Am I missing something? If your code leaks memory, you will see your relevant methods in the details tab, right where you are looking. They are displayed in black as opposed to methods in the APIs which are gray. You can't look into API Methods of course, hence the assembly code. If there is really something wrong in your code, set the slider on the bottom of the tab on the rightmost position and you should see the concerned methods.
If still none of them are in your code, you probably just don't leak anything. There are actually not many scenarios in which ARC-Code can leak memory. Retain cycles are probably the most common one I stumbles over one or two cases in which an API was 'leaking' memory. There is really nothing you can do about it and most likely, it's just a false positive anyway rather than a real leak. If you are only 'leaking' a few bytes, I wouldn't worry about it. Stack Overflow for Teams — Collaborate and share knowledge with a private group.
Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Notice that because of reference type class design problems, all class instances I create get allocated , but never get deallocated — in other words, memory leaks occur. Make sure the Show only leaked blocks button at the bottom of that pane is selected:. Let me zoom in to show you some features in this pane. First, notice that if I have the Show only leaked blocks button pressed, I can type keywords into a text field and find class names that are involved in leaks, like Student.
Minimize the Debug Area and close the Assistant Editor if applicable so you can see the top, middle pane in Xcode. Choose the memory leak you want to examine in the Issue Navigator and then check out its corresponding diagram, like so:. Both are based on strong reference cycles. We identified and solved the same strong reference cycle between the same two classes, Teacher and Student , in a previous post.
Just as discussed in my previous post , the Student objects all hold a strong reference to the Teacher object and the Teacher object holds a strong reference to each of the Student objects.
Yes, the Teacher object does hold strong references to Student objects through an Array , but the Array maintains strong references to its elements by default:. Remember how we solved this memory leak by using the weak keyword? I leave it to you to recapitulate.
I can jump to source code or print debug info like addresses to the console:. The Course object exhibits a strong reference cycle for a closure within one instance of the class itself.
Closures can capture and store references to any constants and variables from the context in which they are defined. This is known as closing over those constants and variables. Swift handles all of the memory management of capturing for you. In terms of my initial definition of the Course class, Apple states :.
A strong reference cycle can also occur if you assign a closure to a property of a class instance, and the body of that closure captures the instance. This strong reference cycle occurs because closures, like classes, are reference types.
When you assign a closure to a property, you are assigning a reference to that closure. However, because the closure refers to self within its body as a way to reference [ self. A strong reference cycle is created between the two. We can visualize this strong reference cycle as in the previous tutorial thusly:.
Notice how the Xcode diagram portrays the Course object with a cyclic arrow. They will both persist in memory as they are required by each other, but nothing else. Leaks are commonly seen in the delegate pattern. Delegate references should always be declared as weak , as a weak reference will allow the runtime to free up the memory.
In swift, references are strong by default. Another common place for leaks are within closures. Any variables, including self, used within a closure will be strongly captured to ensure they still exist when the closure executes.
To avoid a retain cycle here, use a capture list to tell the closure to keep a weak reference. Note that this need not apply to all closures, just those that are escaping , which means they will be stored to be executed later.
John Sundell has an excellent post on this called Capturing objects in Swift closures. Fix this with weak or unowned as appropriate in a capture list:. This somewhat rudimentary method involves logging.
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