On Mon, Jul 14, 2008 at 8:27 AM, Chris Espinosa <email@hidden> wrote:
> On Jul 14, 2008, at 8:04 AM, Clark Cox <email@hidden> wrote:
>
>> On Sun, Jul 13, 2008 at 11:38 PM, Jens Miltner <email@hidden> wrote:
>>>
>>> Am 11.07.2008 um 14:45 schrieb Stéphane Sudre:
>>>
>>>>
>>>> On Jul 11, 2008, at 10:04 AM, Ken Thomases wrote:
>>>>
>>>>> On Jul 11, 2008, at 2:48 AM, Stéphane Sudre wrote:
>>>>>
>>>>>> "Mac OS X version 10.5 or later is needed for zerocost-exception"
>>>>>>
>>>>>> What is this sentence trying to say?
>>>>>
>>>>> I'm not entirely sure. Are you trying to compile some Objective-C for
>>>>> 64-bit architecture but also specifying a deployment target of 10.4?
>>>>>
>>>>> Here's some background: With Leopard, Apple revamped the Objective-C
>>>>> ABI
>>>>> but only for 64-bit. They couldn't do so for 32-bit because it would
>>>>> break
>>>>> binary compatibility. In the 64-bit ABI, Objective-C exceptions were
>>>>> based
>>>>> on the same mechanisms as C++ exceptions, which makes them zero-cost
>>>>> unless
>>>>> an exception actually happens.
>>>>>
>>>>> That message seems to suggest you have asked the compiler to emit code
>>>>> relying on that ABI, but also said you may deploy it on a target not
>>>>> supporting that ABI.
>>>>
>>>>
>>>> It looks like it's what you're describing.
>>>>
>>>> Does this imply that you can not build a project easily on Xcode with
>>>> exceptions support as soon as you want to test a 32/64-bit Universal
>>>> Binary
>>>> application that can run on Tiger and later?
>>>>
>>>> It sounds like it might be the return of the
>>>> "SDK_Deployment_ppc_32_or_something_like_this" options...
>>>
>>> I'd assume that there would be an option to specify the exception
>>> mechanism
>>> to use (i.e. allow for backward-compatible exception support in 64-bit
>>> binaries, too).
>>
>> Backwards compatible with what? Before Leopard, one couldn't build
>> 64-bit Objective-C binaries.
>
> Technically tiger supported 64-bit Objective-C binaries for Foundation, just
> not for AppKit.
Not in any publicly available version. Tiger had no 64-bit Obj-C
runtime, libSystem was as high up the framework stack as you could go.
--
Clark S. Cox III
email@hidden
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