Re: [boost] [shifted_ptr] Documentation

Subject: Re: [boost] [shifted_ptr] Documentation
From: Peter Dimov (pdimov_at_[hidden])
Date: 2011-04-09 06:48:04

Phil Bouchard wrote:
> And an overview is available here:
> http://www.fornux.com/personal/philippe/devel/shifted_ptr/libs/smart_ptr/doc/overview.html
>
> Please let me know if anything isn't clear enough.

It's not clear how shifted_ptr detects cyclic blocks of memory with no 
coding overhead. The methods with which I'm familiar require (a) the ability 
to enumerate all pointer subobjects in an object and (b) the ability to zero 
these pointers so as to break the cycles. Without some sort of registry that 
tracks all pointer instances (overhead on construction/destruction) (a) 
requires cooperation from the pointee, which shifted_ptr does not seem to 
demand.

It's also not clear how cyclic structures are detected immediately. Doing 
this typically either requires a scan (collection cycle) on every pointer 
destruction, or some sort of housekeeping on each construction and copy.

It is also not clear how well does the cyclic collector work when, in 
parallel, other threads create and destroy references to the objects being 
currently scanned.