[#boost-urls-url_view_base-host_ipvfuture]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/url_view_base.adoc[url&lowbar;view&lowbar;base]::host&lowbar;ipvfuture
:relfileprefix: ../../../
:mrdocs:

Return the host IPvFuture address

== Synopsis

Declared in `&lt;https://www.github.com/boostorg/url/blob/develop/include/boost/url/url_view_base.hpp#L1358[boost&sol;url&sol;url&lowbar;view&lowbar;base&period;hpp]&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
core::string&lowbar;view
host&lowbar;ipvfuture() const noexcept;
----

== Description

If the host type is xref:boost/urls/host_type.adoc[`host&lowbar;type&colon;&colon;ipvfuture`], this function returns the address as a string&period; Otherwise, if the host type is not an IPvFuture address, it returns an empty string&period;

== Example

[,cpp]
----
assert( url_view( "http://[v1fe.d:9]/index.htm" ).host_ipvfuture() == "v1fe.d:9" );
----
== Complexity

Constant&period;

== Exception Safety

Throws nothing&period;

== BNF

[,cpp]
----
IPvFuture  = "v" 1*HEXDIG "." 1*( unreserved / sub-delims / ":" )
----
== Specification

* https://datatracker.ietf.org/doc/html/rfc3986#section-3.2.2[3&period;2&period;2&period; Host (rfc3986)]

== Return Value

The IPvFuture address as a string&period;


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