It doesn't produce any output!

ruby-talk
1

Hi,
I wonder if something is wrong with the following code.
Because, it doesn't produce any output.
BTW, I am new to Ruby.

Regards
yc

include ObjectSpace

a=b=c="A"

define_finalizer(a, proc {|id| puts "Finalizer
#{ObjectSpace._id2ref(id)} on #{id}" })
define_finalizer(b, proc {|id| puts "Finalizer
#{ObjectSpace._id2ref(id)} on #{id}" })
define_finalizer(c, proc {|id| puts "Finalizer
#{ObjectSpace._id2ref(id)} on #{id}" })

···

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Posted via http://www.ruby-forum.com/.

2

Your finalizers lock the object in memory. You can find a recent discussion about the topic in the archives.

Please note also that you are defining three finalizers for a single instance which is probably not what you want.

Kind regards

  robert

···

On 02.05.2007 16:50, Yusuf Celik wrote:

Hi,
I wonder if something is wrong with the following code.
Because, it doesn't produce any output.
BTW, I am new to Ruby.

Regards
yc

include ObjectSpace

a=b=c="A"

define_finalizer(a, proc {|id| puts "Finalizer
#{ObjectSpace._id2ref(id)} on #{id}" })
define_finalizer(b, proc {|id| puts "Finalizer
#{ObjectSpace._id2ref(id)} on #{id}" })
define_finalizer(c, proc {|id| puts "Finalizer
#{ObjectSpace._id2ref(id)} on #{id}" })

3

Thanks Robert,

But, without #{ObjectSpace._id2ref(id)} no problem.
You think this statement locks the object in memory.

Thanks again
yc

Robert Klemme wrote:

···

Your finalizers lock the object in memory. You can find a recent
discussion about the topic in the archives.

Please note also that you are defining three finalizers for a single
instance which is probably not what you want.

Kind regards

  robert

--
Posted via http://www.ruby-forum.com/\.

4

No, that's not the one. The mere fact that you define a proc / lambda in the presence of a local variable that references the object is keeping the object around. The proc is a closure and keeps a reference to a even if a goes out of scope (which it does not in your case).

  robert

···

On 03.05.2007 09:18, Yusuf Celik wrote:

Thanks Robert,

But, without #{ObjectSpace._id2ref(id)} no problem.
You think this statement locks the object in memory.

5

it is pretty well documented that you cannot do that. From the docs
of ObjectSpace._id2ref:

Converts an object id to a reference to the object. May not be
     called on an object id passed as a parameter to a finalizer.

···

On 5/3/07, Yusuf Celik <ycelik@oytek.com.tr> wrote:

Thanks Robert,

But, without #{ObjectSpace._id2ref(id)} no problem.
You think this statement locks the object in memory.

Thanks again
yc

Robert Klemme wrote:
> Your finalizers lock the object in memory. You can find a recent
> discussion about the topic in the archives.
>
> Please note also that you are defining three finalizers for a single
> instance which is probably not what you want.
>
> Kind regards
>
> robert

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