.. SPDX-FileCopyrightText: 2019-2020 Intel Corporation .. .. SPDX-License-Identifier: CC-BY-4.0 ================= Size and capacity ================= empty ----- .. code:: cpp 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 ---- .. code:: cpp 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 -------- .. code:: cpp size_type max_size() const; **Returns**: the maximum number of elements that container can hold.