:relfileprefix: ../../../
[#boost-urls-params_view-2constructor]

== xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/params_view.adoc[pass:[params_view]]::params_view

  


Constructor



=== Synopsis
  

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/params_view/2constructor-0d.adoc[pass:[params_view]]() = default;
----

[source,cpp,subs="verbatim,macros,-callouts"]
----
constexpr
xref:boost/urls/params_view/2constructor-091.adoc[pass:[params_view]](xref:boost/urls/params_view.adoc[params_view] const& other) = default;
----

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/params_view/2constructor-01.adoc[pass:[params_view]](
    xref:boost/urls/params_view.adoc[params_view] const& other,
    xref:boost/urls/encoding_opts.adoc[encoding_opts] opt) noexcept;
----

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/params_view/2constructor-09a.adoc[pass:[params_view]](core::string_view s);
----

[source,cpp,subs="verbatim,macros,-callouts"]
----
xref:boost/urls/params_view/2constructor-04.adoc[pass:[params_view]](
    core::string_view s,
    xref:boost/urls/encoding_opts.adoc[encoding_opts] opt);
----
  
=== Description


Default-constructed params have
zero elements.
[,cpp]
----
params_view qp;
----
[,cpp]
----
return params_view( "" );
----

=== Constant.

=== Throws nothing.


=== Exceptions

|===
| Name | Thrown on

| ``s``
| 
contains an invalid query parameter
string.

|===


=== Parameters

|===
| Name | Description 

| *s*
| 
The string to parse.

| *opt*
| 
The options for decoding. If
this parameter is omitted, `space_as_plus`
is used.

|===