Editing Year 2038 problem

{{short description|Computer software bug occurring in 2038}}
[[File:Year 2038 problem.gif|thumb|upright=2.0|An animated visual of the bug in action. The [[integer overflow|overflow]] error will occur at 03:14:08 UTC on 19 January 2038.]]
The '''year 2038 problem''' (also known as '''Y2038''',<ref name=":0" /> '''Y2K38''', '''Y2K38 superbug''' or the '''Epochalypse'''<ref>{{cite web |url=https://www.linaro.org/blog/the-end-of-an-era/ |title=The end of an Era |date=February 6, 2020 |first=Arnd |last=Bergmann |publisher=Linaro |access-date=13 September 2020 |archive-date=7 February 2020 |archive-url=https://web.archive.org/web/20200207034639/https://www.linaro.org/blog/the-end-of-an-era/ |url-status=live }}</ref><ref>{{cite news |url=https://www.tomsguide.com/us/2038-bug-bh2017,news-25551.html |title=Digital 'Epochalypse' Could Bring World to Grinding Halt |first=Paul |last=Wagenseil |date=July 28, 2017 |work=Tom's Guide |access-date=13 September 2020 |archive-date=29 November 2021 |archive-url=https://web.archive.org/web/20211129222317/https://www.tomsguide.com/us/2038-bug-bh2017,news-25551.html |url-status=live }}</ref>) is a [[Time formatting and storage bugs|time computing problem]] that leaves some computer systems unable to represent times after 03:14:07 [[Coordinated Universal Time|UTC]] on 19&nbsp;January&nbsp;2038.

The problem exists in systems which measure [[Unix time]]&mdash;the number of seconds elapsed since the ''Unix [[Epoch (computing)|epoch]]'' (00:00:00 UTC on 1&nbsp;January&nbsp;1970)&mdash;and store it in a [[Integer (computer science)|signed 32-bit integer]]. The data type is only capable of representing integers between &minus;(2{{sup|31}}) and [[2,147,483,647|2<sup>31</sup>&nbsp;&minus;&nbsp;1]], meaning the latest time that can be properly encoded is 2{{sup|31}}&nbsp;&minus;&nbsp;1 seconds after epoch (03:14:07 UTC on 19&nbsp;January&nbsp;2038). Attempting to increment to the following second (03:14:08) will cause the [[integer overflow|integer to overflow]], setting its value to &minus;(2{{sup|31}}) which systems will interpret as 2{{sup|31}} seconds ''before'' epoch (20:45:52 UTC on 13&nbsp;December&nbsp;1901). The problem is similar in nature to the [[year 2000 problem]], the difference being the Year 2000 problem had to do with [[Decimal|base 10 numbers]], whereas the Year 2038 problem involves [[Binary number|base 2 numbers]].

Analogous storage constraints will be reached in [[Time_formatting_and_storage_bugs#Year_2106|2106]], where systems storing Unix time as an ''unsigned'' (rather than signed) 32-bit integer will overflow on 7 February 2106 at 06:28:15 UTC.

Computer systems that use time for critical computations may encounter fatal errors if the year 2038 problem is not addressed. Some applications that use future dates have already encountered the bug.<ref name=":1" /><ref name=":2" /> The most vulnerable systems are those which are infrequently or never updated, such as [[Legacy system|legacy]] and [[embedded system]]s. Modern systems and software updates to legacy systems address this problem by using signed [[64-bit computing|64-bit]] integers instead of 32-bit integers, which will take 292 billion years to overflow—approximately 21 times the estimated [[age of the universe]].

== Cause ==
Many computer systems measure time and date using [[Unix time]], an international standard for digital timekeeping. Unix time is defined as the number of seconds elapsed since 00:00:00 [[Coordinated Universal Time|UTC]] on 1 January 1970 (an arbitrarily chosen time based on the creation of the first [[Unix|Unix system]]), which has been dubbed the ''Unix epoch''.<ref>{{cite web|title=Epoch Time|url=https://www.unixtutorial.org/epoch-time/|access-date=13 April 2023|work=unixtutoria|date=15 March 2019|language=en|archive-date=13 April 2023|archive-url=https://web.archive.org/web/20230413221727/https://www.unixtutorial.org/epoch-time/|url-status=live}}</ref> 

Unix time has historically been encoded as a [[integer (computer science)|signed 32-bit integer]], a data type composed of 32 [[Bit|binary digits]] (bits) which represent an integer value, with 'signed' meaning that the number can represent both positive and negative numbers, as well as zero; and is usually stored in [[two's complement]] format.{{efn|Unless otherwise specified, all the numbers provided in this article have been derived using two's complement for signed integer arithmetic.}} Thus, a signed 32-bit integer can only represent integer values from &minus;(2{{sup|31}}) to [[2,147,483,647|2<sup>31</sup>&nbsp;&minus;&nbsp;1]] inclusive. Consequently, if a signed 32-bit integer is used to store Unix time, the latest time that can be stored is 2<sup>31</sup>&nbsp;&minus;&nbsp;1 (2,147,483,647) seconds after epoch, which is {{#time:H:i:s "on" l, j F Y|@{{#expr:2^31 -1}}}}.<ref name="spinellis">{{cite book|author=Diomidis Spinellis|url=https://books.google.com/books?id=vEN-ckcdtCwC&q=292%2C277%2C026%2C596&pg=PA49|title=Code quality: the open source perspective|publisher=[[Adobe Press]]|year=2006|isbn=978-0-321-16607-4|edition=illustrated|series=Effective software development series in [[Safari Books Online]]|page=49}}</ref> Systems that attempt to increment this value by one more second to 2{{sup|31}} seconds after epoch (03:14:08) will suffer [[integer overflow]], inadvertently flipping the sign bit to indicate a negative number. This changes the integer value to &minus;(2{{sup|31}}), or 2{{sup|31}} seconds ''before'' epoch rather than ''after'', which systems will interpret as 20:45:52 on Friday, 13 December 1901. From here, systems will continue to count up, toward zero, and then up through the positive integers again. As many computer systems use time computations to run critical functions, the bug may introduce serious problems.

== Vulnerable systems ==
Any system using [[data structure]]s with signed 32-bit time representations has an inherent risk of failing. A full list of these data structures is virtually impossible to derive, but there are well-known data structures that have the Unix time problem:
* File systems that use 32 bits to represent times in [[inode]]s, such as [[ext2]], [[ext3]], [[reiserFS]].
* Databases with 32-bit time fields
* Database query languages (such as [[SQL]]) that have <code>UNIX_TIMESTAMP()</code>-like commands

=== Embedded systems ===
[[Embedded system]]s that use dates for either computation or diagnostic logging are most likely to be affected by the Y2038 problem.<ref name=":0">{{cite news|url=https://www.theguardian.com/technology/2014/dec/17/is-the-year-2038-problem-the-new-y2k-bug|title=Is the Year 2038 problem the new Y2K bug?|newspaper=The Guardian|date=17 December 2014|access-date=11 October 2018|archive-date=25 January 2022|archive-url=https://web.archive.org/web/20220125075051/https://www.theguardian.com/technology/2014/dec/17/is-the-year-2038-problem-the-new-y2k-bug|url-status=live}}</ref> Despite the modern [[Moore's law|18–24 month generational update in computer systems technology]], embedded systems are designed to last the lifetime of the machine in which they are a component. It is conceivable that some of these systems may still be in use in 2038. It may be impractical or, in some cases, impossible to upgrade the software running these systems, ultimately requiring replacement if the 32-bit limitations are to be corrected.

Many transportation systems, from flight to automobiles, use embedded systems extensively. <!-- Please do not delete - for decades, there will be plenty of older cars on the road, which will use the same outdated 8/16 bit systems for decades, unless something changes. Actually it already has - engine controllers have been mostly 32-bit for a decade! But the point stands, that legacy systems can't easily be changed. --> In automotive systems, this may include [[anti-lock braking system]] (ABS), [[electronic stability control]] (ESC/ESP), [[Traction control system|traction control]] (TCS) and automatic [[four-wheel drive]]; aircraft may use [[Inertial navigation system|inertial guidance systems]] and [[Satellite navigation device|GPS receivers]].{{efn|GPS suffers its own time counter overflow problem known as [[GPS Week Number Rollover]].}} Another major use of embedded systems is in communications devices, including cell phones and Internet-enabled appliances (e.g. [[Router (computing)|routers]], [[wireless access point]]s, [[IP camera]]s) which rely on storing an accurate time and date and are increasingly based on Unix-like operating systems. For example, the Y2038 problem makes some devices running 32-bit [[Android (operating system)|Android]] crash and not restart when the time is changed to that date.<ref>{{cite web|title=ZTE Blade running Android 2.2 has 2038 problems|url=https://issuetracker.google.com/issues/36928638|access-date=20 November 2018|archive-date=19 May 2022|archive-url=https://web.archive.org/web/20220519230355/https://issuetracker.google.com/issues/36928638|url-status=live}}</ref>

However, this does not imply that all embedded systems will suffer from the Y2038 problem, since many such systems do not require access to dates. For those that do, those systems which only track the difference between times/dates and not absolute times/dates will, by the nature of the calculation, not experience a major problem. This is the case for automotive diagnostics based on legislated standards such as CARB ([[California Air Resources Board]]).<ref>{{cite web|url=http://www.arb.ca.gov/testmeth/testmeth.htm#vehicles|title=ARB Test Methods / Procedures|publisher=[[California Air Resources Board]]|website=ARB.ca.gov|access-date=12 September 2013|archive-date=18 November 2016|archive-url=https://web.archive.org/web/20161118163253/https://www.arb.ca.gov/testmeth/testmeth.htm#vehicles|url-status=dead}}</ref>

== Early problems ==
In May 2006, reports surfaced of an early manifestation of the Y2038 problem in the [[AOLserver]] software. The software was designed with a [[kludge]] to handle a database request that should "never" time out. Rather than specifically handling this special case, the initial design simply specified an arbitrary [[Timeout (computing)|time-out]] date in the future with a default configuration specifying that requests should time out after a maximum of one billion seconds. However, one billion seconds before the 2038 cutoff date is 01:27:28&nbsp;UTC on 13 May 2006, so requests sent after this time would result in a time-out date which is beyond the cutoff. This made time-out calculations overflow and return dates that were actually in the past, causing software to crash. When the problem was discovered, AOLServer operators had to edit the configuration file and set the time-out to a lower value.<ref name=":1">{{cite web|date=28 June 2006|title=The Future Lies Ahead|url=http://substitute.livejournal.com/1430908.html|access-date=19 November 2006|archive-date=28 November 2006|archive-url=https://web.archive.org/web/20061128235428/http://substitute.livejournal.com/1430908.html|url-status=live}}</ref><ref name=":2">[http://www.mail-archive.com/aolserver@listserv.aol.com/msg09844.html Weird "memory leak" problem in AOLserver 3.4.2/3.x] {{Webarchive|url=https://web.archive.org/web/20100104130626/http://www.mail-archive.com/aolserver@listserv.aol.com/msg09844.html |date=4 January 2010 }} 12 May 2006</ref>

== Solutions<span class="anchor" id="Y2106"></span> ==
There is no universal solution for the Year 2038 problem. For example, in the [[C (programming language)|C language]], any change to the definition of the <code>[[time_t]]</code> data type would result in [[binary-code compatibility|code-compatibility]] problems in any application in which date and time representations are dependent on the nature of the signed 32-bit <code>time_t</code> integer.  Changing <code>time_t</code> to an unsigned 32-bit integer, which would extend the range to 2106<ref>{{cite web | url = https://sourceware.org/glibc/wiki/Y2038ProofnessDesign | title = DRAFT: Y2038 Proofness Design | access-date = 2024-05-25 | archive-date = 21 September 2019 | archive-url = https://web.archive.org/web/20190921231248/https://sourceware.org/glibc/wiki/Y2038ProofnessDesign | url-status = live }}</ref> (specifically, 06:28:15 UTC on Sunday, 7 February 2106), would adversely affect programs that store, retrieve, or manipulate dates prior to 1970, as such dates are represented by negative numbers. Increasing the size of the <code>time_t</code> type to 64 bits in an existing system would cause incompatible changes to the layout of structures and the binary interface of functions.

Most operating systems designed to run on 64-bit [[hardware architecture|hardware]] already use signed 64-bit <code>time_t</code> integers. Using a signed 64-bit value introduces a new wraparound date that is over twenty times greater than the estimated [[age of the universe]]: approximately 292&nbsp;billion years from now.<ref>{{cite web | url = https://ximalas.info/2015/03/10/when-does-the-64-bit-unix-time_t-really-end/ | title = When does the 64-bit Unix time_t really end? | access-date = 2022-09-24 | archive-date = 23 September 2022 | archive-url = https://web.archive.org/web/20220923220457/https://ximalas.info/2015/03/10/when-does-the-64-bit-unix-time_t-really-end/ | url-status = live }}</ref> The ability to make [[computation]]s on dates is limited by the fact that <code>tm_year</code> uses a signed 32-bit integer value starting at 1900 for the year. This limits the year to a maximum of 2,147,485,547 (2,147,483,647 + 1900).<ref>{{cite web|url=http://stablecross.com/files/End_Of_Time.html|date=17 April 2010|title=The End of Time|access-date=19 March 2012|first=Bob|last=Felts|website=Stablecross.com|archive-date=11 October 2012|archive-url=https://web.archive.org/web/20121011060328/http://stablecross.com/files/End_Of_Time.html|url-status=live}}</ref>

Alternative proposals have been made (some of which are already in use), such as storing either [[millisecond]]s or [[microsecond]]s since an epoch (typically either 1 January 1970 or 1 January 2000) in a signed 64-bit integer, providing a minimum range of 292,000 years at microsecond resolution.<ref>{{cite web
| url=http://unununium.org/articles/uuutime
| archive-url=https://web.archive.org/web/20060408161959/http://unununium.org/articles/uuutime
| archive-date=8 April 2006 |title=Unununium Time
| access-date=19 November 2006}}</ref><ref>{{cite web
| url=https://docs.oracle.com/javase/9/docs/api/java/lang/System.html#currentTimeMillis--
| title=Java API documentation for System.currentTimeMillis()
| author=Sun Microsystems
| access-date=29 September 2017
| archive-date=30 September 2017
| archive-url=https://web.archive.org/web/20170930040244/https://docs.oracle.com/javase/9/docs/api/java/lang/System.html#currentTimeMillis--
| url-status=live
}}</ref> In particular, Java's and JavaScript's use of 64-bit signed integers to represent absolute timestamps as "milliseconds since 1 January 1970" will work correctly for the next {{tooltip|1=292 million years|2=The theoretical overflow date is 17 August 292278994, 07:12:55.807 UTC.}}.  Other proposals for new time representations provide different precisions, ranges, and sizes (almost always wider than 32 bits), as well as solving other related problems, such as the handling of [[leap second]]s. In particular, TAI64<ref>{{Cite web|url=http://cr.yp.to/libtai/tai64.html|title=TAI64|access-date=4 September 2012|archive-date=26 September 2012|archive-url=https://web.archive.org/web/20120926120001/http://cr.yp.to/libtai/tai64.html|url-status=live}}</ref> is an implementation of the [[International Atomic Time]] (TAI) standard, the current international real-time standard for defining a second and frame of reference.

=== Implemented solutions ===
* Starting with [[Ruby (programming language)|Ruby]] version 1.9.2 (released on 18 August 2010), the bug with year 2038 is fixed,<ref>{{cite web|date=18 August 2010|title=Ruby 1.9.2 is released|url=https://www.ruby-lang.org/en/news/2010/08/18/ruby-1-9-2-released/|access-date=1 April 2022|archive-date=8 April 2022|archive-url=https://web.archive.org/web/20220408110503/https://www.ruby-lang.org/en/news/2010/08/18/ruby-1-9-2-released/|url-status=live}}</ref> by storing time in a signed 64-bit integer on systems with 32-bit <code>time_t</code>.<ref>{{Cite web |title=time.c: use 64bit arithmetic even on platforms with 32bit VALUE |website=[[GitHub]] |url=https://github.com/ruby/ruby/commit/cea57f8fff58d933cd7a452e9ee0745d5a7c7577 |access-date=3 November 2023 |archive-date=3 November 2023 |archive-url=https://web.archive.org/web/20231103040211/https://github.com/ruby/ruby/commit/cea57f8fff58d933cd7a452e9ee0745d5a7c7577 |url-status=live }}</ref>
* Starting with [[NetBSD]] version 6.0 (released in October 2012), the NetBSD operating system uses a 64-bit <code>time_t</code> for both 32-bit and 64-bit architectures. Applications that were compiled for an older NetBSD release with 32-bit <code>time_t</code> are supported via a binary compatibility layer, but such older applications will still suffer from the Y2038 problem.<ref>{{cite web|date=17 October 2012|title=Announcing NetBSD 6.0|url=https://www.netbsd.org/releases/formal-6/NetBSD-6.0.html|access-date=18 January 2016|archive-date=15 January 2016|archive-url=https://web.archive.org/web/20160115091208/http://www.netbsd.org/releases/formal-6/NetBSD-6.0.html|url-status=live}}</ref>
* [[OpenBSD]] since version 5.5, released in May 2014, also uses a 64-bit <code>time_t</code> for both 32-bit and 64-bit architectures. In contrast to [[NetBSD]], there is no binary compatibility layer. Therefore, applications expecting a 32-bit <code>time_t</code> and applications using anything different from <code>time_t</code> to store time values may break.<ref>{{cite web|date=1 May 2014|title=OpenBSD 5.5 released (May 1, 2014)|url=http://www.openbsd.org/plus55.html|access-date=18 January 2016|archive-date=22 December 2015|archive-url=https://web.archive.org/web/20151222005608/http://www.openbsd.org/plus55.html|url-status=live}}</ref>
* [[Linux]] originally used a 64-bit <code>time_t</code> for 64-bit architectures only; the pure 32-bit [[Application binary interface|ABI]] was not changed due to backward compatibility.<ref name="Pondering2038">{{cite web|author=Jonathan Corbet|author-link=Jonathan Corbet|date=14 August 2013|title=Pondering 2038|url=https://lwn.net/Articles/563285/|url-status=live|archive-url=https://web.archive.org/web/20160304081847/https://lwn.net/Articles/563285/|archive-date=4 March 2016|access-date=9 March 2016|website=[[LWN.net]]}}</ref> Starting with version [[Linux kernel version history#Releases 5.x.y|5.6]] of 2020, 64-bit <code>time_t</code> is supported on 32-bit architectures, too. This was done primarily for the sake of [[Linux on embedded systems|embedded Linux]] systems.<ref>{{Cite web|title=LKML: Arnd Bergmann: [GIT PULL] y2038: core, driver and file system changes|url=https://lkml.org/lkml/2020/1/29/355?anz=web|access-date=2020-01-30|website=lkml.org|archive-date=14 February 2020|archive-url=https://web.archive.org/web/20200214070752/https://lkml.org/lkml/2020/1/29/355?anz=web|url-status=live}}</ref>
* [[GNU C Library]] since version 2.34 (released August 2021), added support for using 64-bit <code>time_t</code> on 32-bit platforms with appropriate Linux versions. This support can be activated by defining preprocessor macro <code>_TIME_BITS</code> to <code>64</code> when compiling source code.<ref>{{cite web |last1=O'Donell |first1=Carlos |title=The GNU C Library version 2.34 is now available |url=https://sourceware.org/pipermail/libc-alpha/2021-August/129718.html |website=Sourceware |access-date=2024-04-30 |date=2021-08-02 |archive-date=30 April 2024 |archive-url=https://web.archive.org/web/20240430060406/https://sourceware.org/pipermail/libc-alpha/2021-August/129718.html |url-status=live }}</ref>
* [[FreeBSD]] uses 64-bit <code>time_t</code> for all 32-bit and 64-bit architectures except 32-bit i386, which uses signed 32-bit <code>time_t</code> instead.<ref>{{Cite web|url=https://www.freebsd.org/cgi/man.cgi?arch|title=arch|website=www.freebsd.org|access-date=26 September 2018|archive-date=26 September 2018|archive-url=https://web.archive.org/web/20180926205510/https://www.freebsd.org/cgi/man.cgi?arch|url-status=live}}</ref>
* The [[x32 ABI]] for Linux (which defines an environment for programs with 32-bit addresses but running the processor in 64-bit mode) uses a 64-bit <code>time_t</code>. Since it was a new environment, there was no need for special compatibility precautions.<ref name="Pondering2038" />
* [[Network File System]] version 4 has defined its time fields as <code>struct nfstime4 {int64_t seconds; uint32_t nseconds;}</code> since December 2000.<ref>{{cite IETF|rfc=7530|title=Network File System (NFS) Version 4 Protocol|section=2.2|sectionname=Structured Data Types|date=March 2015|editor1-first=Thomas|editor1-last=Haynes|editor2-first=David|editor2-last=Noveck}}</ref> Version 3 supports unsigned 32-bit values as <code>struct nfstime3 {uint32 seconds; uint32 nseconds;};</code>.<ref>{{cite web | url = https://datatracker.ietf.org/doc/html/rfc1813 | title= NFS Version 3 Protocol Specification | date= June 1995 | access-date = 2024-05-25 | last1= Staubach | first1= Peter | last2= Pawlowski | first2= Brian | last3= Callaghan | first3= Brent }}</ref> Values greater than zero for the seconds field denote dates after the 0-hour, January 1, 1970. Values less than zero for the seconds field denote dates before the 0-hour, January 1, 1970. In both cases, the nseconds (nanoseconds) field is to be added to the seconds field for the final time representation.
* The [[ext4]] filesystem, when used with inode sizes larger than 128 bytes, has an extra 32-bit field per timestamp, of which 30 bits are used for the nanoseconds part of the timestamp, and the other 2 bits are used to extend the timestamp range to the year 2446.<ref>{{cite web|url=https://www.kernel.org/doc/html/latest/filesystems/ext4/dynamic.html#inode-timestamps|title=ext4 Data Structures and Algorithms|access-date=2022-09-13|archive-date=13 September 2022|archive-url=https://web.archive.org/web/20220913224855/https://www.kernel.org/doc/html/latest/filesystems/ext4/dynamic.html#inode-timestamps|url-status=live}}</ref>
* The [[XFS]] filesystem, starting with Linux 5.10, has an optional "big timestamps" feature which extends the timestamp range to the year 2486.<ref>{{cite web|url=https://www.phoronix.com/news/XFS-Linux-5.10|title=XFS File-System With Linux 5.10 Punts Year 2038 Problem To The Year 2486|author=Michael Larabel|website=[[Phoronix]]|date=15 October 2020|access-date=2022-09-13|archive-date=13 September 2022|archive-url=https://web.archive.org/web/20220913232215/https://www.phoronix.com/news/XFS-Linux-5.10|url-status=live}}</ref>
* While the native APIs of [[OpenVMS]] can support timestamps up to 31 July 31086,<ref name="Crazy time, Stanford, 1997">{{Cite web|date=1997-07-24|title=Why is Wednesday, November 17, 1858 the base time for OpenVMS (VAX VMS)?|url=https://www.slac.stanford.edu/~rkj/crazytime.txt|url-status=live|archive-url=https://web.archive.org/web/19970724202734/https://www.slac.stanford.edu/~rkj/crazytime.txt|archive-date=1997-07-24|access-date=2020-01-08|website=[[Stanford University]]|df=dmy-all}}</ref> the C runtime library (CRTL) uses 32-bit integers for <code>time_t</code>.<ref name="vsi-c-rtl">{{cite web|date=November 2020|title=VSI C Run-Time Library Reference Manual for OpenVMS Systems|url=https://vmssoftware.com/docs/VSI_CRTL_REF.pdf|access-date=2021-04-17|publisher=VSI|archive-date=17 April 2021|archive-url=https://web.archive.org/web/20210417113107/https://vmssoftware.com/docs/VSI_CRTL_REF.pdf|url-status=dead}}</ref> As part of Y2K compliance work that was carried out in 1998, the CRTL was modified to use unsigned 32-bit integers to represent time; extending the range of <code>time_t</code> up to 7 February 2106.<ref>{{cite web|title=OpenVMS and the year 2038|url=https://www.zx.net.nz/mirror/h71000.www7.hp.com/2038.html|access-date=2021-04-17|publisher=HP|archive-date=17 April 2021|archive-url=https://web.archive.org/web/20210417113108/https://www.zx.net.nz/mirror/h71000.www7.hp.com/2038.html|url-status=live}}</ref>
* As of [[MySQL]] 8.0.28, released in January 2022, the functions <code>FROM_UNIXTIME()</code>, <code>UNIX_TIMESTAMP()</code>, and <code>CONVERT_TZ()</code> handle 64-bit values on platforms that support them. This includes 64-bit versions of Linux, macOS, and Windows.<ref>{{cite web|title=What Is New in MySQL 8.0|url=https://dev.mysql.com/doc/refman/8.0/en/mysql-nutshell.html#mysql-nutshell-additions|website=dev.mysql.com}}</ref><ref>{{cite web|title=Changes in MySQL 8.0.28 (2022-01-18, General Availability)|url=https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-28.html|website=dev.mysql.com|access-date=14 May 2024|archive-date=8 December 2023|archive-url=https://web.archive.org/web/20231208180456/https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-28.html|url-status=live}}</ref> In older versions, built-in functions like <code>UNIX_TIMESTAMP()</code> will return 0 after 03:14:07 [[UTC]] on 19 January 2038.<ref>{{cite web|title=MySQL Bugs: #12654: 64-bit unix timestamp is not supported in MySQL functions|url=https://bugs.mysql.com/bug.php?id=12654|website=bugs.mysql.com|access-date=28 March 2017|archive-date=29 March 2017|archive-url=https://web.archive.org/web/20170329045924/https://bugs.mysql.com/bug.php?id=12654|url-status=live}}</ref>
* As of [[MariaDB]] 11.5.1, released in May 2024, the data type <code>TIMESTAMP</code> and functions <code>FROM_UNIXTIME()</code>, <code>UNIX_TIMESTAMP()</code>, and <code>CONVERT_TZ()</code> handle unsigned 32-bit values on 64-bit versions of Linux, macOS, and Windows.<ref>{{Cite web|url=https://mariadb.com/kb/en/mariadb-11-5-1-release-notes/|title=MariaDB 11.5.1 Release Notes|website=MariaDB KnowledgeBase}}</ref> This extended the range to 2106-02-07 06:28:15 and allowed users to store such timestamp values in tables without changing the storage layout and thus staying fully compatible with existing user data.
* Starting with [[Visual C++]] 2005, the CRT uses a 64-bit <code>time_t</code> unless the <code>_USE_32BIT_TIME_T</code> preprocessor macro is defined.<ref>{{Cite web |last= |date=2023-05-25 |title=Microsoft C/C++ change history 2003 - 2015 |url=https://learn.microsoft.com/en-us/cpp/porting/visual-cpp-change-history-2003-2015 |access-date=2024-08-13 |website=learn.microsoft.com |language=en-us}}</ref> However, the [[Windows API]] itself is unaffected by the year 2038 bug, as [[Microsoft Windows|Windows]] internally tracks time as the number of 100-nanosecond intervals since 1 January 1601 in a 64-bit signed integer, which will not overflow until year [[Time formatting and storage bugs#Year 30,828|30,828]].<ref>{{Cite web |last= |date=2021-01-07 |title=About Time - Win32 apps |url=https://learn.microsoft.com/en-us/windows/win32/sysinfo/about-time |access-date=2024-08-13 |website=learn.microsoft.com |language=en-us}}</ref>

== See also ==
* [[Time formatting and storage bugs]] lists other similar problems, often caused by rollover similar to the cause of this year 2038 problem.
* A [[GPS week number rollover]] will coincidentally happen later in 2038, for a different reason than this year 2038 problem.

== Notes ==
{{notelist}}

== References ==
{{reflist}}

== External links ==
*[https://sourceware.org/glibc/wiki/Y2038ProofnessDesign Y2038 Proofness Design] [[GNU C Library|glibc]] Wiki
*[https://computer.howstuffworks.com/question75.htm Entry in How Stuff Works]
*[http://maul.deepsky.com/%7Emerovech/2038.html The Project 2038 Frequently Asked Questions]
*[https://people.cs.nctu.edu.tw/~tsaiwn/sisc/runtime_error_200_div_by_0/www.merlyn.demon.co.uk/critdate.htm#Y2038 ''Critical and Significant Dates'' 2038]
*[https://github.com/evalEmpire/y2038/wiki A 2038-safe replacement for time.h on 32 bit systems]
*{{Cite web |title=Solving the Year 2038 problem in the Linux kernel |url=https://opensource.com/article/19/1/year2038-problem-linux-kernel }}
*{{cite news |url=https://www.bbc.com/future/article/20150505-the-numbers-that-lead-to-disaster |title=The number glitch that can lead to catastrophe |work=BBC Future |first=Chris |last=Baraniuk |date=5 May 2015}}
* {{cite web|last=Clewett|first=James|title=2,147,483,647 – The End of Time [Unix]|url=http://www.numberphile.com/videos/unix_time.html|website=Numberphile|publisher=[[Brady Haran]]|access-date=7 April 2013|archive-url=https://web.archive.org/web/20170522031114/http://www.numberphile.com/videos/unix_time.html|archive-date=22 May 2017|url-status=dead}}

{{Year-related problems}}
{{Doomsday}}

{{Use dmy dates|date=August 2019}}

[[Category:2038|Problem]]
[[Category:Future problems|Year 02038 Problem]]
[[Category:Operating system technology]]
[[Category:Time formatting and storage bugs|Year 02038 problem]]
[[Category:Unix]]
[[Category:Linux]]
[[Category:Software bugs]]