## Linux and UNIX Man Pages

Test Your Knowledge in Computers #712
Difficulty: Medium
On a large scale, the ability to treat instructions as data is what makes assemblers, compilers, linkers, loaders, and other automated programming tools possible.
True or False?

# finite(3) [suse man page]

```FINITE(3)						     Linux Programmer's Manual							 FINITE(3)

NAME
finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl - BSD floating-point classification functions

SYNOPSIS
#include <math.h>

int finite(double x);
int finitef(float x);
int finitel(long double x);

int isinf(double x);
int isinff(float x);
int isinfl(long double x);

int isnan(double x);
int isnanf(float x);
int isnanl(long double x);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

finite(), finitef(), finitel(): _BSD_SOURCE || _SVID_SOURCE
isinf(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; cc -std=c99
isinff(), isinfl(): _BSD_SOURCE || _SVID_SOURCE
isnan(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE; cc -std=c99
isnanf(), isnanl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600

DESCRIPTION
The finite() functions return a nonzero value if x is neither infinite nor a "not-a-number" (NaN) value, and 0 otherwise.

The isnan() functions return a nonzero value if x is a NaN value, and 0 otherwise.

The isinf() functions return 1 if x is positive infinity, -1 if x is negative infinity, and 0 otherwise.

NOTES
Note  that these functions are obsolete.  C99 defines macros isfinite(), isinf(), and isnan() (for all types) replacing them.  Further note
that the C99 isinf() has weaker guarantees on the return value.	See fpclassify(3).

fpclassify(3)

COLOPHON
This page is part of release 3.25 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/.

2008-08-05								 FINITE(3)```

## Check Out this Related Man Page

```FINITE(3)						     Linux Programmer's Manual							 FINITE(3)

NAME
finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl - BSD floating-point classification functions

SYNOPSIS
#include <math.h>

int finite(double x);
int finitef(float x);
int finitel(long double x);

int isinf(double x);
int isinff(float x);
int isinfl(long double x);

int isnan(double x);
int isnanf(float x);
int isnanl(long double x);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

finite(), finitef(), finitel():
_BSD_SOURCE || _SVID_SOURCE
isinf():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE;
or cc -std=c99
isinff(), isinfl():
_BSD_SOURCE || _SVID_SOURCE
isnan():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE;
or cc -std=c99
isnanf(), isnanl():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600

DESCRIPTION
The  finite(),  finitef(),  and finitel() functions return a nonzero value if x is neither infinite nor a "not-a-number" (NaN) value, and 0
otherwise.

The isnan(), isnanf(), and isnanl() functions return a nonzero value if x is a NaN value, and 0 otherwise.

The isinf(), isinff(), and isinfl() functions return 1 if x is positive infinity, -1 if x is negative infinity, and 0 otherwise.

ATTRIBUTES
The finite(), finitef(), finitel(), isinf(), isinff(), isinfl(), isnan(), isnanf(), and isnanl() functions are thread-safe.

NOTES
Note that these functions are obsolete.	C99 defines macros isfinite(), isinf(), and isnan() (for all types) replacing them.  Further  note
that the C99 isinf() has weaker guarantees on the return value.	See fpclassify(3).