Re: Two questions about using shared_ptr

From:

"Igor Tandetnik" <itandetnik@mvps.org>

Newsgroups:

microsoft.public.vc.language

Date:

Fri, 21 Nov 2008 07:56:50 -0500

Message-ID:

<uYuJii9SJHA.1484@TK2MSFTNGP03.phx.gbl>

"Hendrik Schober" <Spamtrap@gmx.de> wrote in message
news:%23a9gx%236SJHA.5900@TK2MSFTNGP05.phx.gbl

Igor Tandetnik wrote:

"CppBoy" <aert_fudan@online.hotmail.com> wrote in message
news:F4E8DD51-06EB-4286-A9F2-27722FF3F331@microsoft.com
[...]

2. To ensure good interface as recommended by Scott Meyers in
Effective C++, I normally wrote the function interface as:
void f(shared_ptr<T> pObj);

I would only do this if f() is supposed to take ownership of the
object. Otherwise I'd just take raw pointer.

With 'shared_ptr' you have shared ownership. I'm not sure
how to apply your statement.

Let's put it this way: taking shared_ptr as a parameter indicates that
the function wants to store the pointer somewhere to be used after it
returns, thus sharing ownership with the caller. Of course the caller is
free to drop its reference right after the function call, thus
effectively transferring ownership to whatever entity the called
function works on behalf of.
--
With best wishes,
Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925