NAME
copysign,
copysignf, copysignl
— functions to manipulate
signs
LIBRARY
library “libm”
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);
#include
<tgmath.h>
real-floating
copysign(real-floating
x, real-floating
y);
DESCRIPTION
Thecopysign(),
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 ALSO
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 functions may regard the sign of zero as positive.