Chad Nelson wrote:
I've been studying Boost.Move, with an eye toward using it to incorporate move semantics into the XInt library. Most of it looks pretty straightforward, but I don't understand the reason for the BOOST_COPY_ASSIGN_REF macro. If you already have a copy-constructor that takes a reference, what does it give you?
That's why it's called BOOST_COPY_*ASSIGN*_REF. You use it to define the copy assignment operator. It expands to const T& if BOOST_HAS_RVALUE_REFS, and const rv<T>& otherwise. Boost.Move, in the absence of true rvalue references, depends on copy elision to efficiently construct from rvalues (and reasonably so), so there's no need to do anything special with the copy/move constructor combination.
Also, how close is it to being official? I'd like to use it, but if it's not going to be accepted any time soon, I can't justify it.
I can't answer the "how close", but you can still use it in the sense that you can adopt its conventions regarding boost::rv, and (if you choose) ignore the rest of the library. These conventions are: - boost::rv<T>& emulates an rvalue reference (and hence may be safely moved from); and - a move-enabled class T provides a non-const conversion operator to boost::rv<T>& and a const conversion operator to const boost::rv<T>&. - Jeff