Re: [boost] deleting smart pointer

Subject: Re: [boost] deleting smart pointer
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2011-03-21 07:06:19

pavel wrote:
>  Steven wrote on Saturday, March 19, 2011 at 1:31:51:
>
> >> rephrasing your words: how is 'delete p' a bad idea? it's
> >> obvious it is almost like 'p.reset()'
>
> > No it isn't.  The difference is that assignment
> > is a basic operation for a smart_ptr, and it's
> > behaving in the normal way.  It isn't a matter
> > of being "almost like" reset.
>
> i see your point but you don't want to see mine

There's a difference between seeing another's point and agreeing with it.  Steven understands your proposal just fine from what I've read in the discussion.

> here is the full citation of 5.3.5.2 of ISO/IEC 14882:2003(E) which,
> i guess, you are referring to:
>
> "If the operand has a class type, the operand is converted to
> a pointer type by calling the above-mentioned conversion
> function, and the converted operand is used in place of the
> original operand for the remainder of this section. In either
> alternative, if the value of the operand of delete is the null
> pointer the operation has no effect. In the first alternative
> (delete object), the value of the operand of delete shall be a
> pointer to a non-array object or a pointer to a sub-object
> (1.8) representing a base class of such an object (clause 10).
> If not, the behavior is undefined."

IOW, a shared_ptr sp must provide an implicit conversion to T * in order for delete sp to work, because delete only operates on T *'s, which then introduces an unwanted implicit conversion in shared_ptr.

_____
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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