[boost] Question:shared_count implementation rationale

From: Robert Ramey (ramey_at_[hidden])
Date: 2002-08-25 10:43:01

I am adding small example to the serialization library which implements serialization for shared_ptr.

smart_ptr includes and instance of shared_count

A very short summary of shared count is:

class counted_base
{
}

template<class P, class D>
class counted_base_imp public counted_base
{
};

class shared_count
{
        counted_base *pi_;
};

template<class T>
class shared_ptr
{
        shared_count pn;
        T * px;
};

It turns out this is not really well suited to my purposes.  I'm really interested in knowing something seemingly simpler wasn't used - such as

template<class T>
class shared_count
{
};

template<class T>
class shared_ptr 
{
        shared_count<T> pn;
        T *px;
};

I have perused the mail archives but can't seem to find out how shared_count came to be as it is.  I could use a separate version for my demo, but it would be very useful to me to know more about the rationale for the current implementation.

Robert Ramey