CBTProc not working

[S van Leent]

I'm experimenting with hooking, but when I do the following:

hWndsHook = SetWindowsHookEx(WH_CBT, (HOOKPROC)CBTProc, NULL, NULL);

I expect it to run:

LRESULT CALLBACK CBTProc(int nCode, WPARAM wParam, LPARAM lParam)
{
if (nCode == HCBT_CREATEWND)
{
HWND hWnd = reinterpret_cast<HWND>(wParam);
LPCBT_CREATEWND lpcw = (LPCBT_CREATEWND)lParam;
LONG lpCreateParams = (LONG)lpcw->lpcs->lpCreateParams;
::SetWindowLong(hWnd, GWL_USERDATA, lpCreateParams);
}

return CallNextHookEx(hWndsHook, nCode, wParam, lParam);

}

But it doesn't. There are no compile warnings or whatsoever. I tried to debug it, but when marking it with a breakpoint (at CallNextHookEx) for example, it doesn't break, and it sure doesn't do what I want it to do. And I really am creating windows with CreateWindow, which does do what it needs to do (The MessageLoops work). LPCTSTR Dutch = TEXT("Double Dutch :-)");

[Ernest Laurentin]

Did you check the return value of SetWindowsHookEx? If you specify a thread id NULL, you handle must be valid, and it must be inside of a DLL. If you want to hook your own application, than you must call GetCurrentThreadId(). By the way, hook are pretty difficult to debug. That's the reason for WH_DEBUG! Hope that helps, Good luck! ÿFor the bread of God is he who comes down from heaven and gives life to the world. - John 6:33

[S van Leent]

Well, when I wrote the thing and uploaded it, in a minute I knew the solution, It works great. The function looks like:

static LRESULT CALLBACK CBTProc(int nCode,
								WPARAM wParam,
								LPARAM lParam)
{
	if (nCode == HCBT\_CREATEWND)
	{
		LONG counter = 0;
		HWND hWnd = reinterpret\_cast(wParam);
		LPCBT\_CREATEWND lpcw = (LPCBT\_CREATEWND)lParam;
		LONG lpCreateParams = (LONG)lpcw->lpcs->lpCreateParams;

		// This makes it possible to use "API-style" windows too, where
		// the lpCreateParams does not point to a class

		if (lpCreateParams != 0 && lpcw->lpcs->hInstance == \_\_hInstance\_\_)
		{
			for (iIterator = arrUnboxedClasses.begin(); iIterator != arrUnboxedClasses.end(); iIterator++, counter++)
			{
				if (arrUnboxedClasses.at(counter) == lpCreateParams)
				{
					::SetWindowLong(hWnd, GWL\_USERDATA, lpCreateParams);
					goto end;
				}
			}
			
		}
	}

	end:

	return CallNextHookEx(\_\_hWndsHook\_\_, nCode, wParam, lParam);
}

I still think that another application may not crash because I install a hook, this is not a really good design, I think. LPCTSTR Dutch = TEXT("Double Dutch :-)");