Re: task time-out&abort

[Robert A Duff <bobduff@shell01.TheWorld.com>]

Marius Amado Alves <amado.alves@netcabo.pt> writes:

> > My goal is that the calling process can abort the call after x second
> > if the computation of the entry take too much time.
> 
> Curiously enough on 2001 I wrote this for an Ada-Europe workshop on
> exceptions:
> 
> <<
> The time-out situation is so common that perhaps it deserves a special
> device in a future Ada:
> 
>    begin
>      ...
>    end in 10.0; -- end in 10 seconds, or raise Time_Out
>    exception
>      when Time_Out => ...
>  >>
> (http://www.liacc.up.pt/~maa/files/ehada1.pdf)

How is this better than ATC (select-then-abort) in Ada 95?

Note that dynamically nested time-out regions won't work
very well in the above.  You need a distinct new exception
for each time-out, and you need to prevent hijacking of the
exception.

- Bob