[Queuse]

What

Windows narrow printf can misreport oversized fields or fail while formatting even a valid INT_MAX width into a tiny buffer (#11292). Check field bounds and stream padding and precision zeros while retaining the full output count. Overflow returns -1 with guest EOVERFLOW (84).

Draft for integration coordination: #9087 goes first (confirmed) and is still open. The #9958-first order was confirmed and #9958 is now merged; the follow-up must preserve its console long-double mantissa handling. #11341-first is confirmed by its author; #5021-after remains proposed, awaiting confirmation. The rebase after #9087 lands must retain deferred termination in Pad and preserve #11341's portable GuestLongDoubleLoad path when that stack is combined. The published head and its tests below remain unchanged while this order is coordinated.

Tested

Windows 11 Home 10.0.26200, WinLibs GCC 15.2.0 UCRT r7, Ninja Release, BUILD_TESTING=ON. Head 793a55b on main 33ae5a3.

• Rebuilt libc and guest_formatting_tests, guest_wide_formatting_tests, guest_stdio_variadic_tests; all three focused CTests pass.
• Regressions cover literal/star and positional fields, capacities 0/1/16, sentinels, INT_MAX widths and exact-length precisions, cumulative overflow, negative star precision, typed string arguments and finite/nonfinite floating conversions.
• 32,400 bounded integer cases match Linux libc; 86,400 double and 31,104 long-double cases preserve baseline results (149,904 comparisons, zero differences).
• Linux WSL actual-source harness: six moderate floating fields pass with individual allocations over 64 KiB refused; five failed that allocation check before the streaming change. The 32,400-case integer comparison also passes with the formatter compiled directly on Linux.
• Conventions, public-header audit, test registration and whitespace checks pass.

No full product suite, Linux product build, title or physical-console run. Extreme-field console error behavior remains unmeasured and is recorded in debt/libc.md.

Checklist

• Based on current main; no other open PR implements the same functions
• One topic per PR; follow-ups go in a new PR
• No comments in code except technical debt
• Unimplemented paths throw (NotImplemented_nid_no_patch); silent stubs are listed under Silent stubs in their library's technical debt file
• No notes, investigation .md files or images added to the repository (attach them to this PR)
• New third-party code is a submodule built from source
• Generic behaviour, not specific to one title
• Depends on: fix(libc): follow snprintf_s and sscanf_s constraints as measured on a PS5 #9087 (merge order confirmed, pending); build(libs): support Emscripten memory64 compilation #11341 (merge order confirmed, pending). fix(libc): format %La like titles' libc.prx does #9958 merged.
• Fixes: Fixes libc: narrow snprintf on Windows crashes or misreports on a width or precision beyond int #11292
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: yes

[github-actions]

Some comparisons could not be completed because a pull request conflicts with the base branch. Review these shared files manually before concluding that there is no overlap.

Pull request	Shared files not compared
PR 3965	docs/dev/debt/libc.md
PR 5021	core/libs/prx/libc/include/WindowsFormatting.hpp core/libs/tests/Formatting.cpp docs/dev/debt/libc.md
PR 5303	docs/dev/debt/libc.md
PR 6565	docs/dev/debt/libc.md
PR 6819	docs/dev/debt/libc.md
PR 7447	docs/dev/debt/libc.md
PR 7544	docs/dev/debt/libc.md
PR 7648	docs/dev/debt/libc.md
PR 7715	docs/dev/debt/libc.md
PR 7851	docs/dev/debt/libc.md
PR 8150	docs/dev/debt/libc.md
PR 8397	docs/dev/debt/libc.md
PR 8417	docs/dev/debt/libc.md
PR 8937	docs/dev/debt/libc.md
PR 8965	docs/dev/debt/libc.md
PR 9371	docs/dev/debt/libc.md
PR 9447	docs/dev/debt/libc.md
PR 9466	docs/dev/debt/libc.md
PR 9526	docs/dev/debt/libc.md
PR 9677	docs/dev/debt/libc.md
PR 9761	docs/dev/debt/libc.md
PR 9863	docs/dev/debt/libc.md
PR 9867	docs/dev/debt/libc.md
PR 9873	docs/dev/debt/libc.md
PR 9929	docs/dev/debt/libc.md
PR 9953	docs/dev/debt/libc.md
PR 9964	docs/dev/debt/libc.md
PR 10002	docs/dev/debt/libc.md
PR 10007	docs/dev/debt/libc.md
PR 10113	docs/dev/debt/libc.md
PR 10158	docs/dev/debt/libc.md
PR 10165	docs/dev/debt/libc.md
PR 10200	docs/dev/debt/libc.md
PR 10222	docs/dev/debt/libc.md
PR 10226	docs/dev/debt/libc.md
PR 10229	docs/dev/debt/libc.md
PR 10234	docs/dev/debt/libc.md
PR 10245	docs/dev/debt/libc.md
PR 10247	docs/dev/debt/libc.md
PR 10250	docs/dev/debt/libc.md
PR 10253	docs/dev/debt/libc.md
PR 10265	docs/dev/debt/libc.md
PR 10270	docs/dev/debt/libc.md
PR 10274	docs/dev/debt/libc.md
PR 10315	docs/dev/debt/libc.md
PR 10317	docs/dev/debt/libc.md
PR 10321	docs/dev/debt/libc.md
PR 10324	core/libs/prx/libc/src/Formatting.cpp docs/dev/debt/libc.md
PR 10325	docs/dev/debt/libc.md
PR 10328	docs/dev/debt/libc.md
PR 10345	docs/dev/debt/libc.md
PR 10349	docs/dev/debt/libc.md
PR 10397	docs/dev/debt/libc.md
PR 10405	docs/dev/debt/libc.md
PR 10506	docs/dev/debt/libc.md
PR 10510	docs/dev/debt/libc.md
PR 10512	docs/dev/debt/libc.md
PR 10565	docs/dev/debt/libc.md
PR 10569	docs/dev/debt/libc.md
PR 10615	docs/dev/debt/libc.md
PR 10620	docs/dev/debt/libc.md
PR 10729	docs/dev/debt/libc.md
PR 10749	docs/dev/debt/libc.md
PR 10780	docs/dev/debt/libc.md
PR 10895	docs/dev/debt/libc.md
PR 10953	docs/dev/debt/libc.md
PR 10987	docs/dev/debt/libc.md
PR 10989	docs/dev/debt/libc.md
PR 11077	docs/dev/debt/libc.md
PR 11109	docs/dev/debt/libc.md
PR 11172	docs/dev/debt/libc.md
PR 11214	docs/dev/debt/libc.md
PR 11260	docs/dev/debt/libc.md
PR 11262	docs/dev/debt/libc.md
PR 11266	docs/dev/debt/libc.md
PR 11298	docs/dev/debt/libc.md
PR 11621	docs/dev/debt/libc.md
PR 11625	docs/dev/debt/libc.md
PR 11632	docs/dev/debt/libc.md
PR 11634	docs/dev/debt/libc.md
PR 11661	docs/dev/debt/libc.md
PR 11664	docs/dev/debt/libc.md
PR 11689	docs/dev/debt/libc.md
PR 11698	docs/dev/debt/libc.md
PR 11726	core/libs/prx/libc/src/Formatting.cpp core/libs/tests/Formatting.cpp docs/dev/debt/libc.md
PR 11733	docs/dev/debt/libc.md
PR 11773	docs/dev/debt/libc.md
PR 11793	docs/dev/debt/libc.md
PR 11831	docs/dev/debt/libc.md
PR 11843	docs/dev/debt/libc.md
PR 11848	docs/dev/debt/libc.md
PR 11849	docs/dev/debt/libc.md
PR 11850	docs/dev/debt/libc.md
PR 11870	docs/dev/debt/libc.md
PR 11892	docs/dev/debt/libc.md
PR 11895	docs/dev/debt/libc.md
PR 11907	core/libs/prx/libc/include/WindowsFormatting.hpp core/libs/prx/libc/src/Formatting.cpp core/libs/tests/Formatting.cpp docs/dev/debt/libc.md
PR 11947	docs/dev/debt/libc.md
PR 12053	docs/dev/debt/libc.md
PR 12057	docs/dev/debt/libc.md
PR 12122	docs/dev/debt/libc.md
PR 12149	docs/dev/debt/libc.md
PR 12184	docs/dev/debt/libc.md
PR 12271	docs/dev/debt/libc.md
PR 12292	docs/dev/debt/libc.md
PR 12397	core/libs/prx/libc/include/WindowsFormatting.hpp core/libs/prx/libc/src/Formatting.cpp core/libs/tests/Formatting.cpp docs/dev/debt/libc.md
PR 12428	core/libs/prx/libc/src/Formatting.cpp core/libs/tests/Formatting.cpp docs/dev/debt/libc.md
PR 12480	docs/dev/debt/libc.md
PR 12510	docs/dev/debt/libc.md
PR 12511	docs/dev/debt/libc.md
PR 12514	docs/dev/debt/libc.md
PR 12518	docs/dev/debt/libc.md
PR 12532	core/libs/prx/libc/src/Formatting.cpp core/libs/tests/Formatting.cpp docs/dev/debt/libc.md
PR 12558	core/libs/prx/libc/src/Formatting.cpp core/libs/tests/Formatting.cpp
PR 12560	docs/dev/debt/libc.md
PR 12574	docs/dev/debt/libc.md
PR 12586	docs/dev/debt/libc.md
PR 12592	docs/dev/debt/libc.md
PR 12593	docs/dev/debt/libc.md
PR 12594	docs/dev/debt/libc.md
PR 12595	docs/dev/debt/libc.md
PR 12598	docs/dev/debt/libc.md
PR 12605	docs/dev/debt/libc.md
PR 12622	core/libs/prx/libc/include/WindowsFormatting.hpp core/libs/prx/libc/src/Formatting.cpp core/libs/tests/Formatting.cpp docs/dev/debt/libc.md
PR 12627	docs/dev/debt/libc.md
PR 12682	docs/dev/debt/libc.md
PR 12688	docs/dev/debt/libc.md
PR 12700	docs/dev/debt/libc.md
PR 12704	docs/dev/debt/libc.md
PR 12841	docs/dev/debt/libc.md
PR 12849	docs/dev/debt/libc.md
PR 12920	docs/dev/debt/libc.md
PR 12947	docs/dev/debt/libc.md
PR 12965	docs/dev/debt/libc.md
PR 13186	docs/dev/debt/libc.md
PR 13390	docs/dev/debt/libc.md
PR 13442	docs/dev/debt/libc.md
PR 13449	docs/dev/debt/libc.md
PR 13499	docs/dev/debt/libc.md
PR 13678	docs/dev/debt/libc.md
PR 13732	docs/dev/debt/libc.md
PR 13783	docs/dev/debt/libc.md
PR 13784	docs/dev/debt/libc.md
PR 13793	docs/dev/debt/libc.md
PR 13794	docs/dev/debt/libc.md
PR 13804	docs/dev/debt/libc.md
PR 13809	docs/dev/debt/libc.md
PR 13819	docs/dev/debt/libc.md
PR 13828	docs/dev/debt/libc.md

[MarcZX10]

I checked the exact head 793a55ba18 against the current main (9b197b6ce4). tools/check_main_sync.py reports the PR is 1 commit ahead and 37 behind its merge base 33ae5a314, although git merge-tree currently merges it cleanly. The posted focused test report is against that older base. Because this rewrites the formatter and overlaps the still-open #9087/#9958/#10379 stack, please confirm the intended merge order and refresh onto current main once those prerequisites are integrated, then rerun the focused formatting tests on the resulting exact head. Current hosted checks pass, but the Linux and Windows product jobs are path-skipped.

[MarcZX10]

I inspected the live overlap rather than relying only on the bot table. A two-head git merge-tree preview between this head (793a55ba18) and #11341 (fcb72551ab) conflicts in WindowsFormatting.hpp. #11341 changes FormatArguments::Next<long double> to use GuestLongDoubleLoad and removes the native-long-double layout assertions; this formatter rewrite must preserve that portable long-double path when the two changes are combined. Please coordinate the order with #11341’s author and record the dependency/order in the checklist. The #9958-first / #5021-after order is still marked pending in this draft, so keep it explicit as those authors confirm it; I am not asking anyone to close a PR.

The branch is also 1 ahead and 92 behind current main (fdb3925940), with a clean merge preview but docs/dev/debt/libc.md changed on both sides since the base. CONTRIBUTING says to keep branches current; please rebase after the stack order is settled, preserve the overlapping debt edits, and rerun the focused Windows formatters and local overlap/convention checks on that exact head. I am not approving this draft before those integration and current-head checks.

[Queuse]

I have recorded the new overlap and the proposed #11341-first order. #9958's author confirmed its order and it has now merged. #9087 remains open, so I am following the requested sequence: keep this draft at 793a55ba18, then refresh after that prerequisite lands and rerun the focused formatting tests on the resolved head. That resolution must preserve console long-double digits, bounded emission, deferred Pad termination and the portable long-double load when combined with #11341. The description now distinguishes confirmed, fulfilled and pending orders; its existing test results still refer to the published head.

[Queuse]

#11341's author has now confirmed #11341 → #11332, and I have recorded it as agreed in the description/checklist. #9087 and #11341 are still open, so this draft remains at 793a55ba18 pending those prerequisites. The later rebase will retain GuestLongDoubleLoad, host-layout independence, the console mantissa rules and deferred Pad termination, then rerun the focused tests. #5021-after remains a separate proposal awaiting confirmation.