Question

Is there any difference from Memory perspective between the following two lines

NSString *dbFilePath =[[NSString alloc]initWithString:[[NSBundle mainBundle] pathForResource:dbName ofType:nil]];

and

  NSString *dbFilePath =[[[NSBundle mainBundle] pathForResource:dbName ofType:nil] retain]; 

“[NSString alloc]initWithString:” or just “retain”

Thanks in advance

Answer 1

Practically, there is no difference. However, in the first case, you temporarily have one more NSString object existing than in the second case, i.e. the object returned by pathForResource which will be autoreleased shortly after, and it’s surviving copy.

In the second case, no copy is made. Instead, the object returned by pathForResource is retained directly. One object less at peak time.

I find the second piece of code more straightforward.

However, I wonder why you retain something that is referenced from the stack. I would expect dbFilePath instead to be something more persistent, like a member variable.