Re: some questions re. Ada/GNAT from a C++/GCC user

[bobduff@world.std.com (Robert A Duff)]

In article <4jp17p$17vn@watnews1.watson.ibm.com>,
Norman H. Cohen <ncohen@watson.ibm.com> wrote:
>Jean Ichbiah correctly saw the chaos that could result from approach (b).

I agree.

>He chose approach (c) for an exception occuring while the child task was
>still elaborating the declarative part of its task body and (a) for an
>exception occuring once the child task entered the sequence of statements
>of its task body.

IMHO, he should have chosen approach (c) for all exceptions.  A master
awaits its dependent tasks before continuing.  This would be the perfect
place to raise Tasking_Error if the dependent task(s) raise unhandled
exceptions.  Instead, the dependents silently disappear, like Ms. Rigby,
and then the parent task continues merrily on its way.

>...  (Anyone who has debugged a
>program in which a task raised an unhandled exception has quickly learned
>the value of adding a handler such as
>
>   when others =>
>      Display_Error_Message
>         ("Task of type XYZ abandoned due to unhandled exception.");
>
>to each task body.)

Yes.  Debugging these things is a nightmare, otherwise, because the
problem is not localized.

- Bob