:relfileprefix: ../../../
[#boost-urls-url_view_base-host_ipv4_address]

= xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/url_view_base.adoc[pass:[url_view_base]]::host_ipv4_address


Return the host IPv4 address


== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/url_view_base.hpp#L1209[boost/url/url_view_base.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/ipv4_address.adoc[ipv4_address]
host_ipv4_address() const noexcept;
----

== Description


If the host type is
xref:boost/urls/host_type/ipv4.adoc[host_type::ipv4]
,        this function returns the address as
a value of type
xref:boost/urls/ipv4_address.adoc[ipv4_address]
.        Otherwise, if the host type is not an IPv4
address, it returns a default-constructed
value which is equal to the unspecified
address "0.0.0.0".

=== Example
[,cpp]
----
assert( url_view( "http://127.0.0.1/index.htm?user=win95" ).host_ipv4_address() == ipv4_address( "127.0.0.1" ) );
----

=== Complexity

Constant.

=== Exception Safety

Throws nothing.

=== BNF
[,cpp]
----
IPv4address = dec-octet "." dec-octet "." dec-octet "." dec-octet

dec-octet   = DIGIT                 ; 0-9
            / %x31-39 DIGIT         ; 10-99
            / "1" 2DIGIT            ; 100-199
            / "2" %x30-34 DIGIT     ; 200-249
            / "25" %x30-35          ; 250-255
----

=== Specification

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