Re: [boost] [concept_check] Should OutputIterator check for output_iterator_tag?

Subject: Re: [boost] [concept_check] Should OutputIterator check for output_iterator_tag?
From: Dave Abrahams (dave_at_[hidden])
Date: 2012-01-10 04:09:46

on Mon Jan 09 2012, Ronald Garcia <rxg-AT-cs.cmu.edu> wrote:

> Hello,
>
> In tracking down a problem with Boost.MultiArray, I'd like to write a
> test case that exhibits the failure.  Specifically, certain iterators
> should be models of OutputIterator, and it's my impression that an
> output iterator needs to have an iterator_category that's convertible
> to output_iterator_tag().  However, it looks like the OutputIterator
> Concept checker in the concept checker library does not check that the
> output iterator has such an iterator_category.  Is that an oversight,
> or is it not the case that an output iterator have a category that's
> convertible to output_iterator_tag?  It looks like InputIterator,
> RandomAccessIterator concept checkers perform such a check.

All I can tell you is that I tried not to change the meaning of the
existing checker for OutputIterator... so technically you'll have to ask
Jeremy ;-)

Come to think of it, since random_access_iterator_tag is not convertible
to output_iterator_tag, and char* is definitely an OutputIterator, I
don't think you can make that requirement.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com