Re: Rewriting clone() to return a boost::shared_ptr ?

From:
David Abrahams <dave@boost-consulting.com>
Newsgroups:
comp.lang.c++.moderated
Date:
19 May 2006 23:32:15 -0400
Message-ID:
<uwtci4u2f.fsf@boost-consulting.com>
"helix" <andrew.j.line@gmail.com> writes:

I can see how changing clone() to use smart pointers would violate the
usual standard conventions, as well as causing confusion to other
developers. Would you be happier if I provided two clone functions,
one
which returns a standard pointer and another which returns a smart
pointer?

As for auto_ptr, I generally stay well away as I can't store them in
STL containers.


But you can convert them to shared_ptr. When you're just transferring
ownership (but not across DLL boundaries) and you don't necessarily
know what the receiver wants to do with the pointer, auto_ptr is
usually a better choice. It's cheaper and it lets you interact with
code that might expect to take ownership of a raw pointer. Once you
give ownership to a shared_ptr, you can never get it back.

IMHO this single fact renders it impractical in the real world -
especially when you have boost's superior smart pointers available
to you. I have to confess that I rarely use raw pointers any more,
relying almost entirely on boost's smart pointers.


Boost's smart pointers are indeed great, but (for the most part) it's
not a matter of being superior to auto_ptr: they have different
purposes and characteristics. The Boost smart pointer designs
explicitly acknowledge the role of auto_ptr by including converting
constructors.

--
Dave Abrahams
Boost Consulting
www.boost-consulting.com

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