   The provided <TT
CLASS="PARAMETER"
>attDescs</TT
> are copied into the result.
      If the <TT
CLASS="PARAMETER"
>attDescs</TT
> pointer is <TT
CLASS="SYMBOL"
>NULL</TT
> or
      <TT
CLASS="PARAMETER"
>numAttributes</TT
> is less than one, the request is
      ignored and the function succeeds.  If <TT
CLASS="PARAMETER"
>res</TT
>
      already contains attributes, the function will fail.  If the function
      fails, the return value is zero.  If the function succeeds, the return
      value is non-ze