nextafter

Return the next representable value of the specified return format after x in the direction of y.

Interface Definition

C interface:

float nextafterf(float x, float y);

double nextafter(double x, double y);

Parameters

Parameter	Type	Description	Input/Output
x	For nextafterf, x is of single-precision floating-point type. For nextafter, x is of double-precision floating-point type.	Floating-point value of the input data.	Input
y	For nextafterf, y is of single-precision floating-point type. For nextafter, y is of double-precision floating-point type.	Floating-point value of the input data.	Input

Return Value

The next representable value of the specified return format after x in the direction of y is returned.
errno: ERANGE is returned in overflow scenarios.

The special values are listed in the following table.

Input Value (x)	Input Value (y)	Output Value (result)
Any value but NaN	nan	nan
nan	Any value but NaN	nan
nan	nan	nan
inf	inf	inf
-inf	-inf	-inf
inf	-inf	0x7fefffffffffffff(double) 0x7f7fffff(float)
-inf	inf	0xffefffffffffffff(double) 0xff7fffff(float)

Dependency

C: "km.h"

Example

C interface:

    // typical usage
    double x1 = 1.0, y1 = 2.0, x2 = 3.0, y2 = 4.0;
    // print result
    printf("nextafter(x1, y1) = %.15f\n", nextafter(x1, y1));
    printf("nextafter(x2, y2) = %.15f\n", nextafter(x2, y2));
    /*
     * nextafter(x1, y1) = 1.000000000000000
     * nextafter(x2, y2) = 3.000000000000000
     */

Parent topic: Function Syntax