#include <stdatomic.h>

// https://clang.llvm.org/docs/LanguageExtensions.html#langext-c11-atomic
// if stdatomic.h exists this program will not compile with clang
// (doesn't work at all with g++ because it does not implicitly include its
// own stdatomic)
int main(int argc, char **argv)
{
    _Atomic int x = 23;
    int y = 0;
    int z = 0;
    atomic_compare_exchange_strong(&x, &y, z);

    return 0;
}