Objective-C weakself declaration

Question

I was looking through some Apple sample code for their 2014 WWDC session 'Advanced User Interfaces with Collection Views' and came across a weakself declaration that looked like the following:

__weak typeof(&*self) weakself = self;

My question is: what do the &* mean in the declaration? Why not just have:

__weak typeof(self) weakself = self;

Thanks for your help.

@bikram990 how would it increment retain count? just assigning to a weak reference? Can you explain it in more detail? I don't see how it's possible — Andrey Chernukha, Jul 04 '14 at 03:58
See http://stackoverflow.com/questions/10892361/generic-typeof-for-weak-self-references — matt, Jul 04 '14 at 03:59
@AndreyChernukha My mistake forgot that `__weak` just assigns the value. — bikram990, Jul 04 '14 at 04:49

score 0 · Accepted Answer · answered Jul 04 '14 at 23:33

0

Why not just have:

__weak typeof(self) weakself = self;

You can. This is the normal way to do it. Some previous version of the compiler didn't handle it properly, but that was fixed a long time ago.

answered Jul 04 '14 at 23:33

newacct

119,665
29
163
224

Oxcug · Answer 2 · 2014-07-04T04:28:32.423

-1

self is a MyInstance *. When you say *self, you're dereferencing the self* getting back self. Then when you take the &(*self) you're grabbing the memory address.

edited Jul 04 '14 at 04:28

answered Jul 04 '14 at 04:19

Oxcug

6,524
2
31
46

Objective-C weakself declaration

2 Answers2