# isnan(3) [osx 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.

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

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

HISTORY
3BSD introduced isinf() and isnan() functions, which accepted double arguments; these have been superseded by the macros described above.

BSD								 December 11, 2006							       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.

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

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

HISTORY
3BSD introduced isinf() and isnan() functions, which accepted double arguments; these have been superseded by the macros described above.

BSD								 December 11, 2006							       BSD```
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