A while back, in various threads more or less related to the topic, I posted various ideas and/or code contributions to the effect of improving boost::function in terms of efficiency (concentrated on invocation speed, assignement performance/overhead and reducing template and RTTI bloat) and configurability, however there was no "official response" as to whether it was any good, or whether any of it would be accepted or what's wrong with it if not. IMHO the results { - 'Speed': the test presented here http://marc.info/?l=boost&m=118835709647084&w=2 modified to work with boost::signals2 (because it is a header only library/does not require a recompilation of boost if something in boost::function changes) with the dummy mutex/no threading support and a simple recompilation with the new boost::function<> code yielded a ~10% boost, changing the default policy to be nothrow the boost doubled to ~20% - 'Size': my real life project, that uses heavy metaprograming for generating function objects (that as a consequence have _very_ long type names, and thus RTTI records) to assign to boost::functions shrunk by ~10% simply by using the modified boost::function (with RTTI features disabled)...This post http://lists.boost.org/Archives/boost/2009/12/160202.php has more detailed and updated results when my project grew further (with an even bigger difference) } show/hint that there is room for improvement in boost::function and therefor warrant atleast some kind of response (even if along the lines of 'it's no good' or 'there is no time for this now')...which is the reason for (re)posting this (in a separate thread). The relevant threads with more detail are these: http://thread.gmane.org/gmane.comp.lib.boost.devel/196906 http://thread.gmane.org/gmane.comp.lib.boost.devel/194514/focus=195351 since then I've moved the modified code from the vault into the sandbox SVN (under the obvious name "function" :) -- "That men do not learn very much from the lessons of history is the most important of all the lessons of history." Aldous Huxley