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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>mbstowcs</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="mbstowcs"></a> <a name="tag_03_363"></a><!-- mbstowcs --> <!--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_363_01"></a>NAME</h4><blockquote>mbstowcs - convert a character string to a wide-character string</blockquote><h4><a name="tag_03_363_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><code><tt>#include <<a href="../basedefs/stdlib.h.html">stdlib.h</a>><br><br> size_t mbstowcs(wchar_t *restrict</tt> <i>pwcs</i><tt>, const char *restrict</tt> <i>s</i><tt>,<br> size_t</tt> <i>n</i><tt>);<br></tt></code></p></blockquote><h4><a name="tag_03_363_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>The <i>mbstowcs</i>() function shall convert a sequence of characters that begins in the initial shift state from the arraypointed to by <i>s</i> into a sequence of corresponding wide-character codes and shall store not more than <i>n</i> wide-charactercodes into the array pointed to by <i>pwcs</i>. No characters that follow a null byte (which is converted into a wide-charactercode with value 0) shall be examined or converted. Each character shall be converted as if by a call to <a href="../functions/mbtowc.html"><i>mbtowc</i>()</a>, except that the shift state of <a href="../functions/mbtowc.html"><i>mbtowc</i>()</a> is not affected.</p><p>No more than <i>n</i> elements shall be modified in the array pointed to by <i>pwcs</i>. If copying takes place between objectsthat overlap, the behavior is undefined.</p><p>The behavior of this function shall be affected by the <i>LC_CTYPE</i> category of the current locale. <sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> If<i>pwcs</i> is a null pointer, <i>mbstowcs</i>() shall return the length required to convert the entire array regardless of thevalue of <i>n</i>, but no values are stored. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p></blockquote><h4><a name="tag_03_363_04"></a>RETURN VALUE</h4><blockquote><p>If an invalid character is encountered, <i>mbstowcs</i>() shall return (<b>size_t</b>)-1 <sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> and may set<i>errno</i> to indicate the error. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></p><p>Otherwise, <i>mbstowcs</i>() shall return the number of the array elements modified <sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0"> (or requiredif <i>pwcs</i> is null), <img src="../images/opt-end.gif" alt="[Option End]" border="0"> not including a terminating 0 code, ifany. The array shall not be zero-terminated if the value returned is <i>n</i>.</p></blockquote><h4><a name="tag_03_363_05"></a>ERRORS</h4><blockquote><p>The <i>mbstowcs</i>() function may fail if:</p><dl compact><dt>[EILSEQ]</dt><dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">Invalid byte sequence is detected. <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_363_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_363_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_363_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_363_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_363_10"></a>SEE ALSO</h4><blockquote><p><a href="mblen.html"><i>mblen</i>()</a> , <a href="mbtowc.html"><i>mbtowc</i>()</a> , <a href="wctomb.html"><i>wctomb</i>()</a>, <a href="wcstombs.html"><i>wcstombs</i>()</a> , the Base Definitions volume of IEEE Std 1003.1-2001, <a href="../basedefs/stdlib.h.html"><i><stdlib.h></i></a></p></blockquote><h4><a name="tag_03_363_11"></a>CHANGE HISTORY</h4><blockquote><p>First released in Issue 4. Aligned with the ISO C standard.</p></blockquote><h4><a name="tag_03_363_12"></a>Issue 6</h4><blockquote><p>The <i>mbstowcs</i>() prototype is updated for alignment with the ISO/IEC 9899:1999 standard.</p><p>Extensions beyond the ISO C standard are marked.</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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