:relfileprefix: ../../../
[#boost-urls-url-set_host_ipv4]

== xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/url.adoc[pass:[url]]::set_host_ipv4


Set the host to an address


=== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/url.hpp#L446[boost/url/url.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/url.adoc[url]&
set_host_ipv4(xref:boost/urls/ipv4_address.adoc[ipv4_address] const& addr);
----

=== Description


The host is set to the specified IPv4
address.
The host type is
xref:boost/urls/host_type/ipv4.adoc[host_type::ipv4]
.
[,cpp]
----
assert( url("http://www.example.com").set_host_ipv4( ipv4_address( "127.0.0.1" ) ).buffer() == "http://127.0.0.1" );
----

=== Linear in `this-&gt;size()`.
[,cpp]
----
this->has_authority() == true && this->host_ipv4_address() == addr && this->host_type() == host_type::ipv4
----

=== Strong guarantee.

Calls to allocate may throw.
[,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
----

* link:https://en.wikipedia.org/wiki/IPv4[IPv4 (Wikipedia)]

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





=== Parameters

|===
| Name | Description 

| *addr*
| 
The address to set.

|===




=== See Also


xref:boost/urls/url_base/set_encoded_host.adoc[set_encoded_host]
,
xref:boost/urls/url_base/set_encoded_host_address.adoc[set_encoded_host_address]
,
xref:boost/urls/url_base/set_encoded_host_name.adoc[set_encoded_host_name]
,
xref:boost/urls/url_base/set_host.adoc[set_host]
,
xref:boost/urls/url_base/set_host_address.adoc[set_host_address]
,
xref:boost/urls/url_base/set_host_ipv6.adoc[set_host_ipv6]
,
xref:boost/urls/url_base/set_host_ipvfuture.adoc[set_host_ipvfuture]
,
xref:boost/urls/url_base/set_host_name.adoc[set_host_name]
.