std::function with std::unique_ptr argument

[Jonathan Wakely]

2009/6/5 Rodolfo Lima:
> Hi, I'm trying to use a std::function with std::unique_ptr arguments but
> the std::function invocation ends up using std::unique_ptr copy ctor,
> which is private/deleted.
>
> Since std::function is a forward call wrapper, its operator() should
> have forwarded properly its arguments to the wrapped function, but
>
> M_invoker(_M_functor, __args...);
>
> and
>
> (*_Base::_M_get_pointer(__functor))(__args...);
>
>
> doesn't seem to do that. IMHO it should be
>
> _M_invoker(_M_functor, std::forward<_ArgTypes>(__args)...);
>
> (*_Base::_M_get_pointer(__functor))(std::forward<_ArgTypes>(__args)...);
>
>
> Any objections?

You're right it should forward the args, but see c++/34022 - it would
be dangerous to correctly forward rvalues, as you could end up passing
a dangling reference to the function.

Jonathan