This function opens the clipboard for examination and prevents other applications from modifying the clipboard content.
BOOL OpenClipboard( HWND hWndNewOwner );
[in] Handle to the window to be associated with the open clipboard. If this parameter is NULL, the open clipboard is associated with the current task.
Nonzero indicates success. Zero indicates failure.
OpenClipboard does not fail if another window created by the same thread that created the window identified by hWndNewOwner already opened the clipboard.
An application should call the CloseClipboard function after every successful call to OpenClipboard.
The window identified by the hWndNewOwner parameter does not become the clipboard owner unless the EmptyClipboard function is called.