[boost] Re: potential problem with indirect_iterator (GCC 3.3.2)

From: David Abrahams (dave_at_[hidden])
Date: 2004-03-02 09:23:36

Tom Widmer <tom_usenet_at_[hidden]> writes:

>>If I'm misusing the code, is there some reason for this?  It's
>>inconvenient that the default constructor doesn't initialize pointers
>>to some consistent value; the problem goes away when I change the
>>indirect_iterator default constructor:
>>
>>    94c94,96
>>    <       indirect_iterator() {}
>>    ---
>>    >       indirect_iterator()
>>    >         : super_t( Iterator() )
>>    >       {}
>
> That gives you a false sense of safety. Default initializing many
> iterator types is a no-op - they are still unusable (e.g.
> std::list::iterator).

or, in the same way, int*.

Tom's right.  You don't have a right to expect very much from a
default-constructed iterator.  You can't even copy it without inducing
undefined behavior.

-- 
Dave Abrahams
Boost Consulting
www.boost-consulting.com