XmDragCancel — A Drag and Drop function that terminates a
drag transaction

     #include <Xm/DragDrop.h>
void XmDragCancel(
Widget dragcontext);

     XmDragCancel terminates a drag operation and cancels
any pending actions of the specified DragContext. This
routine can only be called by the initiator client.

          Specifies the ID of the DragContext widget
          associated with the drag and drop transaction to
          be terminated

     For a complete definition of DragContext and its
associated resources, see XmDragContext(3).

     XmDragContext(3) and XmDragStart(3).