> On Dec 16, 2015, at 11:24 AM, Kevin Ballard via swift-dev > <swift-dev@swift.org> wrote: > > On Wed, Dec 16, 2015, at 12:12 AM, Dave Abrahams wrote: >> >>> Come to think of it, what's the actual use-case for withUnsafePointer()? >> >> I'm not sure we still have one that isn't covered by &x; that's my point. >> >>> If a value is mutable, you can already use &x or >>> withUnsafeMutablePointer(), and if it's immutable, you can't call >>> withUnsafePointer() today anyway. The proposed change would just make >>> withUnsafePointer() into the equivalent of `var x = value; >>> callSomethingWith(&x)`. The only reason to really want a >>> withUnsafePointer() function is if it can give you an UnsafePointer to an >>> immutable value without copying it, but we can't do that. I'm inclined to >>> say we should just get rid of withUnsafePointer() entirely, at least until >>> such time as Swift has a way to pass immutable values by-ref. >> >> I'm inclined to agree. Proposal? > > Sure, I'll write one up. I suspect that withUnsafePointer() / > withUnsafeMutablePointer() are likely to be rarely used today, and most uses > can probably be trivially replaced with just passing a &x ref, so this > shouldn't be a big deal.
We can't remove withUnsafe[Mutable]Pointer; as I mentioned to Dave, it's necessary to persist a pointer for more than one immediate call. > > I'll also go ahead and write up one suggesting that we should allow for using > &x when x is immutable when passing a parameter to a function that takes > UnsafePointer. That would be useful, though I would argue that the '&' shouldn't be necessary. We aren't C; '&x' means "this call mutates x", not "I'm taking a pointer to x". -Joe _______________________________________________ swift-dev mailing list swift-dev@swift.org https://lists.swift.org/mailman/listinfo/swift-dev
