Re: [boost] Weak functor: Interested? (How to boost::bind to a weak_ptr)

Subject: Re: [boost] Weak functor: Interested? (How to boost::bind to a weak_ptr)
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2012-01-11 08:43:15

Roman Perepelitsa wrote:
> 2012/1/11 Stewart, Robert <Robert.Stewart_at_[hidden]>
> > Roman Perepelitsa wrote:
> > >
> > > It can be done. In fact, it has already been done. See
> > > http://lists.boost.org/boost-users/2011/09/70647.php.
> >
> > PMFJI, but that code looks suspect.  get_pointer() locks the
> > weak_ptr to get a raw pointer from the related shared_ptr,
> > but then the shared_ptr returned by lock() is allowed to go
> > out of scope.  Thus, the ptr_adapter returned by
> > get_pointer() holds a transiently valid raw pointer.  By the
> > time the pointer is used to call the member function, the
> > last shared_ptr owning the associated memory could release
> > the memory, so the ptr_adapter will have a dangling pointer.
>
> Yes, it's a bug.
>
> > If ptr_adapter were to hold a shared_ptr instead of a raw
> > pointer, then the memory could not be released out from under
> > the ptr_adapter.  That, of course, doesn't work with
> > get_pointer().
>
> Of course it works with get_pointer.

shared_ptr doesn't overload ->* which, I thought, was the purpose of get_pointer().

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer                     using std::disclaimer;
Dev Tools & Components
Susquehanna International Group, LLP  http://www.sig.com

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