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

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


Set the query params


== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/url.hpp#L474[boost/url/url.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/url.adoc[url]&
set_params(xref:std.adoc[std]::initializer_list<xref:boost/urls/param_view.adoc[param_view]> ps);
----

== Description


This sets the query params to the list
of param_view, which can be empty.

An empty list of params is distinct from
having no params.

Reserved characters in the string are
percent-escaped in the result.

=== Example
[,cpp]
----
assert( url( "http://example.com" ).set_params( {"id", "42"} ).query() == "id=42" );
----

=== Postconditions
[,cpp]
----
this->has_query() == true
----

=== Exception Safety

Strong guarantee.
Calls to allocate may throw.

=== Complexity

Linear.

=== BNF
[,cpp]
----
query           = *( pchar / "/" / "?" )

query-param     = key [ "=" value ]
query-params    = [ query-param ] *( "&" query-param )
----

=== Specification

* link:https://datatracker.ietf.org/doc/html/rfc3986#section-3.4
            >3.4.  Query (rfc3986)</a>
        @li <a href=[:&sol;&sol;en.wikipedia.org&sol;wiki&sol;Query_string"            &gt;Query string (Wikipedia)]





== Parameters

|===
| Name | Description 

| *ps*
| 
The params to set.

|===




== See Also


xref:boost/urls/url_base/encoded_params-06.adoc[encoded_params]
,
xref:boost/urls/url_base/remove_query.adoc[remove_query]
,
xref:boost/urls/url_base/set_encoded_query.adoc[set_encoded_query]
,
xref:boost/urls/url_base/set_query.adoc[set_query]
.



