[#bsl-unordered_set-0d2d-2constructor-059]
= xref:bsl.adoc[bsl]::xref:bsl/unordered_set-0d2d.adoc[unordered_set]::unordered_set
:relfileprefix: ../../
:mrdocs:

Constructors

== Synopses

Declared in `<bslstl_unorderedset.h>`

Create an empty unordered set.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:bsl/unordered_set-0d2d/2constructor-00.adoc[unordered_set]();
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-00.adoc[_» more..._]#

Create an unordered set having the same value as the specified `original`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:bsl/unordered_set-0d2d/2constructor-053.adoc[unordered_set](xref:bsl/unordered_set-0d2d.adoc[unordered_set] const& original);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-053.adoc[_» more..._]#

Create an unordered set by moving the contents of the specified `original`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:bsl/unordered_set-0d2d/2constructor-013.adoc[unordered_set](xref:BloombergLP/bslmf/MovableRef.adoc[BloombergLP::bslmf::MovableRef<unordered_set>] original);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-013.adoc[_» more..._]#

Create an empty unordered set using the specified `basicAllocator`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
explicit
xref:bsl/unordered_set-0d2d/2constructor-0a6.adoc[unordered_set](ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-0a6.adoc[_» more..._]#

Create an empty unordered set with the specified parameters.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:bsl/unordered_set-0d2d/2constructor-0d.adoc[unordered_set](
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-0d.adoc[_» more..._]#

Create an unordered set by moving `original`, using `basicAllocator`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:bsl/unordered_set-0d2d/2constructor-056.adoc[unordered_set](
    xref:BloombergLP/bslmf/MovableRef.adoc[BloombergLP::bslmf::MovableRef<unordered_set>] original,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-056.adoc[_» more..._]#

Create an unordered set having the same value as the specified `original` object that uses the specified `basicAllocator` to supply memory.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:bsl/unordered_set-0d2d/2constructor-07.adoc[unordered_set](
    xref:bsl/unordered_set-0d2d.adoc[unordered_set] const& original,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-07.adoc[_» more..._]#

Create an unordered set from the specified `values` initializer list.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class = void>
requires bsl::IsStdAllocator<ALLOCATOR>::value
xref:bsl/unordered_set-0d2d/2constructor-0c.adoc[unordered_set](
    std::initializer_list<KEY> values,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-0c.adoc[_» more..._]#

Create an empty unordered set with the specified parameters.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
xref:bsl/unordered_set-0d2d/2constructor-06.adoc[unordered_set](
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    HASH const& hashFunction,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-06.adoc[_» more..._]#

Create an unordered set from the specified iterator range.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class INPUT_ITERATOR>
xref:bsl/unordered_set-0d2d/2constructor-0a8.adoc[unordered_set](
    INPUT_ITERATOR first,
    INPUT_ITERATOR last,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-0a8.adoc[_» more..._]#

Create an unordered set from the specified `range`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class RANGE>
xref:bsl/unordered_set-0d2d/2constructor-02f.adoc[unordered_set](
    std::from_range_t tag,
    RANGE&& range,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-02f.adoc[_» more..._]#

Create an unordered set from the specified `values` initializer list.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class = void>
requires bsl::IsStdAllocator<ALLOCATOR>::value
xref:bsl/unordered_set-0d2d/2constructor-030e.adoc[unordered_set](
    std::initializer_list<KEY> values,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-030e.adoc[_» more..._]#

Create an empty unordered set with the specified bucket count.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
explicit
xref:bsl/unordered_set-0d2d/2constructor-015.adoc[unordered_set](
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    HASH const& hashFunction = HASH(),
    EQUAL const& keyEqual = EQUAL(),
    ALLOCATOR const& basicAllocator = ALLOCATOR());
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-015.adoc[_» more..._]#

Create an unordered set from the specified iterator range.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class INPUT_ITERATOR>
xref:bsl/unordered_set-0d2d/2constructor-0f.adoc[unordered_set](
    INPUT_ITERATOR first,
    INPUT_ITERATOR last,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-0f.adoc[_» more..._]#

Create an unordered set from the specified `range`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class RANGE>
xref:bsl/unordered_set-0d2d/2constructor-030d.adoc[unordered_set](
    std::from_range_t tag,
    RANGE&& range,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-030d.adoc[_» more..._]#

Create an unordered set from the specified `values` initializer list.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class = void,
    class = void>
requires std::is_invocable_v<HASH, const KEY &> && bsl::IsStdAllocator<ALLOCATOR>::value
xref:bsl/unordered_set-0d2d/2constructor-025.adoc[unordered_set](
    std::initializer_list<KEY> values,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    HASH const& hashFunction,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-025.adoc[_» more..._]#

Create an unordered set from the specified iterator range.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class INPUT_ITERATOR>
xref:bsl/unordered_set-0d2d/2constructor-0b.adoc[unordered_set](
    INPUT_ITERATOR first,
    INPUT_ITERATOR last,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    HASH const& hashFunction,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-0b.adoc[_» more..._]#

Create an unordered set from the specified `range`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class RANGE>
xref:bsl/unordered_set-0d2d/2constructor-010.adoc[unordered_set](
    std::from_range_t tag,
    RANGE&& range,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets,
    HASH const& hashFunction,
    ALLOCATOR const& basicAllocator);
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-010.adoc[_» more..._]#

Create an unordered set from the specified `values` initializer list.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class = void,
    class = void,
    class = void>
requires std::is_invocable_v<HASH, const KEY &> && std::is_invocable_v<EQUAL, const KEY &, const KEY &> && bsl::IsStdAllocator_v<ALLOCATOR>
xref:bsl/unordered_set-0d2d/2constructor-09.adoc[unordered_set](
    std::initializer_list<KEY> values,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets = 0,
    HASH const& hashFunction = HASH(),
    EQUAL const& keyEqual = EQUAL(),
    ALLOCATOR const& basicAllocator = ALLOCATOR());
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-09.adoc[_» more..._]#

Create an unordered set from the specified iterator range.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class INPUT_ITERATOR>
xref:bsl/unordered_set-0d2d/2constructor-03c.adoc[unordered_set](
    INPUT_ITERATOR first,
    INPUT_ITERATOR last,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets = 0,
    HASH const& hashFunction = HASH(),
    EQUAL const& keyEqual = EQUAL(),
    ALLOCATOR const& basicAllocator = ALLOCATOR());
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-03c.adoc[_» more..._]#

Create an unordered set from the specified `range`.


[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<class RANGE>
xref:bsl/unordered_set-0d2d/2constructor-02e.adoc[unordered_set](
    std::from_range_t tag,
    RANGE&& range,
    xref:bsl/unordered_set-0d2d/size_type.adoc[size_type] initialNumBuckets = 0,
    HASH const& hashFunction = HASH(),
    EQUAL const& keyEqual = EQUAL(),
    ALLOCATOR const& basicAllocator = ALLOCATOR());
----

[.small]#xref:bsl/unordered_set-0d2d/2constructor-02e.adoc[_» more..._]#

== Parameters

[cols="1,4"]
|===
| Name| Description
| *original*
| source unordered set
| *basicAllocator*
| allocator used to supply memory
| *initialNumBuckets*
| initial number of buckets
| *values*
| initializer list of values
| *hashFunction*
| hash function
| *first*
| the start of the iterator range
| *last*
| one past the end of the iterator range
| *tag*
| disambiguation tag for the range constructor
| *range*
| range of values to insert
| *keyEqual*
| key‐equality functor
|===


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