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Content-type: text/plain
René,
Thank you for your comments. They are are not very encouraging but useful.
-Doug
René Dorta wrote:
> We have been experimenting with windows threads in Component Pascal for
> a long while. As a matter of fact we have implemented a subset of
> MODULA-3 thread interface in Component Pascal. I can mention the most
> striking troubles we have run into:
>
> 1. Threads can not use Out or StdLog. We have develop /ad hoc/
> modules for multi-thread output.
> 2. Neither can they use ASSERT: if the assertion fails the system
> will hang up. The big problem is that Run Time Support, and
> BlackBox modules do use ASSERT, so even if your code avoid it you
> can be trapped and hang the system up.
> 3. Don't use HALT.
> 4. Finally: garbage collection is not thread safe. Which is a very
> big problem! (It was pointed out to us by Oberon Microsystem at
> the very beginning of our project).
>
> Cheers:
> René Dorta. Universidad de Carabobo. Venezuela.
>
> Douglas G. Danforth wrote:
>
>> Folks,
>> I have implemented a module GftThreads that works for simple tasks and
>> operates in nanosecond response times (16ns on my machine).
>> The simple interface (patterned a little after Services.Action) looks
>> like.
>>
>> DEFINITION GftThreads;
>>
>> TYPE
>> Action = POINTER TO ABSTRACT RECORD
>> (a: Action) Do, NEW, ABSTRACT;
>> (a: Action) Start, NEW;
>> (a: Action) Stop, NEW
>> END;
>>
>> END GftThreads.
>>
>> Calling action.Start puts the function action.Do into a tight loop
>> running in a child thread. Calling action.Stop from the parent
>> terminates this loop and the thread. The child shares the memory
>> space of the parent.
>>
>> However, I am getting in over my head. The functions that the user
>> places in action.Do must be 'thread-safe'. Neither Out.String, nor
>> XYplane.Dot seem to satisfy the 'thread-safe' condition. They both
>> work for a single Start-Stop pair but a second Start causes the
>> system to hang (for Out there seems to be an interaction with the
>> routines that write to the log and preconditions are violated).
>>
>> I would like the user not have to worry about 'thread-safety' and so
>> believe something like critical regions are necessary.
>>
>> Does anyone have experience with Windows' threads that could give some
>> pointers?
>>
>> -Doug
>>
>> --- BlackBox
>> --- send subject HELP or UNSUBSCRIBE to blackbox{([at]})nowhere.xy>>
>>
--- BlackBox
--- send subject HELP or UNSUBSCRIBE to blackbox{([at]})nowhere.xy
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Received on Thu Apr 28 2005 - 18:46:21 UTC