[#boost-urls-url-set_host_ipv6]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/url.adoc[url]::set&lowbar;host&lowbar;ipv6
:relfileprefix: ../../../
:mrdocs:


Set the host to an address

== Synopsis


Declared in `&lt;https://www.github.com/boostorg/url/blob/develop/include/boost/url/url.hpp#L449[boost&sol;url&sol;url&period;hpp]&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:boost/urls/url.adoc[url]&
set&lowbar;host&lowbar;ipv6(xref:boost/urls/ipv6_address.adoc[ipv6&lowbar;address] const& addr);
----

== Description


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


=== 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&hyphen;&gt;size()`&period;


=== Exception Safety

Strong guarantee&period;        Calls to allocate may throw&period;


=== 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&period;2&period;2&period; Host (rfc3986)]



== Parameters


|===
| Name | Description

| *addr*
| The address to set&period;


|===

== See Also


xref:boost/urls/url_base/set_encoded_host.adoc[set&lowbar;encoded&lowbar;host],            xref:boost/urls/url_base/set_encoded_host_address.adoc[set&lowbar;encoded&lowbar;host&lowbar;address],            xref:boost/urls/url_base/set_encoded_host_name.adoc[set&lowbar;encoded&lowbar;host&lowbar;name],            xref:boost/urls/url_base/set_host.adoc[set&lowbar;host],            xref:boost/urls/url_base/set_host_address.adoc[set&lowbar;host&lowbar;address],            xref:boost/urls/url_base/set_host_ipv4.adoc[set&lowbar;host&lowbar;ipv4],            xref:boost/urls/url_base/set_host_ipvfuture.adoc[set&lowbar;host&lowbar;ipvfuture],            xref:boost/urls/url_base/set_host_name.adoc[set&lowbar;host&lowbar;name]&period;






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