automatic-ref-counting

Will dealloc (below) release the NSString pointed to by the static variable exampleString ? // ExampleClass.h @interface ExampleClass : NSObject @end // ExampleClass.m static NSString *exampleString; @implementation ExampleClass - (void)dealloc { exampleString = nil; } - (id)init { self = [super init]; if (self) { exampleString = [NSString stringWithFormat:@"example %@", @"format"]; } return self; } @end Yes, because since you did not specify an ownership qualifier, the LLVM compiler infers that exampleString has __strong ownership qualification. This means that by setting exampleString to nil

I have this strange crash relating to ARC auto-inserting objc_retains in my code. I have the following two classes: @interface MenuItem : NSObject @property (weak, nonatomic) id target; @property (unsafe_unretained, nonatomic) SEL action; @property (strong, nonatomic) id object; - (instancetype)initWIthTarget:(id)target action:(SEL)action withObject:(id)object; - (void)performAction; @end @implementation MenuItem - (void)performAction { if (self.target && self.action) { if (self.object) { [self.target performSelector:self.action withObject:self.object]; } else { [self.target performSelector

Take the below example: - (NSString *)pcen NS_RETURNS_RETAINED { return (__bridge_transfer NSString *)CFURLCreateStringByAddingPercentEscapes(NULL, (__bridge CFStringRef) self, NULL, (CFStringRef) @"!*'();:@&=+$,/?%#[]", kCFStringEncodingUTF8); } Is it correct to put the NS_RETURNS_RETAINED there? Another example: + (UIImage *)resizeImage:(UIImage *)img toSize:(CGSize)size NS_RETURNS_RETAINED { UIGraphicsBeginImageContextWithOptions(size, NO, 0.0); [img drawInRect:...]; UIImage *resizedImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return resizedImage; } That

I know I am supposed to add the compiler flag -fno-objc-arc to the compile sources in XCode 4 to accomplish this. But it isn't working. Even with the added flag I am still getting errors in my KeychainItemWrapper.m file claiming I need to use __bridge for C pointers. My project is ARC safe, but the Apple provided reference for interacting with the Keychain is not. I would like to just disable ARC for that single file. What else am I missing here? I've had this happen more than once for me in 4.2 in different projects, but then I've not been able to reproduce it reliably enough for a bug report

EDIT: changed the title. I didn't know it at the time but this is a duplicate of Why am I crashing after MKMapView is freed if I'm no longer using it? This question is similar to Why is object not dealloc'ed when using ARC + NSZombieEnabled but different enough that I thought it worth throwing out there in case anyone understands and can explain to me what is happening. The other question may be an XCode bug so I presume this could be similar. Scenario: RootViewController has a tableView displaying a bunch of items Selecting a cell presents a modal detailViewController containing another

If I have this code, + (MyCustomClass*) myCustomClass { return [[[MyCustomClass alloc] init] autorelease]; } This code guarantees the returning object is autoreleased. What's the equivalent of this in ARC? There is no equivalent in ARC, as you don't need to do it yourself. it will happen behind the scenes and you are not allowed to do it your self. You simply use - + (MyCustomClass*) myCustomClass { return [[MyCustomClass alloc] init]; } I suggest you to watch the ARC introduction in the 2011 WWDC as it very simple when you get it. Look here: https://developer.apple.com/videos/wwdc/2011/ And

i found memory leak on SecItemCopyMatching. After investigate on SF i was found solution: __block NSString *certificateName = nil; SecKeychainRef keychain; SecKeychainCopyDefault(&keychain); NSMutableDictionary *attributeQuery = [NSMutableDictionary dictionary]; [attributeQuery setObject: (id) kSecClassIdentity forKey:(__bridge_transfer id) kSecClass]; [attributeQuery setObject: (id) kCFBooleanTrue forKey:(__bridge_transfer id) kSecReturnRef]; [attributeQuery setObject: (id) kSecMatchLimitAll forKey:(__bridge_transfer id) kSecMatchLimit]; CFTypeRef attrResult = NULL; OSStatus status =