D1num D1num_sub IsFinite IsFinite_sub IsInf IsInf_sub IsNan IsNan_sub IsNormal IsNormal_sub Signbit Signbit_sub

IsNan() Function IsNan ( X As  Double ) Determine if NaN (Not-a-Number) value Purpose Determines if the given argument has NaN (Not-a-Number) value. Returns Boolean If X has NaN value, True is returned. Otherwise, False is returned. Parameters [in] X Argument to be examined.