Re: trying to debug problems with NSAutoreleasepool

[Richard Frith-Macdonald]

On 2007-11-28 19:45:40 +0000 "Sebastian Reitenbach" 
<sebastia@l00-bugdead-prods.de> wrote:

> Hi,
>
> Richard Frith-Macdonald <richard@tiptree.demon.co.uk> wrote:
> > On 2007-11-27 16:40:36 +0000 "Sebastian Reitenbach" 
> > 1<sebastia@l00-bugdead-prods.de> wrote:
>
>
> > > At least at ten places in opengroupware I commented out a [pool > 
> > > release]; or > equivalent, to prevent these crashers.
> > > > As I doubt, that commenting out these lines, is the right 
> > > solution,
> > Almost certainly not ... that probably introduces a big memory leak.
> >
> > Most likely you have a problem with objects being released more 
> > times than 
> > they are retained.
> >
> > You can call [NSObject enableDoubleReleaseCheck: YES]; to turn on 
> > some 
> > checking for this ... but it will slow down your code quite a bit.
> I added that enableDoubleReleaseCheck directly in the method, after 
> the 
> allocation of the NSAutoreleasepool, but that ended in an exception. 
> Where 
> would be the correct place to enable that?

It needs to be enabled before the creation of any object which might 
be in the autorelease pool causing a crash.
Unless you have a really clear knwledge of the object lifetimes 
involved, that probably means you should do it right at the start of 
your program in the main() function.

> > You can set the environment variable NSZombieEnabled to YES ... 
> > which will 
> > give you diagnostics about any attempt to use a deallocated object, 
> > but 
> > will use lots of memory.
> > You can also set NSDeallocateZombies to YES to avoid leaking memory 
> > as 
> > zombie objects, but this will give you less informative and less 
> > reliable 
> > (the memory from a deallocated object could have been re-used as 
> > another 
> > object) logging.
> I set these environment variables, and also started the ogo-webui-1.1 
> -NSDebugEnabled YES -NSZombieEnabled YES -NSDeallocateZombies YES 
> -WOUseWatchDog NO
> I searched a bit around, and found this:
> http://www.cocoabuilder.com/archive/message/cocoa/2003/9/14/87250
> I also explicitly #include <Foundation/NSDebug.h>
>
> but I did not observed any changes? What should I expect to see with 
> these 
> enabled?

Well, NSDebugEnabled should do nothing as far as I recall it's not an 
option GNUstep uses.

NSZombieEnabled=YES should turn on zombies ... so deallocated objects 
remain allocated and you get a report printed when anything tries to 
send a message to them.

NSDeallocateZombies=YES stops the zombie objects remaining allocated, 
so you probably want NSDeallocateZombies=NO

Including Foundation/NSDebug.h does nothing unless you change your 
code to use the functions and macros declared in it.