Re: [boost] Pimpl Again?

Subject: Re: [boost] Pimpl Again?
From: dariomt (dariomt_at_[hidden])
Date: 2016-06-01 04:29:22

Peter Dimov <lists <at> pdimov.com> writes:
> Howard Hinnant wrote:
> > It has to be outlined, in the source.cpp:
> >
> >     class Book
> >     {
> >         struct implementation;
> >         std::unique_ptr<implementation> impl_;
> >     public:
> >         ~Book();
> >         Book();
> >     };
> 
> You could probably do
> 
> // hpp
> class Book
> {
>     struct implementation;
>     std::unique_ptr<implementation, void(*)(implementation*)> impl_;
> public:
>     Book();
> };
> 
> // cpp
> Book::Book(): impl_( new implementation, 
checked_delete<implementation> ) {}
> 

Sorry if this is a silly question, but wouldn't this double the size of 
member variable impl_ (two pointers), just to save some typing?

To me it doesn't look like a good tradeoff.

I'm quietly following this thread, and I still don't get why 
std::unique_ptr is not good enough for heap-allocated pimpl.