Question

I am trying to understand a little more about memory management. Knowing that I need to release anything that I have init or alloc’ed I am confused about the following:

- (NSMutableArray *)getData {
    NSMutableArray *data = [[NSMutableArray alloc] init];
    NSString *first = @"First object";
    [data addObject:first];
    NSString *second = @"Second object";
    [data addObject:second];

    return data;

}

Since I used alloc and init, I know I need to release my data object. But if I add autorelease to the init part or to the return, it crashes when I run the method.

What is the correct way to do something like this with correct memory management for iPhone?

Answer 1

You should autorelease, like you said. The caller probably needs to retain, like this – especially if storing into an instance variable:

NSMutableArray *array = [[obj getData] retain];

Later, when it’s totally done with it:

[array release]; // balances the retain above