Hello all, I'm not sure if this is possible at all, but let me explain: I have the following function signature: typedef int (*sasl_callback_ft)(void); That function in question gets called with unknown amount of parameters (usually 3 or 4) Now I want to assign a member function to it: class admin { public: int callback_fun(void *context, int id, const char **result, unsigned *len); } boost::function<int(void *, int, const char **, unsigned *)> callback = boost::bind(&admin::callback_fun, this, _1, _2, _3, _4); Obviously the compiler doesn't allow to assign callback to a sasl_callback_ft var sasl_callback_ft fun = callback; I get compiler errors like: matthijs@hammer:~/t2$ clang++ -o main -std=c++11 main.cpp main.cpp:22:19: error: no viable conversion from 'boost::function<int (void *, int, const char **, unsigned int *)>' to 'sasl_callback_ft' (aka 'int (*)()') sasl_callback_ft cbfun = cb; ^ ~~ /usr/include/boost/function/function_template.hpp:894:5: note: candidate function operator safe_bool () const ^ 1 error generated. Attached the testcase I made for this. Regards, Matthijs