DECLAREINTEGER SetClipboardViewer IN user32;
[in] Handle to the window to be added to the clipboard chain.
If the function succeeds, the return value identifies the next window in the clipboard viewer chain. If an error occurs or there are no other windows in the clipboard viewer chain, the return value is NULL.
The windows that are part of the clipboard viewer chain, called clipboard viewer windows, must process the clipboard messages WM_CHANGECBCHAIN and WM_DRAWCLIPBOARD.
Each clipboard viewer window calls the SendMessage function to pass these messages to the next window in the clipboard viewer chain.