void pop_front()
Pop out the front element from the vector.
This function supports auto-commit.
These functions come from std::list and std::deque, and have identical behaviors to their counterparts in std::list/stddeque.
http://www.cplusplus.com/reference/stl/deque/pop_front.html http://www.cplusplus.com/reference/stl/deque/push_front.html