[Vm-dev] Re: [Pharo-project] is it possible to know the memory occupation (bytes) of an object?

[Henrik Johansen]

On Sep 28, 2010, at 6:46 40AM, Nicolas Cellier wrote:

> 
> 2010/9/27 Eliot Miranda <eliot.miranda at gmail.com>:
>> 
>> 
>> 
>> On Mon, Sep 27, 2010 at 12:20 PM, Mariano Martinez Peck <marianopeck at gmail.com> wrote:
>>> 
>>> 
>>> 
>>> 
>>> On Wed, Sep 22, 2010 at 12:34 PM, Mariano Martinez Peck <marianopeck at gmail.com> wrote:
>>>> 
>>>> 
>>>> On Wed, Sep 22, 2010 at 12:12 PM, Henrik Johansen <henrik.s.johansen at veloxit.no> wrote:
>>>>> 
>>>>> On Sep 22, 2010, at 9:59 40AM, Adrian Lienhard wrote:
>>>>> 
>>>>>> Some notes:
>>>>>> 
>>>>>> - What should be answered for small ints? 1 sizeInMemory -->8. That's wrong. Shouldn't this answer 0?
>>>>> 
>>>>> Philosophical question really, imo both 4 (Again, in 32bit images at least) and 0 would be "correct" answers in their own ways. 8 is definitely wrong though :)
>>>>> The method comment should probably highlight which definition is used.
>>>>> 
>>> 
>>> 
>>> So....what should we consider for SmallInteger ?   4 bytes or 0 bytes?
>> 
>> 0 bytes, obviously.  The only space occupied by a SmallInteger is the space of the slot containing it.  There is no SmallInteger object beyond the slot.
>> 
> 
> Or from another POV, it's 4, the size of the slot. But we don't count
> the size of the slots, they are already counted in the containing
> object, that's why it should answer 0.
> 
> Nicolas

Yeah, those were the two I were thinking of, and Mariano also summed them up nicely in a previous mail.
When you want to use it for counting up total space usage of objects, 0 is the one it should answer.

Cheers.
Henry

P.S. I still stand by my statement that the comment should highlight this is the reason why 0 was chosen :)