[FIG(short list)[ [3] [[sentinel value]]

- [CN[NULL]]
- [[ぬるぽ]]
- [[なし (プログラミング言語)]]
- [[日時特殊値]]
- [[番兵]]

]FIG]

[2] [CITE@en[Sentinel value - Wikipedia]], [TIME[2023-11-13T21:03:50.000Z]], [TIME[2023-11-25T05:00:16.577Z]] <https://en.wikipedia.org/wiki/Sentinel_value>


[1] [CITE@en[PEP 661 – Sentinel Values | peps.python.org]], [TIME[2023-11-24T23:08:14.000Z]], [TIME[2023-11-25T04:59:59.999Z]] <https://peps.python.org/pep-0661/>