Boost logo

Boost :

Subject: Re: [boost] [smart_ptr] shared_ptr template type
From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2009-07-15 09:54:23

Hash: SHA1

On Tuesday 14 July 2009, Zachary Turner wrote:
> If traits are going
> to be supported at all, I think they should be supported first-class,
> and allow one to just parameterize the class with a traits class to
> begin with.

> template<class T, class Traits=default_smart_pointer_traits<T> > class
> generic_shared
> {
> };

I don't intend to add additional template parameters to generic_shared. I
like shared_ptr, and plan to stay as close to the shared_ptr design as
possible. If you want to go the route of high configurability and multiple
template parameters, it would probably be better to start from the design of
Loki::SmartPtr than boost::shared_ptr.

My only goal is to make an incremental deviation that adds support for more
than just plain old pointers as the wrapped pointer type. Incidental to that
is defining some concepts that will allow conforming smart pointer classes to
use each other as their underlying pointer type. Other than that, I plan to
ape the shared_ptr interface as closely as possible. It may be that I just
alienate both camps, with the "simplicity" people ignoring it as too complex
and the "configurability" people wanting more, but that's the road I'm on.

The traits stuff in generic_shared is only intended to communicate the
necessary information about a pointer-like class to generic_shared, not to
provide a customization point for the wrapped type. Such customization would
belong in the template parameter list of the wrapped class (the T in
generic_shared<T>) anyways, not the class wrapping it. And if it were really
absolutely necessary, the customization could be inserted as a wrapper class
in between generic_shared and T, like

generic_shared<my_customization_wrapper<T, mypolicy> >
Version: GnuPG v1.4.9 (GNU/Linux)


Boost list run by bdawes at, gregod at, cpdaniel at, john at