Computes the next representable floating-point value following x in the direction of y. Thus, if y is less than x, nextafter shall return the largest representable floating-point number less than x. The nextafter function shall return y if x equals y.

#include <math.h>

double nextafter (double x, double y);

Parameters

x, y

Double-precision floating-point values.

Return Values

• Upon successful completion, these functions shall return the next representable floating-point value following x in the direction of y.
• If x== y, y (of the type x) shall be returned.
• If x is finite and the correct function value would overflow, a range error shall occur and +/-HUGE_VAL (with the same sign as x) shall be returned.
• If x or y is NaN, a NaN shall be returned.
• If x!= y and the correct function value is subnormal, zero, or underflows, a range error shall occur, and either the correct function value (if representable) or 0.0 shall be returned.

Requirements