c/numeric/math/isfinite

Determines if the given floating point number 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.

Return value
Nonzero integral value if has finite value,  otherwise.