Re: Help with NSPointerArray and NSMapTable

Jonathan Dann <[email protected]>
Newsgroups gmane.comp.macosx.devel
Message-ID <[email protected]>
On 23 Sep 2009, at 01:27, Christiaan Hofman wrote:

>
> On Sep 23, 2009, at 1:25, Jonathan Dann wrote:
>
>>
>> On 23 Sep 2009, at 01:10, Christiaan Hofman wrote:
>>
>> [snip]
>>
>>> Right, that's basically what I proposed as well. So I also need to  
>>> use this for simple types like CGFloat that are not pointer-sized?
>>
>> Yep.
>>
>> [snip]
>>
>>> Nice samples, that surely helps. Thanks. I just find it confusing  
>>> that for NSInteger it works differently. Though I guess I could do  
>>> the same.
>>
>> No problem. When you're doing this, you're not casting an integer  
>> to a pointer, so AFAICT the caveats in the 64-bit docs don't apply  
>> here.
>>
>> Jonathan
>
> As I understand it now, you do cast an integer to a pointer when you  
> use NSPointerFunctionsIntegerPersonality. So these caveats do apply.

Yeah but you don't have to use the integer personality with integers  
or floats. If you have a struct with a single int then you can case  
between the struct and an int without loss of precision.
I'm pretty sure that's what we're doing here. See:

http://www.algorithm.com.au/downloads/talks/objective-c-internals/objective-c-internals.pdf

> Christiaan
>
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