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Subject: Re: [boost] [iterator] reverse_iterator<counting_iterator<T>>
From: Stewart, Robert (Robert.Stewart_at_[hidden])
Date: 2010-04-13 06:49:16

Arno Schödl wrote:
> boost::reverse_iterator::dereference() is
> typename super_t::reference dereference() const { return
> *boost::prior(this->base()); }
> boost::constant_iterator<T>::reference_type is T const&.
> So reverse_iterator< constant_iterator<T> >::dereference
> returns a reference to a temporary variable. Not good.

this->base() calls iterator_adaptor<>::base(), which returns a reference to the underlying iterator it holds. Passing that reference to boost::prior() means that prior() pre-decrements the iterator within the iterator_adaptor. It would be odd for that decrement operator to return anything but a reference to the decremented object, so boost::prior() returns a reference to its decremented argument, a reference to the decremented iterator within the iterator_adaptor.

I see no problem.

Rob Stewart robert.stewart_at_[hidden]
Software Engineer, Core Software using std::disclaimer;
Susquehanna International Group, LLP

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