Memory Management 101

[RickMaddy]

Since so many questions come up on this topic I thought I would give a quick summary on the basic rules of iPhone memory management. More specifically about when you should release an object.

Here's the simplest rule: If you directly call any of the following methods on an object then you must call release on the object:

alloc/init
retain
copy
mutableCopy

If you write a method that needs to return an object created with one of the above methods then your return value should look something like this:

return [result autorelease];

This allows your method to fulfill its obligation to release as required but the release won't happen until a little later so the code that calls this method has an opportunity to retain the result if required.

[Steaps]

Thank you!

[DenVog]

Originally Posted by RickMaddy

Since so many questions come up on this topic I thought I would give a quick summary on the basic rules of iPhone memory management.

Great concise summary Rick. Thanks. Much easier for newbies to digest than the Apple Introduction to Memory Management Programming Guide for Cocoa, which is where I had been going. Even the name is long. :P

[DenVog]

Originally Posted by RickMaddy

Here's the simplest rule: If you directly call any of the following methods on an object then you must call release on the object:

alloc/init
retain
copy
mutableCopy

I have a couple simple follow-up questions:

1. Do you need to release statements when you "initWithFormat", "initWithTitle", or "SoundEngine_Initialize"
2. How do you decide when to release within a method (e.g. [actionSheet release]; ) vs. doing it in the - (void)dealloc method