Re: Ravenscar - program termination


Maciej Sobczak <no.spam@xxxxxxxxxxx> writes:

Ludovic Brenta wrote:

Do I understand correctly that Ravenscar programs are by definition
running forever? What about programs that are expected to finish?
Yes, it is my understanding as well, and I'm happy with that.
I remember being impressed with Ada because you could write an
infinite loop without a faked up condition. The idea being that in
Ada the typical infinite loop would normally be terminated by
detonation. -- Larry Wall

:-)

The Ravenscar profile is specifically targeted at high-integrity
systems, where infinite loops are, I think, the norm.

Sorry, but I don't see anything in the concept of high-integrity
software that would make it a norm. High-integrity software is a set
of quality objectives, whereas infinite loops are (or aren't) part of
system requirements. These should stay independent, even though I
understand that expectations for both often come in pairs.

OK, just nit-picking. ;-)
I wanted to be sure that I understand it correctly, thanks.
Still, it looks like I cannot say:

pragma Profile(Ravenscar);

in my Hello World program even though this program meets the
objectives of the profile. That's not fair! :-)

Well, it terminates. What does termination mean in a "high integrity"
embedded system -- does the hardware go away? :-). I think if someone
wants to shutdown such a system the thing happening is, that every
task goes into idle mode and the last thing a controlling task does,
is, to display (or otherwise indicate) "you may now shut off power,
the countdown to eject the warp core has been stopped" or something
like this.

:-)

Regards -- Markus

.

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