# Size and capacity

## empty

>     bool empty() const;

> Returns: `true` if the container is empty; `false`, otherwise.

> The result may differ with the actual container state in case of pending concurrent insertions.

## size

>     size_type size() const;

> Returns: the number of elements in the container.

> The result may differ with the actual container size in case of pending concurrent insertions.

## max_size

>     size_type max_size() const;

> Returns: the maximum number of elements that container can hold.