Usually you don't need to use the full path to libm, and it's only needed sometimes depending on your compiler and toolchain. I typically use something like the following to deal with both the implicit and explicit scenarios:
include(CheckCSourceCompiles) set(LIBM_TEST_SOURCE "#include<math.h>\nfloat f; int main(){sqrt(f);return 0;}") check_c_source_compiles("${LIBM_TEST_SOURCE}" HAVE_MATH) if(HAVE_MATH) set(LIBM_LIBRARIES) else() set(CMAKE_REQUIRED_LIBRARIES m) check_c_source_compiles("${LIBM_TEST_SOURCE}" HAVE_LIBM_MATH) unset(CMAKE_REQUIRED_LIBRARIES) if(NOT HAVE_LIBM_MATH) message(FATAL_ERROR "Unable to use C math library functions") endif() set(LIBM_LIBRARIES m) endif() target_link_libraries(fooTarget PRIVATE ${LIBM_LIBRARIES}) ---------- Chuck Atkins Staff R&D Engineer, Scientific Computing Kitware, Inc. On Fri, Mar 15, 2019 at 7:46 AM frodak17 <froda...@gmail.com> wrote: > > > On Thu, Mar 14, 2019 at 8:53 PM workbe...@gmx.at <workbe...@gmx.at> wrote: > >> Hi everyone, >> >> i'm searching for a way to find the right include dir so that -lm can be >> found, the is not find_package for this, is /usr/lib and /usr/include a >> default because he find it without me adding any include or lib path for >> the build. >> >> >> > It seems strange that you need to do this. In my experience 'm' is just > the math portion of the 'c' library. Depending on which host and toolset > you are using there can be multiple version of the 'm' library depending on > target architecture and other options used. The linker should just use the > correct 'm' library just as it uses the correct 'c' library. It could be > in /usr/lib depending on how the compiler was packaged for your host. > -- > > 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