Re: How to: communication between multiple tasks using protected objects - with no polling?

[Hubert <herrdoktor@fumanchu.com>]

the point of a protected object here is that the code each task spends 
in it should be small, just enough to add an entry to a list or so.
When you send a message to a task, it can be that the task is involved 
in a lengthy operatin and thus your task has  to wait until the received 
task can accept it.

You could also make a more complex setup, perhaps something like

Tx1 -> Pox1 -> Tx2 -> Po-final ->Tfinal
Ty2 -> Poy2 -> Ty2 ^

and then Have one output PO per worker task and each has it's own task 
to forward the data to the final PO from which the final task fetches it 
or so.
The Ada tasking system is easy enough to use to set up stuff like this 
pretty quickly and when tasks sleep waiting for an entry they dont eat time.

Just you have to be careful about the maximimum NOF tasks your system 
can support which is, I believe, depended on the underlying OS. But in 
my experience a few dozen are not problem, pehraps even a few 100, 
depending on how much stack each underlying thread reserves. But I 
wasn't able to get any hard data on that.





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