C++ Help (Hooking a function)

[LaDidi]

If I understand, you want to hook the call of Check_Registration done by another ?
Check_Registration use a function pointer to a callback_function. So, inside its body, you have a call like : Callback_NotifyOnline ( , );

If this API is in a DLL (like its_SDK.dll) and if you want to hook this call :
1. you need to export the same API in your library (my_SDK.DLL) with the same protoype
2. call the old API inside your API (export OR LoadLibrary, GetProcAddress)
3. rename my_SDK to its_SDK and its_SDD to Original_SDK

If this API isn't in a DLL ie resolved by compiler, you have the source so you can do anything !

Yea like that, but i already have hooked Check_Registration, and inside the sdk they can use like you said: Callback_NotifyOnline();

now i want to hook also Callback_NotifyOnline();, but looking thru the sdk, its not defined nowhere except in the routine its self here:

void Check_Registration (
int Registered,
int Licenses,
int LicenseType,
int ChkSum,
int RESERVEDA,
int ( *Callback_CheckDate )( DATE *pDATE ),
void ( *Callback_NotifyOnline)( DATE *pDate, int ChkSum )  // Only time its defined. ) 
{

}

Thanks for all the help

Is the function exported? If not you may have to find the address your self, by searching for certain fragments or memory or using the exact address/offset of it (how ever this can fail if the file gets changed)