Re: [boost] [move] New version with move-aware containers library

Subject: Re: [boost] [move] New version with move-aware containers library
From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2009-04-17 08:46:38

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On Wednesday 15 April 2009, Steven Watanabe wrote:
> AMDG
>
> David Abrahams wrote:
> > Here's one thing I don't love:
> >
> >    Derived(BOOST_RV_REF(Derived) x)             // Move ctor
> >
> >       : Base(boost::move(static_cast<Base&>(x))),
> >
> >         mem_(boost::move(x.mem_)) { }
> >
> > is there a way to get rid of the static_cast and make
> >
> >    Derived(BOOST_RV_REF(Derived) x)             // Move ctor
> >
> >       : Base(boost::move(x)),
> >
> >         mem_(boost::move(x.mem_)) { }
> >
> > work?
>
> FWIW, I always write copy constructors using the cast, after having
> been bitten by templated base class constructors a few times.

What about a

boost::forward<Base>(x) instead of

boost::move(static_cast<Base&>(x))

Isn't forward supposed to be some kind of safe and movable-friendly 
static_cast?  I admit I'm a bit hazy on exactly what std::forward is supposed 
to accomplish.  I see it used in perfect forwarding examples, but they seem 
to work just as well without it.
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