_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED ||
_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99
nextafterf(),
nextafterl():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99
nexttoward(),
nexttowardf(),
nexttowardl():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99
DESCRIPTION
The
nextafter()
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 representable number less than
x.
If x equals y, the functions return y.
The
nexttoward()
functions do the same as the
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,
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 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.
CONFORMING TO
C99, POSIX.1-2001.
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
floating-point
(FE_UNDERFLOW)
exception when an underflow occurs.
This page is part of release 3.27 of the Linux
man-pages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages/.