Re: Multitasking 2 Problem
Robert Craig wrote:
>
> Al Getz wrote:
> > My second question is, why do the tasks have to be created over
> > again after they 'end' normally? Why cant the task id's be
> > persistent until the user removes (or kills or whatever) the task?
> > The reason for asking this is mainly because a "task" will be
> > a routine (with a routine id) that will remain part of the program
> > until the process ends, so it would make sense that if it was
> > declared as a task that it would normally be used as a task until
> > the program ends. The only thing that needs to change is if it
> > is active or not, ie if it should be called or not which i guess
> > would be done with task_schedule(). If the task ends there's really
> > no reason to have to change the id is there? Even with 50 tasks in
> > a program that would only mean 50 id's issued and that would be that.
> > If a task 'ended' it would be taken off the active list. This would
> > also mean there could never be confusion about a task id belonging
> > to one task or another because an id would last till programs end,
> > just like a routine_id.
>
> I'm not sure if you understand that a task is not a routine,
> and a routine is not a task. A program has a fixed number
> of routines, but you can dynamically create 1000
> or 1 million tasks that all run the same (say) quick sort routine
> at the same time, but using different private data, a different
> call stack, and a different "next statement to execute".
> Each of those (potentially) millions of tasks needs its own task id.
> That task id should not be recycled immediately because another
> task might be monitoring the status of that task, and might
> not check the status until long after the first task is dead and gone.
> If another task were assigned the same id, it could be confusing.
>
> If you look at Language War, it has maybe a dozen "fixed" tasks that
> are created near the beginning of the game, and never die.
> Most of them do something like:
> }}}
<eucode>
> global procedure task_life()
> -- independent task: update "life support" energy
> while TRUE do
> if shuttle then
> p_energy(-3)
> else
> p_energy(-13)
> end if
> task_yield()
> end while
> end procedure
> </eucode>
{{{
>
> The infinite while loop prevents this task from ever
> reaching the end and terminating. It can only be terminated
> if another task kills it, or the whole program ends.
> Only one task id is needed.
>
> There are other cases in LW where an infinite-loop task can
> be suspended and later rescheduled by other tasks, as need be,
> but it never runs off the end or returns. Maybe that's
> what you are looking for.
>
> Language War also has tasks that are created, do their thing,
> and then die, so the task id numbers do creep up indefinitely
> as the game progresses. e.g. each phasor that's drawn is
> a separate task that uses up a task id number. If you play a game of
> Language War for 1000 trillion years, the id numbers might roll over.
> Actually, a few days ago, as a test, I changed the 1e14 roll over
> point to something like 20 or 30, and Language War ran fine. It wrapped
> numerous times, but I don't have tasks that check the status of other
> tasks. Most tasks are very independent of each other, or
> else they check global variables to see what has happened so far.
>
> Regards,
> Rob Craig
> Rapid Deployment Software
> <a href="http://www.RapidEuphoria.com">http://www.RapidEuphoria.com</a>
>
Hello again,
Ok that makes sense, so i guess that wont be a problem then.
I guess it wont hurt to let the task end and then create it again
later if needed so i guess i'll leave my programs working that way.
Take care,
Al
And, good luck with your Euphoria programming!
My bumper sticker: "I brake for LED's"
|
Not Categorized, Please Help
|
|
