Re: [boost] [shared_ptr] Why operator< uses internal_less?

Subject: Re: [boost] [shared_ptr] Why operator< uses internal_less?
From: Frank Mori Hess (frank.hess_at_[hidden])
Date: 2008-10-09 11:50:11

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On Thursday 09 October 2008 11:32 am, Sebastian Redl wrote:
> dariomt_at_[hidden] wrote:
> > I see that operator== and operator!= are implemented comparing the
> > pointer inside the shared_ptr's using get(), but operator< uses
> > _internal_less, that does a different thing.
> >
> > I thought that operator< would also be implemented using get(), so
> > please, can you share the rationale behind the need for _internal_less?
>
> get() returns px (the raw pointer), _internal_less compares pn (the
> shared_count).
>
> This is peculiar, since it means that alias pointers to different
> subobjects would compare non-equal, but sort equivalent. I'd like to
> know the rationale of this, too.

There is a rationale in n1590.
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