Re: Dynamic allocation of tasks

[Tucker Taft <stt@averstar.com>]

Florian Weimer wrote:
> ...  The following program
> allocates more and more memory:
> 
> procedure Test_Leak is
> 
>    procedure Use_Tasks is
>       task type Some_Task;
>       task body Some_Task is
>       begin
>          null;
>       end;
> 
>       type Task_Array is array (1 .. 1) of Some_Task;
>       TA : Task_Array;
>    begin
>       null;
>    end;
> 
> begin
>    loop
>       Use_Tasks;
>    end loop;
> end;
> 
> Each elaboration of the declaration of TA allocates a few storage
> elements which are never freed.  The problem disappears if the tasks
> is not wrapped within an array (which is probably the reason why no
> one has noticed it before).
> 
> Of course, this behavior is fully conforming with the letters of the
> RM (simply because the RM doesn't talk about storage leaks, except
> that an instance of Ada.Unchecked_Deallocation "should actually
> reclaim storage" ;), but I wonder whether it violates the spirit of
> the RM...

This seems like it is definitely a bug, whether or not it violates the 
spirit of the RM.  Unfortunately, compilers and run-time systems are complex
beasts, and it is impossible to test all combinations of features.
Storage leaks are particularly difficult to test for, since writing
a self-checking test for storage leaks is a pain in the neck.

I heartily suggest you report the bug to the appropriate authorities ;-).

-- 
-Tucker Taft   stt@averstar.com   http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions  (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.)   Burlington, MA  USA