Question: I have a C++ interface with two methods. Any class implementing this interface need to implement at least one of the two methods but may define both. It is however not necessary to define both. What is the best pattern to use in such situation ?

Answer: 
The `results = 'hide'` option doesn't prevent other messages to be printed.
To hide them, the following options are useful:

* `{r, error=FALSE}`
* `{r, warning=FALSE}`
* `{r, message=FALSE}`

In every case, the corresponding warning, error or message will be printed to the console instead.
```
```{r eval=FALSE}

```

The document will display the code by default but will prevent the code block from being executed, and thus will also not display any results.