Re: [Boost-users] Adding constness to an iterator

on Wed Jan 21 2009, er wrote:

Hello,

I'm looking to define AddConst to be used as below:

template<typename BaseIter> class my_iter : public iterator_adaptor< my_iter, AddConst<BaseIter>::type>{ //... };

There's always boost::add_const in the TypeTraits library, but...

I guess add_const is not the same as range_iterator::type, otherwise I could just take AddConst = add_const.

...exactly, and that's going to be a problem for my_iter because AddConst<BaseIter>::type only makes BaseIter itself non-const (e.g. can't increment) which surely isn't what you meant. Unfortunately, in general, there's no relationship between an iterator and an associated constant iterator. I suggest you build the constant iterator adaptor on the mutable BaseIter type if that's what the user hands you. -- Dave Abrahams BoostPro Computing http://www.boostpro.com