Method test_shared_future

uspace/lib/cpp/src/__bits/test/future.cpp:316–350

    }

    void future_test::test_shared_future()
    {
        auto [p1, f1, s1] = prepare<int>();
        auto sf1 = f1.share();

        test("future invalid after share", !f1.valid());
        test_eq("shared state moved on share", sf1.__state(), s1);
        test_eq("no refcount increment on share", s1->refs(), 2);

        {
            auto sf2 = sf1;
            test_eq("refcount increment on copy", s1->refs(), 3);
            test_eq("shared state shared between copies", sf1.__state(), sf2.__state());
        }
        test_eq("refcount decrement when copy gets destroyed", s1->refs(), 2);

        auto sf2 = sf1;
        int res1{}, res2{};
        std::thread t1{
            [&](){
                res1 = sf1.get();
            }
        };
        std::thread t2{
            [&](){
                res2 = sf2.get();
            }
        };

        std::this_thread::sleep_for(20ms);
        p1.set_value(42);
        std::this_thread::sleep_for(20ms);
        test_eq("first result correct", res1, 42);
        test_eq("second result correct", res2, 42);
    }
}