폴더 감시

HWND hMainWnd;
FILETIME SaveFileTime;
HANDLE g_hEvent = 0;

void OnMyMessage()
{
    WIN32_FIND_DATA data;
    HANDLE handle = FindFirstFile(L"c:\\test\\file.txt", &data);
    if (handle != INVALID_HANDLE_VALUE)
    {
        FindClose(handle);
        if (CompareFileTime(&data.ftLastWriteTime, &SaveFileTime) != 0)
            OutputDebugStringA("file.txt was modified\n");
        else
            OutputDebugStringA("Another file in the same directory was modified\n");
    }
    else
    {
        OutputDebugStringA("file.txt was deleted, or directory was removed/renamed\n");
    }
}

DWORD WINAPI CheckFolder(void* arg)
{
    wchar_t folder[MAX_PATH];
    lstrcpy(folder, (const wchar_t*)arg);
    HANDLE hEvent[2] = {g_hEvent, NULL};

    for (;;)
    {
        HANDLE hfolder = FindFirstChangeNotification(folder, FALSE,
                    FILE_NOTIFY_CHANGE_LAST_WRITE | FILE_NOTIFY_CHANGE_FILE_NAME);
        hEvent[1] = hfolder;
        DWORD dw = WaitForMultipleObjects(2, hEvent, FALSE, INFINITE);
        if (!::IsWindow(hMainWnd))
            break;
        if(dw == WAIT_OBJECT_0)
        {
            OutputDebugStringA("thread exit\n");
            break;
        }
        else if(dw == (WAIT_OBJECT_0+1))
        {
            PostMessage(hMainWnd, WM_COMMAND, ID_MY_MESSAGE, 0);
        }
        FindCloseChangeNotification(hfolder);           
    }
    return 0;
}

void TestMain()
{
    //자동으로 Reset 해주기 위해 두번째 인자를 FALSE로 설정한다.
    g_hEvent = CreateEvent(NULL, FALSE, FALSE, NULL);

    //save last write time
    WIN32_FIND_DATA data;
    HANDLE h = FindFirstFile(L"c:\\test\\file.txt", &data);
    if (h != INVALID_HANDLE_VALUE)
        SaveFileTime = data.ftLastWriteTime;
    FindClose(h);

    //watch for changes
    CreateThread(NULL, 0, CheckFolder, L"c:\\test", 0, NULL);
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    int wmId, wmEvent;
    PAINTSTRUCT ps;
    HDC hdc;

    switch (message)
    {
    case WM_COMMAND:
        wmId    = LOWORD(wParam);
        wmEvent = HIWORD(wParam);
        // 메뉴의 선택 영역을 구문 분석합니다.
        switch (wmId)
        {
        case ID_MY_MESSAGE:
            OnMyMessage();
            break;
       .....

    case WM_DESTROY:
        SetEvent(g_hEvent);
        PostQuitMessage(0);
        break;