Re: Problem with -gnatt

[Niklas Holsti <nobody@nowhere.fi>]

Pascal Obry wrote:
> "Alex R. Mosteo" <devnull@mailinator.com> writes:
> 
> 
>>Whe are talking about no IO inside the protected subprograms, right? Nobody
>>prevents you to use another task to do IO. Or I'm missing something?
> 
> 
> Fine, and in this case you will have to leave the protected operation to let
> another one send/receive the data to/from a task. So we are back to 
> "for a short time" :)

No, the task doing the "long" protected operation can be pre-empted by a 
higher-priority task (that does not use the same protected object) and 
the pre-empting task can then do I/O, even blocking operations, as long 
as it does not call a blocking operation within (another) protected 
operation.

In my experience, a largish real-time program will have tasks and 
protected objects at several priority levels, corresponding 
monotonically to a range of deadlines, and the protected operations on 
the less-urgent priority levels may be quite "long" compared to the 
"short" deadlines of the more-urgent levels.

-- 
Niklas Holsti
Tidorum Ltd

niklas holsti tidorum fi
       .      @       .