Re: Running a background task

["Jeffrey R. Carter" <spam.jrcarter.not@spam.acm.org>]

Bender wrote:
> 
> That's my question in a nutshell.  I need the task to run forever.  I
> need the Handle_Msg procedure to end and start handling other incoming
> messages.

There are at least 2 tasks in your code: Status_Task and the task that calls 
Handle_Msg. In Ada, all execution is part of a task; a purely sequential program 
(without any explicit tasks) is the execution of an implicit task called the 
environment task.

So "the task" is ambiguous, but I presume you mean Status_Task. As written, 
Status_Task does run forever. It's the other task that's blocked.

> Will this solve my problem?  Unfortunately I'm at home at the moment,
> but once I get into work I'll give it a shot.  Once the 'end
> On_String' is reached, will Handle_Msg continue on, while the task
> continues to run?

Yes, IIUC. When the rendezvous ends, at "end On_String", both tasks continue 
(conceptually) in parallel. Handle_Msg will continue with the next statement 
after the call to Status_Task.On_String, and the Status_Task will continue into 
the loop. I think this is what Beneschan meant by 'move the loop out of the 
"accept"'.

If you have fewer tasks than processors, it's possible to write code such that a 
task that is ready to run never executes ("starvation"), but that's probably not 
something that you need to worry about.

-- 
Jeff Carter
"Many times we're given rhymes that are quite unsingable."
Monty Python and the Holy Grail
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