isnan, isnanf, isinf, isinff, finite, finitef[test for exceptional numbers]

f78 isnan, isnanf, isinf, isinff, finite, finitef[test for exceptional numbers]

isnan, isnanf, isinf, isinff, finite, finitef
[test for exceptional numbers]

SYNOPSIS

#include <ieeefp.h> 
int isnan(double arg); 
int isinf(double arg); 
int finite(double arg); 
int isnanf(float arg); 
int isinff(float arg); 
int finitef(float arg);

DESCRIPTION

These functions provide information on the floating point argument supplied.

The following are five major number formats.

zero
A number which contains all zero bits.

subnormal
Used to represent number with a zero exponent, but a non-zero fraction.

normal
A number with an exponent, and a fraction.

infinity
A number with an all 1’s exponent and a zero fraction.

NAN
A number with an all 1’s exponent and a non-zero fraction.

RETURNS

isnan returns 1 if the argument is a NaN.

isinf returns 1 if the argument is infinity.

finite returns 1 if the argument is zero, subnormal or normal.

The isnanf, isinff and finitef perform the same operations as their isnan, isinf and finite counterparts, but on single precision floating point numbers.