From: Lars Christensen <larsch@...>
Date: 2001-08-12T07:13:40+09:00
Subject: [ruby-talk:19550] Forced garbage collection


Hi,

I am testing some code that uses ObjectSpace#define_finalizer, but I can
not force objects to be garbage collected using GC.start or
ObjectSpace.garbace_collect.

This code behaves strangely (to me at least) on my box (linux/i386), ruby
1.6.4 debian build, custom build, ruby-1.7.1 checkout today, and
rubywin-1.6.4-2 on win98se.


==snip==

class Foo
  attr_reader :val
  def initialize(val)
    @val = val
  end
end

Foo.new(1)
f = Foo.new(2); f = nil
(3..5).each{|i| Foo.new(i)}

ObjectSpace.garbage_collect
ObjectSpace.each_object(Foo) { |f|
  puts "Foo #{f.val} is here."
}

==snip==


This code tell me that Foo 1 is still there after the garbage collection
has been invoked. If i change the order of the Foo.new calls to:

f = Foo.new(2); f = nil
Foo.new(1)

Then, both Foo 1 and Foo 2 are in memory after garbage collection.

I cannot reproduce on Solaris (both intel and sparc). Here, all the object
gets deleted.

Why this behaviour? A bug?

-- 
Lars Christensen, larsch@cs.auc.dk