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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Strange warning message
Date: Sat, 02 Dec 2017 08:47:06 +0000
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Xref: reader02.eternal-september.org comp.lang.ada:49319
Date: 2017-12-02T08:47:06+00:00
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Robert Eachus <rieachus@comcast.net> writes:

> For tasks, we have this additional constraint.  You can't leave the
> scope in which a task is declared because the task can still access
> those objects.  So functions, procedures, tasks and even packages can
> need to wait for all the tasks declared locally to be completed (or
> waiting at a terminate alternative).  Again declaring library level
> tasks, if you don't need this complex behavior, eliminates run-time
> code to make it work.

In my experience, when GNAT (with the default static elaboration) has
been unable to find a valid elaboration order, it's almost always been
because of library-level tasks; the binder can't tell whether the task
(which starts executing on completion of its package's elaboration)
actually makes any calls to with'd packages at that point, so assumes
the worst.