This is a request to have FunctionTypes extended to work with Boost.Function. According the current documentation, it does not handle the latter. Rationale: I have a template parameter that can be either a function type or a boost::function, and I would like a uniform method to decompose their signature and return type. Note: an alternative does exist where one to specialize on boost::function and carry out around its underlying signature, but that's just an annoying hassle, and, more importantly, it doesn't work if old style syntax for boost::function is used. Thanks, Mostafa