Null References

Hoare, T. (2009). Null References: The Billion Dollar Mistake.

Type

Book chapter

Intellectual base

Review or monograph

Year

2009

Link

https://www.infoq.com/presentations/Null-References-The-Billion-Dollar-Mistake-Tony-Hoare/

Cited from

computer_science, mathematics

Cited by

2 citations across 2 artifacts.

Each citation links to the sentence it supports in the citing article.

Primes

• Empty Set
  • In programming it is the empty list, array, or map; the typed None/Nothing of Option/Maybe types; the Void and Unit types; and the sharp contrast between an untyped null (danger) and a typed Nothing (safety).

    This sourceIdentifies the conflation of typed empty with untyped null as a foundational error, motivating Option/Maybe types (typed `None`/`Nothing`) that keep operations total.

• Unverified Precondition
  • Software. Null dereference and use-after-free: a reference is used without checking it points to a live object, so the program crashes or proceeds with corrupted state — the canonical computing case.

    This sourceHoare's account of inventing the null reference and its consequence — the null dereference, the canonical computing case of using a reference without checking it points to a live object.

Verification

This reference passed the adversarial substantiation pipeline: it was checked to exist and to support the claim it is attached to. See how references were verified.

Registry ID ref:acb491486b61 · see in the full table