问题
I have tried many things now and have come to some conclusions. Maybe, I oversee something but it seems that I cannot accomplish what I desire.
The question is: Is there any possibility to compile C++ on MacOS High Sierra with OpenMP and boost?
Some findings (correct me if I am wrong):
- OpenMP is supported by Clang BUT not by the standard MacOS-clang compiler delivered with MacOS which is ALSO the only compiler XCode9 supports
- g++ supports OpenMP
- If I install Boost via homebrew, then it will use the clang compiler (which cannot be changed easily), so that libc++ will be used
- g++ uses libstdc++ by default which is not easy to change
As a consequence, it seems that I cannot have both... OpenMP is only supported if I use gcc. But gcc uses libstdc++ instead of libc++, so that I get linker errors if I try to link against boost installed via homebrew with libc++.
Is there any chance to get both OpenMP and and boost running?
PS: Please don't link to some >1 year old threads, XCode8 is another story (earlier XCode versions support different compilers) and clang-omp would be another story (it is no longer supported).
回答1:
Standard Apple's clang supports OpenMP. They just disabled the driver option. But you can use the frontend option instead this way:
clang -Xclang -fopenmp <you_program> -L <path to libomp.a> -lomp
Also, you need to set DYLD_LIBRARY_PATH environmental variable:
export DYLD_LIBRARY_PATH=<path to libomp.dylib>
回答2:
Since you mentioned in passing brew install clang-omp, it's been merged into brew install llvm. That's really a very useful choice if you are willing to do it, since you get llvm 5 and C++17 if you need it. It's fully OpenMP compatible using the standard options (ie, -fopenmp).
You can also try my brew formula to use the built-in clang, but you'd still need to set up custom options as in Alexey Bataev's answer. Install with brew:
brew install cliutils/apple/libomp
This only adds the openMP dynamic library and header, nothing else. Then build with:
clang++ -Xpreprocessor -fopenmp -lomp <other arguments...>
See the readme. If you are using cmake, the helper file here might help.
来源：https://stackoverflow.com/questions/47081991/is-c-compilable-with-openmp-and-boost-on-macos