Re: ABI / ivars policy

[David Chisnall]

On 8 Dec 2009, at 17:33, Quentin Mathé wrote:

> Is there now an official policy that explains how we handle ivar  
> addition/removal? Is it still ok to put them in the header?

If we're going to recommend the new runtime for the next release, then  
it is not such a problem.  Code compiled with -fobjc-nonfragile-abi  
will not notice when ivars are added.  Code compiled without will  
abort at load time if it contains a class that subclasses the class  
that you've added an ivar to or removed one from (unless you've both  
added and removed ivars and the class size remains constant but the  
layout changes, then subclasses which access public / protected ivars  
may have problems).

Either way, make sure that you note ABI changes in NEWS :-)

David

-- Sent from my Difference Engine