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Re: Stupid objective-c question
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Re: Stupid objective-c question


  • Subject: Re: Stupid objective-c question
  • From: Graham Cox <email@hidden>
  • Date: Sat, 24 Sep 2016 15:34:45 +1000

> On 24 Sep 2016, at 12:13 PM, Uli Kusterer <email@hidden> wrote:
>
>> I expect the first thing -isEqualToString: does is a pointer comparison, so it’s unlikely to be significantly less performant for the case of when the pointers are literally identical.
>
> No, Graham, don't do that!
>
> There is no guarantee that the context is a valid object. It is just supposed to be a unique pointer value so your class can tell a KVO notification from notifications for other observers on the same object (e.g. if a subclass observes the same value as a base class).


Yep, I’ve realised (from this discussion) that that’s an invalid assumption of another kind.

I’ve been revising code that does this as a result.

Always something to learn :)

—Graham



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  • Follow-Ups:
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      • From: Slipp Douglas Thompson <email@hidden>
References: 
 >Stupid objective-c question (From: Gabriel Zachmann <email@hidden>)
 >Re: Stupid objective-c question (From: Graham Cox <email@hidden>)
 >Re: Stupid objective-c question (From: Uli Kusterer <email@hidden>)

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