| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON | The Linux Programming Interface |
COPYSIGN(3) Linux Programmer's Manual COPYSIGN(3)
copysign, copysignf, copysignl - copy sign of a number
#include <math.h>
double copysign(double x, double y);
float copysignf(float x, float y);
long double copysignl(long double x, long double y);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
copysign(), copysignf(), copysignl():
_SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
The copysign() functions return a value whose absolute value matches that of
x, but whose sign bit matches that of y.
On success, these functions return a value whose magnitude is taken from x and
whose sign is taken from y.
If x is a NaN, a NaN with the sign bit of y is returned.
No errors occur.
C99, POSIX.1-2001. This function is defined in IEC 559 (and the appendix with
recommended functions in IEEE 754/IEEE 854).
On architectures where the floating-point formats are not IEEE 754 compliant,
the copysign() functions may treat a negative zero as positive.
signbit(3)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
GNU 2010-09-20 COPYSIGN(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface