Differences
This shows you the differences between two versions of the page.
| Both sides previous revisionPrevious revisionNext revision | Previous revision |
| install_actflow [2025/08/30 12:47] – [Troubleshooting] rajit | install_actflow [2025/08/30 12:57] (current) – [MacOS] rajit |
|---|
| Recent versions of MacOS have a C++ compiler issue, namely that the default compiler distributed by Apple does not support the "-fopenmp" flag. To fix this issue, we normally install either ''llvm'' or ''g++'' using homebrew. This normally results in the compiler being installed in a path that looks something like ''/opt/homebrew/Cellar/llvm/<version>/bin/clang++'' or ''/opt/homebrew/Cellar/gcc/<version>/bin/g++-<version>''. Set the environment variable ''CXX'' to the absolute path name of this C++ compiler before running "./build". | Recent versions of MacOS have a C++ compiler issue, namely that the default compiler distributed by Apple does not support the "-fopenmp" flag. To fix this issue, we normally install either ''llvm'' or ''g++'' using homebrew. This normally results in the compiler being installed in a path that looks something like ''/opt/homebrew/Cellar/llvm/<version>/bin/clang++'' or ''/opt/homebrew/Cellar/gcc/<version>/bin/g++-<version>''. Set the environment variable ''CXX'' to the absolute path name of this C++ compiler before running "./build". |
| |
| | More recent versions of LLVM have problems with linking. If you see messages like this: |
| | <code> |
| | Undefined symbols for architecture arm64: |
| | "std::__1::__hash_memory(void const*, unsigned long)", referenced from: |
| | ... |
| | </code> |
| | then chances are you have a known issue in recent LLVM versions on MacOS ([[https://github.com/llvm/llvm-project/issues/155606|github issue]]). The workaround that fixes this at least for the actflow build (see the discussion for details, this may not necessarily be a proper fix) is to edit the ''.cfg'' file installed with LLVM to include |
| | the location of the LLVM C++ standard library. The [[https://github.com/llvm/llvm-project/issues/155606|github issue]] has details and various workarounds, and the root cause appears to be that while the LLVM compiler uses a specific algorithm to find include paths, it uses a different one to find libraries; so the system C++ standard library is being used instead of the LLVM-provided C++ standard library. Explicitly including the LLVM-provided library fixes this issue in the build. |
| ==== OpenMP message ==== | ==== OpenMP message ==== |
| |