atomic/example4.cpp

// atomic::load/store example
#include <iostream>       // std::cout
#include <atomic>         // std::atomic, std::memory_order_relaxed
#include <thread>         // std::thread

std::atomic<int> foo (0);

void set_foo(int x) {
 foo.store(x,std::memory_order_relaxed);     // set value atomically
}

void print_foo() {
 int x;
 do {
   x = foo.load(std::memory_order_relaxed);  // get value atomically
 } while (x==0);
 std::cout << "foo: " << x << '\n';
}

int main ()
{
 std::thread first (print_foo);
 std::thread second (set_foo,10);
 first.join();
 second.join();
 return 0;
}