Hold on to local variable in ARC.

samtakoy · July 2012

Hi,

Suppose I have a variable that is not a member of any class and I still want to hold on to it when the function exits. E.g.

MyVC *a = [[MyVC alloc] init];

// add a.view to the app
// function exits

This approach causes problems since MyVC is released from memory. Is there a quick and dirty way to make it persist.
I understand that the pointer to *a is lost, but I'm OK with it for variables that I know I need for as long as the program is running.

Thank you!

Sam

BrianSlick · July 2012

Make a property for it. Has nothing to do with ARC. The same code pre-ARC simply leaked.

samtakoy · July 2012

Yes, I want to leak. What do I do if I want to leak when it's a good idea?

Son of a Beach · July 2012

What? If you think leaking is EVER a good idea, then you probably don't really understand what it means or what the implications are. In case I'm wrong, please explain in what situation you think it would be a good idea to leak?

GHuebner · July 2012

When you want to test a low memory condition.

BrianSlick · July 2012

Easily done in the simulator. I'm also curious as to when it would ever be a good idea to leak.

GHuebner · July 2012

I was being a little sarcastic. Should have put a lol at the end.

GHuebner · July 2012

I don't see any benefit of having a leak within the code. Eventually, the leaks will just add up and crash your app. It may get past the reviewers if they don't stress test it well but your users would end up with an app that may eventually crash. That is just impolite and inelegant.

samtakoy · July 2012

In the delegate method, I want to use the code

MyVC *vc = [[MyVC alloc] init];
[self.window addSubview:vc.view];

Let's say I'm after saving the extra two lines that it would require to make vc a member variable.

BrianSlick · July 2012

Then you're just going to have to suck it up and deal with it. I'm also willing to bet that pulling the view out of a view controller with the intention of letting the VC die this way is a really bad idea, too.

samtakoy · July 2012

On this note, why doesn't window have an addSubviewController method that itself pulls out the view object?

BrianSlick · July 2012

It does. Rootviewcontroller. Have you not made any new projects since iOS 4 came out?

samtakoy · July 2012

Thanks, I missed that. So if I hand over my view controller to Rootviewcontroller, then I no longer need to worry about retaining it, correct?

Domele · July 2012

Yes, the UIWindow object will retain the view controller.

Howdy, Stranger!

Forums

Hold on to local variable in ARC.

Replies