Простой индикатор раскладки клавиатуры в курсоре на С++

#define OEMRESOURCE
#include <windows.h>

HINSTANCE   g_instance;
HCURSOR     g_hc_ibeam;
UINT_PTR    g_timer = NULL;
DWORD       g_layout = 0;

void CALLBACK UpdateTimer(HWND hWnd, UINT uMsg, UINT_PTR idEvent, DWORD dwTime)
{
    int layout = (int) GetKeyboardLayout(GetWindowThreadProcessId(GetForegroundWindow(), NULL)) & 0xFFFF;
    if (g_layout != layout)
    {
        HCURSOR hc_new = LoadCursor(g_instance, MAKEINTRESOURCE(layout));
        if (hc_new)
        {
            SetSystemCursor(hc_new, OCR_IBEAM);
        }
        else
        {
            SetSystemCursor(CopyCursor(g_hc_ibeam), OCR_IBEAM);
        }
    }
}

int Main()
{
    HANDLE mutex = CreateMutex(NULL, FALSE, "LangCursor");
    if (GetLastError() == ERROR_ALREADY_EXISTS || GetLastError() == ERROR_ACCESS_DENIED) return 1;

    g_hc_ibeam = CopyCursor(LoadCursor(NULL, IDC_IBEAM));
    if (!g_hc_ibeam) return 1;

    g_instance = GetModuleHandle(NULL);
    g_timer = SetTimer(NULL, g_timer, 200, UpdateTimer);
    if (!g_timer) return 1;

    MSG msg;
    while (GetMessage(&msg,0,0,0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    
    DestroyCursor(g_hc_ibeam);
    return 0;
}

EXTERN_C void WINAPI WinMainCRTStartup()
{
    ExitProcess(Main());
}

#define IDC_CURSOR1                     1033
#define IDC_CURSOR2                     1049