[#boost-urls-authority_view-host_ipv4_address]
= xref:boost.adoc[boost]::xref:boost/urls.adoc[urls]::xref:boost/urls/authority_view.adoc[authority_view]::host_ipv4_address
:relfileprefix: ../../../
:mrdocs:


Return the host IPv4 address

== Synopsis


Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/authority_view.hpp#L896[boost/url/authority_view.hpp]>`

[source,cpp,subs="verbatim,replacements,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.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)]





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