C++ Standard Libraries
There are two C++ standard libraries supported by Apple compilers.
The default for 10.9 and later is libc++, which is also the default for clang on older
platforms when building C++11 code.
The default for 10.8 and earlier was libstdc++, supported by Apple GCC
compilers, GNU GCC compilers, and clang. This was marked deprecated with a
warning during compilation as of Xcode 8.
There are subtle incompatibilities between several of the C++ standard libraries, so Homebrew will refuse to install software if a dependency was built with an incompatible C++ library. It’s recommended that you install the dependency tree using a compatible compiler.
If you’ve upgraded to 10.9 or later from an earlier version: Because the default C++ standard library is now libc++, you may not be able to build software using dependencies that you built on 10.8 or earlier. If you’re reading this page because you were directed here by a build error, you can most likely fix the issue if you reinstall all the dependencies of the package you’re trying to build.
Example install using GCC 9:
brew install gcc@9
brew install --cc=gcc-9 <formula>
