I'm sorry, but that's exactly what I wrote in the first example.
"Utilities finalize" does nothing as far as I can tell. It executes
the "Object>>finalize" method which is a no-op. Remove that line and
it will also print to the Transcript immediately.
- Bert -
Am Jan 22, 2007 um 15:38 schrieb abdu chadili:
Or
x := Object new.
x toFinalizeSend: #show: to: Transcript with: 'He''s dead, Jim!\'
withCRs.
Utilities finalize.
x:=nil.
will display the message to the transcript immediately.
----- Original Message ----
From: David Urquhart <david.urquhart@xxxxxxxxxxx>
To: beginners@xxxxxxxxxxxxxxxxxxxxxxxxxx
Sent: Sunday, January 21, 2007 9:42:16 PM
Subject: Re: [Newbies] terminate event?
Thanks for a fantastic answer and sample code.
-Dave
>From: Bert Freudenberg <bert@xxxxxxxxxxxxxxx>
>Reply-To: "A friendly place to get answers to even the most basic
>questionsabout Squeak." <beginners@xxxxxxxxxxxxxxxxxxxxxxxxxx>
>To: "A friendly place to get answers to even the most basic questions
>aboutSqueak." <beginners@xxxxxxxxxxxxxxxxxxxxxxxxxx>
>Subject: Re: [Newbies] terminate event?
>Date: Sun, 21 Jan 2007 15:48:08 +0100 (MET)
>
>
>Am Jan 21, 2007 um 15:21 schrieb Bert Freudenberg:
>
>>Am Jan 21, 2007 um 14:07 schrieb David Urquhart:
>>
>>>Hi
>>>
>>>I'm a Squeak beginner. I want to write to the transcript when
an object
>>>is coming to life and when its terminating. I have an
initialize method
>>>for the birth - what is the method called that fires at death?
>>
>>There is no such method. A message can be send to an object only
if there
>>is a reference to it. As long as a reference to an object
exists, it is
>>not dead, it does only get garbage-collected when the last
reference is
>>removed.
>>
>>About the only thing you can do is to register a *different*
object to be
>>notified when one object is garbage-collected. This is called
>>"finalization".
>
>Here's an example. Evaluate this in a workspace:
>
> x := Object new.
> x toFinalizeSend: #show: to: Transcript with: 'He''s dead, Jim!
\' withCRs
>
>Nothing should happen. Then do
>
> x := nil
>
>which should print "was finalized" immediately. This is because x
still
>holds onto a relatively "new" object, which gets freed very fast.
>
>However, once an object gets "old" it takes until the next full
garbage
>collection (GC)! Create your object again, but this time, do this:
>
> Smalltalk garbageCollect.
> x := nil.
>
>Nothing will be printed, because the GC reclaims all space, but
also marks
>all surviving objects as "old". So even though after assigning
nil to x
>your object is dead, the finalizer does not know it, yet. Only if
you
>trigger a full GC again, the object's space is reclaimed, and the
>finalizer is activated.
>
>- Bert -
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