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Subject: Re: [Boost-users] A forward iterator need not be default-constructible
From: Dave Abrahams (dave_at_[hidden])
Date: 2011-09-30 11:23:28

on Fri Sep 30 2011, Krzysztof Żelechowski <> wrote:

> Dave Abrahams wrote:
>> make it copyable, for example. A wrapper over a plain pointer could
>> initialize the pointer to 0. Now it's a valid past-the-end iterator
>> into an array of length zero. Such an iterator is also comparable with
>> other iterators into the same sequence. That's actually far from
>> being minimally singular.
> I doubt there may be a sequence of length 0 at NULL. How would you allocate
> such a sequence?

It already exists.

   char* p = 0;
   p == p; // defined behavior
   p - p; // defined behavior
   p + 0; // defined behavior

Dave Abrahams
BoostPro Computing

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