Hello, A while back, I proposed a template metafunction called 'is_iterator', but the consensus seemed to be that it was not feasible from an implementation standpoint. At Jonathan Turkanis' suggestion, I went ahead and implemented the less ambitions 'is_dereferenceable', along with two other metafunctions: Requirements: Given t of type T &, if the expression *t is not well-formed, then it must neither be ambiguous nor violate access. Description: is_lvalue_dereferenceable<T> - true if *t is well-formed and an lvalue is_value_dereferenceable<T> - true if *t is well-formed and non-void is_dereferenceable<T> - true if *t is well-formed I would like to offer these up for inclusion in boost, whether in namespace boost or in boost::detail. (presumably the latter, since that's where the similar 'is_incrementable' is found). I have posted the source for these metafunctions along with a unit test in the YahooGroups Files section in a folder called 'is_dereferenceable'. Please let me know if these are of interest to anyone. Alex Chovanec