[heditrigui]

What

Implement timelocal in libc as an alias to libc_mktime_nid_postfix matching FreeBSD/POSIX behavior, and add test coverage in GuestMktime.cpp.

Tested

Ran python tools/check_conventions.py --base upstream/main cleanly (0 errors).
Ran python core/libs/tests/test_public_headers.py --audit-only cleanly.
Ran python tools/progress.py verifying progress increase (libraries 6567/13449 -> 6568/13450).

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: none
• Fixes: none
• Unblocks: none
• GPUs tested: n/a
• AI-assisted: yes

[github-actions]

Progress report (9f748f4 → 9baa878)

📈 System libraries: 27.27% (+0.01%, +1 implemented functions)

✅ 1 implemented

Library	Name
libc	timelocal_nid_postfix

Changed libraries (implemented exports)

Library	Before	After	Change
libc	1480/1496 (98.93%)	1481/1497 (98.93%)	+0.0007%

[oneandonlydean]

@heditrigui Please check timelocal against FreeBSD 11.4 lib/libc/stdtime/localtime.c. If it sets tm_isdst = -1 before converting, as I expect, do the same (and keep the failure path leaving the struct unchanged apart from that), and add a case under a DST zone such as EST5EDT where the input has tm_isdst 0 or 1 in summer, comparing timelocal with mktime. If the source shows a plain alias, say so in the debt entry and cite the line.

[heditrigui]

@oneandonlydean Checked FreeBSD 11 (contrib/tzcode/stdtime/localtime.c lines 2126-2132): timelocal indeed sets tmp->tm_isdst = -1 before calling mktime. Updated timelocal to set tm_isdst = -1 (preserving input fields on failure), cited lines 2126-2132 in the technical debt entry, and added CheckTimelocalDst in GuestMktime.cpp verifying under EST5EDT that summer input with tm_isdst=0 produces the active EDT timestamp (1 hour earlier than mktime's forced standard-time result).

[github-actions]

Other open pull requests touch the same code. Merging one will break the other, or both implement the same thing. If this one builds on them, list them in Depends on.

Pull request	Conflicting files (lines on main)	Same exports	Same new files
PR 10409	core/libs/tests/GuestMktime.cpp L126-127
PR 12593	docs/dev/debt/libc.md L235

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 5021	core/libs/prx/libc/src/Time.cpp docs/dev/debt/libc.md
PR 5303	docs/dev/debt/libc.md
PR 6565	docs/dev/debt/libc.md
PR 7081	docs/dev/debt/libc.md
PR 7386	docs/dev/debt/libc.md
PR 7447	docs/dev/debt/libc.md
PR 7715	docs/dev/debt/libc.md
PR 8150	docs/dev/debt/libc.md
PR 8965	docs/dev/debt/libc.md
PR 9340	docs/dev/debt/libc.md
PR 9371	docs/dev/debt/libc.md
PR 9447	core/libs/prx/libc/src/Time.cpp docs/dev/debt/libc.md
PR 9526	docs/dev/debt/libc.md
PR 9929	docs/dev/debt/libc.md
PR 9964	docs/dev/debt/libc.md
PR 10113	docs/dev/debt/libc.md
PR 10226	docs/dev/debt/libc.md
PR 10245	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 10274	docs/dev/debt/libc.md
PR 10315	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 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 10987	core/libs/prx/libc/src/Time.cpp 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 11332	docs/dev/debt/libc.md
PR 11831	core/libs/prx/libc/include/Api.hpp docs/dev/debt/libc.md
PR 11907	docs/dev/debt/libc.md
PR 12057	docs/dev/debt/libc.md
PR 12122	docs/dev/debt/libc.md
PR 12292	docs/dev/debt/libc.md
PR 12397	docs/dev/debt/libc.md
PR 12514	docs/dev/debt/libc.md
PR 12560	docs/dev/debt/libc.md
PR 12574	docs/dev/debt/libc.md
PR 12627	docs/dev/debt/libc.md
PR 13390	docs/dev/debt/libc.md
PR 13804	docs/dev/debt/libc.md
PR 14212	docs/dev/debt/libc.md
PR 14373	core/libs/prx/libc/include/Api.hpp docs/dev/debt/libc.md
PR 14585	core/libs/prx/libc/include/Api.hpp docs/dev/debt/libc.md
PR 14610	core/libs/prx/libc/include/Api.hpp docs/dev/debt/libc.md

[maskym]

Windows result for head 2a46544885, merged into main 75f3702aed (the PR's Tested section names no Windows run).

Host: Windows 11 26300, Intel i7-12700K, WinLibs GCC 15.2.0 (x86_64-ucrt-posix-seh, r6), Release, BUILD_TESTING=ON, Ninja. Build clean.

guest_mktime aborts in the new CheckTimelocalDst with mktime normalized tm_isdst was not 0 for forced standard time. The checks before it pass: under TZ=EST5EDT the summer instant has tm_isdst == 1, timelocal returns summerTimer, and mktime with tm_isdst = 0 returns summerTimer + 3600. What fails is the expectation that mktime leaves tm_isdst at 0 afterwards: libc_mktime (Time.cpp:583-585) does not take the normalized fields from the host std::mktime, it rebuilds the struct with localtime_s of the resulting time, and that instant is in DST, so tm_isdst comes back as 1 on this host. timelocal itself behaves as the PR describes (tm_isdst 1 in summer, -1 and otherwise untouched fields on the unrepresentable date; those checks come after the abort, so I verified them only by reading). The tree also carried #11793, #11773, #11890 and #11846, which touch neither Time.cpp nor GuestMktime.cpp. Not run on a PS5.

AI-assisted: yes (Claude Code), the runs and the numbers above are from this machine.

[heditrigui]

@maskym Thanks for running and pointing out the Windows mktime struct rebuild behavior with localtime_s in Time.cpp! Dropped the over-specified forMktime.tm_isdst == 0 assertion, keeping the DST-vs-standard conversion return values and forTimelocal.tm_isdst == 1 verification.

[maskym]

Retested head 2dc798856c on Windows, merged into main 2ee8e9751a together with #11848's 581e0c0454 (both merged cleanly).

Host: Windows 11 26300, Intel i7-12700K, WinLibs GCC 15.2.0 (x86_64-ucrt-posix-seh, r6), Release, BUILD_TESTING=ON, Ninja. Build clean.

ctest --test-dir build -R "^guest_mktime$": passed in 0.04 s. The earlier failure at the tm_isdst == 0 expectation no longer occurs with the narrowed check. Not run on a PS5.

AI-assisted: yes (Claude Code), the runs and the numbers above are from this machine.

[B-Howell]

Linux result (the runs so far are Windows only; the EST5EDT case goes through glibc's zone handling here, not UCRT's).

Setup: Ubuntu 22.04 under WSL2, GCC 11.4.0, glibc 2.35, Ninja Release, BUILD_TESTING=ON, AMD Ryzen 7 7800X3D. Head 2dc798856cc1540a2f16a52f8bdd982f4661b6ce merged alone onto main 951399570d4a43e714ee10ed1f9d3ee8c796e749 (clean).

Test: ctest -R '^guest_mktime$' --repeat until-fail:10: passes all 10 runs, including CheckTimelocalDst.

No control: timelocal is a new export, so restoring Time.cpp from main leaves the test unable to link rather than showing a behaviour difference.

Not tested: macOS, any title.

AI-assisted (Claude Code).

[oneandonlydean]

@heditrigui Thank you for adding the summer-time case under EST5EDT. On the Windows run for 4307d56 (job 558, guest_mktime) it stops at this line in CheckTimelocalDst:

Require(mktimeResult == summerTimer + 3600, "mktime did not respect forced standard time tm_isdst=0");

The two checks before it pass on Windows (localtime_s reports summer time, and timelocal returns the summer timer), so timelocal itself looks right. What fails is the extra comparison that mktime with tm_isdst = 0 lands one hour later: the shared mktime hands the broken-down time to the host std::mktime, and the Windows runtime does not give the glibc result for a forced-standard-time request inside a DST period. That behaviour belongs to mktime, not to this change, and the Linux run cannot see it because glibc honours tm_isdst = 0.

Please make the test independent of that host behaviour. Either drop the mktimeResult == summerTimer + 3600 requirement, or compile it only where the host honours it (#ifndef _WIN32), and keep the timelocal checks on every host: the result equals summerTimer when the input says tm_isdst = 0, the normalized tm_isdst is 1, and the failure path leaves the other fields alone. If you want to know what Windows returns there, printing mktimeResult - summerTimer in the failure message would show it on the next run.

No change to timelocal_nid_postfix or the debt entry is needed for this. If you would rather record that mktime ignores a forced tm_isdst = 0 on Windows, that is a separate libc debt line and can come in its own PR.

[heditrigui]

@oneandonlydean Thanks! Guarded the host mktime forced standard time comparison under #ifndef _WIN32\ in \GuestMktime.cpp\ as suggested, keeping the test independent of Windows host \mktime\ behavior while retaining the \ imelocal\ summer normalization and unrepresentable date checks on every platform. Rebased cleanly onto latest upstream/main.

[maskym]

Retested head 9baa8782a7 on Windows, merged into main 9f748f4d8e (the head changed since my earlier runs: the separate "drop mktime normalized isdst assertion" commit is gone, leaving the two timelocal commits).

Host: Windows 11 26300, Intel i7-12700K, WinLibs GCC 15.2.0 (x86_64-ucrt-posix-seh, r6), Release, BUILD_TESTING=ON, Ninja. Build clean.

The tree also carried the open PR #13455, merged cleanly. guest_mktime passes 3 of 3 runs on this head, including the summer DST comparison, where the first head I tested aborted. Not run on a PS5.

AI-assisted: yes (Claude Code), the runs and the numbers above are from this machine.