< cpp‎ | container‎ | flat set
template< class... Args >
std::pair<iterator, bool> emplace( Args&&... args );
(since C++23)

Inserts a new element into the container constructed in-place with the given args, if there is no element with the key in the container.

First, initializes an object t of type value_type with std::forward<Args>(args)..., then inserts t as if by
auto it = ranges::upper_bound(c, t, compare);
c.insert(it, std::move(t));

This overload participates in overload resolution only if std::is_constructible_v<value_type, Args...> is true.

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


[edit] Parameters

args - arguments to forward to the constructor of the element

[edit] Return value

A pair consisting of an iterator to the inserted element (or to the element that prevented the insertion) and a bool value set to true if and only if the insertion took place.

[edit] Exceptions

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

[edit] Complexity

Logarithmic in the size of the container.

[edit] Example

[edit] See also

constructs elements in-place using a hint
(public member function) [edit]
inserts elements
(public member function) [edit]