Generates a value consisting of the absolute value of d1 and the sign of d2.
double copysign(double d1, double d2);
float copysignf(float d1, float d2);
long double copysignl(long double d1, long double d2);
d1 Value of which absolute value is to be used in the generated value
d2 Value of which sign is to be used in the generated value
Normal: Value consisting of absolute value of d1 and sign of d2
Abnormal: Range error: Returns an undetermined value.
When d1 is a not-a-number, the copysign function group generates a not-a-number with the sign bit of d2.