Re: self = [super init], nil?
Re: self = [super init], nil?
- Subject: Re: self = [super init], nil?
- From: Flavio Donadio <email@hidden>
- Date: Sat, 8 May 2010 10:13:25 -0300
Patrick,
I don't really know if I am right, because of lack of experience. Please, correct me if I'm wrong, but... Why would anyone write code like that?
I mean, if one subclasses NSObject and doesn't override +init, it will return self -- or, maybe, nil -- anyways.
So, I would assume that [super init] would only be called inside an +init or +initWithWhatever: method, right? Like this:
+ (id*)init
{
[super init];
// initialize some other instance vars, etc. ...
[return self];
}
So, in case a class' +init method can return nil and you want to subclass it, the code should be more like:
+ (id*)init
{
if ([super init] != nil)
{
...
[return self];
}
else
{
return nil; // or return something else, throw an exception, whatever...
}
}
I am just curious, because I think it's strange to write "self = [super init]" anywhere other than in an overriden +init. Am I right?
Cheers,
Flavio
On 08/05/2010, at 01:23, Patrick M. Rutkowski wrote:
> Will NSObject's init method ever really return nil?
>
> E.g. if I sub-class NSObject, then is it worth checking for nil after
> doing self = [super init]?
>
> I know there are many classes in UIKit and Cocoa which most definitely
> can return nil from their -init's, as an indication of failure. But
> will this ever be the case with NSObject?
>
> -Patrick
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