Re: CoreBase toll-free bridging

[Maxthon Chan]

You should remember as of now, OS X code is still "fat binaries" that runs on 
both 32-bit and 64-bit environments and Carbon libraries are still there, so OS 
X still needs that C-based CF to support Carbon and Cocoa in the same time. 
However on iOS there is no Carbon in the first place thus they can overhaul CF 
totally and place Foundation in a lower layer.

在 2013-3-15，上午8:43，David Chisnall <address@hidden> 写道：

> 
> On 14 Mar 2013, at 20:19, Lars Sonchocky-Helldorf <address@hidden> wrote:
> 
>> 
>> Am 14.03.2013 um 09:42 schrieb Fred Kiefer:
>> 
>>> Having decided that I googled once more and found this article:
>>> http://www.mikeash.com/pyblog/friday-qa-2010-01-22-toll-free-bridging-internals.html
>> 
>> Interesting find in a comment there:
>> 
>> http://www.mikeash.com/pyblog/friday-qa-2010-01-22-toll-free-bridging-internals.html#comment-84b004a6a9b2e8b3a5fdec10f73b2393
>> 
>> "If you look at the Darwin sources, you'll see that the iPhone's 
>> CoreFoundation classes are actually implemented in ObjC."
>> 
>> Is that true? If the code is accessible (I did a cursory search but found 
>> nothing, just this: http://opensource.apple.com/source/CF/ but I can't tell 
>> if there are iPhone versions amongst this) could we use it (given the 
>> license is compatible).
> 
> If that were true, I'd expect CF_IS_OBJC() to return true for everything.  It 
> has the same code path for DEPLOYMENT_TARGET_MACOSX and 
> DEPLOYMENT_TARGET_EMBEDDED (which, I believe, means iOS), and so probably it 
> is not the case.
> 
> That said, it would make sense, because iOS does not have a requirement be 
> able to run Carbon code.  On the other hand, neither did 64-bit OS X.  Core 
> Foundation is used by things like Launchd, and a variety of similar things on 
> OS X (and iOS) that don't use any Objective-C code, so I'm not completely 
> sure it is sensible.  
> 
> On the other hand, Apple decided to use COM for Quick Look, so sensible isn't 
> necessarily a requirement...
> 
> David
> 
> 
> -- Sent from my PDP-11
> 
> 
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