Cesarus85--mjolnir-vr/docs/object_matching_logs/libcmt_sftbuf_obj.md

libs/libcmt/_sftbuf.obj exact-match ledger

Plain-English scope

This object temporarily buffers stdout or stderr when the stream refers to a terminal. _stbuf allocates or reuses one of two 4096-byte buffers, falling back to the stream's two-byte internal storage when allocation fails. _ftbuf flushes and removes that temporary buffer state. The eight-byte _stdbuf array owns the two persistent buffer pointers.

The admission unit is atomic: two functions plus the complete BSS symbol.

Authoritative provenance

• Initial campaign base: 037de80f42ede0554b537056942afe00e94e4533.
• Final revalidation base: b831acac297ea8af5f1b02e1ff321ab70bb9b793.
• XDK 3911 CL 13.00.9254.1; unchanged /O1 /Gy flags.
• XDK libcmt.lib SHA-256: 60aa4c87c97eeb6662b31d9d37cf3caba1afabaec72c47b090e7a0ce8b632f55.
• CodeView source: d:/xbox-finalfre/private/sdktools/crt/crtw32/stdio/_sftbuf.c.
• Microsoft source mirror commit fd00b4b3b2abb1ea6ef9ac64b755419741a3af00, blob 209c6fb70cc72ccde747a568e76801c4c553f6f3.

The authentic archive is independently strict-identical to January before source reconstruction: _stbuf is 136 bytes with six relocations, _ftbuf is 42 bytes with one relocation, and _stdbuf owns eight zeroed BSS bytes.

Experiment table

ID	Readable source shape	Result	Disposition
P0	Authentic Microsoft topology, public XDK FILE, named private flags, two-element zero-initialized _stdbuf	EXACT: _stbuf 136B/6 relocs, _ftbuf 42B/1 reloc, _stdbuf 8B/0 relocs and external ownership exact	Accepted

Original-bug audit

No original defect was found. Retaining the allocated pointer after _ftbuf is intentional: later _stbuf calls reuse the persistent _stdbuf entry.

House/Berth audit

• Typed readable C and named constants; no raw structure offsets.
• Vertically formatted parameters and explicit return in the void routine.
• No assembly, volatile, forced inline, UB, byte forcing, pragmas, flags, or comparator exceptions.
• Original behavior is preserved.
• Credit requires strict code, symbolic relocations, data bytes/storage class, full builds, semantic/admission, regression, and test gates.

Final gates

• Forced build under unchanged /O1 /Gy: passed.
• _stbuf: exact normalized SHA-256 6744ed55bdf8efd5d94fb02ef65a8743349da4a9714fd3764902c9ccc9058b88.
• _ftbuf: exact normalized SHA-256 ae9b3b801289a758903c5e991dce030e62f1e927fc284d3e4406d2a4926e1a81.
• _stdbuf: exact eight zero bytes, no relocations, normalized SHA-256 af5570f5a1810b7af78caf4bc70a660f0df51e42baf91d4de5b2328de0e83dfc, external storage class in both objects.
• Full halobetacache_build: passed.
• Full libcmt_build: passed.
• Full progress/semantic report after rebase: passed with zero unit errors; the campaign is 356/833 Matching overall and libcmt is 89/212. The latter includes another object integrated into canonical during this lane.
• Semantic-match audit after rebase: 457 units scanned, 3,572 functions evaluated, 3,488 accepted exact, zero unit errors.
• Object-admission audit: zero new candidates, zero revocations; the sole pre-existing contradicted unit is source/shell/shell_xbox.
• Test suite: 179/179 passed.
• git diff --check and prohibited-construct scan: passed.
• Clean-tree regression snapshot/check: both functions still_exact, no failures, warnings, changed non-exact siblings, or ownership warnings.
• Every decisive gate above was repeated after rebasing onto the final base.