Richard Kelsey spotted an error in SRFI-6:

>     (OPEN-OUTPUT-STRING)                                  ;procedure
>
>     Returns an output port that will accumulate characters for retrieval
>     by GET-OUTPUT-STRING.  The port can be closed by the procedure
>     CLOSE-INPUT-PORT, though its storage will be reclaimed by the ...
>           ^^^^^
>
> Did you mean CLOSE-OUTPUT-PORT?

Yes.  I just typed this in wrong, because the MacScheme documentation
was correct.

Will