[xml] struct xmlOutputBuffer hand-holding

["Bruce A. Johnson" <bjohnson blueridgenetworks com>]

I've messed around a bit using xmlWriter to write to a file, but now I 
want to write to a socket, which could be a network socket.  Looking at 
the description for xmlNewTextWriter, I see that it wants an 
xmlOutputBuffer structure, which is defined thusly:


  Structure xmlOutputBuffer
  struct _xmlOutputBuffer {
      void *    context
      xmlOutputWriteCallback    writecallback
      xmlOutputCloseCallback    closecallback
      xmlCharEncodingHandlerPtr encoder : I18N conversions to UTF-8
      xmlBufferPtr  buffer  : Local buffer encoded in UTF-8 or ISOLat
      xmlBufferPtr      conv    : if encoder != NULL buffer for output
      int       written : total number of byte written
      int       error
  }

I'm trying to figure out how work with this.  Would one of you be so 
kind as to check my inferences on what this means?

I figure that "context" is a pointer to whatever structure I define that 
has the information I need for my write routine, such as the file 
descriptor, and that it will be passed to me whenever a function like 
xmlTextWriterWriteElement() is called.  It's up to my writecallback 
function to handle cases like not being able to write on the socket, or 
whether to flush the output.  I assume also that closecallback is 
responsible for freeing any memory allocated when I created the socket, 
or any other resources used by writecallback.  Am I on the right track?

As for written and error: Should writecallback maintain them, or will 
the xmlWriter api handle that?

Thanks!
--
Bruce A. Johnson
Chantilly, Virginia
Day of inquiry.  You will be subpoenaed.