Re: [boost] Re: Intrusive smart pointer

From: Peter Dimov (pdimov_at_[hidden])
Date: 2002-04-20 05:56:58

From: "Fernando Cacciola" <fcacciola_at_[hidden]>
> I wonder if this could be confusing: shared_ptr uses a detached or
intrusive
> count depending on how it is constructed.... I find more intuitive to
expect
> that shared_ptr uses a detached or intrusive count depending on the
pointee
> type, regardless of how you create it.

Let's assume that shared_ptr autodetects. Consider my original example:

// some member function

shared_ptr<this_type> f()
{
    return shared_ptr<this_type>(this);
}

Is this correct? Yes, if this_type is derived from counted_base, undefined
behavior otherwise.

Now consider the explicit version:

// some member function

shared_ptr<this_type> f()
{
    return intrusive_ptr<this_type>(this);
}

Now the compiler can verify the correctness.

It's always better when the correctness of the code can be determined
without context.