iPhone memory managment

[freedoom]

I read this article.
10 iPhone Memory Management Tips | akosma software

This statement is still relevant today?
Particularly this:
"Autoreleasing objects is easy and useful, but on the iPhone you should be careful with it. By default there is an NSAutoreleasePool instance created for you at the beginning of the main() function but this pool is not cleared up until your application quits!
I started getting a better performance from my iPhone apps when I stopped using some methods creating autoreleased objects, for example:

// Instead of
NSString *string = [NSString stringWithFormat:@"value = %d", intVariable];

// use
NSString *string = [[NSString alloc] initWithFormat:@"value = %d", intVariable];
...
[string release];"

Thanks for your attention

[BrianSlick]

As performance improves and the devices get more RAM, it becomes less relevant. So the iPhone 4 isn't too bad. But the iPad is almost as bad as the original iPhone, so there is still some relevance to the sentiment.

[TUX2K]

Taken from Loading… :
"The Application Kit automatically creates a pool at the beginning of an event cycle (or event-loop iteration), such as a mouse down event, and releases it at the end, so your code normally does not have to worry about them. There are three cases, though, where you might use your own autorelease pools:

*If you are writing a program that is not based on the Application Kit, such as a command-line tool, there is no built-in support for autorelease pools; you must create them yourself.
*If you spawn a secondary thread, you must create your own autorelease pool as soon as the thread begins executing; otherwise, you will leak objects. (See “Autorelease Pools and Threads” for details.)
*If you write a loop that creates many temporary objects, you may create an autorelease pool inside the loop to dispose of those objects before the next iteration. This can help reduce the maximum memory footprint of the application.

Autorelease pools are used “in line.” There should typically be no reason why you should make an autorelease pool an instance variable of an object."

So yes and no, there is a default autorelease pool and it gets empyty (create also) with in the event loop.

[freedoom]

Thanks!
In my app I have more mapView annotation.
In the cycle ( when I initialize the annotation ) can I
create the autorelease pool for optimize the performance?

[Justinmichael]

Yeah,

NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];

Don't forget to drain / release it at the end of the loop though.

[freedoom]

Thanks Just!
In general, how do I know if an item goes autorelease or not?

[hcarsten]

Originally Posted by freedoom

Thanks Just!
In general, how do I know if an item goes autorelease or not?

In General you have to know this by the documentation. I think there is no way to find out if an object had been added to a pool. NSAutoreleasePool just has a method to addObjects. Anyway the implementation is pretty much just an Array. So the "drain" of the pool will just only send a "release" to any object added.

But you can safely add retain/release to manage the object for yourself.