Consider the following piece of code:

#include <atomic>

int main(void) {
  std::atomic<double> aDouble;
  aDouble = 6.0;
}

G++ compiles it just fine while clang++ produces the following:

clang++ -std=c++11 Main.cpp 
/tmp/Main-d4f0fc.o: In function `std::atomic<double>::store(double, std::memory_order)':
Main.cpp:(.text._ZNSt6atomicIdE5storeEdSt12memory_order[_ZNSt6atomicIdE5storeEdSt12memory_order]+0x31): undefined reference to `__atomic_store_8'
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Do they not link against the same standard library?