Function Pointers in Classes

[blastingblast]

I have made class in c++ which has a function pointer.This function pointer needs to point to a function which is not a part of the class's methods i.e. a function that is in the main cpp.The address of the function to which the pointer points to is passed form the main cpp.However i am unable to get this to work i.e. i cannot store the address of the function in the function pointer as the function pointer has that additional "*this" pointer.I cannot make the function pointer static as each object 's function pointer points to a different function.Any fixes for this problem.

Program looks like this

class A
{
private:
void (*fnpointer)();

public:
void SetPointer(void (*fn)())
{
fnpointer=fn; //ERROR IS HERE.I DONT WANT TO MAKE fnpointer A STATIC FUNCTION
}
}

Main CPP

void func()
{

}

void main
{
A obj1;
obj1.SetPointer(&func);
}

[STLDude]

If you can use boost then try boost::bind.

[S_M_A]

Strange, this console app compiles and runs fine using VC2005

#include "stdafx.h"
class A
{
private:
  void (*fnpointer)();

public:
  void SetPointer(void (*fn)())
  {
    fnpointer=fn; //ERROR IS HERE.I DONT WANT TO MAKE fnpointer A STATIC FUNCTION
  }
  void Run()
  {
    fnpointer();
  }
};
void func()
{
  printf( "Hello\n" );
}
int _tmain(int argc, _TCHAR* argv[])
{
  A obj1;
  obj1.SetPointer(func);
  obj1.Run();
  return 0;
}

Are you using an older version of VC?

[spoon!]

i cannot store the address of the function in the function pointer as the function pointer has that additional "*this" pointer.

No, that makes no sense. The function pointer is declared in that code as a regular function pointer, not as a pointer to member function. Either your compiler is really messed up or you are not posting the real code.

[blastingblast]

Thanks for the replies.Yeah I managed to solve the problem. As the real program was a bit long I posted a short skeleton of the program.My mistake was that i was doing something not required by trying to make the pointer point to a member function.I managed to fix this now.THANKS AGAIN.