C++ Logo

SG12

Advanced search

Subject: Re: [ub] Justification for < not being a total order on pointers?
From: Lawrence Crowl (Lawrence_at_[hidden])
Date: 2013-10-10 16:32:41


On 10/10/13, Gabriel Dos Reis <gdr_at_[hidden]> wrote:
> | At this point, I think we need to ask if we really do want to support machines
> | with small segments. Does anyone know of any current such machines?
>
> That is a good question that we should consider.
>
> Another aspect to consider is that, even though this restriction
> was originally motivated by segmented architecture, it is also useful
> for other things and implementation techniques (including compacting
> GCs). One question is whether we believe we want to forgo implementations
> or implementation techniques that might profit from the current
> restriction.

Wouldn't compacting GCs fall afoul of the existing std::less problem?
I mean, we could still have an std::less that imposed a total order, but
that order might change during execution, and I could see that causing
some difficulties with unordered maps. :-)

> I think this question should be considered independently of whether we
> still want to support segmented architectures, because that may affect
> the form of the outcome.

-- 
Lawrence Crowl

SG12 list run by herb.sutter at gmail.com