Re: [boost] incomplete types in shared_ptr

From: Douglas Gregor (gregod_at_[hidden])
Date: 2003-08-28 18:22:36

On Wednesday 27 August 2003 10:11 am, Thorsten Ottosen wrote:
> shared_ptr<> can hold incomplete types. Aparently the trick
> is to hold a pointer to a destructor function.
>
> However, from reading the code, it is quite hard to understand completely.
>
> Does anyone know some resource that describes the technique
> (or maybe someone could explain it to me)?

When you put a new T* into shared_ptr<T>, T must be a complete type, so that 
that point shared_ptr<T> generates an appropriate deleter for type T because 
it _knows_ the destructor has to be there, and saves a pointer to that 
deleter function. In other translation units, shared_ptr<T> can use the 
deleter by calling through the function pointer without ever instantiating a 
deleter.

        Doug