:relfileprefix: ../../../
[#0A7E46337449C9410D0C9FDDE8B9D8556FA0900E]

= Function url_base::set_host_ipv4

pass:v,q[Set the host to an address]


== Synopsis

Declared in header `</boost/url/url_base.hpp#L1262[boost/url/url_base.hpp,window=blank_]>`

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

== Description

pass:v,q[The host is set to the specified IPv4] pass:v,q[address.] pass:v,q[The host type is]
xref:boost/urls/host_type/ipv4.adoc[host_type::ipv4.]

=== Example
[,cpp]
----
assert( url("http://www.example.com").set_host_ipv4( ipv4_address( "127.0.0.1" ) ).buffer() == "http://127.0.0.1" );
----

=== Complexity
pass:v,q[Linear in `this->size()`.]

=== Postconditions
[,cpp]
----
this->has_authority() == true && this->host_ipv4_address() == addr && this->host_type() == host_type::ipv4
----

=== Exception Safety
pass:v,q[Strong guarantee.]
pass:v,q[Calls to allocate may throw.]

=== 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://en.wikipedia.org/wiki/IPv4[IPv4 (Wikipedia)]

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



== Return Value

* `` 


== Parameters

|===
| Name | Type 

| *addr*
| ``

|===