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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Class with task destructor
Date: Wed, 23 Nov 2011 09:05:51 +0000
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Date: 2011-11-23T09:05:51+00:00
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"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:

> On Tue, 22 Nov 2011 17:50:45 -0800 (PST), Rego, P. wrote:
>
>> So now I have a class with a task inside and a Constructor, and I
>> want to implement a destructor.
> [...]
>
> If you have Start and Finish entries, you don't need terminate
> alternative.  Use Ada.Finalization.Limited_Controlled as the
> base. Make task an access to task component. Initialize should
> allocate the task. You don't need Start entry at all. (The only use
> for Start is passing additional parameters to the task) From Finalize
> you call to Finish and then free the task. The constructing function
> *shall* not use pointers.

You ought to wait until the task has terminated before freeing it. I
can't trace it now, but I think that AdaCore recently fixed a feature
where the TCB would be silently not deallocated if the task wasn't
terminated. I had to fix this problem by handing off all tasks to be
deallocated by a low-priority task, which required some interesting
generic/codegen manipulation.

I think that that's a *must* not a *shall*, but it's a little while
since I did requirementese!