Question

This question addresses how to conditionally include code based on iOS version. But how does it work?

Suppose I set iOS Deployment Target to 3.2 in Xcode 4.5.2. In my code I put in some #ifdef statements:

#if __IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_4_0
  // Some iOS 4+ code
#endif

If I run the code on a 3.2 device, this code won’t be there, but if I run it on a 4.3 device, it will, right? How does that happen? Or am I misunderstanding what’s going on here?

Answer 1

That is a compile time check so it will create the same behavior on any iOS version. Since the Deployment Target is less than 4.0 the code inside the if statement will not run on any device.

If you want the behavior you described you need to do a runtime check. You can see an example of how to do this in the thread that you linked.