Re: [Boost-users] [shared_ptr] boost::shared_ptr deleter question

Subject: Re: [Boost-users] [shared_ptr] boost::shared_ptr deleter question
From: Tamas.Ruszkai_at_[hidden]
Date: 2015-08-14 10:00:47

Hi Glen,

You are right, my example was not complete.

Finally I have figured the problem out: I had also a weak_ptr somewhere to 
the owned class and it did not let the deleter to be removed.

It means:
- Owned class is removed when there is no more strong refrence exist.
- Deleter is destroyed when neither strong nor weak references exist

The reason is: the deleter is stored by value in the reference counter 
class.
I guess, theoretically the deleter would be not necessary any more after 
the owned object is destroyed, but storing it in the reference counter was 
maybe simpler to implement (maybe more efficient as well).

Thanks and sorry for the noise.

Cheers,
Tamas

From:   Glen Fernandes <glen.fernandes_at_[hidden]>
To:     boost-users_at_[hidden], 
Date:   14.08.2015 15:50
Subject:        Re: [Boost-users] [shared_ptr] boost::shared_ptr deleter 
question
Sent by:        "Boost-users" <boost-users-bounces_at_[hidden]>

Tamas,

I find it very surprising that your breakpoint in the destructor is not
being hit at all. This:
    #include <boost/smart_ptr/shared_ptr.hpp>
    #include <iostream>
    struct D {
        ~D() {
            std::cout << "~D\n";
        }
        template<class U>
        void operator()(U*) { 
            std::cout << "operator()\n";
        }
    };
    struct T { };
    int main()
    {
        {
            auto p = boost::shared_ptr<T>(new T, D{});
            std::cout << "...\n";
        }
    }

Outputs:
    ~D
    ~D
    ...
    operator()
    ~D

Glen

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