162 lines
3.7 KiB
HTML
162 lines
3.7 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 COPYSIGN</TITLE>
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</HEAD><BODY>
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<H1>COPYSIGN</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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copysign, copysignf, copysignl - copy sign of a number
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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/math.h">math.h</A>></B>
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<B>double copysign(double </B><I>x</I><B>, double </B><I>y</I><B>);</B>
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<B>float copysignf(float </B><I>x</I><B>, float </B><I>y</I><B>);</B>
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<B>long double copysignl(long double </B><I>x</I><B>, long double </B><I>y</I><B>);</B>
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</PRE>
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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>copysign</B>(),
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<B>copysignf</B>(),
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<B>copysignl</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> || /* 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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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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These functions return a value whose absolute value matches that of
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<I>x</I>,
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but whose sign bit matches that of
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<I>y</I>.
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<P>
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For example,
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<I>copysign(42.0, -1.0)</I>
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and
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<I>copysign(-42.0, -1.0)</I>
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both return -42.0.
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<A NAME="lbAE"> </A>
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<H2>RETURN VALUE</H2>
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On success, these functions return a value whose magnitude is taken from
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<I>x</I>
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and whose sign is taken from
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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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is a NaN,
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a NaN with the sign bit of
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<I>y</I>
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is returned.
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<A NAME="lbAF"> </A>
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<H2>ERRORS</H2>
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No errors occur.
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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>copysign</B>(),
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<B>copysignf</B>(),
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<B>copysignl</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>NOTES</H2>
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On architectures where the floating-point formats are not IEEE 754 compliant,
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these
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functions may treat a negative zero as positive.
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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+signbit">signbit</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="2"><A HREF="#lbAB">NAME</A><DD>
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<DT id="3"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="4"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="5"><A HREF="#lbAE">RETURN VALUE</A><DD>
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<DT id="6"><A HREF="#lbAF">ERRORS</A><DD>
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<DT id="7"><A HREF="#lbAG">ATTRIBUTES</A><DD>
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<DT id="8"><A HREF="#lbAH">CONFORMING TO</A><DD>
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<DT id="9"><A HREF="#lbAI">NOTES</A><DD>
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<DT id="10"><A HREF="#lbAJ">SEE ALSO</A><DD>
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<DT id="11"><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: 00:05:38 GMT, March 31, 2021
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</BODY>
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</HTML>
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