Using OSMemoryBarrier() with KVO
Using OSMemoryBarrier() with KVO
- Subject: Using OSMemoryBarrier() with KVO
- From: Paul Thomas <email@hidden>
- Date: Tue, 22 Apr 2008 12:37:57 +0100
Hi,
I'm trying to implement a basic promise variable and I'm not sure if
OSMemoryBarrier() is enough to make it correct. If anyone is familiar
with the memory model, I'd appreciate a quick look-over.
It's basically like this:
{
BOOL done;
id result;
NSError* error;
NSException* exception;
}
Users ask for KVO notifications on 'done' and don't attempt to access
any other ivars until done == YES. Then whatever thread or NSOperation
or whatever that is responsible for delivering the result calls:
-(void)completeWithResult:(id)res
{
result = res;
[self willChangeValueForKey:@"done"];
done = YES;
OSMemoryBarrier();
[self didChangeValueForKey:@"done"];
}
Is this enough? Or will I need to use a full blown lock?
Thanks,
pt.
_______________________________________________
Cocoa-dev mailing list (email@hidden)
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:
This email sent to email@hidden