porting 32 bit OSX app to 64 bit

Question

I am interested in an open source project that is only available for 32 bit builds. To get 64 bit build, there is a commercial extension.

I am thinking of porting it myself. It is a large medical imaging app. What kind of issus should I be aware of when attempting this? On windows+C#, it is quite easy to recompile for 64 bit. But, this is C++ and Cocoa.

Any advice would be greatly appreciated.

Edit: this is the project: http://www.osirix-viewer.com/ .

Source on github: https://github.com/pixmeo/osirix

Answer 1

Apple's 64-Bit Transition Guide