CMake/Modules/Compiler/MSVC-CXX.cmake

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

include(Compiler/CMakeCommonCompilerMacros)

if ((CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 19.0.24215.1 AND
     CMAKE_CXX_COMPILER_VERSION VERSION_LESS 19.10) OR
   CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 19.10.25017)

  # VS 2015 Update 3 and above support language standard level flags,
  # with the default and minimum level being C++14.
  set(CMAKE_CXX98_STANDARD_COMPILE_OPTION "")
  set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "")
  set(CMAKE_CXX98_STANDARD__HAS_FULL_SUPPORT ON)
  set(CMAKE_CXX11_STANDARD_COMPILE_OPTION "")
  set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "")
  set(CMAKE_CXX14_STANDARD_COMPILE_OPTION "-std:c++14")
  set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "-std:c++14")
  if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 19.11.25505)
    set(CMAKE_CXX17_STANDARD_COMPILE_OPTION "-std:c++17")
    set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-std:c++17")
  else()
    set(CMAKE_CXX17_STANDARD_COMPILE_OPTION "-std:c++latest")
    set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "-std:c++latest")
  endif()
  if (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 19.12.25835)
    set(CMAKE_CXX20_STANDARD_COMPILE_OPTION "-std:c++latest")
    set(CMAKE_CXX20_EXTENSION_COMPILE_OPTION "-std:c++latest")
  endif()

  __compiler_check_default_language_standard(CXX 19.0 14)

  # All features that we define are available in the base mode, except
  # for meta-features for C++14 and above.  Override the default macro
  # to avoid doing unnecessary work.
  macro(cmake_record_cxx_compile_features)
    if (DEFINED CMAKE_CXX20_STANDARD_COMPILE_OPTION)
      list(APPEND CMAKE_CXX20_COMPILE_FEATURES cxx_std_20)
    endif()
    # The main cmake_record_cxx_compile_features macro makes all
    # these conditional on CMAKE_CXX##_STANDARD_COMPILE_OPTION,
    # but we can skip the conditions because we set them above.
    list(APPEND CMAKE_CXX17_COMPILE_FEATURES cxx_std_17)
    list(APPEND CMAKE_CXX14_COMPILE_FEATURES cxx_std_14)
    list(APPEND CMAKE_CXX98_COMPILE_FEATURES cxx_std_11) # no flag needed for 11
    _record_compiler_features_cxx(98)
  endmacro()
elseif (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 16.0)
  # MSVC has no specific options to set language standards, but set them as
  # empty strings anyways so the feature test infrastructure can at least check
  # to see if they are defined.
  set(CMAKE_CXX98_STANDARD_COMPILE_OPTION "")
  set(CMAKE_CXX98_EXTENSION_COMPILE_OPTION "")
  set(CMAKE_CXX11_STANDARD_COMPILE_OPTION "")
  set(CMAKE_CXX11_EXTENSION_COMPILE_OPTION "")
  set(CMAKE_CXX14_STANDARD_COMPILE_OPTION "")
  set(CMAKE_CXX14_EXTENSION_COMPILE_OPTION "")
  set(CMAKE_CXX17_STANDARD_COMPILE_OPTION "")
  set(CMAKE_CXX17_EXTENSION_COMPILE_OPTION "")
  set(CMAKE_CXX20_STANDARD_COMPILE_OPTION "")
  set(CMAKE_CXX20_EXTENSION_COMPILE_OPTION "")

  # There is no meaningful default for this
  set(CMAKE_CXX_STANDARD_DEFAULT "")

  # There are no compiler modes so we only need to test features once.
  # Override the default macro for this special case.  Pretend that
  # all language standards are available so that at least compilation
  # can be attempted.
  macro(cmake_record_cxx_compile_features)
    list(APPEND CMAKE_CXX_COMPILE_FEATURES
      cxx_std_98
      cxx_std_11
      cxx_std_14
      cxx_std_17
      cxx_std_20
      )
    _record_compiler_features(CXX "" CMAKE_CXX_COMPILE_FEATURES)
  endmacro()
endif()