:relfileprefix: ../../../
[#boost-urls-url-set_host_ipv6]

= xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/url.adoc[pass:[url]]::set_host_ipv6


Set the host to an address


== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/url.hpp#L448[boost/url/url.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/url.adoc[url]&
set_host_ipv6(xref:boost/urls/ipv6_address.adoc[ipv6_address] const& addr);
----

== Description


The host is set to the specified IPv6
address.
The host type is
xref:boost/urls/host_type/ipv6.adoc[host_type::ipv6]
.

=== Example
[,cpp]
----
assert( url().set_host_ipv6( ipv6_address( "1::6:c0a8:1" ) ).authority().buffer() == "[1::6:c0a8:1]" );
----

=== Postconditions
[,cpp]
----
this->has_authority() == true && this->host_ipv6_address() == addr && this->host_type() == host_type::ipv6
----

=== Complexity

Linear in `this-&gt;size()`.

=== Exception Safety

Strong guarantee.
Calls to allocate may throw.

=== BNF
[,cpp]
----
IPv6address =                            6( h16 ":" ) ls32
            /                       "::" 5( h16 ":" ) ls32
            / [               h16 ] "::" 4( h16 ":" ) ls32
            / [ *1( h16 ":" ) h16 ] "::" 3( h16 ":" ) ls32
            / [ *2( h16 ":" ) h16 ] "::" 2( h16 ":" ) ls32
            / [ *3( h16 ":" ) h16 ] "::"    h16 ":"   ls32
            / [ *4( h16 ":" ) h16 ] "::"              ls32
            / [ *5( h16 ":" ) h16 ] "::"              h16
            / [ *6( h16 ":" ) h16 ] "::"

ls32        = ( h16 ":" h16 ) / IPv4address
            ; least-significant 32 bits of address

h16         = 1*4HEXDIG
            ; 16 bits of address represented in hexadecimal
----

=== Specification

* link:https://datatracker.ietf.org/doc/html/rfc4291[IP Version 6 Addressing Architecture (rfc4291)]

* link:https://datatracker.ietf.org/doc/html/rfc3986#section-3.2.2[            3.2.2. Host (rfc3986)]





== Parameters

|===
| Name | Description 

| *addr*
| 
The address to set.

|===




== See Also


xref:boost/urls/url_base/set_encoded_host.adoc[set_encoded_host]
,
xref:boost/urls/url_base/set_encoded_host_address.adoc[set_encoded_host_address]
,
xref:boost/urls/url_base/set_encoded_host_name.adoc[set_encoded_host_name]
,
xref:boost/urls/url_base/set_host.adoc[set_host]
,
xref:boost/urls/url_base/set_host_address.adoc[set_host_address]
,
xref:boost/urls/url_base/set_host_ipv4.adoc[set_host_ipv4]
,
xref:boost/urls/url_base/set_host_ipvfuture.adoc[set_host_ipvfuture]
,
xref:boost/urls/url_base/set_host_name.adoc[set_host_name]
.