Fixing C++ compilation bugs for the MacOS Catalina upgrade
I recently updated to macOS Catalina and encountered several issues with programs that use a C/C++ compiler. If you see any of these errors this post might be helpful for you:
/usr/local/Cellar/llvm/7.0.1/include/c++/v1/wchar.h:119:15: fatal error: 'wchar.h' file not found #include_next <wchar.h> ^~~~~~~~~ 1 error generated.
Or any error indicating that a standard library couldn’t be found:
ld: library not found for -ldl clang-10: error: linker command failed with exit code 1 (use -v to see invocation)
What’s the issue?
The issue is that macOS Catalina doesn’t use the
/usr/lib/ directories anymore for all C++ headers and libraries.
A lot of projects rely on these directories to exist, can’t find the files and then break.
Instead they are under the xcode path and you need to tell the C/C++ compiler where to find these libraries now.
How to fix it?
- Optionally, install a C++ compiler like clang / gcc through
brewif one is missing.
- Install Xcode through the App store to get access to the developer command-line tools.
This will install the C++ header files and libraries, albeit, in a different directory. They will be installed in
/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk or a similar directory. To get the correct path for your system you can run the
xcrun --show-sdk-path command.
- The C++ compiler needs to be told to look at this root path instead of
/usr/include. This can be done by setting the
CPLUS_INCLUDE_PATHenv variable. It’s important to also include LLVM’s normal include path because this is where it should search first.This should fix any
# adjust your llvm and CLT include paths to match your setup export CPLUS_INCLUDE_PATH=/usr/local/opt/llvm/include/c++/v1:/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include
fatal error: 'xxx.h' file not founderrors.
- You might still run into linker errors like
ld: library not found for -lxxx. The linker also needs to be told to look for libraries in the CommandLineTools/Xcode paths by setting the
- Make sure to add these
exportstatements to your
.bash_profile, or whatever shell you use, to make these adjusted environment variables available in all terminals.
Thanks a lot to this GitHub post for helping me figure out what’s wrong.