It's relatively unlikely that Swift's concurrency model, once it gains one, 
will look all that similar to Objective-C's. For example*, if Swift were to 
adopt a shared-nothing model where heap storage was per-thread and could only 
be accessed by another thread by copying or moving the value to its heap, then 
a 'synchronized' construct wouldn't be applicable. Until Swift does have a 
concurrency model, it's probably best to focus on library-level solutions like 
libdispatch. 

        David

*and this is just an example, there haven't been any concrete proposals for a 
direction on concurrency beyond a few old speculative drafts you can find in 
the repository

> On Jun 12, 2017, at 2:10 AM, Erik Aigner via swift-evolution 
> <swift-evolution@swift.org> wrote:
> 
> In my day to day tasks, synchronization primitives are used quite often. ObjC 
> had the @synchronized attribute for methods. I didn’t find anything about 
> this in swift evolution, so I thought i bring it up here. I think it would 
> quite easily be possible to introduce a synchronized qualifier for 
> struct/class objects that automatically synthesize a semaphore variable on 
> the object and use it to lock said method. Here is an example of how that 
> would work
> 
> Without the synchronized attribute (code written in mail, not compiled):
> 
> class Obj {
> 
>        private let sema = DispatchSemaphore(value: 1)
> 
>       func synchronizedMethod() {
>               sema.wait()
>               defer {
>                       sema.signal()
>               }
>               // do something...
>       }
> }
> 
> With synchronized attribute (the semaphore/wait/deferred-signal is 
> synthesized by Swift automatically)
> 
> class Obj {
> 
>       synchronized func method() {
>               // semaphore is synthesized automatically, do something…
>       }
> }
> 
> 
> Cheers,
> Erik
> _______________________________________________
> swift-evolution mailing list
> swift-evolution@swift.org
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