std::vector::emplace

 

C++

Language

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Named requirements

Language support library

Concepts library (C++20)

Diagnostics library

Utilities library

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Numerics library

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Regular expressions library (C++11)

Atomic operations library (C++11)

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Technical Specifications

 

Containers library

array (C++11)

vector

deque

forward_list (C++11)

list

set

multiset

map

multimap

unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

stack

queue

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span (C++20)

 

std::vector

Member functions

vector::vector

vector::~vector

vector::operator=

vector::assign

vector::get_allocator

Element access

vector::at

vector::operator[]

vector::front

vector::back

vector::data (C++11)

Iterators

vector::beginvector::cbegin (C++11)

vector::endvector::cend (C++11)

vector::rbeginvector::crbegin (C++11)

vector::rendvector::crend (C++11)

Capacity

vector::empty

vector::size

vector::max_size

vector::reserve

vector::capacity

vector::shrink_to_fit (C++11)

Modifiers

vector::clear

vector::insert

vector::emplace (C++11)

vector::erase

vector::push_back

vector::emplace_back (C++11)

vector::pop_back

vector::resize

vector::swap

Deduction guides(C++17)

 

template< class... Args > iterator emplace( const_iterator pos, Args&&... args );		(since C++11)

Inserts a new element into the container directly before pos. The element is constructed through std::allocator_traits::construct, which typically uses placement-new to construct the element in-place at a location provided by the container. The arguments args... are forwarded to the constructor as std::forward<Args>(args)....

If the new size() is greater than capacity(), all iterators and references are invalidated. Otherwise, only the iterators and references before the insertion point remain valid. The past-the-end iterator is also invalidated.

Parameters

pos	-	iterator before which the new element will be constructed
args	-	arguments to forward to the constructor of the element
Type requirements
- T (the container's element type) must meet the requirements of MoveAssignable, MoveInsertable and EmplaceConstructible.

Return value

Iterator pointing to the emplaced element.

Complexity

Linear in the distance between pos and end of the container.

Exceptions

If an exception is thrown other than by the copy constructor, move constructor, assignment operator, or move assignment operator of the value type, or if an exception is thrown while emplace is used to insert a single element at the end and the value type is either CopyInsertable or nothrow move constructible, there are no effects (strong exception guarantee).

Otherwise, the effects are unspecified.

Notes

The specialization std::vector<bool> did not have emplace() member until C++14.

See also

insert

inserts elements (public member function)