Re: Ada.Text_IO and protected objects

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On 30 Apr 2005 11:07:54 +0200, Jacob Sparre Andersen wrote:

> I am not sure if the appropriate way of handling access to
> Standard_Output is by using a protected object to manage a queue for
> transferring data to the task doing the actual writing to
> Standard_Output, or if the interaction should be through a direct
> rendezvous with the task doing the actual writing to Standard_Output.

#3: It can be also done on the context of the same task using a protected
object implementing a mutex. A controlled object is then used for safe
mutex access.

But a monitor task (the second variant you mention) is cleaner and safer in
my view. It might be slightly slower than mutexes, though that should
depend on the compiler-platform.

> There is a "dining philosophers" example available somewhere on the
> web (written by Feldman, I think), where you probably can find a good
> example of how to solve the combination of tasking and IO.

Dining philosophers is rather an example of why mutexes/semaphores are
dangerous (deadlock) and low-level and what could be done about that.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de