331 lines
6.1 KiB
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331 lines
6.1 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 NEXTAFTER</TITLE>
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</HEAD><BODY>
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<H1>NEXTAFTER</H1>
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Section: Linux Programmer's Manual (3)<BR>Updated: 2017-09-15<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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nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl -
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floating-point number manipulation
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>#include <<A HREF="file:///usr/include/math.h">math.h</A>></B>
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<P>
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<B>double nextafter(double </B><I>x</I><B>, double </B><I>y</I><B>);</B>
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<BR>
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<B>float nextafterf(float </B><I>x</I><B>, float </B><I>y</I><B>);</B>
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<BR>
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<B>long double nextafterl(long double </B><I>x</I><B>, long double </B><I>y</I><B>);</B>
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<P>
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<B>double nexttoward(double </B><I>x</I><B>, long double </B><I>y</I><B>);</B>
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<BR>
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<B>float nexttowardf(float </B><I>x</I><B>, long double </B><I>y</I><B>);</B>
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<BR>
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<B>long double nexttowardl(long double </B><I>x</I><B>, long double </B><I>y</I><B>);</B>
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<P>
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Link with <I>-lm</I>.
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<P>
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Feature Test Macro Requirements for glibc (see
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<B><A HREF="/cgi-bin/man/man2html?7+feature_test_macros">feature_test_macros</A></B>(7)):
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<P>
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<B>nextafter</B>():
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<DL COMPACT><DT id="1"><DD>
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_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
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<BR> || _XOPEN_SOURCE >= 500
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<BR> || /* Since glibc 2.19: */ _DEFAULT_SOURCE
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<BR> || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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</DL>
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<BR>
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<B>nextafterf</B>(),
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<B>nextafterl</B>():
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<DL COMPACT><DT id="2"><DD>
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_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
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<BR> || /* Since glibc 2.19: */ _DEFAULT_SOURCE
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<BR> || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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</DL>
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<BR>
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<B>nexttoward</B>(),
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<B>nexttowardf</B>(),
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<B>nexttowardl</B>():
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<DL COMPACT><DT id="3"><DD>
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_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
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_POSIX_C_SOURCE >= 200112L
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</DL>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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The
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<B>nextafter</B>(),
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<B>nextafterf</B>(),
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and
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<B>nextafterl</B>()
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functions return the next representable floating-point value following
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<I>x</I>
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in the direction of
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<I>y</I>.
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If
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<I>y</I>
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is less than
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<I>x</I>,
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these functions will return the largest representable number less than
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<I>x</I>.
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<P>
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If
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<I>x</I>
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equals
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<I>y</I>,
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the functions return
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<I>y</I>.
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<P>
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The
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<B>nexttoward</B>(),
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<B>nexttowardf</B>(),
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and
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<B>nexttowardl</B>()
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functions do the same as the corresponding
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<B>nextafter</B>()
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functions, except that they have a
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<I>long double</I>
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second argument.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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On success,
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these functions return the next representable floating-point value after
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<I>x</I>
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in the direction of
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<I>y</I>.
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<P>
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If
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<I>x</I>
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equals
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<I>y</I>,
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then
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<I>y</I>
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(cast to the same type as
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<I>x</I>)
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is returned.
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<P>
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If
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<I>x</I>
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or
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<I>y</I>
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is a NaN,
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a NaN is returned.
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<P>
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If
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<I>x</I>
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is finite,
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and the result would overflow,
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a range error occurs,
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and the functions return
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<B>HUGE_VAL</B>,
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<B>HUGE_VALF</B>,
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or
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<B>HUGE_VALL</B>,
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respectively, with the correct mathematical sign.
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<P>
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If
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<I>x</I>
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is not equal to
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<I>y</I>,
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and the correct function result would be subnormal, zero, or underflow,
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a range error occurs,
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and either the correct value (if it can be represented),
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or 0.0, is returned.
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<A NAME="lbAF"> </A>
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<H2>ERRORS</H2>
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See
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<B><A HREF="/cgi-bin/man/man2html?7+math_error">math_error</A></B>(7)
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for information on how to determine whether an error has occurred
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when calling these functions.
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<P>
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The following errors can occur:
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<DL COMPACT>
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<DT id="4">Range error: result overflow<DD>
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An overflow floating-point exception
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(<B>FE_OVERFLOW</B>)
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is raised.
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<DT id="5">Range error: result is subnormal or underflows<DD>
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An underflow floating-point exception
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(<B>FE_UNDERFLOW</B>)
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is raised.
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</DL>
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<P>
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These functions do not set
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<I>errno</I>.
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<A NAME="lbAG"> </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>nextafter</B>(),
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<B>nextafterf</B>(),
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<BR>
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<B>nextafterl</B>(),
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<B>nexttoward</B>(),
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<BR>
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<B>nexttowardf</B>(),
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<B>nexttowardl</B>()
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</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
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</TABLE>
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<A NAME="lbAH"> </A>
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<H2>CONFORMING TO</H2>
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C99, POSIX.1-2001, POSIX.1-2008.
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This function is defined in IEC 559 (and the appendix with
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recommended functions in IEEE 754/IEEE 854).
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<A NAME="lbAI"> </A>
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<H2>BUGS</H2>
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In glibc version 2.5 and earlier, these functions do not raise an underflow
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floating-point
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(<B>FE_UNDERFLOW</B>)
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exception when an underflow occurs.
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<A NAME="lbAJ"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?3+nearbyint">nearbyint</A></B>(3)
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<A NAME="lbAK"> </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="6"><A HREF="#lbAB">NAME</A><DD>
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<DT id="7"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="8"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="9"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="10"><A HREF="#lbAF">ERRORS</A><DD>
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<DT id="11"><A HREF="#lbAG">ATTRIBUTES</A><DD>
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<DT id="12"><A HREF="#lbAH">CONFORMING TO</A><DD>
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<DT id="13"><A HREF="#lbAI">BUGS</A><DD>
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<DT id="14"><A HREF="#lbAJ">SEE ALSO</A><DD>
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<DT id="15"><A HREF="#lbAK">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: 00:05:49 GMT, March 31, 2021
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</BODY>
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</HTML>
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