I helped Yakov Werde test 64bit on his app (129 libraries & 19,000 objects) and the conclusion we came to was that the PBD files were identical between 32bit/64bit. Only the .exe file is different.

You do have the same issue to watch for that you did in 32bit: if a changed object is referred to by an object in a different library, you likely would have to create a new PBD for that library as well

Hi Mayller;

   That is a great question! The answer is two fold and Olan's answer is perfect ... as long as you are making simple changes to the "concrete" layer of your application.

   However, when making changes to the "abstract" or "base" level ancestors, you have to be careful when adding or removing instance variables. These items change the way memory address pointers are calculated. PB generates C++ code that uses "base + off-set" to get to a PB variable's address. So by adding or removing instance variables, the "base+ offset" calculations can derive an invalid address for a PB instance variables.

  So my recommendation is to proceed with some caution on concrete level incremental PBD builds (which should be OK) but where ancestor instance variable changes are encountered, perform a full build on all PBD's to be on the safe side.

HTH

Regards ... Chris

Appeon: Director, Developer Relations.

1.  Just do an incremental build in the 64-bit development mode, then update the client PBD.

2.  A question for you: does your code use the PFC?

Olan