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Fix weird formatting of this old Ada post

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R. Tyler Croy 2016-06-15 12:20:29 -07:00
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14
_posts/2013-03-09-dynamic-tasks-in-ada.markdown
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@ -9,7 +9,7 @@ tags:
A few years ago,
[Ada](https://secure.wikimedia.org/wikipedia/en/wiki/Ada_(programming_language)
become my hobby/tinker programming language of choice, for a [number of
became my hobby/tinker programming language of choice, for a [number of
reasons](/2010/12/06/ada-surely-you-jest-mr-pythonman.html), concurrency being
one of them. In this post I'd like to walk you through an example of dynamic
task creation in Ada, which uses `Ada.Task_Termination` handlers, a new feature
@ -75,10 +75,8 @@ example of might be:
{% highlight ada %}
with Ada.Text_IO;
procedure Main is
task Counter;
task body Counter is
begin
for Count in 1 .. 10 loop
@ -88,14 +86,12 @@ procedure Main is
begin
null;
end Main;
{% endhighlight %}
The way tasks in Ada work means that the `Counter` task will be created,
started and then the execution of the `Main` program will block until the
`Counter` task completes (important detail).
The trickiness starts to arrive when you talk about dynamically allocating task
objects, and combine that with something like an infinite loop, such as one
might find in a server program, e.g.:
@ -147,13 +143,11 @@ need one more component, a protected object with a hash map inside of it:
{% highlight ada %}
package Server.Handlers is
protected Coordinator is
procedure Track (Ptr : in Handler_Ptr);
private
Active_Tasks : Handler_Containers.Map;
end Coordinator;
end Server.Handlers;
{% endhighlight %}
@ -183,9 +177,7 @@ protected procedure off of:
{% highlight ada %}
protected body Server.Handlers is
protected body Coordinator is
procedure Last_Wish (C : Ada.Task_Termination.Cause_Of_Termination;
T : Ada.Task_Identification.Task_Id;
X : Ada.Exceptions.Exception_Occurrence) is
@ -193,21 +185,17 @@ protected body Server.Handlers is
-- Deallocate our task identified by `T`
-- and make sure we remove it from `Active_Tasks`
end Last_Wish;
procedure Track (Ptr : in Handler_Ptr) is
-- Dereference our `Handler` task, and fish out its Task_Id
Handler_Id : Ada.Task_Idenfitication.Task_Id := Ptr.all'Identity
begin
-- Add `Handler_Id` to our `Active_Tasks` map
Active_Tasks.Insert (Handler_Id, Ptr);
-- Set up the Last_Wish procedure to be executed after our task has
-- terminated
Ada.Task_Termination.Set_Specific_Handler (Handler_Id, Last_Wish'Access);
end Track;
end Coordinator;
end Server.Handlers;
{% endhighlight %}