[Boost-users] Re: About indirect_iterator

From: David Abrahams (dave_at_[hidden])
Date: 2005-01-10 09:12:33

Jens Theisen wrote:
> Hello,
> 
> I want to use indirect_iterator and noticed that it subscript operator 
> returns a proxy.
> 
> I found the following explanation in iterator_facade.h:
> 
>      // A proxy return type for operator[], needed to deal with
>      // iterators that may invalidate referents upon destruction.
>      // Consider the temporary iterator in *(a + n)
> 
> But I still don't understand why a proxy is necessary in some cases.

http://www.boost.org/libs/iterator/doc/iterator_facade.html#operator

explains all.

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