Re: [boost] [ptr_container] is Readable?

From: Thorsten Ottosen (thorsten.ottosen_at_[hidden])
Date: 2006-10-23 04:35:32

Shunsuke Sogame wrote:
> Hi,
> 
> 
> If a pointer container holds noncopyable objects,
> the iterators seem not to meet ReadableIteratorConcept
> whose 'value_type' must be CopyConstructible?

From

http://www.boost.org/libs/iterator/doc/new-iter-concepts.html#readable-iterators-lib-readable-iterators

it seems that the iterator type itself must be CC and CA. For a given 
iterator a, *a must be convertible to iterator_traits<X>::value_type 
(we'll use T for this below).

For pointer containers, this currently poses quite a problem because of 
its indirected interface: the conversion could succeed if T was defined 
as iterator_traits<X>::reference, but the ReadableIteratorConcept does 
not allow T to be a reference type.

The only thing I can come up with is that pointer container iterators 
does not satisfy the ReadableIteratorConcept, but only the 
ReadableLvalueIteratorConcept.

Does that make sense?

-Thorsten