:relfileprefix: ../../../
[#boost-urls-ipv6_address-is_unspecified]

= xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/ipv6_address.adoc[pass:[ipv6_address]]::is_unspecified


Return true if the address is unspecified


== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/ipv6_address.hpp#L261[boost/url/ipv6_address.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
bool
is_unspecified() const noexcept;
----

== Description


The address 0:0:0:0:0:0:0:0 is called the
unspecified address. It indicates the
absence of an address.

=== Specification

* link:https://datatracker.ietf.org/doc/html/rfc4291#section-2.5.2[            2.5.2. The Unspecified Address (rfc4291)]