I just ran across a similar issue. Do you have any blocks where you are referring to ‘self’? I had some blocks for notification observation in my init where I was referring to ‘self’. Under ARC self is retained in blocks. My dealloc wasn’t getting called and that was where I was removing the observation. … Read more
Basically: When using ARC, it’s all or nothing. Either the compiler is managing all of the retains/releases/deallocs for you, or it is doing nothing. You cannot intersperse your own calls to them, because the compiler wants to do it all itself. It can make absurd optimizations by doing this (for example, a method that returned … Read more
Yes, strong is the default in Xcode 4.3 and later. It’s documented both in the LLVM docs and in Apple’s guides to using properties and working with ARC.
Generally you don’t need to provide a subclassed dealloc method as ARC manages the lifetime of the instance variables. However it can be useful to perform clean-up other than releasing objects, for example to remove an observer or close a network connection down cleanly. You are therefore allowed to subclass dealloc under ARC, but you … Read more
Zeroing weak references require OS X 10.7 or iOS 5. You can only define weak variables in code, ivars or blocks. AFAIK there is no way to dynamically (at runtime) to create a weak variable because ARC takes effect during compile time. When you run the code it already has the retains and releases added … Read more
Updated answer: In current OS X and iOS, Dispatch objects are now treated as Obj-C objects by ARC. They will be memory-managed the same way that Obj-C objects will, and you should use strong for your property. This is controlled by the OS_OBJECT_USE_OBJC macro, defined in <os/object.h>. It’s set to 1 by default when your … Read more
I had the same issue on my project when I was trying to mix C code (.h and .c) with Objective-C code. Found the reason of the issue: Check your .pch file to make sure every Objective-C framework #import (such as #import <UIKit/UIKit.h>) is enclosed in: #ifdef __OBJC__ #endif If they’re outside of this conditional … Read more
The difference is subtle, but you should opt for the autorelease versions. Firstly, your code is much more readable. Secondly, on inspection of the optimized assembly output, the autorelease version is slightly more optimal. The autorelease version, – (NSString *)hello:(NSString *)name { return [NSString stringWithFormat:@”Hello, %@”, name]; } translates to “-[SGCAppDelegate hello:]”: push {r7, lr} … Read more
What are the advantages and disadvantages of using the new automatic reference counting (ARC) memory management style in an iOS project? An ARC program’s execution is nearly identical to well written MRC. That is, the behavioral differences are often undetectable because both the order of operations and performance are very close. If you already know … Read more
Have a look at the ARC documentation on the LLVM website. You’ll have to use __bridge or one of the other keywords. This is because Core Foundation objects (CF*Refs) are not controlled by ARC, only Obj-C objects are. So when you convert between them, you have to tell ARC about the object’s ownership so it … Read more