D476 - The errno table carries a published tier alongside its measured one

Status: assumed Date: 2026-09-02

A value with no hardware measurement behind it, but a citable published source, is recorded in its own tier alongside the measured errno table, rather than left absent or folded into the measured one.

Why: reporting a wrong value, or the project's own unimplemented-call placeholder, for a call that is fully implemented and whose outcome is known, is worse than a clearly labelled published value. The measured tier's claim to record only observed values must stay exactly true, not loosened to admit an unmeasured one.

Rejected:

• Answering a measured value that is wrong for this condition: a value a guest can act on incorrectly.
• Answering the unimplemented-call placeholder: the call is implemented and its outcome is known.