Precompiled mac os clang 10 doesn't work out of box on Catalina

Hi! I have downloaded precompiled clang 10 on a virgin Mac OS Catalina installation. My attempt to compile C++ code fails with error:

/Users/stepan/Downloads/clang+llvm-10.0.0-x86_64-apple-darwin/bin/…/include/c++/v1/wchar.h:118:15: fatal error:
‘wchar.h’ file not found
#include_next <wchar.h>
1 error generated.

This is kind of know error end was described in stack overflow:

The reason is a wrong configuration of sysroot or include directories.

And yet I have a question. As long a it is a precompiled clang for macos, isn’t it possible to fix it and make it working out of box?

BTW: clang-9 works without any issues.


My bad. Clang-9 also fails.

Last night, I solved this issue, but partially.
Starting from Mojave “/usr/include” was removed from Mac OS. You should either install headers explicitly, or pass “–sysroot” parameter during compilation.
I say “partially”, because imho it breaks default use-case. Since this moment you can’t use clang out of box just like that: “clang++ test.cpp”. I love Apple because you can use things out of the box. But, alas, this is not about clang anymore.

I think we should either update guidelines, or improve sysroot computation in Driver.

Anybody? Any thoughts on that?


There’s an open bug for this, or at least there was… maybe autoclosed?

Exactly as you say an ‘out of the box’ clang build in recent mac os will fail to find the “system” headers. You can read the thread here: