Re: CoW and reference counting in the STL

From:
red floyd <redfloyd@gmail.com>
Newsgroups:
comp.lang.c++.moderated
Date:
Thu, 15 Apr 2010 16:33:39 CST
Message-ID:
<de47924f-12f3-428d-b53a-05ae991076b9@w24g2000vbw.googlegroups.com>
On Apr 14, 4:38 pm, Daniel Kr?gler <daniel.krueg...@googlemail.com>
wrote:

On 14 Apr., 20:44, s5n <sgb...@googlemail.com> wrote:

My question might be slightly off-topic, as it is specific to the STL
(and in fact specific to implementation-defined features), but this is
the best place i know to ask...


The question is not off-topic at all.

std::string typically uses reference counting and CoW to reduce real
allocations to a minimum. i understand that this is an implementation-
defined detail, not standardized, but in my experience STL
implementations do this.


Yes, this is a valid implementation technique for C++03,
but no longer valid for C++0x. Todays implementations often
take advantage of the small-string optimization, though.


Why is CoW no longer valid for C++0x? Is it due to move semantics?

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