How to demonstrate memory leak and zombie objects in Xcode Instruments?

Question

I would like to demonstrate memory leak and zombie object in Xcode Instruments on a class. I've found it pretty hard to trigger on purpose, especially with ARC turned on. Do you know how could I create them?

Are you asking how to use instruments or how to cause a leak? — Ramy Al Zuhouri, Dec 09 '12 at 21:29
How to cause a leak - so I can demonstrate the benefits of Instruments. — itarato, Dec 09 '12 at 22:21

score 3 · Accepted Answer · edited Dec 09 '12 at 22:07

For A leak:

Create two classes, A and B. A should have an @property that strongly references an instance of B. B should have an @property that strongly references an instance of A.

A *a = [A new];
B *b = [B new];
a.b = b;
b.a = a;

That'll create a leak.

For a Zombie

Create a @property that is of type assign (or a variable of type __unsafe_unretained. Then:

A *a = [A new];
A.dangerDanger = [NSObject new];

That should create a zombie situation; a dangling pointer, more specifically.

score 0 · Answer 2 · answered Dec 06 '13 at 08:10

0

A more elegant way to show a leak is to have a class having strong pointer to itself

A* a = [A new];
a.leakingpointer=a;

answered Dec 06 '13 at 08:10

user4951

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How to demonstrate memory leak and zombie objects in Xcode Instruments?

2 Answers2

For A leak:

For a Zombie

Linked