Re: requeue with abort and timed call

[ishikawa@arielworks.com]

On Jan 4, 6:09 am, "Jeffrey R. Carter"
<spam.jrcarter....@spam.acm.org> wrote:
> Delay statements and calls to Ada.Text_IO.Put_Line are potentially blocking
> operations. It is an error to call potentially blocking operations from a
> protected action. See ARM 9.5.1.
I'm sorry, I overlooked it.

How about this one;

with Ada.Text_IO; use Ada.Text_IO;
procedure Timed_Protected is
   Z : boolean := True;

   protected P is
      entry E1;
      entry E2;
   end P;

   protected body P is
      entry E1 when True is
      begin
         -- this entry takes 5 seconds
         while Z loop -- Z will be changed in 5 sec. by T2
            null;
         end loop;
      end E1;

      entry E2 when True is
      begin
         null;
      end E2;
   end P;

   task T1 is
   end T1;

   task body T1 is
   begin
      Put_Line ("E1");
      P.E1;
   end T1;


   task T2 is
   end T2;

   task body T2 is
   begin
      -- to complete E1, change the flag
      delay 5.0;
      Z := False;
      Put_Line ("E1 done");
   end T2;

begin
   delay 0.2; -- to ensure start after T1
   Put_Line ("Parent selecting");
   select
      P.E2;
      Put_Line ("E2");
   else
      Put_Line ("Parent cancelling");
   end select;
end Timed_Protected;


I got the same result from this code.

It seems that the cancellation of entry calls occurs only at the end/
start of protected actions.
If the onging protected action takes long time, timed calls wait for
the end of the onging protected action ignoring its expiration time.