Re: Joint Strike Fighter

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

Well, there may be issues with any given implementation of Ada and how it
chooses to handle things, but there isn't anything that I know of inherent
in Ada that would force pass-by-value of a large record structure. Some
implementations of Ada could be grossly inefficient in all sorts of areas
without that being something intrinsic in the language.

I would think that a sensible implementation of Ada would look at the size
of the item being passed and decide on the most efficient means for the
given architecture. AFAIK, the in/out-ness of a parameter shouldn't force a
pass-by-value (the language lawyers can correct me here) but pretty
definitely an "in out" ought to be able to go by reference. (Again presuming
that the compiler makes an intelligent choice about how to pass the
parameter for maximum efficiency.)

Are there implementations out there that pass a large record or array by
value if the mode is "in out"? (Beyond efficiency, I'd park the PBV/PBR
issue in the "Don't Care" lot. If the compiler picks the fastest possible
means of transferring the parameter (and protects the in/out-ness through
static analysis), but my code depends on side effects of PBR, I've probably
done a bad job of designing the code.)

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Simon Wright" <simon.j.wright@amsjv.com> wrote in message
news:x7v7ks8bf0g.fsf@galadriel.frlngtn.gecm.com...
>
> I'm not sure that this particular issue is the right way round (well,
> it wasn't for me when I encountered it).
>
> I had a Socket (record) type which needed to be passed by reference
> but wasn't; the cure was to make it tagged, which I was less than
> happy with. I forget why 'limited' wouldn't do ..
>
> So I _did_ have to do something explicit to get pass-by-reference.