Binary Format

An LUID is a 64-bit (8-byte) value with the following binary layout:

Offset	Size	Field	Type
0	4	LowPart	uint32, little-endian
4	4	HighPart	uint32, little-endian

The total size of an LUID MUST be exactly 8 bytes with no padding.

Both fields MUST be stored in little-endian byte order.

ⓘ Informative

MS-DTYP defines HighPart as a signed 32-bit integer (LONG). Peios uses unsigned uint32 for both fields. The signed type in MS-DTYP is a Win32 API convention with no semantic purpose -- LUID values are never negative. See §1.4.1 for the full divergence rationale.

§3.1.1 Nil LUID

The nil LUID is the LUID with all 8 bytes set to zero (LowPart = 0, HighPart = 0).

The nil LUID is a valid LUID value. The nil LUID MUST NOT be assigned by the allocation algorithm defined in §3.3.

Specifications that require a non-nil LUID MUST state this requirement explicitly.

§3.1.1 Nil LUID #

§3.1.1 Nil LUID