##### Synopsis

    #include <math.h>
    int isfinite(floating-type x);

##### Description

isfinite determines whether x is a fiinite value (zero, subnormal, or normal, and not infinite or NaN). The isfinite macro returns a non-zero value if and only if its argument has a finite value.

##### Fast math library behavior

As the fast math library does not support NaN and infinite values, isfinite always returns a non-zero value.

##### Portability

isfinite conforms to ISO/IEC 9899:1999 (C99).