get_plane_no_by_utf
plane_no = get_plane_no_by_utf(ucs, &unidx, &cnscode);
static int get_plane_no_by_utf(uint_t, int *, unsigned long *);
plane_no = get_plane_no_by_utf(c1, c2, &unidx, &cnscode);
static int get_plane_no_by_utf(const char, const char, int *, unsigned long *);