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1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
2 | .\" | |
93015253 | 3 | .\" %%%LICENSE_START(VERBATIM) |
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4 | .\" Permission is granted to make and distribute verbatim copies of this |
5 | .\" manual provided the copyright notice and this permission notice are | |
6 | .\" preserved on all copies. | |
7 | .\" | |
8 | .\" Permission is granted to copy and distribute modified versions of this | |
9 | .\" manual under the conditions for verbatim copying, provided that the | |
10 | .\" entire resulting derived work is distributed under the terms of a | |
11 | .\" permission notice identical to this one. | |
c13182ef | 12 | .\" |
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13 | .\" Since the Linux kernel and libraries are constantly changing, this |
14 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
15 | .\" responsibility for errors or omissions, or for damages resulting from | |
16 | .\" the use of the information contained herein. The author(s) may not | |
17 | .\" have taken the same level of care in the production of this manual, | |
18 | .\" which is licensed free of charge, as they might when working | |
19 | .\" professionally. | |
c13182ef | 20 | .\" |
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21 | .\" Formatted or processed versions of this manual, if unaccompanied by |
22 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 23 | .\" %%%LICENSE_END |
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24 | .\" |
25 | .\" References consulted: | |
26 | .\" Linux libc source code | |
27 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
28 | .\" 386BSD man pages | |
29 | .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) | |
30 | .\" Modified 2002-08-10 by Walter Harms (walter.harms@informatik.uni-oldenburg.de) | |
fe0fefbf | 31 | .TH COPYSIGN 3 2015-03-02 "GNU" "Linux Programmer's Manual" |
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32 | .SH NAME |
33 | copysign, copysignf, copysignl \- copy sign of a number | |
34 | .SH SYNOPSIS | |
35 | .nf | |
36 | .B #include <math.h> | |
37 | .sp | |
38 | .BI "double copysign(double " x ", double " y ); | |
39 | .br | |
40 | .BI "float copysignf(float " x ", float " y ); | |
41 | .br | |
42 | .BI "long double copysignl(long double " x ", long double " y ); | |
43 | .fi | |
44 | .sp | |
20c58d70 | 45 | Link with \fI\-lm\fP. |
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46 | .sp |
47 | .in -4n | |
48 | Feature Test Macro Requirements for glibc (see | |
49 | .BR feature_test_macros (7)): | |
50 | .in | |
51 | .sp | |
52 | .ad l | |
53 | .BR copysign (), | |
e0bf9127 | 54 | .BR copysignf (), |
cc4615cc | 55 | .BR copysignl (): |
f6e22dbb | 56 | .RS 4 |
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57 | _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE || |
58 | _POSIX_C_SOURCE\ >=\ 200112L; | |
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59 | .br |
60 | or | |
cc4615cc | 61 | .I cc\ -std=c99 |
f6e22dbb | 62 | .RE |
cc4615cc | 63 | .ad b |
fea681da | 64 | .SH DESCRIPTION |
60a90ecd | 65 | The |
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66 | .BR copysign (), |
67 | .BR copysignf (), | |
68 | and | |
69 | .BR copysignl () | |
60a90ecd | 70 | functions return a value whose absolute value matches |
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71 | that of |
72 | .IR x , | |
73 | but whose sign bit matches that of | |
74 | .IR y . | |
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75 | |
76 | For example, | |
77 | .I "copysign(42.0,\ \-1.0)" | |
78 | and | |
79 | .I "copysign(\-42.0, \-1.0)" | |
80 | both return \-42.0. | |
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81 | .SH RETURN VALUE |
82 | On success, these functions return a value whose magnitude is taken from | |
83 | .I x | |