----- Original Message ----
> From: Jens Bauer <[EMAIL PROTECTED]>
> Subject: Re: Cleanup inside a failed init method
>
> On Dec 6, 2008, at 22:36, Charles Steinman wrote:
>
> > The system will only call dealloc if the object is released. Happily, the
> object should be released anyway if you plan to return nil since otherwise
> you'll leak a half-initialized object every time the method fails. So you
> should
> release self and return nil.
>
> I'm not sure about that. Take a look at this example:
>
> // init only modifies an already allocated buffer.
> // ObjC and the O/S does not know what you are going to name your 'init'
> method:
>
> - (id)initIthMyParameters:(int)aParameter
> {
> self = [super init];
> if(self) // only if super returns a valid buffer
> {
> parameter = aParameter;
> }
> return(self);
> }
>
> ob = [[MyObject alloc] initWithMyParameters:3];
>
> The result of [MyObject alloc] is passed directly to initWithMyParameters:.
>
> If alloc fails, it sends NULL as object to init. [NULL init] returns NULL, no
> matter which object it is, so does [NULL sniff_sniff].
> -However, if +alloc succeeds, you have a buffer, it's passed directly to
> initWithMyParameters:.
>
> You're not guaranteed that you will get the same buffer that [MyObject alloc]
> returns, because -init* will be able to deallocate it and return a different
> (maybe even larger) buffer instead, and perhaps in a different memory zone.
>
> Who/what is supposed to deallocate the allocated buffer between the [MyObject
> alloc] and [myObject init] ?
> (How would the 'system' know that the object is to be deallocated?)
> The only reason would be that the line...
>
> self=NULL;
>
> ...should automatically deallocate the object, and I've never heard that it
> did.
I don't know why you think the object would be dealloced between alloc and
init. If the if(self) conditional evaluates to nil, that's because [super init]
returned nil.
Cheers,
Chuck
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