Making a class friend itself - c++

Question

EDIT: It looks like I'm completely misinformed. Please close this thread. Gah.
For the record, the following compiles and works:
class ForeverAlone
{
private:
int m_friends;
HANDLE m_handle;
public:
ForeverAlone()
{
m_handle = CreateThread(NULL, 0, &ForeverAlone::SadThread, reinterpret_cast<void*>(this), 0, NULL);
}
~ForeverAlone()
{
if (m_handle != NULL)
CloseHandle(m_handle);
}
protected:
static unsigned long WINAPI SadThread(void* param)
{
ForeverAlone* thisObject = reinterpret_cast<ForeverAlone*>(param);
// is there any way for me to access:
thisObject->m_friends;
}
};
Original question: I have a static protected thread method, which I pass an object to. Can I somehow make the class friend itself so I can access its private members?

Answer 1

All class methods, static or not, are automatically "friends" of the class. Friend is used to allow external functions and classes access to a class. The class is always its own "friend".

Answer 2

Do this:
extern "c" DWORD __stdcall CInterfaceSadThread(LPVOID lpThreadParameter);
class ForeverAlone
{
private:
int m_friends;
HANDLE m_handle;
public:
ForeverAlone()
{
m_handle = CreateThread(NULL, 0,
&CInterfaceSadThread,
//
// You may get arguments about using static_cast here
// I still prefer reinterpret_cast as it makes it stick out
// Thus I check it more carefully when I see it.
// For this situation it works correctly
// As casting to void* and back to the original are guaranteed.
reinterpret_cast<void*>(this),
0, NULL);
}
~ForeverAlone()
{
if (m_handle != NULL)
CloseHandle(m_handle)
}
protected:
friend DWORD CInterfaceSadThread(LPVOID lpThreadParameter);
DWORD WINAPI SadThread()
{
// Do Stuff here
// Note: Just because you get here does not mean that the object is finished
// initializing. The parent thread may have been suspended after this
// one was created. Thus checking the state of member variables at this
// point is dangerous unless you can guarantee that construction has finished
return result;
}
};
Then in the callback just access your function;
extern "c" DWORD __stdcall CInterfaceSadThread(LPVOID lpThreadParameter)
{
// Note: You can only cast back to ForeverAlone* so be carefull
// Hence I use reinterpret_cast as this forces me to double check.
ForeverAlone* alone = reinterpret_cast<ForeverAlone*>(lpThreadParameter);
return alone->SadThread();
}