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)
Non-NaN value	nan	nan
nan	Non-NaN value	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: Miscellaneous Functions