Can't get WH_CBT to work right

seaders · #1 13-Dec-2008, 08:21

So I've a simple window program that starts up and hooks to a dll, (I'll try only post relevant parts)

Window and calling the DLL:

CPP / C++ / C Code:

typedef void (*registerCall)(void*);
registerCall registerHooks;

static HINSTANCE hinstLib=NULL;
set_dll_stuff() {
	std::string dll_attrib = "theDLL.dll";
	hinstLib = LoadLibrary(dll_attrib.c_str());
	error_window(hinstLib == NULL,  "ERROR: unable to load DLL, ", dll_attrib);

	dll_attrib = "registerHooks";
	registerHooks = (registerCall)GetProcAddress(hinstLib, dll_attrib.c_str());
	error_window(registerHooks == NULL, "ERROR: unable to find DLL function", dll_attrib);

	registerHooks(NULL);
}
int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nFunsterStil)
{...}

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{...}

DLL side:

CPP / C++ / C Code:

HINSTANCE _hInst= NULL;
DWORD hookThreadId = 0;
HWND display= NULL;

HHOOK llMouseHookHandle;
HHOOK llCBTHookHandle;

size_t bufSize = 32;
char* buf = new char[bufSize]

extern "C"BOOL APIENTRY DllMain(HINSTANCE hInst, DWORD reason, LPVOID reserved) {
	switch (reason) {
	case DLL_PROCESS_ATTACH:
		_hInst = hInst;
		break;
	default:
		break;
	}
}

LRESULT CALLBACK MouseProc(int nCode, WPARAM wParam, LPARAM lParam) {
	if (nCode < 0)
		return CallNextHookEx(NULL, nCode, wParam, lParam);
	
	MOUSEMOVEPOINT * mmp = (MOUSEMOVEPOINT *)*_lParam;

	POINT pt;
	pt.x = mmp->x;
	pt.y = mmp->y;

	if((*_wParam) == WM_LBUTTONUP)
	{
		if (WindowFromPoint(pt) != NULL && (display = WindowFromPoint(pt))) {
			strcpy(buf, "");
			GetClassNameA(display, buf, bufSize);
			cout << buf << endl;
			SendMessage(display, WM_NULL, 0, 0);
		}
	}
}


LRESULT CALLBACK CBTProc(int nCode, WPARAM wParam, LPARAM lParam) {
	cout << "anything!!!" << endl;
	return CallNextHookEx(NULL, nCode, wParam, lParam);
}


__declspec(dllexport) void __stdcall
registerHooks(void* _extra_info) {
	llMouseHookHandle = SetWindowsHookEx(WH_MOUSE_LL, MouseProc, _hInst, 0);
	error_window(llMouseHookHandle == NULL, "llMouseHookHandle");
	llCBTHookHandle = SetWindowsHookEx(WH_CBT, CBTProc, _hInst, 0);
	error_window(llCBTHookHandle == NULL, "llCBTHookHandle");

	hookThreadId = GetCurrentThreadId();
}

__declspec(dllexport) void __stdcall
unregisterHooks() {
	int ret_val = UnhookWindowsHookEx(llMouseHookHandle);
	error_window(ret_val == 0, "Unhook llMouseHookHandle");
	ret_val = UnhookWindowsHookEx(llCBTHookHandle);
	error_window(ret_val == 0, "Unhook llCBTHookHandle");
}

All of this compiles and runs as expected, barring CBT, obviously. I know this because I can have my app running as a taskbar tray icon only and get a cout of window names to my console.

From the CBTProc, I get nothing, no matter what I've tried to do, I've not been able to get it to print out unless the mouse is within it's own process, then if I resize, or move, or whatever, it works like I want it to.

I've read through quite a few forum posts, from here and other places and there are some who think

CPP / C++ / C Code:

llCBTHookHandle = SetWindowsHookEx(WH_CBT, CBTProc, NULL, GetCurrentThreadId());

or variations of that. From my efforts of trying to get it to work, though, none of them have.

Am I doing something elementary that is preventing it to work, or is my whole approach wrong? Would I need to go down the route of injecting my DLL into processes (I've not succeeded in this yet, either, but if I need to I'll incorporate that)?

All I want is to listen for window opening and closing, to get a handle of a particular window and only run when that's open, then if / when that closes, I want my app to close too.

Thank you all for any help that you could give me.

seaders · #2 14-Dec-2008, 15:55

sorry to bump, but is there anyone with an idea as to where I'm going wrong? I'm really stuck with this one.

fyi, for anyone reviewing my code, read wParam for *_wParam and lParam for *_lParam, that was a mistake in my condensing for the post.

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Can't get WH_CBT to work right

Re: Can't get WH_CBT to work right