146 lines
5.8 KiB
HTML
146 lines
5.8 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<link type="text/css" rel="stylesheet" href="style.css"><!-- Generated by The Open Group's rhtm tool v1.2.1 -->
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<!-- Copyright (c) 2001 The Open Group, All Rights Reserved -->
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<title>mblen</title>
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<script type="text/javascript" language="JavaScript" src="../jscript/codes.js">
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<basefont size="3"> <a name="mblen"></a> <a name="tag_03_358"></a><!-- mblen -->
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<!--header start-->
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<center><font size="2">The Open Group Base Specifications Issue 6<br>
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IEEE Std 1003.1-2001<br>
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Copyright © 2001 The IEEE and The Open Group, All Rights reserved.</font></center>
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<!--header end-->
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<hr size="2" noshade>
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<h4><a name="tag_03_358_01"></a>NAME</h4>
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<blockquote>mblen - get number of bytes in a character</blockquote>
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<h4><a name="tag_03_358_02"></a>SYNOPSIS</h4>
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<blockquote class="synopsis">
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<p><code><tt>#include <<a href="../basedefs/stdlib.h.html">stdlib.h</a>><br>
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<br>
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int mblen(const char *</tt><i>s</i><tt>, size_t</tt> <i>n</i><tt>);<br>
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</tt></code></p>
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</blockquote>
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<h4><a name="tag_03_358_03"></a>DESCRIPTION</h4>
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<blockquote>
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<div class="box"><sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]"
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border="0"> The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the
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requirements described here and the ISO C standard is unintentional. This volume of IEEE Std 1003.1-2001 defers to
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the ISO C standard. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></div>
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<p>If <i>s</i> is not a null pointer, <i>mblen</i>() shall determine the number of bytes constituting the character pointed to by
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<i>s</i>. Except that the shift state of <a href="../functions/mbtowc.html"><i>mbtowc</i>()</a> is not affected, it shall be
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equivalent to:</p>
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<pre>
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<tt>mbtowc((wchar_t *)0,</tt> <i>s</i><tt>,</tt> <i>n</i><tt>);
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</tt>
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</pre>
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<p>The implementation shall behave as if no function defined in this volume of IEEE Std 1003.1-2001 calls
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<i>mblen</i>().</p>
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<p>The behavior of this function is affected by the <i>LC_CTYPE</i> category of the current locale. For a state-dependent encoding,
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this function shall be placed into its initial state by a call for which its character pointer argument, <i>s</i>, is a null
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pointer. Subsequent calls with <i>s</i> as other than a null pointer shall cause the internal state of the function to be altered
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as necessary. A call with <i>s</i> as a null pointer shall cause this function to return a non-zero value if encodings have state
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dependency, and 0 otherwise. If the implementation employs special bytes to change the shift state, these bytes shall not produce
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separate wide-character codes, but shall be grouped with an adjacent character. Changing the <i>LC_CTYPE</i> category causes the
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shift state of this function to be unspecified.</p>
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</blockquote>
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<h4><a name="tag_03_358_04"></a>RETURN VALUE</h4>
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<blockquote>
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<p>If <i>s</i> is a null pointer, <i>mblen</i>() shall return a non-zero or 0 value, if character encodings, respectively, do or do
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not have state-dependent encodings. If <i>s</i> is not a null pointer, <i>mblen</i>() shall either return 0 (if <i>s</i> points to
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the null byte), or return the number of bytes that constitute the character (if the next <i>n</i> or fewer bytes form a valid
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character), or return -1 (if they do not form a valid character) <sup>[<a href="javascript:open_code('CX')">CX</a>]</sup> <img src=
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"../images/opt-start.gif" alt="[Option Start]" border="0"> and may set <i>errno</i> to indicate the error. <img src=
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"../images/opt-end.gif" alt="[Option End]" border="0"> In no case shall the value returned be greater than <i>n</i> or the value of
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the {MB_CUR_MAX} macro.</p>
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</blockquote>
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<h4><a name="tag_03_358_05"></a>ERRORS</h4>
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<blockquote>
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<p>The <i>mblen</i>() function may fail if:</p>
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<dl compact>
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<dt>[EILSEQ]</dt>
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<dd><sup>[<a href="javascript:open_code('XSI')">XSI</a>]</sup> <img src="../images/opt-start.gif" alt="[Option Start]" border="0">
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Invalid character sequence is detected. <img src="../images/opt-end.gif" alt="[Option End]" border="0"></dd>
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</dl>
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</blockquote>
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<hr>
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<div class="box"><em>The following sections are informative.</em></div>
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<h4><a name="tag_03_358_06"></a>EXAMPLES</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_358_07"></a>APPLICATION USAGE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_358_08"></a>RATIONALE</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_358_09"></a>FUTURE DIRECTIONS</h4>
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<blockquote>
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<p>None.</p>
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</blockquote>
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<h4><a name="tag_03_358_10"></a>SEE ALSO</h4>
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<blockquote>
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<p><a href="mbtowc.html"><i>mbtowc</i>()</a> , <a href="mbstowcs.html"><i>mbstowcs</i>()</a> , <a href=
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"wctomb.html"><i>wctomb</i>()</a> , <a href="wcstombs.html"><i>wcstombs</i>()</a> , the Base Definitions volume of
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IEEE Std 1003.1-2001, <a href="../basedefs/stdlib.h.html"><i><stdlib.h></i></a></p>
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</blockquote>
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<h4><a name="tag_03_358_11"></a>CHANGE HISTORY</h4>
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<blockquote>
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<p>First released in Issue 4. Aligned with the ISO C standard.</p>
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</blockquote>
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<div class="box"><em>End of informative text.</em></div>
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