How should I handle a failure in an init: method in Objective-C?

Question

Let's say I'm building a new class for the iPhone in Objective-C. In one of my init methods I want to manually allocate some memory. So, I might have something like this:

- (id)initWithSomeObject:(SomeObject *)someObject {   self = [super init];   if (self != nil) {     myObject = someObject;     [myObject retain];     if ( (memory = calloc(1, sizeof(SomeStruct)) == NULL) {       // What should I do here to clean up       [self release];       self = nil;     }   }   return self; } 

Now, assuming that the calloc() could fail, and that failing to allocate memory is catastrophic for my object, what should I do inside the if-body to clean up properly? Is there an Objective-C idiom or pattern that I should be using?

Edit: I included the code posted by Rob Napier. But, I still have to release myObject, right? Or does the added code somehow trigger dealloc()?

Answer 1

Yes, you should release yourself and then return nil.

[self release]; self = nil; 

See Issues with Initializers in the Concepts in Objective-C Programming guide.

Answer 2

You need to clean up anything you need to and then set the self reference to nil. Apple Dev Portal has an article:

Link