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Date: Sun, 3 May 2020 07:45:03 -0700 (PDT)
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Subject: Re: Ravenscar - release multiple tasks when an event occurs
From: Jere <jhb.chat@gmail.com>
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Xref: reader01.eternal-september.org comp.lang.ada:58563
Date: 2020-05-03T07:45:03-07:00
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On Sunday, May 3, 2020 at 6:43:31 AM UTC-4, Simon Wright wrote:
> I have several sensor tasks (in general, 2 at the moment) which will of
> course be created and start execution during elaboration.
> 
> I'd like to ensure that they don't actually start reading and reporting
> input data until the system is in a state to receive them.
> 
> With the Ravenscar profile it's not obvious how to do this (only one
> entry per PO, only one task allowed to queue). I suppose I could just
> ignore the inputs until the system's ready to receive them! but has
> anyone a scheme which is less clunky?
> 
> An alternative would be to try for the Jorvik profile, which does allow
> multiple tasks to queue on one entry.

I don't have any experience using ravenscar, so this is somewhat of 
a question as well as a potential option.  I know you cannot do
relative delays, but can you do absolute delays?  If so, could that 
then give you the option to have a single protected object with a
get function and set procedure (no entries) and you just spin lock
at the beginning of all your tasks looking for that protected 
object to change state?