|COPYSIGN(3)||Linux Programmer's Manual||COPYSIGN(3)|
NAME¶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():
DESCRIPTION¶These functions return a value whose absolute value matches that of x, but whose sign bit matches that of y.
For example, copysign(42.0, -1.0) and copysign(-42.0, -1.0) both return -42.0.
RETURN VALUE¶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.
ERRORS¶No errors occur.
ATTRIBUTES¶For an explanation of the terms used in this section, see attributes(7).
|copysign (), copysignf (), copysignl ()||Thread safety||MT-Safe|
CONFORMING TO¶C99, POSIX.1-2001, POSIX.1-2008. This function is defined in IEC 559 (and the appendix with recommended functions in IEEE 754/IEEE 854).
NOTES¶On architectures where the floating-point formats are not IEEE 754 compliant, these functions may treat a negative zero as positive.
COLOPHON¶This page is part of release 4.10 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.