isfinite

From cppreference.com
< c‎ | numeric‎ | math
 
 
 
Common mathematical functions
Functions
Basic operations
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)(C99)(C99)
Exponential functions
(C99)
(C99)
(C99)
(C99)
Power functions
(C99)
(C99)
Trigonometric and hyperbolic functions
(C99)
(C99)
(C99)
Error and gamma functions
(C99)
(C99)
(C99)
(C99)
Nearest integer floating point operations
(C99)(C99)(C99)
(C99)
(C99)
(C99)(C99)(C99)
Floating point manipulation functions
(C99)(C99)
(C99)
(C99)
Classification
(C99)
isfinite
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)
Macro constants
 
Defined in header <math.h>
#define isfinite(arg) /* implementation defined */
(since C99)

Determines if the given floating point number arg has finite value i.e. it is normal, subnormal or zero, but not infinite or NaN. The macro returns an integral value.

FLT_EVAL_METHOD is ignored: even if the argument is evaluated with more range and precision than its type, it is first converted to its semantic type, and the classification is based on that.

Contents

[edit] Parameters

arg - floating point value

[edit] Return value

Nonzero integral value if arg has finite value, 0 otherwise.

[edit] Example

#include <stdio.h>
#include <math.h>
#include <float.h>
 
int main(void)
{
    printf("isfinite(NAN)         = %d\n", isfinite(NAN));
    printf("isfinite(INFINITY)    = %d\n", isfinite(INFINITY));
    printf("isfinite(0.0)         = %d\n", isfinite(0.0));
    printf("isfinite(DBL_MIN/2.0) = %d\n", isfinite(DBL_MIN/2.0));
    printf("isfinite(1.0)         = %d\n", isfinite(1.0));
    printf("isfinite(exp(800))    = %d\n", isfinite(exp(800)));
}

Possible output:

isfinite(NAN)         = 0
isfinite(INFINITY)    = 0
isfinite(0.0)         = 1
isfinite(DBL_MIN/2.0) = 1
isfinite(1.0)         = 1
isfinite(exp(800))    = 0

[edit] See also

classifies the given floating-point value
(function)
(C99)
checks if the given number is infinite
(function)
(C99)
checks if the given number is NaN
(function)
(C99)
checks if the given number is normal
(function)
C++ documentation for isfinite