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#### 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() 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).

#### SEEALSO

fpclassify(3)

#### COLOPHON

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project,  and information about reporting bugs, can be found at http://man7.org/linux/man-
pages/.

2008-08-05                                  FINITE(3)