Win32 Keyposting

A small Win32 program I made to simulate the space key every 5 minutes to keep a program from idling out. It just inserts the key code into the keyboard stream and does not manipulate anything or touch the program itself. It was compiled in Visual C++ 2008 with the following settings:

Runtime library: /MT (makes it standalone).
Compile as C Code (/TC).

Main code:

#include <windows.h>
#include <time.h>
#include "resource.h"

/* Generic Win32 handler for close, destroy and other OS messages to the program. */
LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam) {
	switch(Msg) {
		case WM_CLOSE:
			DestroyWindow(hWnd);
			break;

		case WM_DESTROY:
			PostQuitMessage(0);
			break;

		default:
			return DefWindowProc(hWnd, Msg, wParam, lParam);
	}
	return 0;
}

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

	/* Declarations. */
	WNDCLASSEX wc;
	HWND hWnd;
	MSG Msg;
	INPUT SpamKey = {0};
	KEYBDINPUT kb = {0};
	time_t timer_start, timer_stop;
	double timer_diff;

	/* Misc initializations. */
	ZeroMemory(&Msg, sizeof(MSG));
	timer_start = time(NULL);
	kb.wVk = VK_SPACE;

	wc.cbSize = sizeof(WNDCLASSEX);
	wc.style = 0;
	wc.lpfnWndProc = (WNDPROC)WndProc;
	wc.cbClsExtra = 0;
	wc.cbWndExtra = 0;
	wc.hInstance = hInstance;
	wc.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON1));
	wc.hIconSm = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON1));
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
	wc.lpszMenuName = NULL;
	wc.lpszClassName = "MainClass";

	/* Register window class. */
	if(!RegisterClassEx(&wc)) { 
		/* Silently exits if it fails. */
		return 0; 
	}

	/* Create the window. */
	if((hWnd = CreateWindowEx(WS_EX_CLIENTEDGE,"MainClass","IdleGuard",WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,250,100,NULL,NULL,hInstance,NULL)) == 0) { 
		return 0; 
	}

	/* Explicitly show the window. */
	ShowWindow(hWnd, SW_SHOW);

	/* Start message loop. */
	while(Msg.message != WM_QUIT) {

		/* Sleep 50 milliseconds to lower the CPU cycle stress */
		Sleep(50);

		/* Properly handle WM_CLOSE and WM_DESTROY messages. */
		if(PeekMessage(&Msg, NULL, 0, 0, PM_REMOVE) != 0) {
			TranslateMessage(&Msg);
			DispatchMessage(&Msg);
		}

		/* Only spam key every 5 minutes, should be ok for most MMO logouts. */
		timer_stop = time(NULL);
		if((timer_diff = difftime(timer_stop,timer_start)) >= 300) {
			/* Simulate the space key. */
			SpamKey.type = INPUT_KEYBOARD;
			kb.dwFlags = 0;
			SpamKey.ki = kb;
			SendInput(1,&SpamKey,sizeof(INPUT));
			Sleep(250);
			kb.dwFlags = KEYEVENTF_KEYUP;
			SpamKey.ki = kb;
			SendInput(1,&SpamKey,sizeof(INPUT));

			timer_start = time(NULL);
		}
	}

	return (int)Msg.wParam;
}