Just read the previous posts...

When you create an instance of a NSRunLoop, it creates an autorelease pool. Any methods/functions/whatevers that get called by this NSRunLoop have an autorelease pool to back it up.

A CFRunLoop does not create an autorelease pool. If a CFRunLoop calls a method/function/whatever, it is not backed up by an autorelease pool. For example, when you create a CFStream with a callback for when bytes arrive, that callback function does not have an autorelease pool.

You might think you can avoid this problem by not using autorelease. This is ridiculous. Just because you don't explicitly send an autorelease message to one of the objects you own doesn't mean that a method you call doesn't send the message autorelease to one of the objects it owns.