Under Automatic Reference Counting (ARC), where do I put my free() statements?

Question

In cocoa, ARC frees you of having to worry about retain, release, autorelease, etc. It also prohibits calling [super dealloc]. A -(void) dealloc method is allowed, but I'm not sure if/when it's called.

I get how this is all great for objects, etc., but where do I put the free() that matches the malloc() I did in -(id) init ?

Example:

@implementation SomeObject

- (id) initWithSize: (Vertex3Di) theSize
{
    self = [super init];
    if (self)
    {
        size = theSize;
        filled = malloc(size.x * size.y * size.z);
        if (filled == nil)
        {
            //* TODO: handle error
            self = nil;
        }
    }

    return self;
}


- (void) dealloc         // does this ever get called?  If so, at the normal time, like I expect?
{
    if (filled)
        free(filled);    // is this the right way to do this?
    // [super dealloc];  // This is certainly not allowed in ARC!
}

Answer 1

You are right, you have to implement dealloc and call free inside of it. dealloc will be called when the object is deallocated as before ARC. Also, you can't call [super dealloc]; as this will be done automatically.

Finally, note that you can use NSData to allocate the memory for filled:

self.filledData = [NSMutableData dataWithLength:size.x * size.y * size.z];
self.filled = [self.filledData mutableBytes];

When you do this, you don't have to explicitly free the memory as it will be done automatically when the object and consequently filledData are deallocated.