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)

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.

Parameters

args	-	arguments to forward to the constructor of the element
Type requirements
- T (the container's element type) must meet the requirements of EmplaceConstructible

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)