Am 05.12.18 um 13:40 schrieb Kim Walisch:
Hi,
I have realized that my C++ primesieve project
(https://github.com/kimwalisch/primesieve) is
compiled using -std=gnu++11 with GCC 7.3 and CMake 3.10 (on Ubuntu 18.10
x64) even
though the default C++ version used by GCC 7.3 is C++14 as checked below:
$ g++ -dM -E -x c++ /dev/null | grep -F __cplusplus
#define __cplusplus 201402L
Note that I have not set CXX_STANDARD manually in my CMakeLists.txt so I
was expecting
that my project would be compiled either with -std=gnu++14 or without
any C++ version flag.
I spent some time investigating where the -std=gnu++11 flag comes from
and I found that it is
related to the use of target_compile_features():
target_compile_features(primesieve PRIVATE cxx_auto_type)
This code tells the compiler that my program uses features from C++11
and that the compiler
should enable C++11 if the default C++ version of the compiler is e.g.
C++98. I would
however expect that if the default C++ version of the compiler is >
C++11 CMake would not
add -std=gnu++11 to the compiler flags.
For me this is a CMake bug.
Thanks,
Kim Walisch
Hi Kim,
this does indeed sound like some unwanted behavior.
I recommend you open an issue in CMake's issue-tracker
(https://gitlab.kitware.com/cmake/cmake/issues) and copy your
email-content there.
Best regards,
Deniz Bahadir
--
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
