Hi guys!

--- Mark van Gulik <ghoul6 at home.com> wrote:
> I believe your code is incorrect.  Does Squeak use a termination 

Could have guessed! :-)

> exception to safely kill processes?  If not, ignore the ramblings of a 
> lunatic.  If so, a window exists between the #wait and the #ensure: 
> (right between the two statements).  If the process is terminated in 

Aha... tricky.

> that window, the semaphore is not released.  I have patched this in 
> VisualWorks (same problem), but the makes use of some interesting 
> conjectures about the VisualWorks jitter.
> 
> If you like, you can use my test:
> 
> 100 timesRepeat: [
> 	| s procs |
> 	s := Semaphore forMutualExclusion.
> 	procs := (1 to: 50) collect: [:i |
> 		[Processor yield. [s critical: []] repeat] forkAt: Processor
> activeProcess priority - 1].
> 	procs do: [:p |
> 		(Delay forMilliseconds: 2) wait.
> 		p terminate].
> 	(Delay forMilliseconds: 100) wait.
> 	s excessSignals = 0 ifTrue: [self error: 'Failure to release critical
> semaphore']].

So... you mean this should work with the original #critical:?
And, I do not really understand your check for failure, if it works shouldn't excessSignals be 0?

I have obviously not been coding too much with Semaphores...

regards, Göran

=====
Göran Hultgren, goran.hultgren at bluefish.se
GSM: +46 70 3933950, http://www.bluefish.se
"Department of Redundancy department." -- ThinkGeek

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