std::queue<T,Container>::emplace (3) - Linux Manuals
template< class... Args > (since C++11)
void emplace( Args&&... args ); (until C++17)
template< class... Args > (since C++17)
decltype(auto) emplace( Args&&... args );
Pushes a new element to the end of the queue. The element is constructed in-place, i.e. no copy or move operations are performed. The constructor of the element is called with exactly the same arguments as supplied to the function.
Effectively calls c.emplace_back(std::forward<Args>(args)...);
args - arguments to forward to the constructor of the element
(none) (until C++17)
The value or reference, if any, returned by the above call to Container::emplace_back. (since C++17)
Identical to the complexity of Container::emplace_back.
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
DR Applied to Behavior as published Correct behavior
LWG_2783 C++17 emplace returned reference, breaking compatibility with pre-C++17 containers returns decltype(auto)
push (public member function)
pop (public member function)