Bert Freudenberg a écrit :
> On Sat, 26 May 2007 14:12:59 +0200, Damien Cassou wrote:
>> Thank you for this comments. That was what I was afraid of. Is it
>> possible to have test that will show #nextPutAll: is not protected?
> 
> I'm not convinced #nextPutAll: should be atomic. It would mean a 
> consumer cannot start processing queued items before all elements are 
> written. Right now, #nextPutAll: uses #nextPut: which is "protected". 
> Nothing to fix IMHO.
> 
> The test to find out whether #nextPutAll: is atomic or not would be to 
> have a higher-priority reader process that reads one element and peeks 
> for the next. If that succeeds, the lower-priority writer process 
> managed to put in more than one element, meaning #nextPutAll: is not 
> atomic. With the current behavior, however, the reader process would be 
> activated as soon as the first element was written and the peek would 
> fail (I mean, answer nil).
> 
> - Bert -
> 
> 
> 
> 

I think Damien was trying to prove that nextPutAll: IS NOT atomic.

It can be pre-empted
- if the process explicitely yield (not possible, there is not a yield 
call under nextPutAll:)
- if the process is blocked on a Semaphore (could occur if write on 
external streams)
- if a higher priority process is unblocked.

But i do not remember: would the Processor give hand to a process of 
same priority if none of above conditions happen? (based on round-robin 
or something).

If not, Damien will have to imagine more tricky code creating one of the 
3 conditions above to demonstrate the feature.

Nicolas