#include <future>
#include <iostream>

void hola() { std::cout << "hola"; }

int main()
{
//	auto policy = std::launch::async;
    auto policy = std::launch::deferred;

    auto s1 = std::async(policy, hola),
         s2 = std::async(policy, [] { std::cout << " mundo!\n"; });

    s1.get();
    s2.get();
}