Adding any parameters to an existing public interface will break
compatibility regardless of whether it is optional or not.  Create a
second function with a similar name to maintain compatibility (i.e.
Function Save, Function Save2).  An example of this is in the Microsoft
Internet Controls Navigate and Navigate2.

-----Original Message-----
From: Tom Carr [mailto:tom@s...]
Sent: Wednesday, February 20, 2002 11:44 AM
To: professional vb
Subject: [pro_vb] Compatibility question

I added some optional arguments to a public function in a class used to
make a .dll.  When I try to compile I get the message asking me if I
want
to break or preserve compatibility, with the warning that if I preserve
compatibility applications using the class will likely crash.  However,
since I am only adding optional arguments, isn't it safe to preserve
compatibility ?