Managed C++/CLI

HDC hDC = GetDC(NULL);
HDC hMemDC = CreateCompatibleDC(hDC);

SIZE size = { GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN) };
HBITMAP hBitmap = CreateCompatibleBitmap(hDC, size.cx, size.cy);

if (hBitmap)
{
    HBITMAP hOld = (HBITMAP) SelectObject(hMemDC, hBitmap);
    BitBlt(hMemDC, 0, 0, size.cx, size.cy, hDC, 0, 0, SRCCOPY);
    SelectObject(hMemDC, hOld);

    Bitmap *pBitmap = Bitmap::FromHbitmap(hBitmap);
    DeleteDC(hMemDC);
    ReleaseDC(NULL, hDC);

    if (pBitmap)
    {
        pBitmap->Save("./test.bmp");
        pBitmap->Dispose();
        pBitmap = 0;
    }

    DeleteObject(hBitmap);
}