:relfileprefix: ../../../
[#boost-urls-params_encoded_ref-append-08]

= xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/params_encoded_ref.adoc[pass:[params_encoded_ref]]::append


Append params


== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/params_encoded_ref.hpp#L436[boost/url/params_encoded_ref.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
template<class FwdIt>
xref:boost/urls/params_encoded_base/iterator.adoc[iterator]
append(
    FwdIt first,
    FwdIt last);
----

== Description


This function appends a range of params
to the view.



The `end()` iterator is invalidated.
[NOTE]

The strings referenced by the inputs
must not come from the underlying url,
or else the behavior is undefined.

=== Mandates
[,cpp]
----
std::is_convertible< std::iterator_traits< FwdIt >::reference_type, param_pct_view >::value == true
----

=== Complexity

Linear in `this-&gt;url().encoded_query().size()`.

=== Exception Safety

Strong guarantee.
Calls to allocate may throw.
Exceptions thrown on invalid input.



== Exceptions

|===
| Name | Thrown on

| `system_error`
| 
The range contains an invalid percent-encoding.

|===


== Return Value


An iterator to the first new element.



== Parameters

|===
| Name | Description 

| *first,*
| 
last The range of params
to append.

|===




