CODEWITHSUNDEEP
objective-cios
Vinayaka Karjigi
Vinayaka Karjigi

Reputation: 1090

UIAlertView and memory leak

UIAlertView* av = [UIAlertView alloc];

int a = [self somefunc];
if (a == 1) 
{
    [[av initWithTitle:nil message:@"test msg 1" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
} 
else if (a == 2) 
{
    [[av initWithTitle:nil message:@"test msg 2" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil] show];
} 

[av release];

when I run anlyze on this code i am getting the error "refence counted object is used after it is released" at line [av release];

can I know, where av got released, does show function of UIAlertView released av?

strangly the below code doesnt show any error when analyze tool is used 

if (a == 1) 
{

    UIAlertView* av = [[UIAlertView alloc] initWithTitle:nil message:@"test msg 1" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [av show];
    [av release];
} 

else if (a == 2) 
{
    UIAlertView* av = [[UIAlertView alloc] initWithTitle:nil message:@"test msg 1" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
    [av show];
    [av release];
}

Upvotes: 0

Views: 1017

Answers (3)

Martin R
Martin R

Reputation: 540105

You must always use the return value of any init call, because an init function can return a different value. Therefore, if you really want to separate alloc and init then you have to do it like this:

UIAlertView *av = [UIAlertView alloc];
// ...
av = [av initWithTitle:...]; // Might change the value of av !!
[av show];
[av release];

The "spurious release" in your code happens here:

[av initWithTitle:...]

because that might (as explained above) release av and return a different object.

Upvotes: 1

Dave
Dave

Reputation: 1181

show function is not releasing the UIAlertView if it is the question here (in the second code).

Upvotes: 0

objectiveCarlo
objectiveCarlo

Reputation: 372

In your first code the object "av" is not sure to be initialized, what if the value of a is not 1 0r 2? av will not be initialized so when your release it there will be some problems.

In your second code av's scope became more specific or local to the conditions of if and else. Thats why xcode is sure that av will be initialized and it is safe to relese av.

Upvotes: 1

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