These routines get and set the CMW label of a property hanging on a window. Refer to the XTSOLgetPropLabel(3) and XTSOLsetPropLabel(3) man page.
Status XTSOLgetPropLabel(Display *display, Window win, Atom property, bclabel_t *cmwlabel); void XTSOLsetPropLabel(Display *display, Window win, Atom property, bclabel_t *cmwLabel, enum setting_flag labelFlag);