298 lines
5.1 KiB
HTML
298 lines
5.1 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of MBRTOWC</TITLE>
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</HEAD><BODY>
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<H1>MBRTOWC</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2019-03-06<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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mbrtowc - convert a multibyte sequence to a wide character
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<PRE>
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<B>#include <<A HREF="file:///usr/include/wchar.h">wchar.h</A>></B>
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<B>size_t mbrtowc(wchar_t *</B><I>pwc</I><B>, const char *</B><I>s</I><B>, size_t </B><I>n</I><B>, mbstate_t *</B><I>ps</I><B>);</B>
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</PRE>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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The main case for this function is when
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<I>s</I>
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is not NULL and
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<I>pwc</I>
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is
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not NULL.
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In this case, the
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<B>mbrtowc</B>()
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function inspects at most
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<I>n</I>
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bytes of the multibyte string starting at
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<I>s</I>,
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extracts the next complete
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multibyte character, converts it to a wide character and stores it at
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<I>*pwc</I>.
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It updates the shift state
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<I>*ps</I>.
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If the converted wide
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character is not L'\0' (the null wide character),
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it returns the number of bytes that were consumed
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from
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<I>s</I>.
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If the converted wide character is L'\0', it resets the shift
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state
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<I>*ps</I>
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to the initial state and returns 0.
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<P>
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If the
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<I>n</I>
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bytes starting at
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<I>s</I>
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do not contain a complete multibyte
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character,
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<B>mbrtowc</B>()
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returns
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<I>(size_t) -2</I>.
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This can happen even if
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<I>n</I>
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>=
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<I>MB_CUR_MAX</I>,
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if the multibyte string contains redundant shift
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sequences.
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<P>
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If the multibyte string starting at
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<I>s</I>
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contains an invalid multibyte
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sequence before the next complete character,
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<B>mbrtowc</B>()
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returns
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<I>(size_t) -1</I>
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and sets
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<I>errno</I>
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to
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<B>EILSEQ</B>.
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In this case,
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the effects on
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<I>*ps</I>
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are undefined.
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<P>
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A different case is when
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<I>s</I>
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is not NULL but
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<I>pwc</I>
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is NULL.
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In this case, the
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<B>mbrtowc</B>()
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function behaves as above, except that it does not
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store the converted wide character in memory.
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<P>
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A third case is when
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<I>s</I>
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is NULL.
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In this case,
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<I>pwc</I>
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and
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<I>n</I>
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are
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ignored.
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If the conversion state represented by
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<I>*ps</I>
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denotes an
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incomplete multibyte character conversion, the
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<B>mbrtowc</B>()
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function
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returns
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<I>(size_t) -1</I>,
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sets
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<I>errno</I>
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to
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<B>EILSEQ</B>,
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and
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leaves
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<I>*ps</I>
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in an undefined state.
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Otherwise, the
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<B>mbrtowc</B>()
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function
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puts
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<I>*ps</I>
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in the initial state and returns 0.
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<P>
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In all of the above cases, if
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<I>ps</I>
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is NULL, a static anonymous
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state known only to the
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<B>mbrtowc</B>()
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function is used instead.
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Otherwise,
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<I>*ps</I>
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must be a valid
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<I>mbstate_t</I>
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object.
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An
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<I>mbstate_t</I>
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object
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<I>a</I>
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can be initialized to the initial state
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by zeroing it, for example using
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<P>
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memset(&a, 0, sizeof(a));
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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The
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<B>mbrtowc</B>()
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function returns the number of bytes parsed from the
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multibyte sequence starting at
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<I>s</I>,
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if a non-L'\0' wide character
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was recognized.
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It returns 0, if a L'\0' wide character was recognized.
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It returns
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<I>(size_t) -1</I>
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and sets
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<I>errno</I>
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to
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<B>EILSEQ</B>,
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if an invalid multibyte sequence was
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encountered.
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It returns
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<I>(size_t) -2</I>
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if it couldn't parse a complete multibyte
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character, meaning that
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<I>n</I>
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should be increased.
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<A NAME="lbAF"> </A>
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<H2>ATTRIBUTES</H2>
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For an explanation of the terms used in this section, see
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<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
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<TABLE BORDER>
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<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
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<TR VALIGN=top><TD>
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<B>mbrtowc</B>()
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</TD><TD>Thread safety</TD><TD>MT-Unsafe race:mbrtowc/!ps<BR></TD></TR>
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</TABLE>
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<A NAME="lbAG"> </A>
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<H2>CONFORMING TO</H2>
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POSIX.1-2001, POSIX.1-2008, C99.
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<A NAME="lbAH"> </A>
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<H2>NOTES</H2>
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The behavior of
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<B>mbrtowc</B>()
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depends on the
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<B>LC_CTYPE</B>
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category of the
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current locale.
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<A NAME="lbAI"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?3+mbsinit">mbsinit</A></B>(3),
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<B><A HREF="/cgi-bin/man/man2html?3+mbsrtowcs">mbsrtowcs</A></B>(3)
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<A NAME="lbAJ"> </A>
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<H2>COLOPHON</H2>
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This page is part of release 5.05 of the Linux
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<I>man-pages</I>
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project.
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A description of the project,
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information about reporting bugs,
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and the latest version of this page,
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can be found at
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<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="1"><A HREF="#lbAB">NAME</A><DD>
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<DT id="2"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="3"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="4"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="5"><A HREF="#lbAF">ATTRIBUTES</A><DD>
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<DT id="6"><A HREF="#lbAG">CONFORMING TO</A><DD>
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<DT id="7"><A HREF="#lbAH">NOTES</A><DD>
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<DT id="8"><A HREF="#lbAI">SEE ALSO</A><DD>
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<DT id="9"><A HREF="#lbAJ">COLOPHON</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:05:48 GMT, March 31, 2021
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