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 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.
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
(according 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.
STANDARDS CONFORMANCE
nextafter(): SVID3, XPG4.2
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