Re: Tasking issues

["Jeffrey R. Carter" <spam.jrcarter.not@acm.nospam.org>]

anon wrote:
> 
>   continue : boolean := True ; -- task to continue running

There's no guarantee that operations on this variable are atomic. You 
can get into pragma Atomic, bu in general, unprotected variables are not 
a good way for tasks to communicate.

>         if Name ( 1 .. 4 ) = "stop" then
>             continue := false ;
>         end if ;

What happens after the following sequence of inputs:

"atopofoldSmokey"
"s"

?

>     -- do nothing!
> 
>   while continue loop
>     delay 0.0 ;
>   end loop ;
> 
>     -- abort tasks.  But because get_name may be in the process of 
>     -- obtaining data from standard_input. it may require a CR/LF 
>     -- to be entered to fully abort the 'get_name' task.
> 
>   abort get_name ;
>   Put_Line ( "EOT -- get_name" ) ;
>   abort print_something ;
>   Put_Line ( "EOT -- print_something" ) ;
>   Put_Line ( "EOJ" ) ;

This does quite a bit. Have the tasks check for the termination 
condition themselves, and the main procedure's SOS can be "null;"

-- 
Jeff Carter
"Sir Lancelot saves Sir Gallahad from almost certain temptation."
Monty Python & the Holy Grail
69