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2026-01-01Update copyright dates with scripts/update-copyrightsPaul Eggert
2025-12-09Handle clang -Wignored-attributes on weak aliasesAdhemerval Zanella
Clang issues a warning for double alias redirection, indicating that thei original symbol is used even if a weak definition attempts to override it. For instance, in the construction: int __internal_impl (...) {} weak_alias (__internal_impl, external_impl); #if SOMETHING weak_alias (external_impl, another_external_impl) #endif Clang warns that another_external_impl always resolves to __internal_impl, even if external_impl is a weak reference. Using the internal symbol for both aliases resolves this warning. This issue also occurs with certain libc_hidden_def usage: int __internal_impl (...) {} weak_alias (__internal_impl, __internal_alias) libc_hidden_weak (__internal_alias) In this case, using a strong_alias is sufficient to avoid the warning (since the alias is internal, there is no need to use a weak alias). However, for the constructions like: int __internal_impl (...) {} weak_alias (__internal_impl, __internal_alias) libc_hidden_def (__internal_alias) weak_alias (__internal_impl, external_alias) libc_hidden_def (external_alias) Clang warns that the internal external_alias will always resolve to __GI___internal_impl, even if a weak definition of __GI_internal_impl is overridden. For this case, a new macro named static_weak_alias is used to create a strong alias for SHARED, or a weak_alias otherwise. With these changes, there is no need to check and enable the -Wno-ignored-attributes suppression when using clang. Checked with a build on affected ABIs, and a full check on aarch64, armhf, i686, and x86_64. Reviewed-by: Sam James <sam@gentoo.org>
2025-12-03time: Add TIME_MONOTONIC, TIME_ACTIVE, and TIME_THREAD_ACTIVEAdhemerval Zanella
The TIME_MONOTONIC maps to POSIX's CLOCK_MONOTONIC, TIME_ACTIVE to CLOCK_PROCESS_CPUTIME_ID, and TIME_THREAD_ACTIVE to CLOCK_THREAD_CPUTIME_ID. No Linux specific timer are added as extension. Co-authored-by: Yonggang Luo <luoyonggang@gmail.com> Reviewed-by: Paul Eggert <eggert@cs.ucla.edu>
2025-11-27Define C23 header version macrosJoseph Myers
C23 defines library macros __STDC_VERSION_<header>_H__ to indicate that a header has support for new / changed features from C23. Now that all the required library features are implemented in glibc, define these macros. I'm not sure this is sufficiently much of a user-visible feature to be worth a mention in NEWS. Tested for x86_64. There are various optional C23 features we don't yet have, of which I might look at the Annex H ones (floating-point encoding conversion functions and _Float16 functions) next. * Optional time bases TIME_MONOTONIC, TIME_ACTIVE, TIME_THREAD_ACTIVE. See <https://sourceware.org/pipermail/libc-alpha/2023-June/149264.html> - we need to review / update that patch. (I think patch 2/2, inventing new names for all the nonstandard CLOCK_* supported by the Linux kernel, is rather more dubious.) * Updating conform/ tests for C23. * Defining the rounding mode macro FE_TONEARESTFROMZERO for RISC-V (as far as I know, the only architecture supported by glibc that has hardware support for this rounding mode for binary floating point) and supporting it throughout glibc and its tests (especially the string/numeric conversions in both directions that explicitly handle each possible rounding mode, and various tests that do likewise). * Annex H floating-point encoding conversion functions. (It's not entirely clear which are optional even given support for Annex H; there's some wording applied inconsistently about only being required when non-arithmetic interchange formats are supported; see the comments I raised on the WG14 reflector on 23 Oct 2025.) * _Float16 functions (and other header and testcase support for this type). * Decimal floating-point support. * Fully supporting __int128 and unsigned __int128 as integer types wider than intmax_t, as permitted by C23. Would need doing in coordination with GCC, see GCC bug 113887 for more discussion of what's involved.
2025-10-30Cleanup some recently added whitespace.Collin Funk
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2025-10-29Annotate swtich fall-throughAdhemerval Zanella
The clang default to warning for missing fall-through and it does not support all comment-like annotation that gcc does. Use C23 [[fallthrough]] annotation instead. proper attribute instead. Reviewed-by: Collin Funk <collin.funk1@gmail.com>
2025-05-16Remove <libc-tsd.h>Florian Weimer
Use __thread variables directly instead. The macros do not save any typing. It seems unlikely that a future port will lack __thread variable support. Some of the __libc_tsd_* variables are referenced from assembler files, so keep their names. Previously, <libc-tls.h> included <tls.h>, which in turn included <errno.h>, so a few direct includes of <errno.h> are now required. Reviewed-by: Frédéric Bérat <fberat@redhat.com>
2025-01-01Update copyright dates with scripts/update-copyrightsPaul Eggert
2024-12-16Use empty initializer to silence GCC 4.9 or olderH.J. Lu
Use empty initializer to silence GCC 4.9 or older: getaddrinfo.c: In function ‘gaih_inet’: getaddrinfo.c:1135:24: error: missing braces around initializer [-Werror=missing-braces] / sizeof (struct gaih_typeproto)] = {0}; ^ Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Sam James <sam@gentoo.org>
2024-12-15Revert "Add braces in initializers for GCC 4.9 or older"H.J. Lu
This reverts commit 8aa2a9e0339215012354f3c4a262edda838134e8. as not all targets need braces.
2024-12-15tst-difftime.c: Use "main (void)"H.J. Lu
Use "main (void)" instead of "main (void)" to avoid GCC 4.9 warning: tst-difftime.c:62:1: error: function declaration isn’t a prototype [-Werror=strict-prototypes] main () ^ tst-difftime.c: In function ‘main’: tst-difftime.c:62:1: error: old-style function definition [-Werror=old-style-definition] cc1: all warnings being treated as errors Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
2024-12-15Return EXIT_UNSUPPORTED if __builtin_add_overflow unavailableH.J. Lu
Since GCC 4.9 doesn't have __builtin_add_overflow: In file included from tst-stringtable.c:180:0: stringtable.c: In function ‘stringtable_finalize’: stringtable.c:185:7: error: implicit declaration of function ‘__builtin_add_overflow’ [-Werror=implicit-function-declaration] else if (__builtin_add_overflow (previous->offset, ^ return EXIT_UNSUPPORTED for GCC 4.9 or older. Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Sam James <sam@gentoo.org>
2024-12-14Add braces in initializers for GCC 4.9 or olderH.J. Lu
Add braces to silence GCC 4.9 or older: getaddrinfo.c: In function ‘gaih_inet’: getaddrinfo.c:1135:24: error: missing braces around initializer [-Werror=missing-braces] / sizeof (struct gaih_typeproto)] = {0}; ^ Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Sam James <sam@gentoo.org>
2024-10-31Link tst-clock_gettime with $(librt)Joseph Myers
This is needed to avoid link failures for the timer_* functions on Hurd. Tested with build-many-glibcs.py for i686-gnu.
2024-10-30Add tests of time, gettimeofday, clock_gettimeJoseph Myers
There are no tests specifically focused on the functions time, gettimeofday and clock_gettime, although there are some incidental uses in tests of other functions. Add tests specifically for these three functions. Tested for x86_64 and x86.
2024-07-12time/Makefile: Split and sort testsSamuel Dobron
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2024-06-27time: Avoid memcmp overread in tzset (bug 31931)Florian Weimer
The test does not necessarily trigger the crash, depending on memcmp behavior. A crash was observed in __memcmp_ia32 on i686 builds. Reviewed-by: Paul Eggert <eggert@cs.ucla.edu>
2024-06-15Modernize and fix doc’s “Date and Time” (BZ 31876)Paul Eggert
POSIX.1-2024 (now official) specifies tm_gmtoff and tm_zone. This is a good time to update the manual’s “Date and Time” chapter so I went through it, fixed some outdated stuff that had been in there for decades, and improved it to match POSIX.1-2024 better and to clarify some implementation-defined behavior. Glibc already conforms to POSIX.1-2024 in these matters, so this is merely a documentation change. * manual/examples/strftim.c: Use snprintf instead of now-deprecated function asctime. Check for localtime failure. Simplify by using puts instead of fputs. Prefer ‘buf, sizeof buf’ to less-obvious ‘buffer, SIZE’. * manual/examples/timespec_subtract.c: Modernize to use struct timespec not struct timeval, and rename from timeval_subtract.c. All uses changed. Check for overflow. Do not check for negative return value, which ought to be OK since negative time_t is OK. Use GNU indenting style. * manual/time.texi: Document CLOCKS_PER_SEC, TIME_UTC, timespec_get, timespec_getres, strftime_l. Document the storage lifetime of tm_zone and of tzname. Caution against use of tzname, timezone and daylight, saying that these variables have unspecified values when TZ is geographic. This is what glibc actually does (contrary to what the manual said before this patch), and POSIX is planned to say the same thing <https://austingroupbugs.net/view.php?id=1816>. Also say that directly accessing the variables is not thread-safe. Say that localtime_r and ctime_r don’t necessarily set time zone state. Similarly, in the tzset documentation, say that it is called by ctime, localtime, mktime, strftime, not that it is called by all time conversion functions that depend on the time zone. Say that tm_isdst is useful mostly just for mktime, and that other uses should prefer tm_gmtoff and tm_zone instead. Do not say that strftime ignores tm_gmtoff and tm_zone, because it doesn’t do that. Document what gmtime does to tm_gmtoff and tm_zone. Say that the asctime, asctime_r, ctime, and ctime_r are now deprecated and/or obsolescent, and that behavior is undefined if the year is < 1000 or > 9999. Document strftime before these now-obsolescent functions, so that readers see the useful function first. Coin the terms “geographical format” and “proleptic format” for the two main formats of TZ settings, to simplify exposition. Use this wording consistently. Update top-level proleptic syntax to match POSIX.1-2024, which glibc already implements. Document the angle-bracket quoted forms of time zone abbreviations in proleptic TZ. Say that time zone abbreviations can contain only ASCII alphanumerics, ‘+’, and ‘-’. Document what happens if the proleptic form specifies a DST abbreviation and offset but omits the rules. POSIX says this is implementation-defined so we need to document it. Although this documentation mentions ‘posixrules’ tersely, we need to rethink ‘posixrules’ since I think it stops working after 2038. Clarify wording about TZ settings beginning with ‘;’. Say that timegm is in ISO C (as of C23). Say that POSIX.1-2024 removed gettimeofday. Say that tm_gmtoff and tm_zone are extensions to ISO C, which is clearer than saying they are invisible in a struct ISO C enviroment, and gives us more wiggle room if we want to make them visible in strict ISO C, something that ISO C allows. Drop mention of old standards like POSIX.1c and POSIX.2-1992 in the text when the history is so old that it’s no longer useful in a general-purpose manual. Define Coordinated Universal Time (UTC), time zone, time zone ruleset, and POSIX Epoch, and use these phrases more consistently. Improve TZ examples to show more variety, and to reflect current practice and timestamps. Remove obsolete example about Argentina. Add an example for Ireland. Don’t rely on GCC extensions when explaining ctime_r. Do not say that difftime produces the mathematically correct result, since it might be inexact. For clock_t don’t say “as in the example above” when there is no such example, and don’t say that casting to double works “properly and consistently no matter what”, as it suffers from rounding and overflow. Don’t say broken-down time is not useful for calculations; it’s merely painful. Say that UTC is not defined before 1960. Rename Time Zone Functions to Time Zone State. All uses changed. Update Internet RFC 822 → 5322, 1305 → 5905. Drop specific years of ISO 8601 as they don’t matter. Minor style changes: @code{"..."} → @t{"..."} to avoid overquoting in info files, @code → @env for environment variables, Daylight Saving Time → daylight saving time, white space → whitespace, prime meridian → Prime Meridian.
2024-06-04difftime can throw exceptionsPaul Eggert
difftime can signal an inexact conversion when converting to double, so it should not be marked as pure or nothrow (BZ 31808). Although we could do something more complicated, in which difftime is plain on modern platforms but const and nothrow on obsolescent platforms with 32-bit time_t, it hardly seems worth the trouble. difftime is used so rarely that it's not worth taking pains to optimize calls to it on obsolescent platforms. Reviewed-by: DJ Delorie <dj@redhat.com>
2024-05-27difftime is pure, not constPaul Eggert
Because difftime's behavior depends on the floating-point environment, the function is pure, not const (BZ 31802). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2024-05-01time: Allow later version licensing.Carlos O'Donell
The FSF's Licensing and Compliance Lab noted a discrepancy in the licensing of several files in the glibc package. When timespect_get.c was impelemented the license did not include the standard ", or (at your option) any later version." text. Change the license in timespec_get.c and all copied files to match the expected license. This change was previously approved in principle by the FSF in RT ticket #1316403. And a similar instance was fixed in commit 46703efa02f6ddebce5ee54c92f7c32598de0de6.
2024-04-02Always define __USE_TIME_BITS64 when 64 bit time_t is usedAdhemerval Zanella
It was raised on libc-help [1] that some Linux kernel interfaces expect the libc to define __USE_TIME_BITS64 to indicate the time_t size for the kABI. Different than defined by the initial y2038 design document [2], the __USE_TIME_BITS64 is only defined for ABIs that support more than one time_t size (by defining the _TIME_BITS for each module). The 64 bit time_t redirects are now enabled using a different internal define (__USE_TIME64_REDIRECTS). There is no expected change in semantic or code generation. Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, and arm-linux-gnueabi [1] https://sourceware.org/pipermail/libc-help/2024-January/006557.html [2] https://sourceware.org/glibc/wiki/Y2038ProofnessDesign Reviewed-by: DJ Delorie <dj@redhat.com>
2024-02-01Refer to C23 in place of C2X in glibcJoseph Myers
WG14 decided to use the name C23 as the informal name of the next revision of the C standard (notwithstanding the publication date in 2024). Update references to C2X in glibc to use the C23 name. This is intended to update everything *except* where it involves renaming files (the changes involving renaming tests are intended to be done separately). In the case of the _ISOC2X_SOURCE feature test macro - the only user-visible interface involved - support for that macro is kept for backwards compatibility, while adding _ISOC23_SOURCE. Tested for x86_64.
2024-01-01Update copyright dates with scripts/update-copyrightsPaul Eggert
2023-06-30Add checks for wday, yday and new date formatsMartin Coufal
tm time struct contains tm_wday and tm_yday that were previously not checked in this test. Also added new test cases for date formats containing %D, %R or %h. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-06-22Call "CST" a time zone abbreviation, not a namePaul Eggert
In documentation, call strings like "CST" time zone abbreviations, not time zone names. This terminology is more precise, and is what tzdb uses. A string like "CST" is ambiguous and does not fully name a time zone.
2023-06-12tst-getdate: Improve testcase flexibility and add test.Joe Simmons-Talbott
The getdate testcases all expect successful results. Add support for negative testcases and testcases where a full date and time are not supplied by skipping the tm checks in the test. Add a testcase that would catch a use-after-free that was recently found. Reviewed-by: Arjun Shankar <arjun@redhat.com>
2023-06-09Remove unused DATEMSK file for tst-getdateMartin Coufal
tst-getdate used to rely on an in-tree datemsk file that was subsequently replaced by a file created during test execution. This commit removes the unused file and corresponding env-var and uses a more appropriate name for the temp file. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-06-06time: Fix use-after-free in getdateArjun Shankar
getdate would free the buffer pointed to by the result of its call to strptime, then reference the same buffer later on -- leading to a use-after-free. This commit fixes that. Reported-by: Martin Coufal <mcoufal@redhat.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2023-06-05time: Also check for EPERM while trying to clock_settimeAdhemerval Zanella
Container management default seccomp filter [1] only accepts clock_settime if process has also CAP_SYS_TIME. So also handle EPERM as well. Also adapt the test to libsupport and add a proper Copyright header. Checked on aarch64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-06-02Fix all the remaining misspellings -- BZ 25337Paul Pluzhnikov
2023-06-01tests: replace write by xwriteFrédéric Bérat
Using write without cheks leads to warn unused result when __wur is enabled. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-05-29time: strftime_l: Avoid an unbounded alloca.Joe Simmons-Talbott
Avoid possible stack overflow by removing alloca() and converting to wide characters within the buffer. Suggested-by: Paul Eggert <eggert@cs.ucla.edu>
2023-05-05time: Remove alloca() from getdateJoe Simmons-Talbott
Reduce the usage of alloca() to the bare minimum to avoid the potential for stack overflow. Use __strndup to simplify the code. Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2023-03-31time: Fix strftime(3) API regarding nullabilityAlejandro Colomar
strftime(3) doesn't accept null pointers in any of the parameters. Cc: Paul Eggert <eggert@cs.ucla.edu> Signed-off-by: Alejandro Colomar <alx@kernel.org> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2023-03-27Move libc_freeres_ptrs and libc_subfreeres to hidden/weak functionsAdhemerval Zanella Netto
They are both used by __libc_freeres to free all library malloc allocated resources to help tooling like mtrace or valgrind with memory leak tracking. The current scheme uses assembly markers and linker script entries to consolidate the free routine function pointers in the RELRO segment and to be freed buffers in BSS. This patch changes it to use specific free functions for libc_freeres_ptrs buffers and call the function pointer array directly with call_function_static_weak. It allows the removal of both the internal macros and the linker script sections. Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2023-02-07Use 64-bit time_t interfaces in strftime and strptime (bug 30053)Andreas Schwab
Both functions use time_t only internally, so the ABI is not affected.
2023-01-06Update copyright dates with scripts/update-copyrightsJoseph Myers
2023-01-05time: Set daylight to 1 for matching DST/offset change (bug 29951)Florian Weimer
The daylight variable is supposed to be set to 1 if DST is ever in use for the current time zone. But __tzfile_read used to do this: __daylight = rule_stdoff != rule_dstoff; This check can fail to set __daylight to 1 if the DST and non-DST offsets happen to be the same.
2022-12-09time: Use 64 bit time on tzfileAdhemerval Zanella Netto
The tzfile_mtime is already compared to 64 bit time_t stat call. Reviewed-by: DJ Delorie <dj@redhat.com>
2022-11-01configure: Use -Wno-ignored-attributes if compiler warns about multiple aliasesAdhemerval Zanella
clang emits an warning when a double alias redirection is used, to warn the the original symbol will be used even when weak definition is overridden. However, this is a common pattern for weak_alias, where multiple alias are set to same symbol. Reviewed-by: Fangrui Song <maskray@google.com>
2022-09-22Use '%z' instead of '%Z' on printf functionsAdhemerval Zanella Netto
The Z modifier is a nonstandard synonymn for z (that predates z itself) and compiler might issue an warning for in invalid conversion specifier. Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-09-08mktime: improve heuristic for ca-1986 Indiana DSTPaul Eggert
This patch syncs mktime.c from Gnulib, fixing a problem reported by Mark Krenz <https://bugs.gnu.org/48085>, and it should fix BZ#29035 too. * time/mktime.c (__mktime_internal): Be more generous about accepting arguments with the wrong value of tm_isdst, by falling back to a one-hour DST difference if we find no nearby DST that is unusual. This fixes a problem where "1986-04-28 00:00 EDT" was rejected when TZ="America/Indianapolis" because the nearest DST timestamp occurred in 1970, a temporal distance too great for the old heuristic. This also also narrows the search a bit, which is a minor performance win.
2022-09-08Assume HAVE_TZSET in time/mktime.cPaul Eggert
This patch does not affect glibc. It affects only Gnulib-specific code and is for coordination with Gnulib.
2022-06-06Declare timegm for ISO C2XJoseph Myers
The next revision of the ISO C standard has added the timegm function (that was already supported in glibc). Update the feature test conditionals on its declaration in <time.h> accordingly. Tested for x86_64.
2022-05-23locale: Remove private union from struct __locale_dataFlorian Weimer
This avoids an alias violation later. This commit also fixes an incorrect double-checked locking idiom in _nl_init_era_entries. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2022-05-23locale: Remove cleanup function pointer from struct __localedataFlorian Weimer
We can call the cleanup functions directly from _nl_unload_locale if we pass the category to it. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2022-05-05clock_settime/clock_gettime: Use __nonnull to avoid null pointerXiaoming Ni
clock_settime() clock_settime64() clock_gettime() clock_gettime64() Add __nonnull((2)) to avoid null pointer access. Link: https://sourceware.org/bugzilla/show_bug.cgi?id=27662 Link: https://sourceware.org/bugzilla/show_bug.cgi?id=29084 Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com> Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2022-01-01Update copyright dates with scripts/update-copyrightsPaul Eggert
I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2021-12-30timezone: handle truncated timezones from tzcode-2021d and later (BZ #28707)Hans-Peter Nilsson
When using a timezone file with a truncated starting time, generated by the zic in IANA tzcode-2021d a.k.a. tzlib-2021d (also in tzlib-2021e; current as of this writing), glibc asserts in __tzfile_read (on e.g. tzset() for this file) and you may find lines matching "tzfile.c:435: __tzfile_read: Assertion `num_types == 1' failed" in your syslog. One example of such a file is the tzfile for Asuncion generated by tzlib-2021e as follows, using the tzlib-2021e zic: "zic -d DEST -r @1546300800 -L /dev/null -b slim SOURCE/southamerica". Note that in its type 2 header, it has two entries in its "time-types" array (types), but only one entry in its "transition types" array (type_idxs). This is valid and expected already in the published RFC8536, and not even frowned upon: "Local time for timestamps before the first transition is specified by the first time type (time type 0)" ... "every nonzero local time type index SHOULD appear at least once in the transition type array". Note the "nonzero ... index". Until the 2021d zic, index 0 has been shared by the first valid transition but with 2021d it's separate, set apart as a placeholder and only "implicitly" indexed. (A draft update of the RFC mandates that the entry at index 0 is a placeholder in this case, hence can no longer be shared.) * time/tzfile.c (__tzfile_read): Don't assert when no transitions are found. Co-authored-by: Christopher Wong <Christopher.Wong@axis.com>