std::unordered_multiset<Key,Hash,KeyEqual,Allocator>:: emplace

template < class ... Args > iterator emplace ( Args && ... args ) ;		(since C++11) (constexpr since C++26)

Inserts a new element into the container constructed in-place with the given args .

The constructor of the new element is called with exactly the same arguments as supplied to emplace , forwarded via std:: forward < Args > ( args ) ... .

If value_type is not EmplaceConstructible into unordered_multiset from args , the behavior is undefined.

If after the operation the new number of elements is greater than old max_load_factor() * bucket_count() a rehashing takes place.
If rehashing occurs (due to the insertion), all iterators are invalidated. Otherwise (no rehashing), iterators are not invalidated.

Contents 1 Parameters 2 Return value 3 Exceptions 4 Complexity 5 Notes 6 Example 7 See also

Parameters

args

-

arguments to forward to the constructor of the element

Return value

An iterator to the inserted element.

Exceptions

If an exception is thrown for any reason, this function has no effect ( strong exception safety guarantee ).

Complexity

Amortized constant on average, worst case linear in the size of the container.

Notes

Careful use of emplace allows the new element to be constructed while avoiding unnecessary copy or move operations.

Example

This section is incomplete Reason: no example

See also

emplace_hint	constructs elements in-place using a hint (public member function)
insert	inserts elements or nodes (since C++17) (public member function)