COPYSIGN(3) BSD Library Functions Manual COPYSIGN(3)NAME
copysign, copysignf, copysignl — functions to manipulate signs
LIBRARY
Math Library (libm, -lm)
SYNOPSIS
#include <math.h>
double
copysign(double x, double y);
float
copysignf(float x, float y);
long double
copysignl(long double x, long double y);
DESCRIPTION
The copysign(), copysignf(), and copysignl() functions return a value
whose absolute value matches x, but whose sign bit is taken from y.
RETURN VALUES
Upon successful completion, all three functions return a value with the
magnitude of x and the sign of y. If x is NaN , the functions return a
NaN with the sign of y.
SEE ALSOmath(3), signbit(3)STANDARDS
The described functions conform to ISO/IEC 9899:1999 (“ISO C99”).
CAVEATS
Note that on implementations that represent a signed zero but do not
treat negative zero consistently in arithmetic operations, these func‐
tions may regard the sign of zero as positive.
BSD April 13, 2011 BSD