:relfileprefix: ../../../
[#boost-urls-params_encoded_base-const_iterator]

== xref:boost.adoc[pass:[boost]]::xref:boost/urls.adoc[pass:[urls]]::xref:boost/urls/params_encoded_base.adoc[pass:[params_encoded_base]]::const_iterator


A Bidirectional iterator to a query parameter


=== Synopsis

Declared in header `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/params_encoded_base.hpp#L107[boost/url/params_encoded_base.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
using const_iterator = xref:boost/urls/params_encoded_base/iterator.adoc[iterator];
----

=== Description


Objects of this type allow iteration
through the parameters in the query.
Strings returned by iterators may
contain percent escapes.
The values returned are read-only;
changes to parameters must be made
through the container instead, if the
container supports modification.




The strings produced when iterators
are dereferenced refer to the underlying
character buffer.
Ownership is not transferred; the caller
is responsible for ensuring that the
lifetime of the buffer extends until
it is no longer referenced by any
container or iterator.



