rr" indicates that this function returns an error value.
This is not the value returned to NSBasic.  All shared library
functions for NSBasic should return errNone, indicating no
error.  The function contains one argument, a refNum.  This is
always the same.  It is the reference number of one particular
instance of a shared library.  (They are shared, so several
applications can use them.  Each has a unique reference number.)
You will not need to use this unless you want to keep values
between funct