[llvm-dev] [cfe-dev] clang++ build from source is not able to find C++ headers

Tim Northover via llvm-dev llvm-dev at lists.llvm.org
Thu Jun 23 07:06:11 PDT 2016

On 23 June 2016 at 06:31, vivek pandya via cfe-dev
<cfe-dev at lists.llvm.org> wrote:
> I am running OS X, when I build clang++ from source and use it to compile
> .cpp files it fails as it is not able to find C++ header. I am not building
> libc++ along with llvm and clang.

When I'm not building with libcxx in-tree I find it easiest to just
symlink Xcode's libc++ headers into the build directory. Something
like "ln -s /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++

> using -stdlib=libstdc++ solves problem partially but it fails when using
> C++11 threads, again it can't find <thread>, to get this work clang++ should
> work with -stdlib=libc++ but it fails with previous error of not finding C++
> headers.

Yes, the libstdc++ included with OS X is ancient (from GCC 4.2 I
think) and there only for compatibility reasons. It has virtually no
support for C++11, which LLVM needs.



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