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List:       ms-atl
Subject:    Re[2]: Versioning of Simple Object Interfaces in ATL project
From:       Doug Brubacher <Doug_Brubacher () COMPUWARE ! COM>
Date:       1997-07-30 9:02:25
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     Rodney,

     Your explanation makes perfect sense.  I do not use VB extensively so
     I have commonly just added methods to the new interface to add new
     functionality.  Recognize that obtaining a reference to a second
     interface does not instantiate a new object, rather it just gives you
     access to additional functionality of the same COM object.

     Regards,

     Doug Brubacher


______________________________ Reply Separator _________________________________
Subject: Re: Versioning of Simple Object Interfaces in ATL projects
Author:  ATL - Active Template Library <ATL@LISTSERV.MSN.COM> at CWUS-Internet
Date:    7/29/97 5:31 PM


Thanks for the response Doug.  The re-assurance of my current direction
on this issue is comforting.

You asked, "Do you really want to copy the entire definition?", meaning
IBlob to IBlob2.  Yes, I think I do.  My goal is to make it so that some
client (including VB client's) of IBlob can now simply instantiate an
instance of IBlob2 instead of IBlob and get all of the original
functionality of IBlob as well as the new Open() method definition of
IBlob2.  If a VB client Dim'd a single instance of IBlob before, it would
only be required to change the one Dim line to pick up the new Open()
method definition.  I don't want such a client to be required to Dim an
IBlob as always AND now Dim an IBlob2 just to pick up the one Open()
method.

Am I missing something simple?  Is there a better approach to this?

-----
L. Rodney Ford
Days:   Intergraph Corp., rford@ingr.com, (205)730-1024
Nights: lrod@hiwaay.net, http://hiwaay.net/~lrod
"Paranoia is just reality on a finer scale.", Strange Days

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