I've been thinking about this issue and wonder if the following wouldn't solve the problem neatly for both conforming and non-conforming compilers: // whatever/foo.h namespace whatever { class foo { ... }; // for conforming compilers unspecified begin(foo const &) { ... }; ... } // for non-conforming compilers namespace boost { namespace range { using whatever::begin; } } // boost/range/begin.hpp namespace boost { inline template <T> unspecified begin(T const & range_i) { using boost::range::begin; return begin(range_i); } } If the author of foo has no other need for begin(), then whatever/foo.h could be done like this instead: // whatever/foo.h namespace whatever { class foo { ... }; } namespace boost { namespace range { unspecified begin(foo const &) { ... }; } } If whatever::foo belongs to a user of Boost.Range that only uses conforming compilers, then foo.h only needs to be: // whatever/foo.h namespace whatever { class foo { ... }; unspecified begin(foo const &) { ... }; ... } If whatever::foo provides get_begin() instead, for whatever reason, then foo.h becomes: // whatever/foo.h namespace whatever { class foo { ... }; unspecified get_begin(foo const &) { ... }; ... } namespace boost { namespace range { inline unspecified begin(foo const & foo_i) { return get_begin(foo_i); } } } This approach provides a number of benefits: - we can use the most obvious name, boost::range::begin, for the point of customization - benefits from ADL when supported - Types in namespace std or built-in types (pointers) can be retrofitted in boost::range and will work like everything else (though you must include the appropriate header to get the required boost::range::begin() overload) - flexibility for those wishing to support Boost.Range - non-conformance code can be excised easily later Did I miss something? -- Rob Stewart stewart@sig.com Software Engineer http://www.sig.com Susquehanna International Group, LLP using std::disclaimer;