FINITE
NAME
finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl -
BSD floating point classification functions
SYNOPSIS
#define _BSD_SOURCE
#include <math.h>
I int finite(double x );
I int finitef(float x );
I int finitel(long double x );
I int isinf(double x );
I int isinff(float x );
I int isinfl(long double x );
I int isnan(double x );
I int isnanf(float x );
I int isnanl(long double x );
DESCRIPTION
The
R finite ()
functions return a non-zero value if x is neither infinite
nor a "not-a-number" (NaN) value, and 0 otherwise.
The
R isnan ()
functions return a non-zero value if x is a NaN value,
and 0 otherwise.
The
R isinf ()
functions return 1 if x is plus infinity, -1 is x
is minus 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).
On a glibc system, these functions are declared by
<math.h>
when
_BSD_SOURCE
or
_SVID_SOURCE
or
_GNU_SOURCE
is defined.
The isnan() functions will also be declared when
_XOPEN_SOURCE
is defined.
SEE ALSO