copysignf(3) · carta

Usage

double copysign(double x, double y); float copysignf(float x, float y); long double copysignl(long double x, long double y);

_ISOC99_SOURCE { | | _POSIX_C_SOURCE >= 200112L}

Math library (libm, -lm)

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.

No errors occur.

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
copysign(), copysignf(), copysignl()	Thread safety	MT-Safe

On architectures where the floating-point formats are not IEEE 754 compliant, these functions may treat a negative zero as positive.