.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\"
+.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
+.\" %%%LICENSE_END
.\"
.\" References consulted:
.\" Linux libc source code
.\" 386BSD man pages
.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
.\" Modified 2002-08-10 by Walter Harms (walter.harms@informatik.uni-oldenburg.de)
-.TH COPYSIGN 3 2010-09-20 "GNU" "Linux Programmer's Manual"
+.TH COPYSIGN 3 2013-10-14 "GNU" "Linux Programmer's Manual"
.SH NAME
copysign, copysignf, copysignl \- copy sign of a number
.SH SYNOPSIS
.ad b
.SH DESCRIPTION
The
-.BR copysign ()
+.BR copysign (),
+.BR copysignf (),
+and
+.BR copysignl ()
functions return a value whose absolute value matches
-that of \fIx\fP, but whose sign bit matches that of \fIy\fP.
+that of
+.IR x ,
+but whose sign bit matches that of
+.IR y .
+
+For example,
+.I "copysign(42.0,\ \-1.0)"
+and
+.I "copysign(\-42.0, \-1.0)"
+both return \-42.0.
.SH RETURN VALUE
On success, these functions return a value whose magnitude is taken from
.I x
and whose sign is taken from
.IR y .
-If \fIx\fP is a NaN,
-a NaN with the sign bit of \fIy\fP is returned.
+If
+.I x
+is a NaN,
+a NaN with the sign bit of
+.I y
+is returned.
.SH ERRORS
No errors occur.
-.SH "CONFORMING TO"
+.SH ATTRIBUTES
+.SS Multithreading (see pthreads(7))
+The
+.BR copysign (),
+.BR copysignf (),
+and
+.BR copysignl ()
+functions are thread-safe.
+.SH CONFORMING TO
C99, POSIX.1-2001.
.\" 4.3BSD.
This function is defined in IEC 559 (and the appendix with
recommended functions in IEEE 754/IEEE 854).
.SH NOTES
On architectures where the floating-point formats are not IEEE 754 compliant,
-the
-.BR copysign ()
+these
functions may treat a negative zero as positive.
-.SH "SEE ALSO"
+.SH SEE ALSO
.BR signbit (3)
+.SH COLOPHON
+This page is part of release 3.79 of the Linux
+.I man-pages
+project.
+A description of the project,
+information about reporting bugs,
+and the latest version of this page,
+can be found at
+\%http://www.kernel.org/doc/man\-pages/.