irb> class A; end
=> nil
irb> a=A.new
=> "#<A:0x3094638>"
irb> a.inspect
=> "#<A:0x3094638>"
irb> b=[]
=> []
irb> b.inspect
=> "[]"
How to get memory address of an array object?
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1 Answer
Use the method Object#object_id.
Returns an integer identifier for obj. The same number will be returned on all calls to id for a given object, and no two active objects will share an id.
#object_idis a different concept from the:namenotation, which returns the symbol id of name.
Example :-
Arup-iMac:arup_ruby $ irb
2.1.2 :001 > s = "I am a string"
=> "I am a string"
2.1.2 :002 > obj_id = s.object_id
=> 2156122060
2.1.2 :003 > ObjectSpace._id2ref obj_id
=> "I am a string"
2.1.2 :004 >
6 Comments
Paul
If
object_id differ could I say for sure that there are two different objects? And if these ids are the same is this the same object?
Arup Rakshit
@Paul Yes.. You should.
Amadan
Not necessarily a memory address, though. In particular, it won't be a memory address for
3, :foo, nil, false... (although it still will be unique). But for most objects, it will be a pointer, at least on MRI. Fun fact: for small integers n, object_id should be n * 2 + 1. -1.object_id == -1! :)Arup Rakshit
@Amadan Humm.. True...True.
object_id is enough to get the object address and the same address can be used to get the object back. :-)Paul
I have
@channels array in a class. The class should be instantiated once, but when I call the instance from one thread @channels.length is 1 and from other thread = 0. object_id is the same. Array is created and filled only during object's initialization. What could go on? |