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Subject: Re: [boost] [shared_ptr] enable_shared_from_any ?
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-05-18 08:22:46

Philip Warner wrote:
> On 18/05/2010 10:33 AM, Frank Mori Hess wrote:
> from my original post:
> > Specifically, what I would like to see is a solution to the
> > following code:
> >
> > C1 *p = new C1();
> > shared_ptr<C1> ptr(p);
> > ...
> > ...some time later....
> > shared_ptr<C1> ptr2<p>;
> >
> > and the resulting mess because of double-deallocation.
> I am very happy to provide a patch that:
> - adds a class, enable_shared_from_any, that can be inherited from
> - updates shared_ptr to work in the above code, if C1 inherits from
> enable_shared_from_any
> What we have at the moment is something like 'SafeSharedPtr' that
> inherits from 'shared_ptr' which does what I want, but which is less
> efficient than a native implementation would be

I don't see how inheriting from a special base class helps. Instantiating instances of a special type is no safer than calling a different function for this purpose. The issue is merely one of supplying external knowledge that the new shared_ptr should not assume sole ownership of the raw pointer. enable_shared_from_this was created to express a special use case of, as you point out, a more general need.

Rob Stewart robert.stewart_at_[hidden]
Software Engineer, Core Software using std::disclaimer;
Susquehanna International Group, LLP

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