Re: Blocking protected ops (was: Tasks and C/C++ code)

["Jean-Pierre Rosen" <rosen.adalog@wanadoo.fr>]

Mats Weber a �crit dans le message
<365BE117.59209A5@elca-matrix.ch>...
>I still don't see why an accept statement is allowed to contain a
>potentially blocking call, but a protected procedure is not.
>
Because a protected type is much lower level than tasks.
On a multi-processor, the protection can be implemented
by busy-waiting on a global lock; you don't want to allow
a task to be stuck in the protected object for a long time.
There is no such issue for tasks (which is BTW why
tasks and rendezvous are still useful).

My own rule of thumb:
if it's simple, low-level and quick, use a protected type.
Otherwise, and especially if it's a high level operation,
or if you need to do more that checking a boolean or
bumping a counter, use tasks.

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                  J-P. Rosen (Rosen.Adalog@wanadoo.fr)
      Visit Adalog's web site at http://perso.wanadoo.fr/adalog