gtk:widget-set-cursor-from-name (widget name)

widget -- a gtk:widget object
name -- a string for the name of the cursor or nil to use the default cursor

Sets a named cursor to be shown when pointer devices point towards widget. This is a utility function that creates a cursor via the gdk:cursor-new-from-name function and then sets it on widget with the gtk:widget-cursor function. See those two functions for details.

On top of that, this function allows name to be nil, which will do the same as calling the gtk:widget-cursor function with a nil cursor.