[CMake] 'No known features for CXX compiler' warning with custom Clang

[Robert Maynard]

That is odd. Inside your build/CMakeFiles should be a file called
feature_tests.cxx, and that file is how we determine what features the
clang compiler supports.

I would use that to determine why feature detection is failing, since
currently it believes that none of the features listed in it are
valid.

Now if the file is empty, that means we are looking at a CMake logic
bug somewhere before this.

On Fri, Dec 16, 2016 at 5:41 PM, James Turner <james.turner at kdab.com> wrote:
>
>> On 16 Dec 2016, at 15:30, Robert Maynard <robert.maynard at kitware.com> wrote:
>>
>> <build_dir>/CMakeFiles/3.7.0/CMakeCXXCompiler.cmake
>>
>> The important information being what CMAKE_CXX_COMPILER_ID and
>> CMAKE_CXX_COMPILER_VERSION are set too.
>
> Here’s what I have. I note the _FEATURES variables are all empty.
>
> set(CMAKE_CXX_COMPILER "/usr/local/bin/clang-omp++")
> set(CMAKE_CXX_COMPILER_ARG1 "")
> set(CMAKE_CXX_COMPILER_ID "Clang")
> set(CMAKE_CXX_COMPILER_VERSION "3.5.0")
> set(CMAKE_CXX_COMPILER_WRAPPER "")
> set(CMAKE_CXX_STANDARD_COMPUTED_DEFAULT "98")
> set(CMAKE_CXX_COMPILE_FEATURES "")
> set(CMAKE_CXX98_COMPILE_FEATURES "")
> set(CMAKE_CXX11_COMPILE_FEATURES "")
> set(CMAKE_CXX14_COMPILE_FEATURES "")
>
> set(CMAKE_CXX_PLATFORM_ID "Darwin")
> set(CMAKE_CXX_SIMULATE_ID "")
> set(CMAKE_CXX_SIMULATE_VERSION “")
>
>
>
> Kind regards,
> James
>
> --
> James Turner - Senior Software Developer
> KDAB - The Qt, C++ and OpenGL Experts
>
>
>
>