How to force py2app to run app in 32-bit mode

Question

I am trying to build an app bundle with py2app on Mac OS X 10.6. The app uses some libraries which are only compiled for 32-bit, so when the app is run there is an ImportError "no appropriate 64-bit architecture". How can I tell py2app to force the app to run in 32-bit mode?

Answer 1

If you want to run only in 32 bit mode, then you don't need the 64 bit architecture. So you can just strip out all the non-i386 architectures from your resulting application bundle using the ditto utility.

Example:

ditto --rsrc --arch i386 YourApplication.app YourApplicationStripped.app

Your application bundle will be smaller and will run as a 32 bit application for sure, even on 64 bit Intel systems.

Manual: http://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/man1/ditto.1.html

Or just run in a terminal: man ditto

Answer 2

One way is to use a 32-bit-only Python, such as the 32-bit-only versions downloadable from python.org, with py2app. Another is to set the LSArchitecturePriority to i386 and possibly ppc in the generated app bundle's Info.plist. See here for more info.