[squeak-dev] problem with threads

> On Mon, Mar 30, 2009 at 5:03 PM, Jordi Delgado  
> <[hidden email]> wrote:
>> | s p1 p2 |
>> s := SharedQueue new: 20.
>> p1 := [1 to: 10 do: [:i | s nextPut: i. Processor yield.]]  
>> newProcess.
>> p2 := [11 to: 20 do: [:i | s nextPut: i. Processor yield.]]  
>> newProcess.
>> p1 priority: Processor activePriority - 1.
>> p2 priority: Processor activePriority - 1.
>> p1 resume. p2 resume.
>> s inspect.
>
> Try to rename your block variables i to i1 and i2. You can also try
> sending the message #fixTemps to the blocks.

> Hi,
>
> I've been spending some time improving my poor understanding of processes
> in Squeak.
>
> After studying through the usual suspects (essentially the bluebook and
> X.Briffault french book, I've not used yet any VW focused book, to avoid
> confusion) and some google-ing, I am trying to find clear examples with
> almost-trivial behavior in order to illustrate the main points of squeak
> concurrency (I want to teach it, fortunately that will not happen anytime
> soon).
>
> Well, I need to re-define "almost trivial". Let's see. I thought that
> the following code (executed from a Workspace):
>
> | s p1 p2 |
> s := SharedQueue new: 20.
> p1 := [(1 to: 10) do: [:i | s nextPut: i. Processor yield.]] newProcess.
> p2 := [(11 to: 20) do: [:i | s nextPut: i. Processor yield.]] newProcess.
> p1 priority: Processor activePriority - 1.
> p2 priority: Processor activePriority - 1.
> p1 resume. p2 resume.
> s inspect.
>
> was almost-trivial. It behaves as one would expect: s contains
> #(1 11 2 12 3 13 4 14 5 15 6 16 7 17 8 18 9 19 10 20)
>
> But, if you agree with me in the "almost-triviality" of the example,
> probably you should be able to explain why the following code:
>
> | s p1 p2 |
> s := SharedQueue new: 20.
> p1 := [1 to: 10 do: [:i | s nextPut: i. Processor yield.]] newProcess.
> p2 := [11 to: 20 do: [:i | s nextPut: i. Processor yield.]] newProcess.
> p1 priority: Processor activePriority - 1.
> p2 priority: Processor activePriority - 1.
> p1 resume. p2 resume.
> s inspect.
>
> ends up with s containing:
> #(1 11 13 14 15 16 17 18 19 20 nil nil nil nil nil nil nil nil nil nil)
>
> (notice that the only difference is that I am sending a to:do: message
> to a SmallInteger, instead of a do: message to an Interval).
>
> So, as of now, I am unable to figure out what is going on.
>
> Any clue? please? I'd rather prefer a sophisticated answer,
> otherwise I'm going to feel like an idiot :-))
>
> Thanks a lot in advance,
>
> Bests,
>
> Jordi
>
> PS: This behavior is identical in Squeak 3.9, 3.10 and Pharo, and
> in a Linux VM and a Mac VM.
>
>
>

> Your problem comes from a compiler issue that is fixed with the new  
> closure support from Eliot. If you run your example in a closure  
> converted image[1] using a very recent VM [2] it will work as you  
> expect.
>
> [1] http://squeakvm.org/win32/release/Squeak-3.10.2-Closures.zip
> [2] http://squeakvm.org/win32/release/SqueakVM-Win32-3.11.2-bin.zip
>
> Cheers,
>  - Andreas