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From: jsa@alexandria (Jon S Anthony)
Subject: Re: How to wait for task completion
Date: 1996/09/16
Message-ID: <JSA.96Sep16170139@alexandria>#1/1
X-Deja-AN: 180994734
sender: news@organon.com (news)
references: <01bba2e8$c45aad90$35208b82@wd>
organization: Organon Motives, Inc.
newsgroups: comp.lang.ada
Date: 1996-09-16T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <01bba2e8$c45aad90$35208b82@wd> "wiljan" <W.Derks@nl.cis.philips.com> writes:

> Is there a simply way to wait until a task has completed in Ada?
> I have a pointer to a task type:
>       task type tsk;
>       type ptsk is access tsk;
>       p:ptsk;
> At a certain point I want to clean up the resources that the task is
> using but this can only be done when the task is completed.

Depending on your needs and constraints, the simplest trick would be:

in some code where you require P,
...
    declare
        type Ptsk is access Tsk; -- Put access type here to make block master
        P : Ptsk;
        ...
    begin
        null;
    end;      -- Wait until 

You can also put the block in another "parent" task to avoid blocking
the whole program (if that is desirable and deemed "cheap" enough).

For example:

with Text_IO;
with Objs;  use Objs;
procedure Wait_Ex is
 
    task type Tks;
 
    task body Tks is
    begin
        for I in 1..20 loop
            delay 0.1;
            Text_IO.Put_Line("Hi" & Integer'Image(i));
        end loop;
    end;
 
 
begin
    declare
        type Ptsk is access Tks;
        T : Ptsk := new Tks; 
    begin
        null;
    end;
    Text_IO.Put_Line("Done");
end Wait_Ex;

$ gnatmake wait_ex.adb
$ wait_ex.adb
Hi 1
Hi 2
Hi 3
Hi 4
Hi 5
Hi 6
Hi 7
Hi 8
Hi 9
Hi 10
Hi 11
Hi 12
Hi 13
Hi 14
Hi 15
Hi 16
Hi 17
Hi 18
Hi 19
Hi 20
Done
$
-- 
Jon Anthony
Organon Motives, Inc.
1 Williston Road, Suite 4
Belmont, MA 02178

617.484.3383
jsa@organon.com