XDefineCursor(), XUndefineCursor() - define cursors
XDefineCursor (Display *display, Window w, Cursor cursor)
XUndefineCursor (Display *display, Window w)
If a cursor is set, it will be used when the pointer is in the window. If the cursor is None, it is equivalent to XUndefineCursor.
XDefineCursor(3) can generate BadCursor and BadWindow errors.
The XUndefineCursor(3) function undoes the effect of a previous XDefineCursor(3) for this window. When the pointer is in the window, the parent's cursor will now be used. On the root window, the default cursor is restored.
XUndefineCursor(3) can generate a BadWindow error.
Xlib