Re: [boost] [intrusive_ptr] atomic ref counting?

From: Peter Dimov (pdimov_at_[hidden])
Date: 2006-04-17 16:03:21

Eric Niebler wrote:

> The implementation is quite trivial (see below).

Seems pretty complicated to me. The "canonical" counted_base is (assuming 
namespace boost):

class counted_base
{
private:

    mutable detail::atomic_count count_;

protected:

    counted_base(): count_( 0 ) {}
    virtual ~counted_base() {}
    counted_base( counted_base const & ): count_( 0 ) {}
    counted_base& operator=( counted_base const & ) { return *this; }

public:

    inline friend void intrusive_ptr_add_ref( counted_base const * p )
    {
        ++p->count_;
    }

    inline friend void intrusive_ptr_release( counted_base const * p )
    {
        if( --p->count_ == 0 ) delete p;
    }

    long use_count() const { return count_; }
};

Seeing so many variations of it is a pretty good indication that we need it 
in Boost. :-)