:relfileprefix: ../../../
[#BAC57C288C40243B978B4564FAB69440E9AE8E6A]

= Function param::param

pass:v,q[Constructor]


== Synopsis

Declared in header `</boost/url/param.hpp#L278[boost/url/param.hpp,window=blank_]>`

[source,cpp,subs="verbatim,macros,-callouts"]
----
template<class OptionalString>
param(
    string_view key,
    const OptionalString& value);
----

== Description

pass:v,q[This constructs a parameter with a key] pass:v,q[and value.]
pass:v,q[No validation is performed on the strings.]
pass:v,q[Ownership of the key and value is acquired]
pass:v,q[by making copies.]

=== Example
[,cpp]
----
param qp( "key", "value" );
----
[,cpp]
----
param qp( "key", optional<core::string_view>("value") );
----
[,cpp]
----
param qp( "key", boost::none );
----
[,cpp]
----
param qp( "key", nullptr );
----
[,cpp]
----
param qp( "key", no_value );
----

=== Postconditions
[,cpp]
----
this->key == key && this->value == value && this->has_value == true
----

=== Complexity
pass:v,q[Linear in `key.size() + value.size()`.]

=== Exception Safety
pass:v,q[Calls to allocate may throw.]



== Return Value

* `void` 


== Parameters

|===
| Name | Type 

| *key*
| `string_view`

| *value*
| ``

|===