.TH dns_ip6_qualify 3
.SH NAME
dns_ip6_qualify \- qualify name and look up IPv6 addresses
.SH SYNTAX
.B #include <libowfat/dns.h>

int \fBdns_ip6_qualify\fP(stralloc* \fIout\fR,stralloc* \fIfqdn\fR,
                    const stralloc* \fIudn\fR);
.SH DESCRIPTION
dns_ip6_qualify feeds the name \fIudn\fR through qualification and looks up
16-byte IPv6 addresses for the result. It puts the fully qualified domain name
into \fIfqdn\fR, puts the concatenation of the IP addresses into \fIout\fR, and
returns 0. If the domain does not exist in DNS, or has no IP addresses,
\fIout\fR will be empty.

dns_ip6_qualify 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_qualify has trouble with the qualification, has trouble with DNS, or
runs out of memory, it returns -1, setting errno appropriately. It may or may
not change \fIout\fR and \fIfqdn\fR.
.SH QUALIFICATION
See http://cr.yp.to/djbdns/qualification.html
.SH "SEE ALSO"
dns_ip6(3), dns_ip6_packet(3), dns_ip4_qualify(3)