Re: [boost] [block_ptr] Request for a review manager

Subject: Re: [boost] [block_ptr] Request for a review manager
From: Bjorn Reese (breese_at_[hidden])
Date: 2016-02-07 07:59:46

On 02/06/2016 10:05 PM, Phil Bouchard wrote:

> But it's like comparing apples with oranges because shared_ptr is a
> smart pointer and block_ptr really is a memory manager there to replace
> the garbage collector.

The documentation is doing that apples and oranges comparison when it
claims that the performance of block_ptr "is comparable to shared_ptr".
Furthermore, that claim is questionable as the benchmarks show that
block_ptr is slower by several factors. If the benchmarks are unfair,
then you should design better ones.

The presentation claims "Constant complexity O(1) for all operations".
Looking at the code I can see several loops (e.g. release() or redir()
in block_header) so destruction does not appear to be constant.

I also have an unrelated comment about the documentation: the Reference
section is very confusing. It lists lots of detail functions rather
than the public API.

> Unless the counter is intrusive but that's the thing because block_ptr
> abstracts all of this and it is much less confusing to the end
> developer.  And I'm not sure how intrusive counters can deal with
> multiple / virtual inheritance.

Which intrusive counter are you talking about? Are you thinking of
intrusive_ptr<T>?