Is C++'s std::thread a wrapper for pthread on all platforms?

Question

I'm learning the use of std::thread, I used to think std::thread is a completely different threading library independent of pthread , I use the following code to test:

void run(void) {
    std::cout << "Hello World" <<endl;
}

int main(void) {
    std::thread t(run);
    t.join();
}

I thought it could be compiled directly via:

$ g++ main.cpp -o main

But it tells me that the "pthread_create" function is not defined:

/usr/bin/ld: /tmp/ccZpJ3EI.o: in function `std::thread::thread<void (&)(), , void>(void (&)())':
main.cpp:(.text._ZNSt6threadC2IRFvvEJEvEEOT_DpOT0_[_ZNSt6threadC5IRFvvEJEvEEOT_DpOT0_]+0x2f): undefined reference to `pthread_create'
collect2: error：ld return 1

I have to add the link for pthread:

$ g++ main.cpp -o main -lpthread

My OS is archlinux/manjaro, the C++ standard version is C++ 17.

Do I also need to link pthreads if I'm on another OS?