On 26/05/2010 13:46, vicente.botet wrote:
Hi,
The following doesn't compiles. void fct(BOOST_RVALUE_REF(movable_only) mo, int x){...} ... movable_only m; boost::function<void()> f_one = boost::bind(&fct, boost::move(m), 1);
Im not sure if the following is correct, boost::function<void()> f_one = boost::bind(&fct, boost::ref(boost::move(m)), 1);
What is the correct way to use move semantics with Boost.Bind? Do we need some Boost.Bind adaptations?
I don't know, maybe Boost.Bind should catch rvalues differently, but like with perfect forwarding (after all, bind is about forwarding) we'll need some limitations or tweaks. Maybe we need some ::boost::rv_ref()/boost::rv_reference_wrapper in Boost.Ref to pass rvalues to bind. And them Bind could forward them to the target call. Bind documentation says: "By default, bind makes a copy of the provided function object. boost::ref and boost::cref can be used to make it store a reference to the function object, rather than a copy. This can be useful when the function object is noncopyable, expensive to copy, or contains state; of course, in this case the programmer is expected to ensure that the function object is not destroyed while it's still being used." So evidently we can't pass movable-only objects unless we have some rvalue reference wrapper. Best, Ion