Re: [boost] Pimpl Again?

Subject: Re: [boost] Pimpl Again?
From: Emil Dotchevski (emildotchevski_at_[hidden])
Date: 2016-05-29 22:36:24

My 2c:

In foo.h, instead of

class foo
{
  class pimpl
  pimpl * p_;
public:
  foo();
  ~foo();
  void do_something();
};

It's better to do it the C way: simply leave foo incomplete:

struct foo;
foo * create_foo();
void destroy_foo( foo * );
void do_something( foo * );

The above is much improved using shared_ptr:

struct foo;
shared_ptr<foo> create_foo();
void do_something( foo * );

Emil

On Fri, May 27, 2016 at 10:41 PM, Vladimir Batov <
Vladimir.Batov_at_[hidden]> wrote:

> Don't laugh but it is only fairly recently at work that I managed to move
> all our supported platforms to C++11. So, then, I started moving our code
> to C++11 (what a delight!) and stumbled upon my old pimpl which is used
> quite a bit around my workplace for all its good properties... :-)
>
> Now C++11-ed piml turned out to be very small and very basic. So basic it
> felt it did not have the right to exist. Still, it encapsulates and
> enforces the "proper" pimpl properties and behavior, reduces implementation
> minutia and offers a recognizable deployment pattern (helps other people
> reading the code).
>
> Over the years IMO the technique has been proven as legitimate and useful,
> a basic but important building block... rather than a curiosity item.
> Unfortunately, despite many articles and a few Sutter's GotWs about it
> there is nothing ready-to-go like std::unique_ptr.
>
> I feel that pimpl and its deployment pattern need to be codified,
> described, "standardized" and in our toolboxes to stop/avoid everyone
> re-inventing the pimpl and making the same mistakes. IMO Boost is best
> positioned for that.
>
> Do you think we might review what I've got and/or maybe collectively come
> up with something better... It's no MPL or Hana but as std::unique_ptr it's
> one of the first "little things" I personally reach out for in my everyday
> work. IMO having pimpl in Boost would save quite a few hours of frustration
> for many.
>
> Thoughts? No pressure. I am easy either way. :-)