Re: [boost] cannot pass objects of non-POD type ‘class boost::detail::shared_count’ through ‘...’; call will abort at runtime

Subject: Re: [boost] cannot pass objects of non-POD type ‘class boost::detail::shared_count’ through ‘...’; call will abort at runtime
From: Stefan Strasser (strasser_at_[hidden])
Date: 2009-09-17 08:19:32

Am Thursday 17 September 2009 14:58:23 schrieb Peter Dimov:
> The signature of sp_enable_shared_from_this has changed, it now takes a
> pointer to a shared_ptr as its first argument. Look at the current
> shared_ptr constructor:
>
>     template<class Y>
>     explicit shared_ptr( Y * p ): px( p ), pn( p ) // Y must be complete
>     {
>         boost::detail::sp_enable_shared_from_this( this, p, p );
>     }
>
> Relying on implementation details has its maintenance costs. :-)

I wondered before why shared_count is an implementation detail.
there are obviously use cases besides shared_ptr for this. one of those use 
cases is even endorsed by boost, by offering intrusive_ptr.
and the implementation of shared_count has performance advantages over every 
portable solution possible, as its implemented compiler- and 
platform-specific for many combinations.
so, why's shared_count an implementation detail?