HP-UX Reference (11i v1 05/09) - 3 Library Functions N-Z (vol 7)
n
nextafter(3M) nextafter(3M)
NAME
nextafter(), nextafterf() - next representable floating-point value
SYNOPSIS
#include <math.h>
double nextafter(double x, double y);
float nextafterf(float x, float y);
DESCRIPTION
The nextafter() function computes the next representable double-precision floating-point value follow-
ing x in the direction of y. Thus, if y is less than x,
nextafter() returns the largest representable
floating-point number less than x.
The
nextafter() function is recommended by the IEEE-754 standard for floating-point arithmetic. The
ISO/ANSI C committee has approved the
nextafter() function for inclusion in the C9X draft standard.
nextafterf() is a float version of nextafter()
; it takes float arguments and returns a
float result.
To use these functions, compile either with the default -Ae option or with the -Aa
and
-D_HPUX_SOURCE options. Make sure your program includes <
math.h>. Link in the math library by
specifying
-lm on the compiler or linker command line.
RETURN VALUE
The nextafter() and nextafterf() functions return the next representable double-precision or
single-precision floating-point value following x in the direction of y.
If x or y is NaN,
nextafter() returns NaN.
If x is finite and the correct function value would overflow, nextafter() returns
±HUGE_VAL (accord-
ing to the sign of x) and sets
errno to [ERANGE].
ERRORS
If nextafter() fails, errno is set to the following value.
[ERANGE] The correct value would overflow.
SEE ALSO
math(5), limits(5).
STANDARDS CONFORMANCE
nextafter() : SVID3, XPG4.2
HP-UX 11i Version 1: September 2005 − 1 − Hewlett-Packard Company Section 3−−583