XML4PR400 API, QxmlMemBufInputSource_new, parameter help

This is a question for anybody that is using the RPG Interface for XML
parsing.  

I am trying to figure out what all of the parms are supposed to be doing in
the QxmlMemBufInputSource_new API.  Here is an example and my theory on what
each parm is.

QxmlMemBufInputSource_new(a:b:c:d:e:f);

a = Pointer to variable that has XML string.
b = Length of string in XML variable.
c = ??? I can't figure this one out. What is a String Indicator?
d = CCSID, I use Qxml_CCSID37.
e = String Length - why does it need this when I specified it on parm b?
f = ADOPTBUF?  What is ADOPTBUF?


Here is the prototype provided by IBM.
      *

      *  Create a new MemBufInputSource object

      *  return              - pointer to MemBufInputSource

      * corresponding XML C++ function - new MemBufInputSource()

      *

     D QxmlMemBufInputSource_new...

     D                 PR              *
EXTPROC('QxmlMemBufInputSource_new')                     
     D*                                    MemBufFileInputSource

     D  MEMBUF                         *   VALUE

     D  MEMBUFLEN                    10I 0 VALUE

     D  BUFID                          *   VALUE

     D  STRINGIND                    10I 0 VALUE

     D*                                    String indicator

     D  STRLENGTH                    10I 0 VALUE

     D*                                    String length or 0 if null-term

     D  ADOPTBUF                     10I 0 VALUE  

Thanks for any assistance,
Aaron Bartell