# isnan(3) [freebsd man page]

```FPCLASSIFY(3)						   BSD Library Functions Manual 					     FPCLASSIFY(3)

NAME
fpclassify, isfinite, isinf, isnan, isnormal -- classify a floating-point number

LIBRARY
Math Library (libm, -lm)

SYNOPSIS
#include <math.h>

int
fpclassify(real-floating x);

int
isfinite(real-floating x);

int
isinf(real-floating x);

int
isnan(real-floating x);

int
isnormal(real-floating x);

DESCRIPTION
The fpclassify() macro takes an argument of x and returns one of the following manifest constants.

FP_INFINITE   Indicates that x is an infinite number.

FP_NAN	   Indicates that x is not a number (NaN).

FP_NORMAL	   Indicates that x is a normalized number.

FP_SUBNORMAL  Indicates that x is a denormalized number.

FP_ZERO	   Indicates that x is zero (0 or -0).

The isfinite() macro returns a non-zero value if and only if its argument has a finite (zero, subnormal, or normal) value.  The isinf(),
isnan(), and isnormal() macros return non-zero if and only if x is an infinity, NaN, or a non-zero normalized number, respectively.

The symbol isnanf() is provided as an alias to isnan() for compatibility, and its use is deprecated.  Similarly, finite() and finitef() are
deprecated versions of isfinite().

isgreater(3), math(3), signbit(3)

STANDARDS
The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros conform to ISO/IEC 9899:1999 (``ISO C99'').

HISTORY
The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros were added in FreeBSD 5.1.  3BSD introduced isinf() and isnan() func-
tions, which accepted double arguments; these have been superseded by the macros described above.

BSD								 January 26, 2005							       BSD```

## Check Out this Related Man Page

```FPCLASSIFY(3)						   BSD Library Functions Manual 					     FPCLASSIFY(3)

NAME
fpclassify, isfinite, isinf, isnan, isnormal -- classify a floating-point number

LIBRARY
Math Library (libm, -lm)

SYNOPSIS
#include <math.h>

int
fpclassify(real-floating x);

int
isfinite(real-floating x);

int
isinf(real-floating x);

int
isnan(real-floating x);

int
isnormal(real-floating x);

DESCRIPTION
The fpclassify() macro takes an argument of x and returns one of the following manifest constants.

FP_INFINITE   Indicates that x is an infinite number.

FP_NAN	   Indicates that x is not a number (NaN).

FP_NORMAL	   Indicates that x is a normalized number.

FP_SUBNORMAL  Indicates that x is a denormalized number.

FP_ZERO	   Indicates that x is zero (0 or -0).

The isfinite() macro returns a non-zero value if and only if its argument has a finite (zero, subnormal, or normal) value.  The isinf(),
isnan(), and isnormal() macros return non-zero if and only if x is an infinity, NaN, or a non-zero normalized number, respectively.

The symbol isnanf() is provided as an alias to isnan() for compatibility, and its use is deprecated.  Similarly, finite() and finitef() are
deprecated versions of isfinite().

isgreater(3), math(3), signbit(3)

STANDARDS
The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros conform to ISO/IEC 9899:1999 (``ISO C99'').

HISTORY
The fpclassify(), isfinite(), isinf(), isnan(), and isnormal() macros were added in FreeBSD 5.1.  3BSD introduced isinf() and isnan() func-
tions, which accepted double arguments; these have been superseded by the macros described above.

BSD								 January 26, 2005							       BSD```
Man Page

## Apache config issue

I want to build a little website on a Sun Blade 100 running Solaris 10. I just went out to apache.org and downloaded Unix Source: httpd-2.2.8.tar.gz After unpacking the tarball, I CD'd into the subdirectory and ran the configure utility. Of course, it crapped out. I see that it is...

## strange ksh arithmetic

Hello, I would like to understand this... I'm using ksh and doing (( z = y - 1 )) if y=34, then the result for z is 33, but if y=034 the result is z=27. Why?? Thanks

## Input arguments with C++

I am using getopt_long to pass arguments to a C++ program. Arguments are passed with a key and a value separated by a space of '=' sign. Some options do not need to assign a value to them. Example: ./raytrac dist=0.3 --color I have some classes that need to use some of these...

## Javascript to force decimals in 0.25 steps

I have a few input values on a form that must be in 0.25 steps, how do I force this ? alternatively how do I automatically enter the correct vales as the user types and disallow any other values ie: as the firstnumber is typed (say 3) then .00 is added, then as the decimal point and the first...

## The Terminal on Mac OS X

Does anyone know the differences in commands when it come to Linux and Mac OS X? I'm wanting to know if I use "this" command in Linux and It doesn't work in Mac then what command is equivalent to the one in Linux. Example Ctrl+Alt+f2 switches to (tty2) so what equivalent switches to ttys2 on Mac?

## Compiling problem - AIX 7.2

Hi We meet errors while running configuration scripts to prepare compiling source code on AIX 7.2. This error does not happen on AIX5.3 and AIX6.1 With the “/usr/bin/sh” from AIX7.2, sometimes , the script runs sucessfully, sometimes not. It’s unstable, and I don’t know why. When...