On Jul 16, 2008, at 10:43 AM, David Abrahams wrote:
on Wed Jul 16 2008, Mathias Gaunard <mathias.gaunard-AT-ens- lyon.org> wrote:
Mathias Gaunard wrote:
I personally don't see the point in dynamic deleters, they're only specializations of dynamic ones.
I meant static ones, sorry.
One point is to simplify the type information that ends up in interfaces.
Here's one code snippet that is likely to satisfy stability requirements for both API and ABI that might arise over time: struct B; class A { public: typedef std::unique_ptr<B, void(*)(B*)> handle; private: handle p_; public: static void reclaim(B*); // used as the deleter A(); // p_ constructed with reclaim handle get() {return std::move(p_);} }; int main() { A a; A::handle p = a.get(); // ... } // call A::reclaim(p.get()) B's layout is hidden (can change over time). The details of how to destruct B are hidden (and can change over time). The details of how to create a B are hidden (and can change over time). Destruction of B is automatic. One can pass (move) a handle (if desired) to the resource B and still have it destructed automatically and correctly. If one can suffer ABI changes, but not API changes, the type of the smart pointer is hidden behind a typedef (and can change over time). -Howard