std::deque<T,Allocator>:: emplace_front

template < class ... Args > void emplace_front ( Args && ... args ) ;		(since C++11) (until C++17)
template < class ... Args > reference emplace_front ( Args && ... args ) ;		(since C++17) (constexpr since C++26)

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

All iterators (including the end() iterator) are invalidated. No references are invalidated.

Contents 1 Parameters 2 Return value 3 Complexity 4 Exceptions 5 See also

Parameters

args	-	arguments to forward to the constructor of the element
Type requirements
- If T is not EmplaceConstructible into deque from args... , the behavior is undefined.

Return value

(none)	(until C++17)
A reference to the inserted element.	(since C++17)

Complexity

Constant.

Exceptions

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

See also

push_front

inserts an element to the beginning (public member function)