ns_class
#define ns_rr_class(rr) ((ns_class)((rr).rr_class + 0))
ns_class, ns_type, unsigned long, const unsigned char *,
ns_class qclass);
ns_type type, ns_class rr_class, uint32_t ttl, uint16_t rdlen,
ns_class r_class; /*%< class number */
int res_findzonecut(res_state, const char *, ns_class, int,
int res_findzonecut2(res_state, const char *, ns_class, int,
const char *name, ns_class class, ns_type type,