NEXTAFTER(3) Library Functions Manual NEXTAFTER(3)

nextafternext representable double-precision floating-point number

#include <math.h>

double nextafter(double x, double y);

The nextafter() function computes the next representable double-precision floating-point value following x in the direction of y . Thus, if y is less than x , nextafter() returns the largest representable floating-point number less than x .

An application wishing to check for error situations should set errno to 0 before calling nextafter(). If errno is non-zero on return, or the value NaN is returned, an error has occurred.

The nextafter() function returns the next representable double-precision floating-point value following x in the direction of y .

If x or is NaN, then nextafter() returns NaN and may set errno to [EDOM].

If x is finite and the correct function value would overflow, HUGE_VAL is returned and errno is set to [ERANGE].

The nextafter() function will fail if:

The correct value would overflow.

The nextafter() function may fail if:

The x or y argument is NaN.

None.

None.

None.

<math.h> .

February 1997 posix.fail