Xcode 4 Refactor > Convert to Objective-C ARC transforms: @interface XYZ : NSObject { id delegate; } @property (assign) id delegate; … @synthesize delegate; into: @interface XYZ : NSObject { id __unsafe_unretained delegate; } @property (unsafe_unretained) id delegate; … @synthesize delegate; If I remember correctly it is also mentioned in WWDC 2011 video about ARC.
Yes, you can use the following: #if __has_feature(objc_arc) … #endif Even if you’re using the latest version of LLVM, this will only evaluate to true if you’re compiling with the -fobjc-arc option.
Yup: add the -fobjc-arc flag the same way.
Automatic Reference Counting – 3.2.4. Bridged casts You should use __bridge cast for it. AudioSessionInitialize(NULL, NULL, NULL, (__bridge void *)self);
I wrote a clean ‘drop in’ version of reachability for ARC and iOS5 – you can get it here: https://github.com/tonymillion/Reachability
Globally: Go to “Build Settings”, look for “Apple LLVM compiler 3.0 – Language”. Set the field “Objective-C Automatic Reference Counting” to “No”. For individual files: Go to “Build Phases”, select the file, double-click the “Compiler Flags” column and put “-fno-objc-arc” in it.
From http://clang.llvm.org/docs/AutomaticReferenceCounting.html#autoreleasepool: @autoreleasepool may be used in non-ARC translation units, with equivalent semantics. and Greg Parker says [1] [2]: LLVM 3.0’s @autoreleasepool { … } is much faster than NSAutoreleasePool if your deployment target is new enough. No ARC required. (…) always works, but it’s faster with deployment target of OS X 10.7 or iOS … Read more