[swift-dev] Thread safety of weak properties

[Kevin Ballard]

On Mon, Dec 14, 2015, at 12:19 PM, Greg Parker via swift-dev wrote:
> 
> > On Dec 14, 2015, at 9:47 AM, John McCall via swift-dev <swift-dev at swift.org> wrote:
> > 
> >> On Dec 12, 2015, at 7:04 PM, Chris Lattner <clattner at apple.com> wrote:
> >> #3 sounds like a great approach to me.  I agree with Kevin that if we keep the object husk approach that any use of a weak pointer that returns nil should drop any reference to a husk.
> > 
> > Spin locks are, unfortunately, illegal on iOS, which does not guarantee progress in the face of priority inversion.
> 
> There is a spinlock algorithm that does work (in practice if not in theory), but it requires a full word of storage instead of a single bit.

Is that what OSSpinLock uses?

-Kevin Ballard