C++ template design with function pointers -

im bit new c++, please let me describe problem. have class called csubcriber, main purpose execute callback function, of type , number of arguments. example callbacks can be:

typedef void (*cb1)(void) typedef int (*cb2)(int, int) typedef char (*cb3)(int, int, void); 

class is:

template <class callbacktype>  class csubscriber { public:     csubscriber();     virtual ~csubscriber();     callbacktype (*m_callback_newway)(void *params);     void (*m_callback)(void *params);     int (*m_callback_int)(void *params);     void *m_cb_params;     int execute_cb();     void *m_params;      csubscriber(void (*callback)(void *params), void *cb_params);     csubscriber(int (*callback)(void *params), void *cb_params);  };  csubscriber::csubscriber(void (*callback)(void *params), void *cb_params){     m_callback = callback;     m_cb_params = cb_params; }  csubscriber::csubscriber(int (*callback)(void *params), void *cb_params){     m_callback_int = callback;     m_cb_params = cb_params; } 

my main problem now, how write constructor, handle variable arguments callback. after constructing object in particular moment, callback may fired, example:

typedef int (*callback)(void *params); csubscriber s(callback, params); 

or

typedef void (*callback2)(void *params, int arr, char *ptr); csubscriber s(callback, params, arr, ptr); 

now, calling

s->m_callback() 

i want execute callback arguments passed constructor. i'd avoid writing ten different constructors, each different number of arguments passed callback function. possible ?

try this.

#include <iostream>  using namespace std;  typedef void (*cb1)(void); typedef int (*cb2)(int, int); typedef char (*cb3)(int, int, char);  template <class callbacktype> class csubscriber { public:     csubscriber(): fcn1(0), fcn2(0), fcn3(0) {};     virtual ~csubscriber(){};      csubscriber(cb1 fcn): fcn1(fcn), fcn2(0), fcn3(0), a(), b() {};     csubscriber(cb2 fcn, int p1, int p2): fcn1(0), fcn2(fcn), fcn3(0), a(p1), b(p2)  {};      int execute_cb() {         if ( fcn1 != 0 ) {             (*fcn1)();         }         if ( fcn2 != 0 ) {             (*fcn2)(a,b);         }     };  protected:     cb1  fcn1;     cb2  fcn2;     cb3  fcn3;      int a, b; };  void fcn1() {     cout << "in fcn1" << endl; };  int fcn2(int a, int b) {     cout << "in fcn2, " << << ", b " << b << endl; };  int main() {     csubscriber<int> cs;     csubscriber<int> cs1(&fcn1);     csubscriber<int> cs2(&fcn2, 1, 100);      cs.execute_cb();     cs1.execute_cb();     cs2.execute_cb();  }