Mailing Lists: Apple Mailing Lists
Image of Mac OS face in stamp
Re: property 'atomic' keyword?
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: property 'atomic' keyword?



On Mar 8, 2012, at 10:25 AM, Sean McBride wrote:
> On Thu, 8 Mar 2012 10:08:29 -0800, John McCall said:
>>>> (Aside: I wish Obj-C had an ISO standard.  It seems the language is a
>> moving target, constantly being redefined as llvm changes.  Or if not a
>> standard, how about at least version numbers?  We're clearly past
>> "Objective-C 2" but there seems to be no organized list of language
>> changes since, and which version of Xcode/clang supports them.)
>>>
>>> There have been many attempts in the past to create a standard, but
>> they never succeeded. I guess we just have to live with the fact that we
>> will never have an ObjC standard and have multiple, incompatible
>> standards. At least, the incompatibilities are less now that POC is
>> dead, but still, there's a lot.
>>
>> I don't anticipate there ever being a language standard.  It is
>> reasonable to wish for a language specification, though, akin to the
>> specifications of individual features like blocks and ARC.  Such a
>> specification would ideally annotate individual features with the Xcode
>> release that first supported them.  Unfortunately, all of the people at
>> Apple who could write that specification are not lacking in other things
>> to do.
>
> I should have omitted my "aside" comment... :)
>
> Back to the "atomic" keyword...  Again, the docs *explicitly* state "There is no keyword to denote atomic" and yet some compilers accept it and some do not.  Which is right?
>
> Is clang accepting it as a artifact from a time when it was considered but rejected?  Or is clang now supporting something new and not-yet-documented?  (I suspect the latter.)  If the latter, what is the minimun version of clang and Xcode that support this?

It is new and intentionally supported, partly on the general principle that there should be an explicit way to get any implicit behavior, and partly to support the (optional) warning about implicitly atomic properties.  Please file a bug against the documentation.  I don't know off-hand exactly which Xcode first supported it, but I would guess somewhere between 4.0 and 4.2.

John.
 _______________________________________________
Do not post admin requests to the list. They will be ignored.
Objc-language mailing list      (email@hidden)
Help/Unsubscribe/Update your Subscription:

This email sent to email@hidden


References: 
 >property 'atomic' keyword? (From: Sean McBride <email@hidden>)
 >Re: property 'atomic' keyword? (From: Jonathan Schleifer <email@hidden>)
 >Re: property 'atomic' keyword? (From: John McCall <email@hidden>)
 >Re: property 'atomic' keyword? (From: Sean McBride <email@hidden>)



Visit the Apple Store online or at retail locations.
1-800-MY-APPLE

Contact Apple | Terms of Use | Privacy Policy

Copyright © 2011 Apple Inc. All rights reserved.