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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head><meta name="generator" content="HTML Tidy, see www.w3.org"><meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"><link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 --><!-- Copyright (c) 2001-2003 The Open Group, All Rights Reserved --><title>strerror</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="strerror"></a> <a name="tag_03_727"></a><!-- strerror --> <!--header start--><center><font size="2">The Open Group Base Specifications Issue 6<br>IEEE Std 1003.1, 2003 Edition<br>Copyright © 2001-2003 The IEEE and The Open Group, All Rights reserved.</font></center><!--header end--><hr size="2" noshade><h4><a name="tag_03_727_01"></a>NAME</h4><blockquote>strerror, strerror_r - get error message string</blockquote><h4><a name="tag_03_727_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><code><tt>#include <<a href="../basedefs/string.h.html">string.h</a>><br><br> char *strerror(int</tt> <i>errnum</i><tt>);<br></tt></code></p><div class="box"><code><tt><sup>[<a href="javascript:open_code('TSF')">TSF</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> int strerror_r(int</tt> <i>errnum</i><tt>, char *</tt><i>strerrbuf</i><tt>, size_t</tt><i>buflen</i><tt>); <img src="../images/opt-end.gif" alt="[Option End]" border="0"></tt></code></div><tt><br></tt></blockquote><h4><a name="tag_03_727_03"></a>DESCRIPTION</h4><blockquote><p>For <i>strerror</i>(): <sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> The functionality described on this reference page is aligned with the ISO C standard. Anyconflict between the requirements described here and the ISO C standard is unintentional. This volume ofIEEE Std 1003.1-2001 defers to the ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p><p>The <i>strerror</i>() function shall map the error number in <i>errnum</i> to a locale-dependent error message string and shallreturn a pointer to it. Typically, the values for <i>errnum</i> come from <i>errno</i>, but <i>strerror</i>() shall map any valueof type <b>int</b> to a message.</p><p>The string pointed to shall not be modified by the application, but may be overwritten by a subsequent call to <i>strerror</i>()<sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> or <a href="../functions/perror.html"><i>perror</i>()</a>. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p><p><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> Thecontents of the error message strings returned by <i>strerror</i>() should be determined by the setting of the <i>LC_MESSAGES</i>category in the current locale. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p><p>The implementation shall behave as if no function defined in this volume of IEEE Std 1003.1-2001 calls<i>strerror</i>().</p><p><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> The<i>strerror</i>() function shall not change the setting of <i>errno</i> if successful.</p><p>Since no return value is reserved to indicate an error, an application wishing to check for error situations should set<i>errno</i> to 0, then call <i>strerror</i>(), then check <i>errno</i>.</p><p>The <i>strerror</i>() function need not be reentrant. A function that is not required to be reentrant is not required to bethread-safe. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p><p><sup>[<a href="javascript:open_code('TSF')">TSF</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">The <i>strerror_r</i>() function shall map the error number in <i>errnum</i> to a locale-dependent error message string and shallreturn the string in the buffer pointed to by <i>strerrbuf</i>, with length <i>buflen</i>. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p></blockquote><h4><a name="tag_03_727_04"></a>RETURN VALUE</h4><blockquote><p>Upon successful completion, <i>strerror</i>() shall return a pointer to the generated message string. On error <i>errno</i> maybe set, but no return value is reserved to indicate an error.</p><p><sup>[<a href="javascript:open_code('TSF')">TSF</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">Upon successful completion, <i>strerror_r</i>() shall return 0. Otherwise, an error number shall be returned to indicate the error.<img src="../images/opt-end.gif" alt="[Option End]" border="0"></p></blockquote><h4><a name="tag_03_727_05"></a>ERRORS</h4><blockquote><p>These functions may fail if:</p><dl compact><dt>[EINVAL]</dt><dd>The value of <i>errnum</i> is not a valid error number.</dd></dl><p>The <i>strerror_r</i>() function may fail if:</p><dl compact><dt>[ERANGE]</dt><dd><sup>[<a href="javascript:open_code('TSF')">TSF</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">Insufficient storage was supplied via <i>strerrbuf</i> and <i>buflen</i> to contain the generated message string. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_727_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_727_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_727_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_727_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_727_10"></a>SEE ALSO</h4><blockquote><p><a href="perror.html"><i>perror</i>()</a> , the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/string.h.html"><i><string.h></i></a></p></blockquote><h4><a name="tag_03_727_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 3.</p></blockquote><h4><a name="tag_03_727_12"></a>Issue 5</h4><blockquote><p>The DESCRIPTION is updated to indicate that <i>errno</i> is not changed if the function is successful.</p><p>A note indicating that this function need not be reentrant is added to the DESCRIPTION.</p></blockquote><h4><a name="tag_03_727_13"></a>Issue 6</h4><blockquote><p>Extensions beyond the ISO C standard are marked.</p><p>The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:</p><ul><li><p>In the RETURN VALUE section, the fact that <i>errno</i> may be set is added.</p></li><li><p>The [EINVAL] optional error condition is added.</p></li></ul><p>The DESCRIPTION is updated to avoid use of the term "must" for application requirements.</p><p>The <i>strerror_r</i>() function is added in response to IEEE PASC Interpretation 1003.1c #39.</p><p>The <i>strerror_r</i>() function is marked as part of the Thread-Safe Functions option.</p></blockquote><div class="box"><em>End of informative text.</em></div><hr><hr size="2" noshade><center><font size="2"><!--footer start-->UNIX ® is a registered Trademark of The Open Group.<br>POSIX ® is a registered Trademark of The IEEE.<br>[ <a href="../mindex.html">Main Index</a> | <a href="../basedefs/contents.html">XBD</a> | <a href="../utilities/contents.html">XCU</a> | <a href="../functions/contents.html">XSH</a> | <a href="../xrat/contents.html">XRAT</a>]</font></center><!--footer end--><hr size="2" noshade></body></html>⌨️ 快捷键说明
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