dns_ip6 - look up IPv6 addresses

       dns_ip6  looks  up  16-byte  IPv6  addresses  for  the  fully-qualified  domain name in fqdn. It puts the
       concatenation of the IPv6 addresses into out and returns 0. If the domain does not exist in DNS,  or  has
       no IP addresses, out will be empty.

       dns_ip6  also  looks  up  4-byte  IPv4  addresses  and  converts  them  into  IPv4-mapped  IPv6 addresses
       (::ffff:1.2.3.4) to provide easy backwards compatibility for IPv6 applications.

       If dns_ip6 has trouble with the DNS  lookup  or  runs  out  of  memory,  it  returns  -1,  setting  errno
       appropriately. It may or may not change out.

       If  fqdn  is an IPv6 address, dns_ip6 puts that IP address into out without checking DNS.  IPv4 addresses
       are also used directly without DNS lookup.

       dns_ip6 - look up IPv6 addresses

dns_ip6_packet(3), dns_ip4(3), dns_name6(3)

                                                                                                      dns_ip6(3)

#include<libowfat/dns.h>

       int dns_ip6(stralloc* out,stralloc* fqdn);