Does the C++ standard require that dynamic initialization of static variables be performed in the main thread?

Question

Does the C++ standard require that dynamic initialization of non-local static variables, be performed in the same thread that calls main()?

More specifically, in C++11, is std::this_thread::get_id() guaranteed to return the same result in static initializers and inside main()?

Edit:

Even more specifically, given the following code:

#include <iostream>
#include <thread>

static std::thread::id id = std::this_thread::get_id();

int main()
{
        std::cout << id << "\n";
        std::cout << std::this_thread::get_id() << "\n";
        return 0;
}

are the two emitted thread IDs required/guaranteed to match?

Answer 1

No. The standard nowhere provides such a guarantee, and in fact the contrary is implied by [basic.start.init]/p2:

If a program starts a thread (30.3), the subsequent initialization of a variable is unsequenced with respect to the initialization of a variable defined in a different translation unit. Otherwise, the initialization of a variable is indeterminately sequenced with respect to the initialization of a variable defined in a different translation unit. If a program starts a thread, the subsequent unordered initialization of a variable is unsequenced with respect to every other dynamic initialization. Otherwise, the unordered initialization of a variable is indeterminately sequenced with respect to every other dynamic initialization.

There would be no need to weaken the sequencing guarantee in the presence of threads if all initializations had to be performed on the same thread.