std::iterator_traits provides access to five associated types -of any iterator: its value_type, reference, pointer, -iterator_category, and difference_type. Unfortunately, +of any iterator: its value_type, reference, pointer, +iterator_category, and difference_type. Unfortunately, such a "multi-valued" traits template can be difficult to use in a -metaprogramming context. <boost/iterator/iterator_traits.hpp> +metaprogramming context. <boost/iterator/iterator_traits.hpp> provides access to these types using a standard metafunctions.
Header <boost/iterator/iterator_traits.hpp>:
+Header <boost/iterator/iterator_traits.hpp>:
template <class Iterator> struct iterator_value @@ -98,21 +98,6 @@ struct iterator_category };
Because of workarounds in Boost, you may find that these -metafunctions actually work better than the facilities provided by -your compiler's standard library.
-On compilers that don't support partial specialization, such as -Microsoft Visual C++ 6.0 or 7.0, you may need to manually invoke -BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION on the -value_type of pointers that are passed to these metafunctions.
-Because of bugs in the implementation of GCC-2.9x, the name of -iterator_category is changed to iterator_category_ on that -compiler. A macro, BOOST_ITERATOR_CATEGORY, that expands to -either iterator_category or iterator_category_, as -appropriate to the platform, is provided for portability.
-