Safe way to create singleton with init method in Objective-C

Question

I would like to take the GCD approach of using shared instances to the next step so I created the following code:

@implementation MyClass

static id sharedIn         


        

Answer 1

The general opinion is that trying to protect your singleton against that kind of bug is pointless. Whoever calls [[LUIMain alloc] init] and creates a singleton gets what they deserved.

And the code that you wrote isn't thread safe anyway. If I call [[LUIMain alloc] init] while someone else calls sharedInstance, sharedInstance will return a different object than on the next call. (@synchronized (self) in the init method is pointless, because a second caller will have a different self).