Re: Task origin track from a class

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Tue, 12 Jul 2011 17:36:29 -0700 (PDT), Shark8 wrote:

> On Jul 12, 5:31�am, Simon Wright <si...@pushface.org> wrote:
>> Simon Wright <si...@pushface.org> writes:
>>> "Dmitry A. Kazakov" <mail...@dmitry-kazakov.de> writes:
>>
>>>> So the unfortunate rule of the thumb is: never use task components,
>>>> but access to task instead. From Finalize you would call Stop entry or
>>>> an equivalent and then free the task object using
>>>> Unchecked_Deallocation.
>>
>>> With GNAT, best not to free the task object until 'Terminated is True
>>> (GNAT's I have used would silently fail to actually free the TCB!
>>> resulting in an insidious memory leak).
>>
>> Oops, I forgot to add that I'd aborted the task first (as Dmitry said,
>> it's not always possible to arrange a clean shutdown).
> 
> Hm, would it be a usable idea for say the memory manager for an OS,
> such that the requests to the manager from programs (and perhaps even
> compilers) are delegated to the task; after all you don't want to shut
> the memory-manager down (terminate the task) at any point in normal
> operation.

The issue has nothing to do with memory management. The actual problems
are:

1. The procedure of destruction of the objects having task components.
Tasks are completed *before* Finalize is called. Ada's approach to
construction/destruction is very much broken. This is just one example of
this.

2. The usage of the terminate alternative which cannot be mixed with for
example the delay alternative.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de