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Asked: 2026-05-30T11:07:59+00:00

I am in the process of optimizing my app and making sure memory management

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I am in the process of optimizing my app and making sure memory management is properly implemented. As I found the didUnload / dealloc / willAppear not reliable for implementing my memory cleanup, I decided to implement my own method so I can have full control of this memory management.

Definition of my arrays in the header file

@property (retain) NSMutableArray *selectedCardIDs;
@property (retain) NSMutableArray *selectedRowArray;
@property (retain) NSMutableArray *cardArray;
@property (retain) NSMutableArray *cardIDArray;

Here the release method:

- (void) willReleaseObjects {
[self.aCopyOfCardIDArray release];
[self.listOfItems release];
[self.aCopyListOfItems release];
[self.selectedCardIDs release];
[self.selectedRowArray release];
[self.cardArray release];
[self.cardIDArray release];

}

The arrays can get very large (> 1’000 entry each), why a release of those arrays is essential after the view is unloaded. I explicitly call this function in the IBAction method, such as:

- (IBAction) stopDictionary:(UIBarButtonItem *) sender {
[self closeDatabase];
[self willReleaseObjects];
[self dismissModalViewControllerAnimated:YES];

}

I debugged the code and it is actually executing each release, however when I diagnose the memory allocation with Instruments, it seems to free up only partial memory, actually almost nothing why the memory consumption of course is increasing every time I load this view again, which is no good at all.
Any idea, why my memory is not released here? Thanks.

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1 Answer

  1. Editorial Team

    Don’t call release on a property as you risk something very bad happening in case you have any properties declared as assign or copy. You could potentially release a returned instance which is already autoreleased.

    Instead either release the instance variable behind it or set the property to nil. Either way you will achieve the correct result. In case you have any Key/Value observers on your properties the best way is to set the properties to nil which will automatically propagate the values to any observers:

    - (void) willReleaseObjects {
  self.aCopyOfCardIDArray = nil;
  self.listOfItems = nil;
  ...
}
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