Re: [boost] [smart_ptr] shared_ptr<T> T destructor requiredevenifadeleter function is provided

Subject: Re: [boost] [smart_ptr] shared_ptr<T> T destructor requiredevenifadeleter function is provided
From: vicente.botet (vicente.botet_at_[hidden])
Date: 2008-09-29 07:19:53

----- Original Message ----- 
From: "Peter Dimov" <pdimov_at_[hidden]>
To: <boost_at_[hidden]>
Sent: Monday, September 29, 2008 12:44 PM
Subject: Re: [boost] [smart_ptr] shared_ptr<T> T destructor 
requiredevenifadeleter function is provided

>
> vicente.botet:
>> Hello Peter,
>>
>> what about the following in which we don't transfer ownership. (Note that 
>> now X::create() return X*)
>>
>> int main () {
>>    shared_ptr<X> ptr(X::create(), X::deleter());
>>    ptr.reset(X::create());
>
> This is the equivalent of doing
>
>    shared_ptr<X> ptr( X::create() );
>
> which you're explicitly trying to prevent. The equivalent of
>
>>    shared_ptr<X> ptr(X::create(), X::deleter());
>
> is
>
>    ptr.reset( X::create(), X::deleter() );
>
>>    return 0;
>> }
>

Peter ,

thanks for pointing me to
template<class Y, class D> void reset(Y * p, D d);

I was not aware that deleter is associated to the pointer instance and not 
to the shared_ptr. I see now.

I suppose that you have already discused about a template version of 
shared_ptr and that you have good raisons no not include them for the 
standard. Please could you point me to the rational?

Has a wrapper class that takes the deleter and allocators as template 
parameter has a sence?

template <typename T, typename Deleter, typename Allocator>
struct shared_ptr_wrapper : private shared_ptr<T>
{
    ...
    void reset(T * p) {
        this->shared_ptr::reset(p, Deleter())
    }
    ...
}

Sorry for the noice and thanks again,

Vicente