What CMake variable is used to set C++ Standard Library in XCode?

Question

I have a pure C++11 DLL (No dependencies of any kind) I have been able to compile on Linux and Windows for some time now using CMake to generate the project files and make/MSVC to compile in each respective native system.

I want to compile on OSX now and I have been having a lot of problems getting CMake to set the correct project settings in XCode to compile the DLL.

Software versions:

XCode v5.0
CMake v2.8.12

The relevant CMake script code:

# Set output directory if Apple OSX:
IF(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
    message("CMAKE HAS DETECTED A OSX SYSTEM - BUILDING FOR XCODE!")

    set(CMAKE_XCODE_ATTRIBUTE_GCC_VERSION "com.apple.compilers.llvm.clang.1_0")
    set(CMAKE_XCODE_ATTRIBUTE_CLANG_CXX_LANGUAGE_STANDARD "c++0x")
    set(CMAKE_XCODE_ATTRIBUTE_CLANG_CXX_LIBRARY "libc++")
    set(CMAKE_CXX_FLAGS "${CMAKE_C_FLAGS} -std=c++0x -stdlib=libc++")

    IF(CMAKE_BUILD_TYPE MATCHES Release)
        SET(LIBRARY_OUTPUT_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../bin/OSX/Release)
    ENDIF(CMAKE_BUILD_TYPE MATCHES Release)
    IF(CMAKE_BUILD_TYPE MATCHES Debug)
        SET(LIBRARY_OUTPUT_PATH ${CMAKE_CURRENT_SOURCE_DIR}/../bin/OSX/Debug)
    ENDIF(CMAKE_BUILD_TYPE MATCHES Debug)
ENDIF(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")

However the settings do not correctly come through into the XCode project file:

You can see that the CMake commands make their way into the 'Other C++ Flags' area. But XCode will still fail to compile. However, if I change the 'C++ Standard Library' variable to 'libc++' it will compile fine.

Note: I could post the compile error logs however I think that the above correctly identifies the root cause - I just need to know what CMake command actually sets the correct XCode property above.

Answer 1

For a minimal test project the following does the job:

SET(CMAKE_XCODE_ATTRIBUTE_CLANG_CXX_LIBRARY "libc++")

Maybe it's interfering with the following line:

set(CMAKE_CXX_FLAGS "${CMAKE_C_FLAGS} -std=c++0x -stdlib=libc++")

Also one remark on this line, is there the ${CMAKE_C_FLAGS} on intention, or did you really mean ${CMAKE_CXX_FLAGS}?