Concurrently safe modifiers#

All member functions in this section can be performed concurrently with each other, lookup methods and while traversing the container.

Emplacing elements#

template <typename... Args>
std::pair<iterator, bool> emplace( Args&&... args );

Attempts to insert an element constructed in-place from args into the container.

Returns: std::pair<iterator, bool> where iterator points to the inserted element or to an existing element with equal key. Boolean value is true if insertion took place; false, otherwise.

Requirements: the type value_type must meet the EmplaceConstructible requirements from the [container.requirements] ISO C++ Standard section.

template <typename... Args>
iterator emplace_hint( const_iterator hint, Args&&... args );

Attempts to insert an element constructed in-place from args into the container.

Optionally uses the parameter hint as a suggestion to where the node should be placed.

Returns: an iterator to the inserted element or to an existing element with equal key.

Requirements: the type value_type must meet the EmplaceConstructible requirements from the [container.requirements] ISO C++ Standard section.

Inserting values#

std::pair<iterator, bool> insert( const value_type& value );

Attempts to insert value into the container.

Returns: std::pair<iterator, bool>, where iterator points to the inserted element or to an existing element with equal key. Boolean value is true if insertion took place; false, otherwise.

Requirements: the type value_type must meet the CopyInsertable requirements from the [container.requirements] ISO C++ Standard section.

iterator insert( const_iterator hint, const value_type& value );

Attempts to insert value into the container.

Optionally uses the parameter hint as a suggestion to where the element should be placed.

Returns: an iterator to the inserted element or to an existing element with equal key.

Requirements: the type value_type must meet the CopyInsertable requirements from the [container.requirements] ISO C++ Standard section.

template <typename P>
std::pair<iterator, bool> insert( P&& value );

Equivalent to emplace(std::forward<P>(value)).

This overload only participates in overload resolution if std::is_constructible<value_type, P&&>::value is true.

template <typename P>
iterator insert( const_iterator hint, P&& value );

Equivalent to emplace_hint(hint, std::forward<P>(value)).

This overload only participates in overload resolution if std::is_constructible<value_type, P&&>::value is true.

std::pair<iterator, bool> insert( value_type&& value );

Attempts to insert value into the container using move semantics.

value is left in a valid, but unspecified state.

Returns: std::pair<iterator, bool>, where iterator points to the inserted element or to an existing element with equal key. Boolean value is true if insertion took place; false, otherwise.

Requirements: the type value_type must meet the MoveInsertable requirements from the [container.requirements] ISO C++ Standard section.

iterator insert( const_iterator hint, value_type&& other );

Attempts to insert value into the container using move semantics.

Optionally uses the parameter hint as a suggestion to where the element should be placed.

value is left in a valid, but unspecified state.

Returns: an iterator to the inserted element or to an existing element with equal key.

Requirements: the type value_type must meet the MoveInsertable requirements from the [container.requirements] ISO C++ Standard section.

Inserting sequences of elements#

template <typename InputIterator>
void insert( InputIterator first, InputIterator last );

Attempts to insert all items from the half-open interval [first, last) into the container.

If the interval [first, last) contains multiple elements with equal keys, it is unspecified which element should be inserted.

Requirements: the type InputIterator must meet the requirements of InputIterator from the [input.iterators] ISO C++ Standard section.

void insert( std::initializer_list<value_type> init );

Equivalent to insert(init.begin(), init.end()).

Inserting nodes#

std::pair<iterator, bool> insert( node_type&& nh );

If the node handle nh is empty, does nothing.

Otherwise, attempts to insert the node owned by nh into the container.

If the insertion fails, node handle nh keeps ownership of the node.

Otherwise, nh is left in an empty state.

No copy or move constructors of value_type are performed.

The behavior is undefined if nh is not empty and get_allocator() != nh.get_allocator().

Returns: std::pair<iterator, bool>, where iterator points to the inserted element or to an existing element with key equal to nh.key(). Boolean value is true if insertion took place; false, otherwise.

iterator insert( const_iterator hint, node_type&& nh );

If the node handle nh is empty, does nothing.

Otherwise, attempts to insert the node owned by nh into the container.

Optionally uses the parameter hint as a suggestion to where the node should be placed.

If the insertion fails, node handle nh keeps ownership of the node.

Otherwise, nh is left in an empty state.

No copy or move constructors of value_type are performed.

The behavior is undefined if nh is not empty and get_allocator() != nh.get_allocator().

Returns: an iterator pointing to the inserted element or to an existing element with key equal to nh.key().

Merging containers

template <typename SrcHash, typename SrcKeyEqual>
void merge( concurrent_unordered_map<Key, T, SrcHash, SrcKeyEqual, Allocator>& source );

template <typename SrcHash, typename SrcKeyEqual>
void merge( concurrent_unordered_map<Key, T, SrcHash, SrcKeyEqual, Allocator>&& source );

template <typename SrcHash, typename SrcKeyEqual>
void merge( concurrent_unordered_multimap<Key, T, SrcHash, SrcKeyEqual, Allocator>& source );

template <typename SrcHash, typename SrcKeyEqual>
void merge( concurrent_unordered_multimap<Key, T, SrcHash, SrcKeyEqual, Allocator>&& source );

Transfers those elements from source which keys do not exist in the container.

In case of merging with the container with multiple elements with equal keys, it is unspecified which element would be transferred.

No copy or move constructors of value_type are performed.

The behavior is undefined if get_allocator() != source.get_allocator().