Window functions use window handles (hwnd). These are macro handles to open source file windows. Windows display file buffers in them. An hwnd is typically a small integer value. An hwnd of zero indicates an error.
Note that a macro hwnd is similar in concept, but is not exactly the same as a window handle HWND in the Microsoft Windows API.
Each window has a selection in it which describes what characters are selected. See the GetWndSel function for more information.
SetWndSel (hwnd, selection_record)
ScrollWndVert (hwnd, line_count)
ScrollWndHoriz (hwnd, pixel_count)
