vfork testing

vfork-nightmares.cpp

// This code is all kinds of illegal and tests whether other threads
// keep running while there is an outstanding vfork

#include <atomic>
#include <thread>
#include <iostream>
#include <unistd.h>

std::atomic<bool> child_running;
std::atomic<bool> child_signaled;
std::atomic<bool> child_done;

void writer() {
	while (!child_running) continue;
	std::cout << "T2 saw write from vfork child; signalling back\n";
	child_signaled = true;
	while (!child_done) continue;
	std::cout << "T2 saw final child write\n";
}
void forker() {
	std::cout << "T1 vforking\n";
	if (vfork() == 0) {
		child_running = true;
		while (!child_signaled) continue;
		child_done = true;
		_exit(0);
	}
	std::cout << "T1 back\n";
}

int main() {
    std::thread t1(writer);
    std::thread t2(forker);
    t1.join();
    t2.join();

	return 0;
}