From: Arlen Christian Mart Cuss <celtic@...>
Date: 2007-09-27T01:09:09+09:00
Subject: Re: object_id 1, 2, 3


> One should keep in mind that these are interesting implementation
> artifacts.  I don't believe that there's any guarantee that such ids
> would be the same in an arbitrary ruby implementation or even between
> versions of the same implementation.
> 

No -- nor should they be expected to be, under any circumstance.

At best, they're used for comparing objects (Object#==), and should
never be explicitly stored or used for comparisons or hash lookups *in
their own right*. Even two similar strings can have different
object_ids.

irb(main):001:0> "a".object_id
=> 23739988544880
irb(main):002:0> "a".object_id
=> 23739988519760
irb(main):003:0> 

Be careful, and remember that you should anticipate them to never remain
constant between executions of even the same interpreter. (though they
will for your numbers, but beware.. :))

Arlen