question on tasks

question on tasks

[Peter Walker]

Hi, is it possible to have a task do the following two things 
simultaneously:

1) sent a finite number of message to another task as random times
2) listen in on incoming messages and acknowledge them.

for example, the taskA would send 3 messages at random times to some 
communication_buffer (which relays messages to other tasks). taskA would 
also listen for incoming messages and print them to standard output.

I have tried to use the following to perform the above, but it does not 
work. Would anyone know how to implement the above?

Many thanks.
Peter

----------------------------
   task A is
      entry Incoming (Source : Location; Destination : Location; Message : 
String);
   end A;


   task body A is
      Done : Boolean := False;
      Messages_To_Send : Integer := 3;
      ...
   begin

      while not Done loop

         select

            accept Incoming (Source : Location; Destination : Location) do
               Put_Line("Recieved message " & Message & " from " & 
Location'Image(Source));
            end C1;

         else

            if Messages_To_Send > 0 then
               delay Duration(Random_Time.Random(Seed)); -- some random 
number between 1 and 10
               Communication_Buffer.C1(A, B, "Hello");
               Messages_To_Send := Messages_To_Send - 1;
               ...
            end if;

         end select;

      end loop;

   end A;
-----------------------------

Re: question on tasks

[Martin Dowie]

"Peter Walker" <p.walker@trinet.com> wrote in message 
news:414bf572@dnews.tpgi.com.au...
> Hi, is it possible to have a task do the following two things 
> simultaneously:

No _exactly_ at the same time but I think I know what you mean...

...is this what you're after?

with Ada.Numerics.Float_Random; use Ada.Numerics;
with Ada.Text_Io; use Ada.Text_Io;
procedure Peter is
   type Location is (Alpha, Beta);
   package Communication_Buffer is
      procedure C1 (A, B : Integer; C : String);
   end Communication_Buffer;
   package body Communication_Buffer is
      procedure C1 (A, B : Integer; C : String) is
      begin
         Put_Line ("C1 got [" & C & "]");
      end C1;
   end Communication_Buffer;
   task A is
      entry Incoming (Source : Location; Destination : Location; Message : 
String);
   end A;
   task body A is
      Done : Boolean := False;
      Messages_To_Send : Integer := 3;
      A, B : Integer := 0;
      G : Float_Random.Generator;
   begin
      while not Done loop
         select
            accept Incoming (Source : Location; Destination : Location; 
Message : String) do
               Put_Line ("Recieved message " & Message & " from " & 
Location'Image (Source));
            end Incoming;
         or
            -- delay Duration (Random_Time.Random (Seed));
            delay Duration (Float_Random.Random (G));
            if Messages_To_Send > 0 then
               Communication_Buffer.C1 (A, B, "Hello");
               Messages_To_Send := Messages_To_Send - 1;
            end if;
         end select;
      end loop;
   end A;
begin
   A.Incoming (Alpha, Beta, "foo");
end Peter;

Re: question on tasks

[Peter Walker]

Martin, thanks for that! Your example worked out just great. Much 
appreciated!!!

Peter 

Re: question on tasks

[Martin Dowie]

Peter Walker wrote:
> Martin, thanks for that! Your example worked out just great. Much
> appreciated!!!

No probs :-)

Cheers

-- Martin