Hi Daniel & all, I'm updating the patch for ticket 7753 ( https://svn.boost.org/trac/boost/ticket/7753). I've made the requested changes to the patch, but I had a question on how to best explain which macro to define if, for example, you want result_of to work with C++11 lambdas. In the past, users with a pre-N3276 decltype have been advised to just #define BOOST_RESULT_OF_USE_DECLTYPE, with the explanation that "it's probably just going to work." While that advice is true, there are cases where this doesn't work; hence the addition of BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK. To explain why you'd define the FALLBACK macro over the USE_DECLTYPE macro, I'm thinking of including a paragraph like the following. "The question naturally arises on why have both BOOST_RESULT_OF_USE_DECLTYPE and BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK. In many situations, BOOST_RESULT_OF_USE_DECLTYPE will work well, even with pre-N3276 decltype. However, there are cases where a post-N3276 decltype is required to correctly deduce the return type of a functor. If a translation unit includes a functor whose return type is only deducible with TR1 or a post-N3276 decltype, using result_of with, e.g. a C++11 lambda function, will fail without BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK. If the macro BOOST_NO_CXX11_DECLTYPE_N3276 is defined and BOOST_NO_CXX11_DECLTYPE is not defined when including result_of.hpp, defining BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK is the safest option that will allow you to deduce C++11 lambda return types." My question is, am I over explaining it? Of course, I'd rather have BOOST_RESULT_OF_USE_TR1_WITH_DECLTYPE_FALLBACK defined automatically for compilers like VC10, g++4.5, etc., and include text like the following: "If you rely on the result of calling a nullary functor to be void, regardless of the actual return type, or if your code is not written to handle cases other than BOOST_RESULT_OF_USE_TR1 and BOOST_RESULT_OF_USE_DECLTYPE, you may wish to explicitly define one of those symbols prior to including result_of." Either way, comments welcome. Thanks, Nate