Can Blocks built for the iPhone 4 SDK work when deployed to iPhone OS 3.0?

Question

The latest Xcode IDE requires you to target iPhone SDK 4 while dynamically handling deprecated and new functionality if you set the application to deploy to earlier releases

Answer 1

As far as I know, blocks won't work pre-3.2 because the Blocks runtime is not included (classes like __NSStackBlock__ or whatever). Other than that, my understanding is that you can compile code with blocks if you use a new enough compiler. A solution would be to include a custom blocks runtime conditionally with your project.