ares_init.c

   * still rely on it.
   */
  if (IN_CLASSA(addr.s_addr))
    pat->mask.s_addr = htonl(IN_CLASSA_NET);
  else if (IN_CLASSB(addr.s_addr))
    pat->mask.s_addr = htonl(IN_CLASSB_NET);
  else
    pat->mask.s_addr = htonl(IN_CLASSC_NET);
}
#endif