# ObjectSpace reveals order? **URL:** \ **Category:** Ruby\ **Created:** [September 29, 2007, 3:19am UTC](https://www.ruby-forum.com/t/objectspace-reveals-order/115846 "2007-09-29T03:19:20Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![toadkicker](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5fc32e/32.png) [@toadkicker](https://www.ruby-forum.com/u/toadkicker)\ **Post date:** [September 29, 2007, 3:19am UTC](https://www.ruby-forum.com/t/objectspace-reveals-order/115846/1 "2007-09-29T03:19:20Z")
If I do… ObjectSpace.each\_object { |o| puts o; gets } will it give me the consecutive order of the loading of the objects (i.e. the time order that memory is allocated on the heap)? Or is it a tree structure underneath or something strange like that? Why do I get String objects right off the bat like… ’ does not evaluate to a gem specification This appears to be source that the interpreter ran and outputted. I see it on a WindowsXP machine using the 1.8.6 one-click installer. Todd P.S. I understand that this question is hard to answer exactly because you have to create objects to read the objects you have. ---
**Author:** ![toadkicker](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5fc32e/32.png) [@toadkicker](https://www.ruby-forum.com/u/toadkicker)\ **Post date:** [September 29, 2007, 5:33am UTC](https://www.ruby-forum.com/t/objectspace-reveals-order/115846/2 "2007-09-29T05:33:11Z")
On 9/28/07, Todd B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > ’ does not evaluate to a gem specification > > This appears to be source that the interpreter ran and outputted. > I see it on a WindowsXP machine using the 1.8.6 one-click installer. ObjectSpace has everything. Including the String objects that are sitting around in memory, waiting for you to (in this case) someday try to load a faulty RubyGem. It’s true that ascending object ids indicate creation order, but I doubt it would be a good idea to rely on that. Not every Ruby implementation handles them the same way. object\_ids are meant to be unique, and nothing else. ---
**Author:** ![toadkicker](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5fc32e/32.png) [@toadkicker](https://www.ruby-forum.com/u/toadkicker)\ **Post date:** [September 29, 2007, 6:03am UTC](https://www.ruby-forum.com/t/objectspace-reveals-order/115846/3 "2007-09-29T06:03:00Z")
On 9/28/07, Wilson B. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > > It’s true that ascending object ids indicate creation order, but I > doubt it would be a good idea to rely on that. Not every Ruby > implementation handles them the same way. object\_ids are meant to be > unique, and nothing else. Thanks for the answer. I think I understand a tiny bit how the Ruby memory is allocated. I was just wondering if it was a question of when. But, as you say, every implementation may be different. The question arose out of a couple of things out of other threads. I started thinking about code obfuscation, and also whether you can – within Ruby – hold on to all interpreted source if need be (while recalling some other threads on the topic). Then I started thinking about things like, if you do a count (within the process), you’ll have to allocate memory just to see what’s going on in an already volatile environment. I suppose I’ll have to read up on GC stuff. I’m personally not a big fan of obfuscation, but I’m starting to see how it could be accomplished (legally) without hurting anyone’s feelings. the jury is still out for me on ethicality Todd ---
**Author:** ![toadkicker](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5fc32e/32.png) [@toadkicker](https://www.ruby-forum.com/u/toadkicker)\ **Post date:** [September 30, 2007, 11:52pm UTC](https://www.ruby-forum.com/t/objectspace-reveals-order/115846/4 "2007-09-30T23:52:59Z")
On 9/29/07, Eric H. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > {1001940=\>[“a”, “b”]} > > [] was allocated first, then ‘a’, then ‘b’, not the other way around. Ok, logistically this makes sense. I see. > - This example was too small to invoke the garbage collector, so it > will be in reverse order. With garbage collection you aren’t > guaranteed any ordering. > > > Or is it a tree structure underneath or something strange like that? > > You can infer the structure of ruby’s heap if you make enough > objects. Replace items = [‘a’, ‘b’] with (‘a’…‘aaa’).to\_a and add > GC.disable OK. Got ya. > > ’ does not evaluate to a gem specification > > You have RUBYOPT=-rubygems Thanks! Todd ---
**Author:** ![toadkicker](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/5fc32e/32.png) [@toadkicker](https://www.ruby-forum.com/u/toadkicker)\ **Post date:** [September 30, 2007, 1:47am UTC](https://www.ruby-forum.com/t/objectspace-reveals-order/115846/5 "2007-09-30T01:47:54Z")
On Sep 28, 2007, at 18:18 , Todd B. wrote: > If I do… > > ObjectSpace.each\_object { |o| puts o; gets } > > will it give me the consecutive order of the loading of the objects > (i.e. the time order that memory is allocated on the heap)? Well, its kinda backwards\*: $ cat test.rb items = [‘a’, ‘b’] ObjectSpace.each\_object do |o| p o.object\_id =\> o end $ ruby test.rb | head -3 {1001920=\>“b”} {1001930=\>“a”} {1001940=\>[“a”, “b”]} [] was allocated first, then ‘a’, then ‘b’, not the other way around. - This example was too small to invoke the garbage collector, so it will be in reverse order. With garbage collection you aren’t guaranteed any ordering. > Or is it a tree structure underneath or something strange like that? You can infer the structure of ruby’s heap if you make enough objects. Replace items = [‘a’, ‘b’] with (‘a’…‘aaa’).to\_a and add GC.disable and you’ll see something like: {987780=\>“aaa”} # \<-- end (bottom) of first heap {987800=\>“zz”} {987820=\>“zy”} […] {1035860=\>Kernel} {1035900=\>Class} {1035910=\>Module} {1035920=\>Object} # \<-- start (top) of first heap {1820790=\>“Object”} # \<-- last used address of second heap {1820800=\>“Object”} {1820810=\>“1035920”} {1820820=\>"{1035920=\>Object}"} […] {1828610=\>“1022660”} {1828620=\>"{1022660=\>“Errno::EREMOTE”}"} {1828630=\>{1022660=\>“Errno::EREMOTE”}} # \<-- start (top) of second heap Ruby’s heaps look something like: heaps = [ […], # objects live in here … # more arrays of objects, as necessary ] This was on OS X. > Why do I get String objects right off the bat like… > > ’ does not evaluate to a gem specification You have RUBYOPT=-rubygems