copysign, copysignf—sign of y, magnitude of x #include <math.h>
double copysign (double x, double y);
float copysignf (float x, float y);
Description
copysign constructs a number with the magnitude (absolute value)
of its first argument, x, and the sign of its second argument,
y.
copysignf does the same thing; the two functions differ only in
the type of their arguments and result.
Returns
copysign returns a double with the magnitude of
x and the sign of y.
copysignf returns a float with the magnitude of
x and the sign of y.
Portability
copysign is not required by either ANSI C or the System V Interface
Definition (Issue 2).