Question

after Analyze my cocos2d game I’ve got an warning “Potential leak of an object allocated on line 525 and stored into ‘valueString'” in this code

525  NSString * valueString=[[[NSString alloc] initWithString:[NSString stringWithFormat:@"%@: %@",kGameTimeeng,[allFunctions getTimeFormat:(int) _timeLimit]]] retain];

    if([_language isEqualToString:@"rus"]){
        [valueString release];
        valueString=[[[NSString alloc] initWithString:[NSString stringWithFormat:@"%@: %@",kGameTimerus,[allFunctions getTimeFormat:(int) _timeLimit]]] retain];
    }    

    id sequence=[CCSequence actions:
                 [CCCallFuncND actionWithTarget: allFunctions selector: @selector(setLabelColor:withIndex:) data:(void*)color],
                 [CCCallFuncND actionWithTarget: allFunctions selector: @selector(setLabelValue:withValue:) data:(NSString*)valueString],
                // [CCCallFuncND actionWithTarget: self selector: @selector(setLabelStroke:withTag:) data:(void*)TagCurentPointsLabelStroke],
                 [CCBlink actionWithDuration:0.5f blinks:2],
                 [CCShow action], 
                 [CCCallFuncND actionWithTarget: allFunctions selector: @selector(setLabelColor:withIndex:) data:(void*)colorAfter],

                 nil];

    [_timeLimitLabel runAction:sequence];
    [valueString release];

allFunctions.m

-(void) setLabelValue:(id) sender withValue:(NSString*) value
{   
    CCLabelTTF *label=(CCLabelTTF *)sender;
    NSString * valueString=[[[NSString alloc] initWithString:[NSString stringWithFormat:@"%@",value]] autorelease];
    [label setString:[NSString stringWithFormat:@"%@",valueString]];
   //[valueString release];
}

can you explain me why?

Answer 1

valueString = [[[NSString alloc] initWithString:[NSString stringWithFormat:@"%@: %@",kGameTimerus,[allFunctions getTimeFormat:(int) _timeLimit]]] retain];

You retained twice here: alloc & retain. And then you only release once:

[valueString release];

That’s why there’s a potential leak (actually, it’s a leak).

And for

NSString * valueString = [[[NSString alloc] initWithString:[NSString stringWithFormat:@"%@",value]] autorelease];

you retain once (alloc), and release (autorelease) when valueString is not needed anymore. This is okay.