I was wondering what use an rvalue reference member has
class A {
// ...
// Is this one useful?
Foo &&f;
};
Does it have any bene
I've seen one very motivating use case for rvalue reference data members, and it is in the C++0x draft:
template
tuple
forward_as_tuple(Types&&... t) noexcept;
Effects: Constructs a tuple of references to the arguments in t suitable for forwarding as arguments to a function. Because the result may contain references to temporary variables, a program shall ensure that the return value of this function does not outlive any of its arguments. (e.g., the program should typically not store the result in a named variable).
Returns:
tuple
(std::forward (t)...)
The tuple has rvalue reference data members when rvalues are used as arguments to forward_as_tuple, and otherwise has lvalue reference data members.
I've found forward_as_tuple subsequently helpful when needing to catch variadic arguments, perfectly forward them packed as a tuple, and re-expand them later at the point of forwarding to a functor. I used forward_as_tuple in this style when implementing an enhanced version of tuple_cat proposed in LWG 1385:
http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1385