nexttowardl

```NEXTAFTER(3)               Linux Programmer's Manual              NEXTAFTER(3)

NAME
nextafter, nextafterf, nextafterl, nexttoward, nexttowardf, nexttowardl
- floating-point 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);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

nextafter():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| _XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
nextafterf(), nextafterl():
_ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
nexttoward(), nexttowardf(), nexttowardl():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L

DESCRIPTION
The  nextafter(),  nextafterf(),  and nextafterl() functions return the
next representable floating-point value following x in the direction of
y.  If y is less than x, these functions will return the largest repre-
sentable 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  floating-
point 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,  respec-
tively, with the correct mathematical sign.

If  x  is not equal to y, and the correct function result would be sub-
normal, zero, or underflow, a range error occurs, and either  the  cor-
rect 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 floating-point exception (FE_OVERFLOW) is raised.

Range error: result is subnormal or underflows
An underflow floating-point exception (FE_UNDERFLOW) is raised.

These functions do not set errno.

ATTRIBUTES
For an  explanation  of  the  terms  used  in  this  section,  see  at-
tributes(7).

+-----------------------------+---------------+---------+
|Interface                    | Attribute     | Value   |
+-----------------------------+---------------+---------+
|nextafter(), nextafterf(),   | Thread safety | MT-Safe |
|nextafterl(), nexttoward(),  |               |         |
|nexttowardf(), nexttowardl() |               |         |
+-----------------------------+---------------+---------+
CONFORMING TO
C99,  POSIX.1-2001,  POSIX.1-2008.  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  un-
derflow  floating-point  (FE_UNDERFLOW) exception when an underflow oc-
curs.