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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>mbrlen</title></head><body bgcolor="white"><script type="text/javascript" language="JavaScript" src="../jscript/codes.js"></script><basefont size="3"> <a name="mbrlen"></a> <a name="tag_03_359"></a><!-- mbrlen --> <!--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_359_01"></a>NAME</h4><blockquote>mbrlen - get number of bytes in a character (restartable)</blockquote><h4><a name="tag_03_359_02"></a>SYNOPSIS</h4><blockquote class="synopsis"><p><code><tt>#include <<a href="../basedefs/wchar.h.html">wchar.h</a>><br><br> size_t mbrlen(const char *restrict</tt> <i>s</i><tt>, size_t</tt> <i>n</i><tt>,<br> mbstate_t *restrict</tt> <i>ps</i><tt>);<br></tt></code></p></blockquote><h4><a name="tag_03_359_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 not a null pointer, <i>mbrlen</i>() shall determine the number of bytes constituting the character pointed to by<i>s</i>. It shall be equivalent to:</p><pre><tt>mbstate_t internal;mbrtowc(NULL, s, n, ps != NULL ? ps : &internal);</tt></pre><p>If <i>ps</i> is a null pointer, the <i>mbrlen</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>mbrlen</i>().</p><p>The behavior of this function is affected by the <i>LC_CTYPE</i> category of the current locale.</p></blockquote><h4><a name="tag_03_359_04"></a>RETURN VALUE</h4><blockquote><p>The <i>mbrlen</i>() function shall return the first of the following that applies:</p><dl compact><dt>0</dt><dd>If the next <i>n</i> or fewer bytes complete the character that corresponds to the null wide character.</dd><dt><i>positive</i></dt><dd>If the next <i>n</i> or fewer bytes complete a valid character; the value returned shall be the number of bytes that completethe character.</dd><dt>(<b>size_t</b>)-2</dt><dd>If the next <i>n</i> bytes contribute to an incomplete but potentially valid character, and all <i>n</i> bytes have beenprocessed. When <i>n</i> has at least the value of the {MB_CUR_MAX} macro, this case can only occur if <i>s</i> points at asequence of redundant shift sequences (for implementations with state-dependent encodings).</dd><dt>(<b>size_t</b>)-1</dt><dd>If an encoding error occurs, in which case the next <i>n</i> or fewer bytes do not contribute to a complete and validcharacter. In this case, [EILSEQ] shall be stored in <i>errno</i> and the conversion state is undefined.</dd></dl></blockquote><h4><a name="tag_03_359_05"></a>ERRORS</h4><blockquote><p>The <i>mbrlen</i>() function may fail if:</p><dl compact><dt>[EINVAL]</dt><dd><i>ps</i> points to an object that contains an invalid conversion state.</dd><dt>[EILSEQ]</dt><dd>Invalid character sequence is detected.</dd></dl></blockquote><hr><div class="box"><em>The following sections are informative.</em></div><h4><a name="tag_03_359_06"></a>EXAMPLES</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_359_07"></a>APPLICATION USAGE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_359_08"></a>RATIONALE</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_359_09"></a>FUTURE DIRECTIONS</h4><blockquote><p>None.</p></blockquote><h4><a name="tag_03_359_10"></a>SEE ALSO</h4><blockquote><p><a href="mbsinit.html"><i>mbsinit</i>()</a> , <a href="mbrtowc.html"><i>mbrtowc</i>()</a> , the Base Definitions volume ofIEEE Std 1003.1-2001, <a href="../basedefs/wchar.h.html"><i><wchar.h></i></a></p></blockquote><h4><a name="tag_03_359_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_359_12"></a>Issue 6</h4><blockquote><p>The <i>mbrlen</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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