1COPYSIGN(3)                Linux Programmer's Manual               COPYSIGN(3)
2
3
4

NAME

6       copysign, copysignf, copysignl - copy sign of a number
7

SYNOPSIS

9       #include <math.h>
10
11       double copysign(double x, double y);
12       float copysignf(float x, float y);
13       long double copysignl(long double x, long double y);
14
15       Link with -lm.
16
17   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
18
19       copysign(), copysignf(), copysignl(): _SVID_SOURCE || _BSD_SOURCE ||
20       _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99
21

DESCRIPTION

23       The copysign() functions return a value whose  absolute  value  matches
24       that of x, but whose sign bit matches that of y.
25

RETURN VALUE

27       On  success,  these  functions  return a value whose magnitude is taken
28       from x and whose sign is taken from y.
29
30       If x is a NaN, a NaN with the sign bit of y is returned.
31

ERRORS

33       No errors occur.
34

CONFORMING TO

36       C99, POSIX.1-2001.  This function is defined in IEC 559 (and the appen‐
37       dix with recommended functions in IEEE 754/IEEE 854).
38

NOTES

40       On architectures where the floating-point formats are not IEEE 754 com‐
41       pliant, the copysign() functions may treat a negative zero as positive.
42

SEE ALSO

44       signbit(3)
45

COLOPHON

47       This page is part of release 3.22 of the Linux  man-pages  project.   A
48       description  of  the project, and information about reporting bugs, can
49       be found at http://www.kernel.org/doc/man-pages/.
50
51
52
53GNU                               2008-08-05                       COPYSIGN(3)
Impressum