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<!DOCTYPE HTML PUBLIC "-//W3O//DTD W3 HTML 2.0//EN"><!-- This collection of hypertext pages is Copyright 1995-2005 by Steve Summit. --><!-- Content from the book "C Programming FAQs: Frequently Asked Questions" --><!-- (Addison-Wesley, 1995, ISBN 0-201-84519-9) is made available here by --><!-- permission of the author and the publisher as a service to the community. --><!-- It is intended to complement the use of the published text --><!-- and is protected by international copyright laws. --><!-- The on-line content may be accessed freely for personal use --><!-- but may not be published or retransmitted without explicit permission. --><!-- --><!-- this page built Sat Dec 24 21:47:46 2005 by faqproc version 2.7 --><!-- from source file libdatetime.sgml dated Wed Dec 21 12:57:15 2005 --><!-- corresponding to FAQ list version 4.0 --><html><!-- Mirrored from c-faq.com/lib/y2k.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:58:59 GMT --><head><meta name=GENERATOR content="faqproc"><title>Question 13.14b</title><link href="calendar.html" rev=precedes><link href="rand.html" rel=precedes><link href="index.html" rev=subdocument></head><body bgcolor="#ffffff"><a href="calendar.html" rev=precedes><img src="../images/buttonleft.gif" alt="prev"></a><a href="index.html" rev=subdocument><img src="../images/buttonup.gif" alt="up"></a><a href="rand.html" rel=precedes><img src="../images/buttonright.gif" alt="next"></a> <a href="../index-2.html"><img src="../images/buttontop.gif" alt="top/contents"></a><a href="../search.html"><img src="../images/buttonsrch.gif" alt="search"></a><hr><p><!-- qbegin --><h1>comp.lang.c FAQ list<font color=blue>·</font><!-- qtag -->Question 13.14b</h1><p><font face=Helvetica size=8 color=blue><b>Q:</b></font>Did C have any Year 2000 problems?</p><p><hr><p><font face=Helvetica size=8 color=blue><b>A:</b></font>No, although poorly-written C programs might have.</p><p>The<TT>tm_year</TT>field of <TT>struct tm</TT>holds the value of the year minus 1900;this field therefore contains the value 100 for the year 2000.Code that uses <TT>tm_year</TT> correctly(by adding or subtracting 1900when converting to or from human-readable 4-digit year representations)has no problems at the turn of the millennium.Any code that used <TT>tm_year</TT> incorrectly, however,such as byusing it directly as a human-readable 2-digit year,or setting it from a 4-digit year with code like<pre> tm.tm_year = yyyy % 100; /* WRONG */</pre>or printing it as an allegedly human-readable 4-digit yearwith code like<pre> printf("19%d", tm.tm_year); /* WRONG */</pre>would have hadgrave y2k problems indeed.See also question <a href="../misc/leapyear.html">20.32</a>.</p><p>(The y2k problem is now mostly old history;all we have left to dois fix all the 32-bit <TT>time_t</TT> problems by 2038...)</p><p>References:K&R2 Sec. B10 p. 255<br>ISO Sec. 7.12.1<br>H&S Sec. 18.4 p. 401<br></p><!-- aend --><p><hr><a href="calendar.html" rev=precedes><img src="../images/buttonleft.gif" alt="prev"></a><a href="index.html" rev=subdocument><img src="../images/buttonup.gif" alt="up"></a><a href="rand.html" rel=precedes><img src="../images/buttonright.gif" alt="next"></a> <a href="../questions.html"><img src="../images/buttontop.gif" alt="contents"></a><a href="../search.html"><img src="../images/buttonsrch.gif" alt="search"></a><br><!-- lastfooter --><a href="../about.html">about this FAQ list</a> <a href="../eskimo.html">about eskimo</a> <a href="../search.html">search</a> <a href="../feedback.html">feedback</a> <a href="copyright.html">copyright</a><p>Hosted by<a href="http://www.eskimo.com/"><img src="../../www.eskimo.com/img/link/eskitiny.gif" alt="Eskimo North"></a></body><!-- Mirrored from c-faq.com/lib/y2k.html by HTTrack Website Copier/3.x [XR&CO'2008], Sat, 14 Mar 2009 07:58:59 GMT --></html>⌨️ 快捷键说明
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