Re: [boost] Proposal to add smart_ptr to the boost library

From: David Maisonave (boost_at_[hidden])
Date: 2006-01-29 19:15:11

"Larry Evans" <cppljevans_at_[hidden]> wrote in message
news:<drafuf$v06$1_at_[hidden]>...

> On 01/24/2006 09:45 AM, David Maisonave wrote:

> > Since the current smart_ptr (policy_ptr) class at boost vault is on 

> > hold, I like to propose adding the following smart_ptr class to the 

> > boost library:

> > http://code.axter.com/smart_ptr.h

> Could you eliminate the tabs and reformat to something like 75 or 80 

> columns to ease reading.  An example is in 

> http://boost-consulting.com/vault/Memory.  Also, boost convention is 

> .hpp (or hxx or something like that) extension instead of .h.

 

I didn't get a chance to see the above link.

I'll try to cut it down to 100 columns.  I find 80 to be too limiting, and
most developers now days have access to editors with wider column view.

On my editor, the 80 column point actually is in the center of my screen.

 

> > 

> > IMHO, the above class has more functional features, than the class 

> > in

> 

> I notice policy_ptr has a weak_ptr class.  Does axter smart_ptr has 

> something similar to handle cycles in pointer graph?

No.  Currently it does not support weak_ptr, although it does support
(pointee) comparison

Semantics like weak_ptr.  It does not support any other weak_ptr specific
feature.

 

> > the boost vault, and the class is ready for use.

> 

> I've compiled and run the policy_ptr tests with g++.

 

Do you have any example code?

I like to see some usage example for policy_ptr.  Just looking at the
policy_ptr code is very confusing, and it is hard to tell how to use it.

 

> > In my performance test, the shared and COW policies along with 

> > reference-link policy, are able to out perform the 

> > boost::shared_ptr.

> 

> Could this be due to shared_ptr having two refcounts and smart_ptr 

> having just one?

 

No.  In general, reference-link is able to out perform reference-count
logic.  Smart_ptr has a policy for both methods, where-as shared_ptr only
does reference-count.