Question

I have a function that resides in a class in an application my objective is to inject a dll into the target proccess and call that member function by its address.
Here is the function:

void GameAudio::StopAllSounds(void) // this is at address 0x004A0656

I have tried calling it like this

typedef void(__stdcall * caller)(void);
caller call = (caller)0x004A0656;

I have used everything: __stdcall , __cdecl, __thiscall you name it.

Answer 1

Class’s non-static member function signature is different than the normal function.
For example,

class X {
public:
  void foo ();
};
void foo ();

In above case X::foo() and ::foo() are different from each other. Remember that, X::foo() under the hood is somewaht like:

void X::foo (X* const this);
             ^^^^^ implicitly added

Thus what you are attempting to do would result in an undefined behavior.

If you insists to call the member function using its address, then better to make it a static member function.

class X {
public:
  static void foo ();
};
void foo ();

Signature for X::foo() and ::foo() are same.

Edit: From your comment, it seems that you don’t have the control over the source code. I would suggest to use the proper calling convention for the function signature instead of hard coded address. Pseudo code

typedef void (GameAudio::*caller_type)();
caller_type caller = &GameAudio::StopAllSounds;
GameAudio object;
(object.*caller)();