[swift-users] Memory Address of value types and reference types

[somu subscribe]

Hi Quinn,

Thanks for the reply,

It is an iOS Swift project (uses Foundation, UIKit, CloudKit and other native frameworks) in which I would like to check the memory address for debugging (and out of enthusiasm). There is no C code I am using.

I have some asynchronous call back functions from CloudKit frameworks which return CKUserIdentity objects.

So thought it would be nice if I could print the memory address of CKUserIdentity objects and to check if it was unique.

And there are some other custom Swift Structs which I would like to know the memory address of.

Thanks and regards,
Muthu


> On 12 Sep 2017, at 10:35 PM, Quinn The Eskimo! via swift-users <swift-users at swift.org> wrote:
> 
> 
> On 12 Sep 2017, at 13:44, somu subscribe via swift-users <swift-users at swift.org> wrote:
> 
>> 1. Is the above shown the correct way to get reference type memory address ?
>> 2. What Is it the correct way to get value type memory address ?
> 
> It’s hard to answer that without knowing how you’re intended to use these techniques.  If you can explain more about where you’re going with this, I should be able to make some specific recommendations.
> 
> For example, if you’re goal were to pass a Swift object to a C API that takes a callback function pointer and a ‘cookie’ value, and hen calls that function with that cookie (like the `qsort_r` function), the to/from opaque mechanism provider by `Unmanaged` is the recommended way to pass a Swift object through such a cookie value.
> 
>> 3. Is it possible to get the memory address of immutable value type (declared as let)
> 
> No, because such values don’t necessarily exist in memory.
> 
> Share and Enjoy
> --
> Quinn "The Eskimo!"                    <http://www.apple.com/developer/>
> Apple Developer Relations, Developer Technical Support, Core OS/Hardware
> 
> 
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