:relfileprefix: ../../
[#76131245504820822D6345111D273CAF01DC7534]

= Class ipv6_address

pass:v,q[An IP version 6 style address.]


== Synopsis

Declared in header `</boost/url/ipv6_address.hpp#L64[boost/url/ipv6_address.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
class ipv6_address;
----

==  Types
[,cols=2]
|===
|Name |Description
|xref:boost/urls/ipv6_address/bytes_type.adoc[`pass:v[bytes_type]`] |
pass:v,q[The type used to represent an address as an array of bytes.]

|===
==  Member Functions
[,cols=2]
|===
|Name |Description
|xref:boost/urls/ipv6_address/2constructor.adoc[`pass:v[ipv6_address]`] |
pass:v,q[Construct from a string.]

pass:v,q[Construct from an IPv4 address.]

pass:v,q[Construct from an array of bytes.]

pass:v,q[Constructor.]

|xref:boost/urls/ipv6_address/is_loopback.adoc[`pass:v[is_loopback]`] |
pass:v,q[Return true if the address is a loopback address]

|xref:boost/urls/ipv6_address/is_unspecified.adoc[`pass:v[is_unspecified]`] |
pass:v,q[Return true if the address is unspecified]

|xref:boost/urls/ipv6_address/is_v4_mapped.adoc[`pass:v[is_v4_mapped]`] |
pass:v,q[Return true if the address is a mapped IPv4 address]

|xref:boost/urls/ipv6_address/operator_assign.adoc[`pass:v[operator=]`] |
pass:v,q[Copy Assignment]

|xref:boost/urls/ipv6_address/to_buffer.adoc[`pass:v[to_buffer]`] |
pass:v,q[Write a dotted decimal string representing the address to a buffer]

|xref:boost/urls/ipv6_address/to_bytes.adoc[`pass:v[to_bytes]`] |
pass:v,q[Return the address as bytes, in network byte order]

|xref:boost/urls/ipv6_address/to_string.adoc[`pass:v[to_string]`] |
pass:v,q[Return the address as a string.]

|===
==  Static Member Functions
[,cols=2]
|===
|Name |Description
|xref:boost/urls/ipv6_address/loopback.adoc[`pass:v[loopback]`] |
pass:v,q[Return an address object that represents the loopback address]

|===
==  Static Data Members
[,cols=2]
|===
|Name |Description
|xref:boost/urls/ipv6_address/max_str_len.adoc[`pass:v[max_str_len]`] |
pass:v,q[The number of characters in the longest possible IPv6 string.]

|===
==  Friends
[,cols=2]
|===
|Name |Description
|xref:boost/urls/ipv6_address/8friend-01.adoc[`pass:v[operator!=]`] |
pass:v,q[Return true if two addresses are not equal]

|xref:boost/urls/ipv6_address/8friend-0b.adoc[`pass:v[operator<<]`] |

|xref:boost/urls/ipv6_address/8friend-0d.adoc[`pass:v[operator==]`] |
pass:v,q[Return true if two addresses are equal]

|===

== Description

pass:v,q[Objects of this type are used to construct,] pass:v,q[parse, and manipulate IP version 6 addresses.]

=== 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)]