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

libs/libcmt/fileatt.obj exact-match ledger

This is an isolated atomic reconstruction from authoritative campaign commit 1b270ed1. Before editing, configuration index 835 was MISSING; the unit was absent from config/parked.json, source/history/logs, all active worktrees, and the other agents' active claims.

Plain-English behavior

These two Microsoft CRT helpers adapt wide-character paths to the Xbox's narrow Win32-style file-attribute APIs. Each helper converts at most 260 bytes into a stack buffer, forces both the first and final bytes to be safe terminators, then asks the narrow API either to read or set the attributes.

The original code deliberately does not branch on wcstombs's result. That legacy behavior is preserved: adding a conversion-error check would change observable behavior and the January machine code. A modern caller that wants stricter behavior should validate conversion success before invoking the file API, rather than silently changing this reconstruction.

Primary provenance and inventory

The exact obj\i386\fileatt.obj member was extracted from the local XDK 3911 libcmt.lib. Its CodeView records name the original Microsoft source d:\xbox-finalfre\private\sdktools\crt\crtw32\awxapi\fileatt.c, contain ordinary function and line records, and prove this is compiled C rather than handwritten assembly.

The historical Microsoft CRT source at that exact crtw32\awxapi\fileatt.c path was independently recovered from the Easy-Build-2k NT source mirror, commit 36fce23389e43918faf4cd88688c64aa2668ff8f. It expresses the same two 260-byte conversion-buffer wrappers through the original OCHAR, tcstoocs, and Get/SetFileAttributes portability macros. January bytes and relocations remain the acceptance authority.

Before production source work, the extracted member compared strict-equal to January for both runtime functions:

• ___crtGetFileAttributesW: 57 bytes, two REL32 relocations at +0x20 to _wcstombs and +0x33 to _GetFileAttributesA@4, normalized SHA-256 815148338ca4d151152660fe6262cd5d7c468a93c04d449741934770492a27db;
• ___crtSetFileAttributesW: 60 bytes, two REL32 relocations at +0x20 to _wcstombs and +0x36 to _SetFileAttributesA@8, normalized SHA-256 5bcb591913cde9f9fa4f9e16f3fe7029ea17f5b4d0547cba7937065f23f4fa67.

The archive also carries select-any XDK header tables and build metadata. January's linked object owns neither; only the two external function COMDATs belong to this runtime unit. Those discarded archive definitions must not be recreated as source-owned data.

Source-shape experiments

ID	Readable C shape	Measured result
E01	Expand the authentic portability macros into typed wchar_t input, a 260-byte char buffer, wcstombs, an explicit final terminator, and the matching narrow API call	Both functions strict exact on the first configured /O1 /Gy rebuild, including all four relocation identities

No assembly, byte patch, volatile, forced inline, undefined behavior, opaque offset, optimizer pragma, flag change, or comparator exception is permitted.

Acceptance evidence

The candidate was built with XDK 3911 CL under this unit's configured /O1 /Gy flags. Both functions compare strict-equal to both the January split target and the extracted archive member, including sizes, normalized bytes, all relocation addresses/types/destinations, COMDAT flags, linkage, and symbol ownership. January and the candidate each own exactly two external .text COMDATs and no runtime .data, .bss, or .rdata; the archive-only select-any definitions are correctly absent.

A forced clean followed by the full Halo and libcmt builds passed, along with semantic and progress generation. The semantic ledger accepted both functions with zero unit errors. The admission audit reported no candidate, contradiction, or revocation for libs/libcmt/fileatt. All 179 tooling tests and git diff --check passed. The final clean-commit whole-unit regression snapshot/check then rebuilt the object and reported both functions as still_exact, with zero failures, warnings, changed-nonexact functions, or unreviewed newly-exact functions.

House, Berth, readability, and original-bug audit

This is ordinary typed C recovered from primary archive and Microsoft source provenance: parameters occupy their own lines, returns are explicit, the 260-byte limit is named, and all external calling conventions and types are stated. There is no assembly, volatile, forced inline, undefined behavior, byte forcing, raw structure offset, optimization pragma, flag change, comparator exception, or ownership fiction. Neither function is zero-argument, so the project's explicit (void) rule does not apply.

The preserved conversion-error/truncation behavior is called out directly in the production source as an original bug, together with the defensive fix a future non-matching port could choose. The exact reconstruction intentionally does not apply that fix because doing so would change the original runtime's observable behavior and bytes.