Question

Let’s say I’m developing a game. I run the following class method thousands of times:

NSBundle *bundle=[NSBundle mainBundle];

I do not create an autorelease pool and release the objects that call the above class method all the time. I create an object, it calls the above class method, I release it, and on, and on, thousands of times.

3 questions:

• Is memory leaked?
• If I ran:

NSAutoReleasePool *pool=[[NSAutoReleasePool alloc] init];
[pool drain];

would it then effectively release all those NSBundles created in the class method?

• if I wrote:

pool=nil;

instead of writing:

[pool drain];

Would the same effect be achieved? Is this good practice?

The three questions are correlated and I will boost the one that clarifies them 🙂

Answer 1

1. No, memory is not leaked. [NSBundle mainBundle] returns an autoreleased object, so the autorelease pool will take care of it. However, if you’re going to call it a bunch of times in one function or something, you’d be better off either getting a reference to it once and just holding on to it while you need it, or creating your own autorelease pool.
2. Not exactly. Everything after NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; that is autoreleased will go into pool, and after you drain the pool, they’ll be released. Note: [pool drain]; also releases the pool, so don’t call [pool drain]; [pool release]; or you will send the release message to the object twice and probably crash.
3. No. pool = nil; would just lose the reference to pool and the actual pool object would be leaked. You have to call either [pool drain]; or [pool release]; and good practice would be to set pool = nil; afterwards.