WORKSPACE -DCMAKE_BUILD_TYPE=$BUILD_TYPE
  shell: bash
  env:
   CC:   gcc-10
   CXX:  g++-10

当您想使用 clang 时，同样的解决方案也适用。