cmake\ConfigureCXX_Version.cmake

#set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CXX_EXTENSIONS OFF)

if(NOT CMAKE_CXX_STANDARD)
    if("cxx_std_20" IN_LIST CMAKE_CXX_COMPILE_FEATURES)
        set(CMAKE_CXX_STANDARD 20)
        message(STATUS "C++20: OK")
    elseif("cxx_std_17" IN_LIST CMAKE_CXX_COMPILE_FEATURES)
        set(CMAKE_CXX_STANDARD 17)
        message(STATUS "C++17: OK")
    elseif("cxx_std_14" IN_LIST CMAKE_CXX_COMPILE_FEATURES)
        set(CMAKE_CXX_STANDARD 14)
        message(STATUS "C++14: OK")
        message(WARNING "C++14 is old, please use newer compiler.")
    elseif("cxx_std_11" IN_LIST CMAKE_CXX_COMPILE_FEATURES)
        set(CMAKE_CXX_STANDARD 11)
        message(STATUS "C++11: OK")
        message(WARNING "C++11 is old, please use newer compiler.")
    else()
        message(FATAL_ERROR "The compiler ${CMAKE_CXX_COMPILER} has no C++11 or above support. Please use a different C++ compiler.")
    endif()
endif()