[cfe-dev] Function accepting rvalue and lvalue references

[James Dennett]

On Tue, Oct 2, 2012 at 5:03 PM, Michael Lehn <michael.lehn at uni-ulm.de> wrote:
>
> Assume I have some templated class
>
>    template <typename T>
>    struct Dummy {
>        // ...
>    };
>
> and that I want to overload a fucntion 'foo' such that it accepts a lvalue or
> rvalue reference of it.  I can do this using some 'IsDummy trait' as follows:
>
>    template <typename A>
>    std::enable_if<IsDummy<A>::value, void>
>    foo(A &&dummy)
>    {
>        // ....
>    }
>
> So this is not the problem.  However, I somehow think that for some time a function
> like
>
>    template <typename A>
>    void
>    foo(Dummy<A> &&dummy)
>    {
>        // ....
>    }
>
> was capturing both, lvalue and rvalue reference.  Does my memory trick me?

Possibly so: it works for
  template <typename A> void foo(A&&)
because A can be deduced as an lvalue ref there (so that A&& is T& for
some T), but not for your case.

-- James