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# isfinite

From cppreference.com
< c‎ | numeric‎ | math

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.

### [edit] Parameters

arg | - | floating point value

### [edit] Return value

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

### [edit] Example

Run this code

    #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));

        return 0;
    }

Possible output:

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

### [edit] See also

fpclassify (C99) | classifies the given floating-point value (function) [edit]
isinf (C99) | checks if the given number is infinite (function) [edit]
isnan (C99) | checks if the given number is NaN (function) [edit]
isnormal (C99) | checks if the given number is normal (function) [edit]
C++ documentation for isfinite

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