[Q] OmniThreadLibrary - TaskGroup

[DPStano 15]

I have multiple tasks like

  var Task := CreateTask(
    procedure(const Task: IOmniTask)
    begin
    end).Unobserved.Join(GlobalTaskGroup);

  Parallel.Start(Task , Parallel.TaskConfig.CancelWith(GlobalCancellationToken));

they can run for various times from seconds to minutes and some tasks can even run multiple times at once, and I need to terminate them and wait for termination all living task (some of them are already finished) at some point

  GlobalCancellationToken.Signal;
  GlobalTaskGroup.WaitForAll();

so the question is how to properly manage task group to keep just living tasks in it?

 

...

 

i don't see any code how could TaskGroup remove task after its termination, it will keep reference until the task is explicitly removed by calling TaskGroup.remove.

Edited May 15, 2020 by DPStano

[Primož Gabrijelčič 223]

Does this not already work out of the box? If a task is finished, WaitForAll should now that.

[DPStano 15]

yes it works but without clearing taskgroup i can have taskgroup with like 100k finished tasks which won't be very effective

 

at first i was searching for something like 

CreateTask(
    procedure(const Task: IOmniTask)
    begin
try
// do some work
finally
  GlobalTaskGroup.Remove(Task)
end
    end).Unobserved.Join(GlobalTaskGroup);

but IOmniTaskGroup is not a group of IOmniTask but a group of IOmniTaskControl but i found solution OnTerminated can give me IOmniTaskControl so i'll unregister task from group there

[Primož Gabrijelčič 223]

Indeed, OnTerminated is the correct approach.