Re: elaboration circularity detected problem, How to fix?

[Simon Wright <simon@pushface.org>]

"Scott Travak" <s.travak@j-inet.com> writes:

> Hi everyone, I was hoping to obtain some assistance with a program I am 
> constructing. Essentially my program is made up as follows:
> 
> 1) Two packages (one of which is a generic package).
> 2) Each package essentially contains a task
> 3) Each task contains a reference to (operates on) the other task
> 
> I am encountering a "elaboration circularity detected" error (see
> below).

The thing to do is to avoid having library level tasks.

The tasks start up as they are elaborated and, since they reference
each other, the compiler can't tell that there isn't a problem (even
if you use the

  task body ...
  begin
     accept Start;

idiom to stop things happening until you are ready).

One way round this is to use access-to-task-type's and only actually
allocate the tasks when you are ready.


Of course there are other ways of getting a circularity (our record
was a loop of 534 in a program with only 530 packages!! I think there
may have been a bug somewhere .. but that was GNAT 3.11 or
thereabouts), but the task way is a winner.


-- 
Simon Wright                               100% Ada, no bugs.