Section (3) nextafter
Name
nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl — floatingpoint number manipulation
Synopsis
#include <math.h>
double
nextafter( 
double x, 
double y) ; 
float
nextafterf( 
float x, 
float y) ; 
long double
nextafterl( 
long double x, 
long double y) ; 
double
nexttoward( 
double x, 
long double y) ; 
float
nexttowardf( 
float x, 
long double y) ; 
long double
nexttowardl( 
long double x, 
long double y) ; 
Note  


Note  

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DESCRIPTION
The nextafter
(),
nextafterf
(), and nextafterl
() functions return the next
representable floatingpoint value following x
in the direction of
y
. If y
is less than x
, these functions will return
the largest representable number less than x
.
If x
equals
y
, the functions
return y
.
The nexttoward
(),
nexttowardf
(), and nexttowardl
() functions do the same as the
corresponding nextafter
()
functions, except that they have a long
double second argument.
RETURN VALUE
On success, these functions return the next representable
floatingpoint value after x
in the direction of
y
.
If x
equals
y
, then y
(cast to the same type as
x
) is returned.
If x
or y
is a NaN, a NaN is
returned.
If x
is finite,
and the result would overflow, a range error occurs, and the
functions return HUGE_VAL
,
HUGE_VALF
, or HUGE_VALL
, respectively, with the correct
mathematical sign.
If x
is not equal
to y
, and the correct
function result would be subnormal, zero, or underflow, a
range error occurs, and either the correct value (if it can
be represented), or 0.0, is returned.
ERRORS
See math_error(7) for information on how to determine whether an error has occurred when calling these functions.
The following errors can occur:
 Range error: result overflow

An overflow floatingpoint exception (
FE_OVERFLOW
) is raised.  Range error: result is subnormal or underflows

An underflow floatingpoint exception (
FE_UNDERFLOW
) is raised.
These functions do not set errno
.
ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7).
Interface  Attribute  Value 

Thread safety  MTSafe 
CONFORMING TO
C99, POSIX.12001, POSIX.12008. This function is defined in IEC 559 (and the appendix with recommended functions in IEEE 754/IEEE 854).
BUGS
In glibc version 2.5 and earlier, these functions do not
raise an underflow floatingpoint (FE_UNDERFLOW
) exception when an underflow
occurs.
COLOPHON
This page is part of release 4.16 of the Linux manpages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
Copyright 2002 Walter Harms (walter.harmsinformatik.unioldenburg.de) and Copyright 2008, Linux Foundation, written by Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(GPL_NOVERSION_ONELINE) Distributed under GPL %%%LICENSE_END Based on glibc infopages 