Array as class attribute?

Question

I'm currently in the process of learning Objective-C and Cocoa, however I've run into an issue with some of my code.
I want to have an array that other objects will be able to access from my main class, so I set it to be an attribute of that class in the interface: NSObject section of my class header with the following line of code:
NSMutableArray *qArray;
The main issue I'm getting with this is that although the array can be accessed properly, I'm not sure how to initialise it. I used the following code that seemed to work, but only when called from the same IBAction, if sent from another control or menu then it would crash to the debugger:
qArray = [NSMutableArray array];
I'm guessing that qArray is being destroyed after the IBAction is finished, but how would I initialise it otherwise?

Answer 1

The message +array is called a "convenience method", it returns an auto-released instance of the class, here it's an NSArray. So you have two solution, one one hand you simply use the alloc/init methods :
qArray = [[NSArray allocWithZone: [self zone]] init]; // you can use the simple +alloc method if you want.
Or you can retain the object returned by +array, like that :
qArray = [[NSArray array] retain];
In both cases, you need at the end to send the object a -release or -autorelease message :
[qArray release];
NB : the brackets might be not displayed in that message.