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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><html><head><!-- Copyright 1997 The Open Group, All Rights Reserved --><title>mbrlen</title></head><body bgcolor=white><center><font size=2>The Single UNIX ® Specification, Version 2<br>Copyright © 1997 The Open Group</font></center><hr size=2 noshade><h4><a name = "tag_000_007_520"> </a>NAME</h4><blockquote>mbrlen - get number of bytes in a character (restartable)</blockquote><h4><a name = "tag_000_007_521"> </a>SYNOPSIS</h4><blockquote><pre><code>#include <<a href="wchar.h.html">wchar.h</a>>size_t mbrlen(const char *<i>s</i>, size_t <i>n</i>, mbstate_t *<i>ps</i>);</code></pre></blockquote><h4><a name = "tag_000_007_522"> </a>DESCRIPTION</h4><blockquote>If<i>s</i>is not a null pointer, <i>mbrlen()</i>determines the number of bytes constituting the character pointed to by <i>s</i>.It is equivalent to:<pre><code>mbstate_t internal;mbrtowc(NULL, s, n, ps != NULL ? ps : &internal);</code></pre><p>If<i>ps</i>is a null pointer, the<i>mbrlen()</i>function uses its own internal<b>mbstate_t</b>object, which is initialised at program startup to the initialconversion state. Otherwise, the <b>mbstate_t</b>object pointed to by<i>ps</i>is used to completely describe the current conversion state of theassociated character sequence.The implementation will behave as if no function defined in thisspecification calls<i>mbrlen()</i>.<p>The behaviour of this function is affected by the LC_CTYPE category ofthe current locale. </blockquote><h4><a name = "tag_000_007_523"> </a>RETURN VALUE</h4><blockquote>The<i>mbrlen()</i>function returns the first of the following that applies:<dl compact><dt>0<dd>If the next<i>n</i>or fewer bytes complete the character that corresponds tothe null wide-character.<dt><i>positive</i><dd>If the next<i>n</i>or fewer bytes complete a valid character; the valuereturned is the number of bytes that complete the character.<dt><b>(size_t)-2</b><dd>If the next<i>n</i>bytes contribute to an incomplete but potentially valid character, and all<i>n</i>bytes have been processed.When<i>n</i>has at least the value of the MB_CUR_MAX macro, this case can onlyoccur if <i>s</i>points at a sequence of redundant shift sequences (for implementationswith state-dependent encodings).<dt><b>(size_t)-1</b><dd>If an encoding error occurs, in which case the next<i>n</i>or fewer bytes do not contribute to a complete and valid character. In this case, EILSEQ is stored in<i>errno</i>and the conversion state is undefined.</dl></blockquote><h4><a name = "tag_000_007_524"> </a>ERRORS</h4><blockquote>The<i>mbrlen()</i>function may fail if:<dl compact><dt>[EINVAL]<dd><i>ps</i>points to an object that contains an invalid conversion state.<dt>[EILSEQ]<dd>Invalid character sequence is detected.</dl></blockquote><h4><a name = "tag_000_007_525"> </a>EXAMPLES</h4><blockquote>None.</blockquote><h4><a name = "tag_000_007_526"> </a>APPLICATION USAGE</h4><blockquote>None.</blockquote><h4><a name = "tag_000_007_527"> </a>FUTURE DIRECTIONS</h4><blockquote>None.</blockquote><h4><a name = "tag_000_007_528"> </a>SEE ALSO</h4><blockquote><i><a href="mbsinit.html">mbsinit()</a></i>,<i><a href="mbrtowc.html">mbrtowc()</a></i>,<i><a href="wchar.h.html"><wchar.h></a></i>.</blockquote><h4>DERIVATION</h4><blockquote>Derived from the ISO/IEC 9899:1990/Amendment 1:1995 (E).</blockquote><hr size=2 noshade><center><font size=2>UNIX ® is a registered Trademark of The Open Group.<br>Copyright © 1997 The Open Group<br> [ <a href="../index.html">Main Index</a> | <a href="../xshix.html">XSH</a> | <a href="../xcuix.html">XCU</a> | <a href="../xbdix.html">XBD</a> | <a href="../cursesix.html">XCURSES</a> | <a href="../xnsix.html">XNS</a> ]</font></center><hr size=2 noshade></body></html>⌨️ 快捷键说明
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