swap temporary tuples of references

Question

I\'m writing a custom iterator that, when dereferenced returns a tuple of references. Since the tuple itself is ephemeral, I don\'t think I can return a reference from oper

Answer 1

On rare occasions it may be desirable to get an lvalue reference to temporary. This easily achieved with a cast opposite to std::move:

template 
T & stay(T && t) { return t; }

Usage:

std::swap(stay(foo()), stay(bar()));

---

As you already said, if you can't change the call site, your best option may be to write your own reference wrapper and use ADL for that:

namespace detail
{
    struct IntRefPair
    {
        int & a, & b;
        IntRefPair(int & x, int & y) : a(x), b(y) {}
    };

    void swap(IntRefPair && lhs, IntRefPair && rhs)
    { 
        std::swap(lhs.a, rhs.a);
        std::swap(lhs.b, rhs.b);
    }
}

// ...

IntRefPair operator*() { return IntRefPair(v1[5], v2[5]); } }