Re: GNAT: pragma Ravenscar

[Jean-Marc Bourguet <bourguet@my-deja.com>]

In article <87vh6j4tpo.fsf@deneb.cygnus.argh.org>,
  " "@deneb.cygnus.argh.org (Florian Weimer) wrote:
> Alfred Hilscher <Alfred.Hilscher@icn.siemens.de> writes:
>
> > I thought when I build the same program twice, once with this pragma
> > and again without this pragma then I would get different sized
> > exe-files (because a smaller runtime included). But when I did so,
> > I've got both times the same size. Do I missunderstand what the
> > pragma does or do I miss some GNAT switches ? I've looked to the
> > documentation but I found no answer there.

As I understood it, pragma Ravenscar aim was to enforce some
restrictions, not to reduce the run time size. (I seems to recall
another pragma Resticted_Run_Time which had this goal). I've never
used these pragmas so I may be wrong.

> The GNAT No Runtime support (GNORT) doesn't seem to be part of the
> public distribution.

With 3.12p, gnat does accept the pragma and seems to make something
with it. What I've not found is the manual which is referenced in
the gnat documentation. It does nearly was I was expecting, except
for one time where it generated non linkable code where I'd have
expected a warning, but as I've done something which was meaningless,
without the documentation I may not say it is a bug. What I succeeded
to do is boot a PC and after a bootstrap in asm, jump to a main program
written in Ada using several packages some of which needed elaboration.

Pragma Ravenscar is something else than GNORT, which is as far
as I known completely documented in the publicly available gnat
documentation.

> (Of course, this is a GNAT-specific question and should have been
> asked on chat@gnat.com. ;)

Never a bad advice.

-- Jean-Marc


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