isfinite

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.

Parameters

Return value

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

Example

#include <float.h>
#include <math.h>
#include <stdio.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)));
}

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

References

See also