pmap = XCreateBitmapFromData(dpy, w, curs, 8, 8);
invisible = XCreatePixmapCursor(dpy, pmap, pmap, &black, &black, 0, 0);
XDefineCursor(dpy, w, invisible);
pmap = XCreateBitmapFromData(dpy, w, curs, 8, 8);
invisible = XCreatePixmapCursor(dpy, pmap, pmap, &black, &black, 0, 0);
XDefineCursor(dpy, w, invisible);