copysignf (3) Linux Manual Page
copysign, copysignf, copysignl – copy sign of a number
Synopsis
#include <math.h>Link with -lm.
double copysign(double x, double y);
float copysignf(float x, float y);
long double copysignl(long double x, long double y);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
copysign(), copysignf(), copysignl():
- _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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).| Interface | Attribute | Value |
| copysign(), copysignf(), copysignl() | Thread safety | MT-Safe |