Re: out_ptr -- alternatives

From: Rainer Deyke (rainerd_at_[hidden])
Date: 2019-06-28 10:09:30

On 28.06.19 10:08, Andrzej Krzemienski via Boost wrote:
> What I am missing from the motivation of out_ptr is the comparison with a
> full RAII wrapper solution. You can argue that the scope of out_ptr is just
> different: provide interpoperation between `init(T**)`functions and smart
> pointers. But I would argue that this latter goal is wrong. In fact, I am
> concerned that we might be encouraging a bad programming style: "need to
> work with init(T**) APIs? use shared_ptr." instead of promoting RAII
> wrappers that directly wrap the resource.

It seems to me that out_ptr is a useful tool for writing such wrapper.

class my_wrapper {
public:
   my_wrapper() {
     if (acquire_my_c_resource(out_ptr(this->p))) {
       handle_error();
     }
   }
   // No need to muck about with destructor or copy/move constructors
private:
   std::unique_ptr<my_c_resource, void (*)(my_c_resource *)>
       p{nullptr, release_my_c_resource};
}

-- 
Rainer Deyke (rainerd_at_[hidden])