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)):
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.
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.
signbit(3)