One of the drawbacks of using functors with Boost.Bind is that the result type of the functor must be specified either as a typedef inside the functor's definition or as a template argument when building the binding. As the documentation states it: "In the general case, the return type of the generated function object's operator() has to be specified explicitly (without a typeof operator the return type cannot be inferred)" It seems that result_of() would be a good implementation of the "typeof" operator referenced in the above, instead of relying upon a single result_type typedef inside the functor struct/class. This would allow the use of functors whose result type depends upon the arguments passed to the functor. It looks like there was a proof-of-concept patch submitted for this a couple years ago: https://svn.boost.org/trac/boost/ticket/4542 It doesn't appear to have received any attention, however. Is this something that might happen? -- View this message in context: http://boost.2283326.n4.nabble.com/bind-Request-use-result-of-instead-of-res... Sent from the Boost - Dev mailing list archive at Nabble.com.