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finite(), finitef()

Determine if a number is finite

Synopsis:

#include <math.h>

int finite ( double x );

int finitef ( float x);

Arguments:

x

The number you want to test.

Library:

libm

Use the -l m option to qcc to link against this library.

Description:

The finite() and finitef() functions determine if x is finite.

Returns:

True (1)

The value of x is finite.

False (=/= 1)

The value of x is infinity or NAN.

Examples:

#include <stdio.h>
#include <errno.h>
#include <inttypes.h>
#include <math.h>
#include <fpstatus.h>

int main(int argc, char** argv) 
{
  double a, b, c, d;

  a = 2;
  b = -0.5;
  c = NAN;
  fp_exception_mask(_FP_EXC_DIVZERO, 1);
  d = 1.0/0.0;
  printf("%f is %s \n", a, (finite(a)) ? "finite" : "not-finite");
  printf("%f is %s \n", b, (finite(b)) ? "finite" : "not-finite");
  printf("%f is %s \n", c, (finite(c)) ? "finite" : "not-finite");
  printf("%f is %s \n", d, (finite(d)) ? "finite" : "not-finite");

  return(0);
}

produces the output:

2.000000 is finite
-0.500000 is finite
NAN is not-finite
Inf is not-finite

Classification:

Unix

See also:

isinf(), isnan()