Question

To me, the following code looks like it will create a leak — I might be wrong about this though:

-(NSString*) myString{

   NSString* foo  = @"bar";
   return foo;

}

My question is:

1) Will is create a memory leak as foo is not released?

2) If it IS a memory leak then how do I avoid it?

Answer 1

Short answer. This code will not give a leak.

Long answer:

With NSString it is not always visible leak, because of strings intern and because you do not call alloc/new/copy methods. But yes, this is a classic point of memory leak in general.

There are two ways of dealing with it.

• tracing all objects that you are returning from this (or similar) method and releasing them. That’s extremely buggy possibility and a very bad one almost every time.
• returning autoreleased instance. In fact, you did something like it implicitly here. This string assignment is similar to:

NSString *foo = [NSString stringWithString:@"bar"];

And this one is similar to:

NSString *foo = [[[NSString alloc] initWithString:@"bar"] autorelease];

So, you will return an object, that has retain count 1, but is autoreleased. So, when NSAutoreleasePool will be drained, this object will go away.