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When I run the following program ... application is holding some 5MB of memory even after releasing all objects ... when I don't add an object to list everything works fine ... but I am not sure why application is holding memory even after releasing the list.

I have read this link "NSMutableArray big memory hog?" and even tried with custom mutable array by mikeash MACollections -- in all the cases ... the memory allocated in the loop never get released if I add the object into list.

Please advice me some suggestion to know what is going wrong in the code flow. I appreciate your valuable time and help.

@interface TestData : NSObject 
{
    NSString *strData;
}
@property (nonatomic,retain)NSString* strData;

@end

@implementation TestData

@synthesize strData;

- (void)dealloc
{
    self.strData = nil;
    [super dealloc];
}

@end

int main(int argc, char *argv[])
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];

    NSMutableArray *list = [[NSMutableArray alloc] init];
    TestData *_object = nil;
    NSString *val = nil;
    for (long i = 0; i < 100000; i++)
    {
        _object = [[TestData alloc] init];
        val = [[NSString alloc] initWithFormat:@"%lu",_object];
        _object.strData = val;
        [val release];

        [list addObject:_object];
        [_object release];
    }

    [list release];


    [pool release];

    return NSApplicationMain(argc, (const char **)argv);
}

Update: I used "vmmap" command in terminal ... I can see some thing like this ... 

                                     VIRTUAL   RESIDENT      DIRTY ALLOCATION      BYTES MALLOC ZONE                             SIZE     SIZE       SIZE      COUNT  ALLOCATED  % FULL
===========                          =======  =========  =========  =========  =========  ======

DefaultMallocZone_0x100005000          37.0M      5868K      2692K     8548      1210K      3% 
DispatchContinuations_0x1000cc000      4096K   48K        48K          1         32      0% 

unnamed_zone_0x100037000  0K         0K         0K          0         0K

===========                          =======  =========  =========  =========  =========  ====== 
TOTAL                                  41.0M      5916K      2740K       8549      1210K      2%

so looks like though the object is released ... it is still app memory as unused space ... not sure what can be done in this case. I am not sure is it a fragmentation issue ... or behavior.

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  • In `TestData`s `dealloc`, I wouldn't use `self.value = nil;`, it's not safe to use `self.` when the object is deallocing. Instead, use `[value release]` – WDUK Dec 11 '12 at 11:06
  • How are you calculating that 5MB of memory is still being held after release? This is quite old style code, is there a reason you don't want to use ARC? – WDUK Dec 11 '12 at 11:10
  • @WDUK I am referring memory used by app in Activity monitor. – Girish Kolari Dec 11 '12 at 11:13
  • Few days back I answered similar kind of problem, where release was not working as it should be... check this link..http://stackoverflow.com/questions/13737571/memory-management-of-objective-c-2-0/13737691#13737691 – Anoop Vaidya Dec 11 '12 at 11:19
  • I suspect there's nothing wrong. I've never used that tool, but I think it's just reporting the unused but still allocated heap -- the "high water mark" reached during execution. Running Analyzer is the best way to smoke out storage bugs. – Hot Licks Dec 12 '12 at 13:11
  • This seems odd: `val = [[NSString alloc] initWithFormat:@"%lu",_object];`. You will print the decimal representation of the object address. Is this what you intended? – Hot Licks Dec 12 '12 at 13:17
  • I just intender to create different string objects .... – Girish Kolari Dec 13 '12 at 06:30

0 Answers0