[#bsl-Pair_ConstructionParametersPackLength]
= xref:bsl.adoc[bsl]::Pair&lowbar;ConstructionParametersPackLength
:relfileprefix: ../
:mrdocs:

Metafunction giving the piecewise&hyphen;construction argument&hyphen;pack length&period;

== Synopsis

Declared in `&lt;bslstl&lowbar;pair&period;h&gt;`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template&lt;
    class TYPE,
    class&period;&period;&period; ARGS&gt;
struct Pair&lowbar;ConstructionParametersPackLength
    : xref:bsl/integral_constant-02.adoc[integral&lowbar;constant&lt;int, sizeof&period;&period;&period;(ARGS) &plus; Pair&lowbar;BslmaIdiom&lt;TYPE&gt;&colon;&colon;value&gt;]
----

== Description

This component&hyphen;private component&hyphen;private meta&hyphen;function determines the number of elements in a tuple containing parameters for piecewise construction of a `bsl&colon;&colon;pair` member having the specified `TYPE`&period; Result value depends on the `TYPE`, whether it takes a `bslma&colon;&colon;Allocator&ast;` constructor argument and, if so, whether that argument follows an argument of type `bsl&colon;&colon;allocator&lowbar;arg&lowbar;t`&period;

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `xref:bsl/integral_constant-02.adoc[integral&lowbar;constant&lt;int, sizeof&period;&period;&period;(ARGS) &plus; Pair&lowbar;BslmaIdiom&lt;TYPE&gt;&colon;&colon;value&gt;]`
| Metafunction representing a compile&hyphen;time constant of the specified (template parameter) `t&lowbar;TYPE` with the specified (template parameter) `t&lowbar;VALUE`&period;
|===

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:bsl/integral_constant-02/type.adoc[`type`] 
| Alias for this `integral&lowbar;constant` specialization&period;
| xref:bsl/integral_constant-02/value_type.adoc[`value&lowbar;type`] 
| Alias for the (template parameter) `t&lowbar;TYPE`&period;
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/integral_constant-02/operator_call.adoc[`operator()`] 
| Return a copy of the template argument `t&lowbar;VALUE`&period;
| xref:bsl/integral_constant-02/2conversion.adoc[`operator t&lowbar;TYPE`] 
| Return a copy of the template argument `t&lowbar;VALUE`&period;
|===


== Static Data Members

[cols="1,4"]
|===
| Name| Description
| xref:bsl/integral_constant-02/value.adoc[`value`] 
| The compile&hyphen;time constant value of this metafunction&period;
|===



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