Re: Translating to Swift
On 13 Aug 2014, at 17:35, Jean-Daniel Dupas mail...@xenonium.com wrote:
At global scope
var sharedThing : Thing = Thing();
Excellent. Just what I needed.
But: is this thread-safe? What if several threads are trying to use the
sharedThing? The Swift book doesn't mention the word thread.
Kind regards,
Gerriet.
Le 13 août 2014 à 12:30, Gerriet M. Denkmann gerr...@mdenkmann.de a écrit :
How could I translate this to Swift?
+ (Thing *)sharedThing
{
static Thing *commonThing;
static dispatch_once_t justOnce;
dispatch_once( justOnce, ^void
{
commonThing = [ [ Thing alloc ] init ];
}
);
return commonThing;
}
Gerriet.
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Re: Translating to Swift
On Aug 14, 2014, at 11:44 , Gerriet M. Denkmann gerr...@mdenkmann.de wrote: But: is this thread-safe? What if several threads are trying to use the sharedThing? Jean-Daniel is teasing you slightly. It *is* thread-safe. For the reason, look at the August 1 entry in the Swift blog: https://developer.apple.com/swift/blog/ It’s in the 2nd-last paragraph of the entry. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Translating to Swift
In fact, this is actually exactly equivalent to you sample. Global and class
variable initialization on Swift is performed lazily and is implemented using
dispatch_once().
And after a second thought, I think that it should be 'let' and not 'var', and
you don't want the pointer to be changed after initialization.
I don't remember if static class variable are supported yet, but if they are,
you can also use one instead of a global.
Le 14 août 2014 à 20:44, Gerriet M. Denkmann gerr...@mdenkmann.de a écrit :
On 13 Aug 2014, at 17:35, Jean-Daniel Dupas mail...@xenonium.com wrote:
At global scope
var sharedThing : Thing = Thing();
Excellent. Just what I needed.
But: is this thread-safe? What if several threads are trying to use the
sharedThing? The Swift book doesn't mention the word thread.
Kind regards,
Gerriet.
Le 13 août 2014 à 12:30, Gerriet M. Denkmann gerr...@mdenkmann.de a écrit :
How could I translate this to Swift?
+ (Thing *)sharedThing
{
static Thing *commonThing;
static dispatch_once_t justOnce;
dispatch_once( justOnce, ^void
{
commonThing = [ [ Thing alloc ] init ];
}
);
return commonThing;
}
Gerriet.
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Re: Translating to Swift
I don't remember if static class variable are supported yet, but if they are, you can also use one instead of a global. Not yet. Not yet even confirmed for Swift 1.0 release as far as I recall from the last devforum message I read on this. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Translating to Swift
On 15 Aug 2014, at 02:50, Quincey Morris quinceymor...@rivergatesoftware.com wrote: On Aug 14, 2014, at 11:44 , Gerriet M. Denkmann gerr...@mdenkmann.de wrote: But: is this thread-safe? What if several threads are trying to use the sharedThing? Jean-Daniel is teasing you slightly. It *is* thread-safe. For the reason, look at the August 1 entry in the Swift blog: https://developer.apple.com/swift/blog/ It’s in the 2nd-last paragraph of the entry. This paragraph reads: The lazy initializer for a global variable (also for static members of structs and enums) is run the first time that global is accessed, and is launched as dispatch_once to make sure that the initialization is atomic. This enables a cool way to use dispatch_once in your code: just declare a global variable with an initializer and mark it private. So it is indeed thread-safe via using dispatch_once. Good. But does global variable means var? Jean-Daniel rightly says: I think that it should be 'let' and not 'var', and you don't want the pointer to be changed after initialization So this: let sharedMaker : Maker = Maker(); seems to do exactly what I need in a thread-safe way. Thanks for your help! Kind regards, Gerriet. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Translating to Swift
On Aug 14, 2014, at 19:17 , Gerriet M. Denkmann gerr...@mdenkmann.de wrote: But does global variable means var? Jean-Daniel rightly says: I think that it should be 'let' and not 'var', and you don't want the pointer to be changed after initialization I know nothing about the real answer, but my guess is that writes to a global var after initialization would not be atomic, but the initialization itself would be. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Translating to Swift
How could I translate this to Swift?
+ (Thing *)sharedThing
{
static Thing *commonThing;
static dispatch_once_t justOnce;
dispatch_once( justOnce, ^void
{
commonThing = [ [ Thing alloc ] init ];
}
);
return commonThing;
}
Gerriet.
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Re: Translating to Swift
At global scope
var sharedThing : Thing = Thing();
Le 13 août 2014 à 12:30, Gerriet M. Denkmann gerr...@mdenkmann.de a écrit :
How could I translate this to Swift?
+ (Thing *)sharedThing
{
static Thing *commonThing;
static dispatch_once_t justOnce;
dispatch_once( justOnce, ^void
{
commonThing = [ [ Thing alloc ] init ];
}
);
return commonThing;
}
Gerriet.
___
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