CppStandardLibraryModule/EnableStandardLibraryModule.cmake at main · ZhangYMGanix/CppStandardLibraryModule · GitHub

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cmake_minimum_required(VERSION 3.26.0 FATAL_ERROR)

# Check compiler support for C++23 Standard Library Module.
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "17.0.0")
    if (CMAKE_CXX_STANDARD LESS 20)
        message(FATAL_ERROR "C++20 or newer is required.")
    endif()

    set(CMAKE_CXX_STANDARD_REQUIRED YES)
    set(CMAKE_CXX_EXTENSIONS OFF)

    include(FetchContent)
    FetchContent_Declare(
            std
            URL "file://${LIBCXX_BUILD}/modules/c++/v1/"
            DOWNLOAD_EXTRACT_TIMESTAMP TRUE
            SYSTEM
    )
    FetchContent_MakeAvailable(std)

    link_libraries(std c++)
    link_libraries(std.compat c++)
elseif (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL "19.36")
    if (CMAKE_CXX_STANDARD VERSION_LESS 20)
        message(FATAL_ERROR "C++20 or newer is required.")
    elseif (CMAKE_CXX_STANDARD VERSION_LESS 23 AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "19.38")
        message(FATAL_ERROR "C++23 Standard library module in C++20 is only supported with MSVC 19.38 or newer.")
    endif()

    # 如果环境变量没写进来，手动从编译器位置推算
    if(NOT VCTOOLS_INSTALL_DIR OR "${VCTOOLS_INSTALL_DIR}" STREQUAL "")
        get_filename_component(MSVC_BIN_DIR "${CMAKE_CXX_COMPILER}" DIRECTORY)
        # MSVC 的目录结构通常是 .../bin/Hostx64/x64/cl.exe
        # 我们向上跳 3 级回到 VC 根目录
        get_filename_component(VCTOOLS_INSTALL_DIR "${MSVC_BIN_DIR}/../../.." ABSOLUTE)
    endif()
    # 此时再转换路径就不会变成 "/modules" 了

    file(TO_CMAKE_PATH "${VCTOOLS_INSTALL_DIR}" VCTOOLS_INSTALL_DIR)
    message(STATUS "Check VCTOOLS_INSTALL_DIR: ${VCTOOLS_INSTALL_DIR}")

    file(TO_CMAKE_PATH "${VCTOOLS_INSTALL_DIR}" VCTOOLS_INSTALL_DIR)

    include(FetchContent)
    FetchContent_Declare(
            std
            URL "file://${VCTOOLS_INSTALL_DIR}/modules"
            DOWNLOAD_EXTRACT_TIMESTAMP TRUE
            SYSTEM
    )
    FetchContent_MakeAvailable(std)

    add_library(std)
    target_sources(std PUBLIC
            FILE_SET CXX_MODULES
            BASE_DIRS ${std_SOURCE_DIR}
            FILES
            ${std_SOURCE_DIR}/std.ixx
            ${std_SOURCE_DIR}/std.compat.ixx
    )

    link_libraries(std)
else()
    message(FATAL_ERROR "C++23 Standard library module is not supported with current compiler.")
endif()