If you have standard required enabled the compiler version shouldn't decay down to 14 when asking for 17.
I recommend having a small test repo and using cmake --trace/--trace-expand to determine where the gnu++1y is coming from. It is not clear when looking at Modules/Compiler/Clang-CXX.cmake how gnu++1y would be used unless CMake is thinking you are asking for C++14 on clang 3.5. On Sun, May 6, 2018 at 1:35 PM Andrew Brownsword < andrew.e.brownsw...@gmail.com> wrote: > Well, I am specifying: > set(CMAKE_CXX_STANDARD_REQUIRED ON) > set(CMAKE_CXX_STANDARD 17) > set(CMAKE_CXX_EXTENSIONS ON) > and the compiler line contains “-std=gnu++1y”. I’m using a very recent source build of CLang and libc++. Any idea why cmake would fall back to 1y in this case? > On May 6, 2018, at 9:05 AM, Jean-Michaël Celerier < jeanmichael.celer...@gmail.com> wrote: > Note that c++17 is c++1z. c++1y was C++14. > ------- > Jean-Michaël Celerier > http://www.jcelerier.name > On Sun, May 6, 2018 at 5:00 PM, Andrew Brownsword < andrew.e.brownsw...@gmail.com> wrote: >> Hi, >> Is there a way to get cmake 3.11 to emit 17 vs 1y when setting CMAKE_CXX_STANDARD? I’m finding that it seems to be a common practice to use the value of the preprocessor define __cplusplus (which is a date), and the value differs depending on whether 17 or 1y is used (at least with CLang). I haven’t figured out how to get cmake to emit -std=c++17, it always seems to use 1y, which is causing problems with code that assumes the __cplusplus date reflects the c++17 standardization date. >> Thanks, >> Andrew >> -- >> Powered by www.kitware.com >> Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ >> Kitware offers various services to support the CMake community. For more information on each offering, please visit: >> CMake Support: http://cmake.org/cmake/help/support.html >> CMake Consulting: http://cmake.org/cmake/help/consulting.html >> CMake Training Courses: http://cmake.org/cmake/help/training.html >> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html >> Follow this link to subscribe/unsubscribe: >> https://cmake.org/mailman/listinfo/cmake > -- > Powered by www.kitware.com > Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ > Kitware offers various services to support the CMake community. For more information on each offering, please visit: > CMake Support: http://cmake.org/cmake/help/support.html > CMake Consulting: http://cmake.org/cmake/help/consulting.html > CMake Training Courses: http://cmake.org/cmake/help/training.html > Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html > Follow this link to subscribe/unsubscribe: > https://cmake.org/mailman/listinfo/cmake -- Powered by www.kitware.com Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ Kitware offers various services to support the CMake community. For more information on each offering, please visit: CMake Support: http://cmake.org/cmake/help/support.html CMake Consulting: http://cmake.org/cmake/help/consulting.html CMake Training Courses: http://cmake.org/cmake/help/training.html Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html Follow this link to subscribe/unsubscribe: https://cmake.org/mailman/listinfo/cmake
