ceph/src/fmt/support/cmake/cxx14.cmake

   1 # C++14 feature support detection
   2
   3 include(CheckCXXCompilerFlag)
   4 function (fmt_check_cxx_compiler_flag flag result)
   5   if (NOT MSVC)
   6     check_cxx_compiler_flag("${flag}" ${result})
   7   endif ()
   8 endfunction ()
   9
  10 if (NOT CMAKE_CXX_STANDARD)
  11   set(CMAKE_CXX_STANDARD 11)
  12 endif()
  13 message(STATUS "CXX_STANDARD: ${CMAKE_CXX_STANDARD}")
  14
  15 if (CMAKE_CXX_STANDARD EQUAL 20)
  16   fmt_check_cxx_compiler_flag(-std=c++20 has_std_20_flag)
  17   fmt_check_cxx_compiler_flag(-std=c++2a has_std_2a_flag)
  18
  19   if (has_std_20_flag)
  20     set(CXX_STANDARD_FLAG -std=c++20)
  21   elseif (has_std_2a_flag)
  22     set(CXX_STANDARD_FLAG -std=c++2a)
  23   endif ()
  24
  25 elseif (CMAKE_CXX_STANDARD EQUAL 17)
  26   fmt_check_cxx_compiler_flag(-std=c++17 has_std_17_flag)
  27   fmt_check_cxx_compiler_flag(-std=c++1z has_std_1z_flag)
  28
  29   if (has_std_17_flag)
  30     set(CXX_STANDARD_FLAG -std=c++17)
  31   elseif (has_std_1z_flag)
  32     set(CXX_STANDARD_FLAG -std=c++1z)
  33   endif ()
  34
  35 elseif (CMAKE_CXX_STANDARD EQUAL 14)
  36   fmt_check_cxx_compiler_flag(-std=c++14 has_std_14_flag)
  37   fmt_check_cxx_compiler_flag(-std=c++1y has_std_1y_flag)
  38
  39   if (has_std_14_flag)
  40     set(CXX_STANDARD_FLAG -std=c++14)
  41   elseif (has_std_1y_flag)
  42     set(CXX_STANDARD_FLAG -std=c++1y)
  43   endif ()
  44
  45 elseif (CMAKE_CXX_STANDARD EQUAL 11)
  46   fmt_check_cxx_compiler_flag(-std=c++11 has_std_11_flag)
  47   fmt_check_cxx_compiler_flag(-std=c++0x has_std_0x_flag)
  48
  49   if (has_std_11_flag)
  50     set(CXX_STANDARD_FLAG -std=c++11)
  51   elseif (has_std_0x_flag)
  52     set(CXX_STANDARD_FLAG -std=c++0x)
  53   endif ()
  54 endif ()