[boost] Re: String Algo bug.

From: David Abrahams (dave_at_[hidden])
Date: 2004-07-18 17:50:06

Stefan Slapeta <stefan_nospam__at_[hidden]> writes:

> Stefan Slapeta wrote:
>
> I think I just wrote down the logic reason for the bug:
>
>> I'm not sure if I understand correctly what you mean, but the
>> default constructed iterator is inteded to represent the
>> past-the-end value.
>> 
>
> When two iterators are compared, STLPort (in debug mode) checks if
> they have the same 'owner'. Of course, this owner can never be set for
> an iterator which behaves like above.

If STLPort is complaining about that, it's because what you're doing
is illegal.  A default constructed standard container iterator is
"singular", and no operations on it (including comparison) are legal
other than assigning a non-singular iterator value into it.  Although
a few specialized iterators in std:: work differently
(e.g. istream_iterator), in general you have to make the same
assumption for any other iterator.

> Any solution which doesn't break the syntax? I don't have any idea
> which could be implemented easily...

Post some more detail about what you mean by "the syntax" please.

-- 
Dave Abrahams
Boost Consulting
http://www.boost-consulting.com