I've found that in a lot of examples much of the NS variables are released in the method it's instantiated in, but when synthesizing a component they place the release in the dealloc method. You never send a dealloc message directly. See Memory Management Programming Guide for more details on the use of these methods. Subclasses must implement their own versions of dealloc to allow the release of any additional memory consumed by the object—such as dynamically allocated storage for data or object instance variables owned by the deallocated object.
After performing the class-specific deallocation, the subclass method should incorporate superclass versions of dealloc through a message to super:. For this and other reasons, you should not manage scarce resources in dealloc. Another SO question iPhone - when is dealloc for a viewcontroller called?
When you load the nib file, there's got to be an owner which is an object that exists in the application. If you open the nib file in interface builder you will see a proxy icon that represents the owner of the nib file.
You can make connections to it but the connections are not established UNTIL the nib file is loaded and you specify who the onwer really is. Anyways, you can have an outlet e. When you load the nib file and specify the owner that i-var will now point to the UI object.
Let's say it is a window. Eventually when you decide to get rid of the UI objects you simply release the owner and if it reaches a retain count of zero the dealloc method will get called. Several Apple code examples show this! I purchased 2 different books to help with my Cocoa adventure, and EACH of them shows examples of - void dealloc.. Apple should fix this.. Come on… I have been programming for 25 years.. I am not quite that gullible anymore. Object lifetime and clean-up should not be a riddle.
What leads people to believe this is a bug or oversight? There is nothing else to call it. How do you suggest that these resources get released or shutdown properly? Jerking the rung out from under an object is a bad plan.. It can lead to many stability and reliablity issues. There are many resources in a system, not just memory….
Objects MUST have defined lifetimes and be closed properly and reliably for software to work in the real world. A whole lot of Java, Lisp, SmallTalk, and Python programmers were no doubt shocked to realize that none of the software they have ever written works in the real world. Relying on dealloc to free external resources is a bad idea.
This is hardly unique to Cocoa. Java and other garbage-collected languages heavily discourage it since garbage collection is nondeterministic, and so there is no guarantee your external resource will ever get freed. Cocoa with autorelease pools are in a similar situation, so relying on dealloc to release your external resources is a poor idea.
Programming is inherently difficult. Complaining about this one little difference that takes five seconds to understand and which occurs in many other programming environments is just ridiculous. Class destruction is not a preconception… It is a reality, a rule, and a generally expected behaviour.
My point is this.. If I create an instance of a class, it is my responsiblity to destroy that instance.. I find that a little bit shocking! If I let my programming staff code that way, I would hate to think of the support calls we would have! I agree programming is difficult, but a few rules, consistently applied, sure make life easier.
The framework create the instance of this class, so IT is responsible to destroy it properly.. Do you really think that is a preconception? Therefore, I submit that this is the bug Apple should fix.. I would prevent everyone from jumping through hoops to try to accomplish a work-around, and hours of wasted time trying to justify a mistake. For sure, I will move on..
Nothing is being leaked in the standard case. The only time you will leak resources is if you incorrectly rely on dealloc to release external resources. Your strawman attack annoys me greatly. Garbage collection is not a different issue. GC makes no guarantees that any one object will ever be destroyed. So you would still leak in that case. Better to clean up properly. The standard technique is to simply have a -close call that you invoke manually.
If this disturbs you too much, have your objects listen for NSApplicationWillTerminate notifications. My understanding is that I know declared property generates accessor method which is someway just syntax sugar. I found quite a lot people use self. So I thought I had all these questions all figured out. Then all of a sudden I get an error a crash I can't figure out. Then after doing I noticed the following in Objective-C with ARC enabled: Let's have simple class A and autosynthesized weak property interface A property nonatomic, weak id Login using GitHub.
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Instead [airplane release] you write safeRelease x where safeRelease is the following macro that you add to your. This macro doesn't respect zombies. If you nil its object reference, any call sent to him will be ignored. This guarantees a crash during debug time if zombies are not enabled, but leaves the zombies be otherwise.
Apple doesn't have a recommendation on which one is best. If you want to read the thoughts of the community here are some links the comment threads are great too :. You can use the method -forwardInvocation: for that.
It takes a full NSInvocation object which represents the method call, and you can handle it however you wish. If you do this, you should also override -methodSignatureForSelector: to return the correct NSMethodSignature required for -forwardInvocation: to work on unknown selectors. It's also recommended that you override -respondsToSelector: to declare that you can handle the selector in question.
Your problem is absolutely the timer.
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