# 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.