# isinf(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tions, which accepted double arguments; these have been superseded by the macros described above.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

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