Re: [sc-dev] Re: Still occasional memory corruption...

[Jonatan Liljedahl <lijon@xxxxxxxxxxxx>]

I can evaluate the above any number of times, it always prints:

abc is 2
3

This is on OSX, master commit 0081056d8bd7db6e96a368be5764162ab11c7596

(Having a concert soon so not willing to update to origin/master right now)

/Jonatan

On Wed, Nov 20, 2013 at 12:05 PM, Miguel Negrão
<miguel.negrao-lists@xxxxxxxxxxxxxxxxx> wrote:
> Em 20-11-2013 10:36, James Harkins escreveu:
>> On Nov 20, 2013 6:18 PM, "James Harkins" <jamshark70@xxxxxxxxx
>> <mailto:jamshark70@xxxxxxxxx>> wrote:
>>> Wait... here it is... the error happens in collectAs. My call stack
>> shows that the "class" argument is Array, and one item is successfully
>> added into the array. By the time it gets to the second iteration,
>> somehow "res" has changed from an array to a TempoClock, despite the
>> fact that res IS NEVER REASSIGNED in this method! That is,
>> function.value(elem, i) has had a side effect in a scope to which that
>> function has NO ACCESS.
>>
>> Another (likely more plausible) explanation is stack corruption. I just
>> remembered that the stack trace shows res is still an array. So,
>> probably when the VM gets around to sending the message "add," it gets
>> the clock off the stack instead of what ought to be the receiver.
>>
>> Either way, not good.
>>
>> hjh
>>
> I'm afraid I can't help much at all, but just so you feel less lonelly,
> I was at some point getting similar behaviour from sclang. At some point
> the same variable, without being changed, would output completelly
> random results.
>
> https://github.com/supercollider/supercollider/issues/999
>
> Stating the obvious, indeed one of the advantages of using a mainstream
> language is that you have people that can look into this sort of stuff
> that know exactly what is going on, freeing the sc developers to focus
> on the musical aspect of things. But then again, I'm afraid there will
> never be consensus on a language... sclang is kind of the glue that
> keeps us together, for the better or worse ;-)
>
>> evaluating the above a couple of times :
>>
>> abc: emacs
>> Some(2)
>> abc: a Function
>> Some(2)
>> abc: nil
>> Some(2)
>> abc: 0
>> Some(2)
>> abc: SystemClock
>> Some(2)
>> abc: true
>> Some(2)
>> abc: true
>> Some(2)
>> abc: a Function
>> Some(2)
>> abc: true
>> Some(2)
>> abc: SystemClock
>> Some(2)
>> abc: true
>> Some(2)
>> abc: AppClock
>> Some(2)
>> abc: 512
>> Some(2)
>> abc: AppClock
>> Some(2)
>> abc: 57110
>> Some(2)
>> abc: SystemClock
>> Some(2)
>> abc: true
>> Some(2)
>> abc: true
>> Some(2)
>> abc: false
>> Some(2)
>
> best,
> Miguel
>



-- 
/Jonatan
http://kymatica.com

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