CMakeBackwardCompatibilityCXX.cmake 1.77 KB
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# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.

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#[=======================================================================[.rst:
CMakeBackwardCompatibilityCXX
-----------------------------

define a bunch of backwards compatibility variables

::

  CMAKE_ANSI_CXXFLAGS - flag for ansi c++
  CMAKE_HAS_ANSI_STRING_STREAM - has <strstream>
  include(TestForANSIStreamHeaders)
  include(CheckIncludeFileCXX)
  include(TestForSTDNamespace)
  include(TestForANSIForScope)
#]=======================================================================]
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if(NOT CMAKE_SKIP_COMPATIBILITY_TESTS)
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  # check for some ANSI flags in the CXX compiler if it is not gnu
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  if(NOT CMAKE_COMPILER_IS_GNUCXX)
    include(TestCXXAcceptsFlag)
    set(CMAKE_TRY_ANSI_CXX_FLAGS "")
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    if(CMAKE_SYSTEM_NAME MATCHES "OSF")
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      set(CMAKE_TRY_ANSI_CXX_FLAGS "-std strict_ansi -nopure_cname")
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    endif()
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    # if CMAKE_TRY_ANSI_CXX_FLAGS has something in it, see
    # if the compiler accepts it
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    if(NOT CMAKE_TRY_ANSI_CXX_FLAGS STREQUAL "")
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      CHECK_CXX_ACCEPTS_FLAG(${CMAKE_TRY_ANSI_CXX_FLAGS} CMAKE_CXX_ACCEPTS_FLAGS)
      # if the compiler liked the flag then set CMAKE_ANSI_CXXFLAGS
      # to the flag
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      if(CMAKE_CXX_ACCEPTS_FLAGS)
        set(CMAKE_ANSI_CXXFLAGS ${CMAKE_TRY_ANSI_CXX_FLAGS} CACHE INTERNAL
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        "What flags are required by the c++ compiler to make it ansi." )
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      endif()
    endif()
  endif()
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  set(CMAKE_CXX_FLAGS_SAVE ${CMAKE_CXX_FLAGS})
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  string(APPEND CMAKE_CXX_FLAGS " ${CMAKE_ANSI_CXXFLAGS}")
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  include(TestForANSIStreamHeaders)
  include(CheckIncludeFileCXX)
  include(TestForSTDNamespace)
  include(TestForANSIForScope)
  include(TestForSSTREAM)
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS_SAVE}")
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endif()
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