http://stackoverflow.com/questions/28623287/using-stdmove-to

struct A
{
    std::vector<int> x;
    A()
    {
        std::cout << "A()" << std::endl;
    }

    A(const A&a)
    {
        std::cout << "A(const A&)" << std::endl;
        x = a.x;
    }

    A(A&&a)
    {
        std::cout << "A(A&&)" << std::endl;
        x = std::move(a.x);
    }

    ~A()
    {
        std::cout << "~A()" << std::endl;
    }
};

struct B : public A
{
    std::vector<int> y;

    B()
    {
        std::cout << "B()" << std::endl;
    }

    B(const A&a)
    {
        std::cout << "B(const A&)" << std::endl;
        x = a.x;
        y.resize(x.size());
    }

    B(A&&a) :A(std::move(a))
    {
        std::cout << "B(A&&)" << std::endl;
        std::cout << "a.x.size=" << a.x.size() << std::endl;
        std::cout << "x.size=" << x.size() << std::endl;
        y.resize(x.size());
    }

    B(const B&)
    {
        std::cout << "B(const B&)" << std::endl;
    }

    ~B()
    {
        std::cout << "~B()" << std::endl;
    }
};

A ret_a()
{
    A a;
    a.x.resize(10);
    return a;
}

int _tmain(int argc, _TCHAR* argv[])
{
    std::cout << "section I" << std::endl << std::endl;

    A a = ret_a();
    B b(a);
    std::cout << "a.x.size=" << a.x.size() << std::endl;

    std::cout << std::endl << "section II" << std::endl << std::endl;

    B b2(ret_a());
    std::cout << "b.x.size=" << b.x.size() << std::endl;

    std::cout << std::endl << "section III" << std::endl << std::endl;

    return 0;
}

/* Output:

section I

A()
A()
B(const A&)
a.x.size=10

section II

A()
A(A&&)
B(A&&)
a.x.size=0
x.size=10
~A()
b.x.size=10

section III

~B()
~A()
~B()
~A()
~A()

*/