Disable Automatic Reference Counting for Some Files

183
votes

I have downloaded the iOS 5 SDK and found that ARC is a great feature of the new Apple compiler. For the time being, many third party frameworks don't support ARC. Could I use ARC for my new code and keep the current retain/release code unchanged? The ARC converter doesn't work here, because some frameworks, such as JSONKit, cannot be converted to ARC by using the converter.

Edit:

The answer is to add -fno-objc-arc to the compiler flags for the files you don't want ARC. In Xcode 4, you can do this under your target -> Build Phases -> Compile Sources.

4
objective-cios5automatic-ref-counting
ARC is publicly documented on the LLVM site. – Peter Hosey
To clarify, you just add it to the .m file. Not the .h file. – ma11hew28
I found this conversation: github.com/gowalla/AFNetworking/issues/36 Maybe it help someone how to integrated JSONKit in a iOS5 ARC Supported Project ;-) But i have not try it at the moment... – user998652
This method worked for me. I was adding the AsyncUdpSocket for UDP Multicast to my project and those files [at least the current version] are NOT supporting ARC. So I used the method above to add the compiler flag to the AsyncUdpSocket.m file and I can get the code to work fine with my application. – Ashu Joshi
This works perfectly! Specifics: Go to your Target and choose Build Phases, then Compile Sources. If you double-click on the .m file in question, it'll pop up a box where you can type/paste: "-fno-objc-arc" – mpemburn

4 Answers

73
votes

The public ARC docs, while not directly clear on this point, seem to suggest that as long as each class is either all ARC or all manually-managed, the classes can be integrated into a single program.

You only can't mix ARC and non-ARC in a single class; the document says that sending retain, release, autorelease, or retainCount messages by any means (including timers and delayed performs, which use @selector) is banned in ARC code. So you can't do non-ARC in an ARC class (because the necessary messages are banned) and you can't do ARC in a non-ARC class (because ARC adds syntax elements that are invalid without ARC).

The same document is a bit clearer on whether you can integrate non-ARC libraries/frameworks into an ARC program: Yes. It doesn't mention whether you can use ARC libraries/frameworks in a program where all your code is non-ARC, but given all of the above, the implication seems to be yes.

78
votes

It is not very intuitive how to disable ARC on MULTIPLE files, for a while I was do it one by one until a figured out how to do that.

  1. Select desired files at Target/Build Phases/Compile Sources in Xcode (CMD+click or Shift+click)
  2. PRESS ENTER (double click will reset the selection, so it does't work)
  3. Type -fno-objc-arc
  4. Press Enter or Done
35
votes

If you want to disable Automatic Reference Counting for some Files then its really simple to do just follow the steps.You add compiler flags in Targets -> Build Phases -> Compile Sources.

xcode

The flag used is -fno-objc-arc press enter after writing it.! You have to double click on the right column of the row under Compiler Flags. Hope it helps Thanks :)

2
votes

It is possible to disable ARC for individual files by adding the -fno-objc-arc compiler flag for those files.

How can I disable ARC for a single file in a project?