[#bsl-Pair_First-02]
= xref:bsl.adoc[bsl]::xref:bsl/Pair_First-00.adoc[Pair_First]<TYPE&>
:relfileprefix: ../
:mrdocs:

Component‐private base holding a pair's `first` member by lvalue reference.

== Synopsis

Declared in `<bslstl_pair.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class TYPE>
struct xref:bsl/Pair_First-00.adoc[Pair_First]<TYPE&>;
----

== Description

This component‐private `class` holds the `first` data member of a `pair` when that member is an lvalue‐reference. Note that the C++ Standard defines the assignment operator to assign through the reference in this case, where the implicitly declared assignment operator would be deleted.

== Protected Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/Pair_First-02/2constructor-0ec.adoc[`Pair_First`]         [.small]#[constructor]#
| Constructors
| xref:bsl/Pair_First-02/operator_assign.adoc[`operator=`] 
| Assign through the `first` reference from `rhs.first`.
|===


== Protected Data Members

[cols="1,4"]
|===
| Name| Description
| xref:bsl/Pair_First-02/first.adoc[`first`] 
| The `first` element of the pair, held by lvalue reference.
|===



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