Re: Interrupts handling in ADA

[Ada BRL <ada.brl.2011@gmail.com>]

On 13 Dic, 18:14, Simon Wright <si...@pushface.org> wrote:
> Ada BRL <ada.brl.2...@gmail.com> writes:
> > On 13 Dic, 15:07, Simon Wright <si...@pushface.org> wrote:
> >> Also, this isn't called an accept statement; it's an entry call. The
> >> way a task indicates it's prepared to accept an entry call is by an
> >> accept statement; protected objects are different. So if instead of
> >> Queue being protected it was a task (not something I'd recommend) the
> >> corresponding body part would have looked like
>
> >>    accept Get (M : out Message) when not Buffer.Is_Empty do
>
> > I haven't understood you...
> > What does it mean "declaring a protected task"? You would not
> > recommend it, ok, but what does it mean?
> > In the example above is the Buffer (member of main) the unique
> > protected object or the main function itself has to be declared as
> > protected?
>
> > Sorry but I'm beginning to loose the thread...
>
> Not surprised, it seems to me we're giving you answers well above your
> current level of knowledge of Ada. Sorry about that.
>
> [1] is a better explanation of tasking & protected types than I can
> provide quickly (maybe at all!)
>
> [2] contains two implementations; queueing_po* are the files for a
> protected object implementation, queueing_task* for a task
> implementation. You will see that the structures of the two main
> programs (queueing_po_main, queueing_task_main) are identical.
>
> One of the reasons I wouldn't use a task here is that you have to manage
> the active thread of the task. An example of the sort of thing I mean is
> that when you run queueing_po_main it stops after 20 ines of output, but
> when you run queueing_task_main it hangs at that point and you have to
> stop it from the outside (by Crtl-C, for example). The reason is that
> the task Queue has no reason to stop and just waits forever (in this
> simple case you could probably fix that fairly simply, but in general
> it's not easy at all; best to avoid the problem).
>
> [1]http://en.wikibooks.org/wiki/Ada_Programming/Tasking(sections 1, 2)
> [2]http://dl.dropbox.com/u/34783908/Ada/queueing.zip

Yes, I have never worked with Ada...but it's good for me to have
people explaining real world programs instead of dummy ones... :-), it
makes me learning more!
I have to read carefully the wikibook about Ada, this will be useful!