> On Jul 20, 2016, at 6:53 AM, Dave Abrahams <[email protected]> wrote: > > There is; it's basically impossible to implement reliably given the > state of Objective-C reference-counting. I'll let Greg Parker explain > the details, as he has many times to me (but I don't retain them as well > as he does).
I don't necessarily need to know them (although I'd be curious to hear). I think something that implies the possibility of false negatives, like `isKnownUniquelyReferenced(_:)` or (flipping the sense of the return value) `mayBeShared(_:)`, is probably the best strategy. Or, if COW is the only use case we want to support, we could even call it something along the lines of `needsCopyBeforeMutating(_:)`, which would strongly imply it was unsuitable for any other purpose. -- Brent Royal-Gordon Architechies _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
