Re: [boost] [shared_ptr] aliasing constructor mischief

From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2008-04-29 09:51:43

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On Tuesday 29 April 2008 09:26 am, Daniel Frey wrote:
> On Tue, 2008-04-29 at 09:02 -0400, Frank Mori Hess wrote:
> > I've noticed it is possible to construct a half-empty shared_ptr that has
> > an empty shared_count but a non-null pointer (brief example program
> > attached). Perhaps the aliasing constructor, and similarly the
> > shared_count constructor should do some argument checking?
>
> I think this is already a known problem/feature, see n2588
> <http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2008/n2588.pdf>,
> 20.6.12.2.1/18. I don't know what it's good for, though.

There's a note saying it is possible to create an empty shared_ptr with a 
non-null stored pointer, but it also states that get() is required to return 
null for an empty shared_ptr, and operator* and operator-> require get() != 
0.

- -- 
Frank
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