[swift-evolution] [Draft] UnsafeRawPointer API

[Dmitri Gribenko]

On Tue, Jun 28, 2016 at 2:17 PM, Andrew Trick <atrick at apple.com> wrote:
>
>> On Jun 28, 2016, at 1:53 PM, Dmitri Gribenko <gribozavr at gmail.com> wrote:
>>
>> Hi Andy,
>>
>> Everything is clear now, thank you!
>>
>> On Tue, Jun 28, 2016 at 1:02 PM, Andrew Trick <atrick at apple.com> wrote:
>>> Initializing via a typed pointer, in addition to changing the temporal memory state, also imposes a type on the allocated memory for the entire lifetime of the memory itself, from allocation to deallocation.
>>
>> I see.  Given that UnsafeMutablePoiner.initialize() has this very
>> important difference in semantics, did you consider reflecting it in
>> the name?  Something like '.bindTypeAndInitialize()' -- but I'm sure a
>> better wording is possible.
>
> Yes, I did consider that. I’m still open to it--maybe ‘.typedInitialize(with:). But...
>
> (1) It’s awkward. The developer isn’t interested in binding the type at that point. It’s just a side effect of the way their unsafe pointer is being used.
>
> (2) It would imply that the ‘.bindAndInitialize' entry point is the only way to bind the type of allocated memory. But once you have a typed pointer, it’s easy to initialize memory via a simple assignment:
> ptrToA[0] = A() // where A is trivial
> If ptrToA was in an uninitialized state, then that also binds the type.

It would be good to call this out in the proposal (I did not get this
part from the clarifications that you posted this morning.)  So the
rule is that every typed store binds the type?

> Instead, I tried to focus on discouraging the unsafe pointer cast that leads to this situation. The important thing is that we have an alternate “safe” API so that most developers just don’t need to think about it.

That's a good goal.

Dmitri

-- 
main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if
(j){printf("%d\n",i);}}} /*Dmitri Gribenko <gribozavr at gmail.com>*/