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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>wcrtomb</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="wcrtomb"></a> <a name="tag_03_825"></a><!-- wcrtomb --> <!--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_825_01"></a>NAME</h4><blockquote>wcrtomb - convert a wide-character code to a character (restartable)</blockquote><h4><a name="tag_03_825_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><code><tt>#include <<a href="../basedefs/stdio.h.html">stdio.h</a>><br><br> size_t wcrtomb(char *restrict</tt> <i>s</i><tt>, wchar_t</tt> <i>wc</i><tt>, mbstate_t *restrict</tt> <i>ps</i><tt>);<br></tt></code></p></blockquote><h4><a name="tag_03_825_03"></a>DESCRIPTION</h4><blockquote><div class="box"><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. Any conflict between therequirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers tothe ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div><p>If <i>s</i> is a null pointer, the <i>wcrtomb</i>() function shall be equivalent to the call:</p><pre><tt>wcrtomb(</tt><i>buf</i><tt>, L'\0',</tt> <i>ps</i><tt>)</tt></pre><p>where <i>buf</i> is an internal buffer.</p><p>If <i>s</i> is not a null pointer, the <i>wcrtomb</i>() function shall determine the number of bytes needed to represent thecharacter that corresponds to the wide character given by <i>wc</i> (including any shift sequences), and store the resulting bytesin the array whose first element is pointed to by <i>s</i>. At most {MB_CUR_MAX} bytes are stored. If <i>wc</i> is a null widecharacter, a null byte shall be stored, preceded by any shift sequence needed to restore the initial shift state. The resultingstate described shall be the initial conversion state.</p><p>If <i>ps</i> is a null pointer, the <i>wcrtomb</i>() function shall use its own internal <b>mbstate_t</b> object, which isinitialized at program start-up to the initial conversion state. Otherwise, the <b>mbstate_t</b> object pointed to by <i>ps</i>shall be used to completely describe the current conversion state of the associated character sequence. The implementation shallbehave as if no function defined in this volume of IEEE Std 1003.1-2001 calls <i>wcrtomb</i>().</p><p><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> Ifthe application uses any of the _POSIX_THREAD_SAFE_FUNCTIONS or _POSIX_THREADS functions, the application shall ensure that the<i>wcrtomb</i>() function is called with a non-NULL <i>ps</i> argument. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p><p>The behavior of this function shall be affected by the <i>LC_CTYPE</i> category of the current locale.</p></blockquote><h4><a name="tag_03_825_04"></a>RETURN VALUE</h4><blockquote><p>The <i>wcrtomb</i>() function shall return the number of bytes stored in the array object (including any shift sequences). When<i>wc</i> is not a valid wide character, an encoding error shall occur. In this case, the function shall store the value of themacro [EILSEQ] in <i>errno</i> and shall return (<b>size_t</b>)-1; the conversion state shall be undefined.</p></blockquote><h4><a name="tag_03_825_05"></a>ERRORS</h4><blockquote><p>The <i>wcrtomb</i>() function may fail if:</p><dl compact><dt>[EINVAL]</dt><dd><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"><i>ps</i> points to an object that contains an invalid conversion state. <img src="../images/opt-end.gif" alt="[Option End]"border="0"></dd><dt>[EILSEQ]</dt><dd>Invalid wide-character code is detected.</dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_825_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_825_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_825_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_825_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_825_10"></a>SEE ALSO</h4><blockquote><p><a href="mbsinit.html"><i>mbsinit</i>()</a> , the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/wchar.h.html"><i><wchar.h></i></a></p></blockquote><h4><a name="tag_03_825_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 5. Included for alignment with ISO/IEC 9899:1990/Amendment 1:1995 (E).</p></blockquote><h4><a name="tag_03_825_12"></a>Issue 6</h4><blockquote><p>In the DESCRIPTION, a note on using this function in a threaded application is added.</p><p>Extensions beyond the ISO C standard are marked.</p><p>The DESCRIPTION is updated to avoid use of the term "must" for application requirements.</p><p>The <i>wcrtomb</i>() prototype is updated for alignment with the ISO/IEC 9899:1999 standard.</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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