optional?

/*
 *  call-seq:
 *     WIN32OLE_PARAM#optional?
 * 
 *  Returns true if argument is optional.
 *     tobj = WIN32OLE_TYPE.new('Microsoft Excel 9.0 Object Library', 'Workbook')
 *     method = WIN32OLE_METHOD.new(tobj, 'SaveAs')
 *     param1 = method.params[0]
 *     puts "#{param1.name} #{param1.optional?}" # => Filename true
 */
static VALUE foleparam_optional(self)
    VALUE self;
{
    struct oleparamdata *pparam;
    Data_Get_Struct(self, struct oleparamdata, pparam);
    return ole_param_flag_mask(pparam->pTypeInfo, pparam->method_index, 
                               pparam->index, PARAMFLAG_FOPT);
}