[#boost-urls-params_base]
= xref:boost/urls/params_base.adoc[boost::urls::params_base]
:relfileprefix: ../../
:mrdocs:

Common functionality for query parameter containers

== Synopsis

Declared in `<https://www.github.com/boostorg/url/blob/develop/include/boost/url/params_base.hpp#L48[boost/url/params_base.hpp]>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
class params_base;
----

== Types

[cols=2]
|===
| Name
| Description
| xref:boost/urls/params_base/const_iterator.adoc[`const_iterator`] 
| A Bidirectional iterator to a query parameter
| xref:boost/urls/params_base/const_reference.adoc[`const_reference`] 
| The reference type
| xref:boost/urls/params_base/difference_type.adoc[`difference_type`] 
| A signed integer type used to represent differences.
| xref:boost/urls/params_base/reference.adoc[`reference`] 
| The reference type
| xref:boost/urls/params_base/size_type.adoc[`size_type`] 
| An unsigned integer type to represent sizes.
| xref:boost/urls/params_base/value_type.adoc[`value_type`] 
| The value type
|===

== Member Functions

[cols=2]
|===
| Name
| Description
| xref:boost/urls/params_base/begin.adoc[`begin`] 
| Return an iterator to the beginning
| xref:boost/urls/params_base/buffer.adoc[`buffer`] 
| Return the referenced character buffer.
| xref:boost/urls/params_base/contains.adoc[`contains`] 
| Return true if a matching key exists
| xref:boost/urls/params_base/count.adoc[`count`] 
| Return the number of matching keys
| xref:boost/urls/params_base/empty.adoc[`empty`] 
| Return true if there are no params
| xref:boost/urls/params_base/end.adoc[`end`] 
| Return an iterator to the end
| xref:boost/urls/params_base/find-0f.adoc[`find`] 
| Find a matching key
| xref:boost/urls/params_base/find_last-04b.adoc[`find_last`] 
| Find a matching key
| xref:boost/urls/params_base/size.adoc[`size`] 
| Return the number of params
|===

== Static Member Functions

[cols=2]
|===
| Name
| Description
| xref:boost/urls/params_base/max_size.adoc[`max_size`] 
| Return the maximum number of characters possible
|===

== Friends

[cols=2]
|===
| Name
| Description
| `xref:boost/urls/params_view.adoc[boost::urls::params_view]`
| A view representing query parameters in a URL
| `xref:boost/urls/params_ref.adoc[boost::urls::params_ref]`
| A view representing query parameters in a URL
| `xref:boost/urls/url_view_base.adoc[boost::urls::url_view_base]`
| Common functionality for containers
| `xref:boost/urls/params_view.adoc[boost::urls::params_view]`
| A view representing query parameters in a URL
| `xref:boost/urls/params_ref.adoc[boost::urls::params_ref]`
| A view representing query parameters in a URL
| `xref:boost/urls/url_view_base.adoc[boost::urls::url_view_base]`
| Common functionality for containers
|===

== Derived Classes

[cols=2]
|===
| Name
| Description
| xref:boost/urls/params_ref.adoc[`params_ref`]
| A view representing query parameters in a URL
| xref:boost/urls/params_view.adoc[`params_view`]
| A view representing query parameters in a URL
|===

== Description

The library uses this base class to provide common member functions for containers of query parameters.

This class should not be instantiated directly; Instead, use one of the containers or functions:

== Containers
* `params_ref`
* `params_view`
* `params_encoded_ref`
* `params_encoded_view`


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