oldstyle

#include <boost/preprocessor/repetition/repeat.hpp>
#include <boost/preprocessor/repetition/enum_params.hpp>
#include <boost/preprocessor/repetition/enum_binary_params.hpp>
#include <boost/preprocessor/repetition/enum_trailing_params.hpp>

#include <iostream>


#ifdef __GNUC__
# define MACRO_THREAD_LOCAL __thread
#elif _MSC_VER
# define MACRO_THREAD_LOCAL __declspec(thread)
#else
# error No idea how you use TLS on other compilers.
#endif


#define MACRO_CREATE_CALLBACK_STRUCT(z, n, data) \
template<typename ObjT, typename R BOOST_PP_ENUM_TRAILING_PARAMS(n, typename ArgT)> \
class Callback ## n \
{ \
public: \
    typedef R (*CallbackFunc)(BOOST_PP_ENUM_PARAMS(n, ArgT)); \
 \
private: \
    static MACRO_THREAD_LOCAL ObjT const* obj; \
 \
    static R theCallbackFunc(BOOST_PP_ENUM_BINARY_PARAMS(n, ArgT, arg)) \
    { \
        if(obj) \
        { \
            (*obj)(BOOST_PP_ENUM_PARAMS(n, arg)); \
        } \
    } \
public: \
    static CallbackFunc use(ObjT const& o) \
    { \
        obj = &o; \
        return &theCallbackFunc; \
    } \
}; \
 \
template<typename ObjT, typename R BOOST_PP_ENUM_TRAILING_PARAMS(n, typename ArgT)> \
MACRO_THREAD_LOCAL ObjT const* Callback ## n<ObjT, R BOOST_PP_ENUM_TRAILING_PARAMS(n, ArgT)>::obj = 0; \
 \
template<typename R BOOST_PP_ENUM_TRAILING_PARAMS(n, typename ArgT), typename ObjT> \
typename Callback ## n<ObjT, R BOOST_PP_ENUM_TRAILING_PARAMS(n, ArgT)>::CallbackFunc \
useCCallback ## n(ObjT const& obj) \
{ \
    return Callback ## n<ObjT, R BOOST_PP_ENUM_TRAILING_PARAMS(n, ArgT)>::use(obj); \
} \


#define MACRO_CREATE_C_CALLBACK_HELPER(n) BOOST_PP_REPEAT(n, MACRO_CREATE_CALLBACK_STRUCT, )


// Create callback helper for up to 9 parameters.
MACRO_CREATE_C_CALLBACK_HELPER(10)


typedef void (*CallbackPtr)(char const*);

void cFunction(CallbackPtr ptr)
{
    ptr("Hello!");
}


struct Output
{
    char const* user;

    void operator ()(char const* message) const
    {
        std::cout << user << ": " << message << std::endl;
    }
};


int main()
{
    Output output = { "KFS1_GOD" };
    cFunction(useCCallback1<void, char const*>(output));

    return 0;
}