Re: strange crasher that puzzles me

[David Chisnall]

On 31 Mar 2009, at 16:12, Sebastian Reitenbach wrote:

> Are there any easy rules of thumb to follow, any good documentation  
> about
> memory-management in objective-c for the "beginner" like me?
> So if anyone remembers a document that made him think after reading:  
> "ah,
> thats the way how it works" then you could make me happy pointing me  
> to such
> a document ;)

I wrote a short introduction here:

http://etoileos.com/dev/docs/languages/obj-c/

Simple rules of thumb:

- Any object created with +alloc or +new is retained and must be - 
release'd when you're done with it.  The same is true of objects  
created with -copy and -copyWithZone:

- Any object you get by any other means is autoreleased and you should  
not assume that the pointer will be valid beyond the current  
function / method.

- If you want to keep a pointer to an object, send it a -retain  
message (unless you just created it with +alloc or +new).

- When you are done with an object, send it a -release message.

- If you need to return an object, but don't want to keep a reference  
to it, send it an -autorelease message.

- Never assume that an object you have sent a -release or -autorelease  
message to is still valid.  Never send it any other messages.  Only  
ever use autoreleased objects return values for functions or methods.

- Use the ASSIGN() macro when assigning an object to an ivar, with  
these exceptions:
        - You just created the object, using -copy, +new, or +alloc.
        - The object has a pointer to this object (this would create a loop).

- Always implement -dealloc in your objects if they have any object  
ivars, but never call it directly.

I think this covers pretty much everything,

David