Tk_ClearSelection(tkwin, selection)
Tk_Window tkwin
(in) Atom selection
(in) Tk_ClearSelection cancels the selection specified by the atom selection for the display containing tkwin. The selection need not be in tkwin itself or even in tkwin's application. If there is a window anywhere on tkwin's display that owns selection, the window will be notified and the selection will be cleared. If there is no owner for selection on the display, then the procedure has no effect.