$ cat atomic.cxx
#include <atomic>
int main(void) {
return (0);
}
$ clang++-mp-9.0 -stdlib=libstdc++ atomic.cxx
atomic.cxx:1:10: fatal error: 'atomic' file not found
#include <atomic>
^~~~~~~~
1 error generated.$ clang++-mp-9.0 -stdlib=macports-libstdc++ atomic.cxx <OK> h$ clang++-mp-9.0 -stdlib=libc++ atomic.cxx <OK>
