Re: Tasking differences

[Martin Dowie <martin.dowie@baesystems.com>]

i should have been clearer - yes the output is non-deterministic, but the
outcome that wasn't 'expected' was that it hangs when attempting a second
'select ... else' - the non-deterministic output was entirely expected!

on removal of timer variables, pragma priorities and most text_io, except from
the 'stop' subprogram that is called by the main program, we still see the same
'hanging'/'non-hanging' differences.

the best guess so far is that there is a bug in the behaviour of 'select ...
else' statements and delays (thanks pete).

Robert Dewar wrote:
> 
> In article <396AECA4.30B03835@baesystems.com>,
>   Martin Dowie <martin.dowie@baesystems.com> wrote:
> > sorry, but I can't see why there should be any difference in
> *results* of the
> > two - if they were so different, why does GNAT produce the
> same results for both
> > versions? I understand that the scheduling of the 2 tasks can
> change given the
> > differences, but in this case I don't see why that should
> affect the outcome.
> 
> Running code locked instead of unlocked makes a big difference
> in the set of possible outcomes, the fact that with one
> particular scheduling discipline you see no differences proves
> nothing about the possible non-deterministic set of outcomes!
> 
> Sent via Deja.com http://www.deja.com/
> Before you buy.

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