Re: [boost] [xint] Third release is ready, requesting preliminary review

Subject: Re: [boost] [xint] Third release is ready, requesting preliminary review
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-05-03 07:34:02

DE wrote:
> on 02.05.2010 at 20:05
>  vicente.botet wrote :
>
> > Why do you say on Boost.Move is not  as fast as COW?
>
> for example if you make 10 copies of an object
>
> cow (or implict sharing) aware objects will share only one
> representation among all instances, i.e. there is only one allocation,
> initialization and no copy processes at all
>
> in this circumstances move enabled objects would not act as efficient
> supposing none of that ten copies are temporary you get ten "deep"
> copies of the first object
> this involves ten allocations, initializations and costs associated
> with them

PMFJI, but the point of move semantics is to avoid copying, not to make it faster.  If Using COW is faster than move semantics, that means there are copies being made.  If move semantics were applied with the expectation of reducing copies where they weren't really needed, from rvalues, then perhaps Boost.Move has been misapplied.

_____
Rob Stewart                           robert.stewart_at_[hidden]
Software Engineer, Core Software      using std::disclaimer;
Susquehanna International Group, LLP  http://www.sig.com

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