How do I end the program?

How do I end the program?

[David Starner]

How do I exit the program? It may seem like a silly question, but I'm
trying to exit from a function called from a callback written in C, so I
can't just return or raise an exception. glutMainLoop never returns, so
I can't run off the end of the main function. I used
GNAT.OS_Lib.OS_Exit. Is there a pure Ada alternative?

-- 
David Starner - starner@okstate.edu, dvdeug/jabber.com (Jabber)
Pointless website: http://dvdeug.dhis.org
What we've got is a blue-light special on truth. It's the hottest thing 
with the youth. -- Information Society, "Peace and Love, Inc."

Re: How do I end the program?

[dale]

starner@okstate.edu wrote:

> How do I exit the program? It may seem like a silly question, but I'm
> trying to exit from a function called from a callback written in C, so I
> can't just return or raise an exception. glutMainLoop never returns, so
> I can't run off the end of the main function. I used
> GNAT.OS_Lib.OS_Exit. Is there a pure Ada alternative?


No not really. One way of doing it is to define an exception...

   Quit_Program : Exception;


then have a handler at the main program level....

   exception 
      when Quit_Program => null;
   end;


Before you do that you can call Ada.Command_Line.Set_Exit_Status.


Dale

Re: How do I end the program?

[Simon Wright]

dale <dale@cs.rmit.edu.au> writes:

> starner@okstate.edu wrote:
> 
> > How do I exit the program? It may seem like a silly question, but I'm
> > trying to exit from a function called from a callback written in C, so I
> > can't just return or raise an exception. glutMainLoop never returns, so
> > I can't run off the end of the main function. I used
> > GNAT.OS_Lib.OS_Exit. Is there a pure Ada alternative?
> 
> 
> No not really. One way of doing it is to define an exception...

There has been at least one thread on this on cla; it's particularly
interesting when you have tasks you don't know about. The general idea
is to abort the environment task.

Re: How do I end the program?

[Dmitriy Anisimkov]

> > GNAT.OS_Lib.OS_Exit. Is there a pure Ada alternative?
>
> No not really. One way of doing it is to define an exception...
>
>    Quit_Program : Exception;
>
> then have a handler at the main program level....
>
>    exception
>       when Quit_Program => null;
>    end;
>
> Before you do that you can call Ada.Command_Line.Set_Exit_Status.

You could not terminate programm this way from task.
But the GNAT.OS_Lib.OS_Exit could.

Re: How do I end the program?

[David C. Hoos]

If you don't want to use a compiler-specific solution,
you can always do a Pragma Import of the exit function from the
C library.

----- Original Message ----- 
From: "David Starner" <dvdeug@x8b4e53cd.dhcp.okstate.edu>
Newsgroups: comp.lang.ada
To: <comp.lang.ada@ada.eu.org>
Sent: Monday, February 04, 2002 5:15 PM
Subject: How do I end the program?


> How do I exit the program? It may seem like a silly question, but I'm
> trying to exit from a function called from a callback written in C, so I
> can't just return or raise an exception. glutMainLoop never returns, so
> I can't run off the end of the main function. I used
> GNAT.OS_Lib.OS_Exit. Is there a pure Ada alternative?
> 
> -- 
> David Starner - starner@okstate.edu, dvdeug/jabber.com (Jabber)
> Pointless website: http://dvdeug.dhis.org
> What we've got is a blue-light special on truth. It's the hottest thing 
> with the youth. -- Information Society, "Peace and Love, Inc."
> _______________________________________________
> comp.lang.ada mailing list
> comp.lang.ada@ada.eu.org
> http://ada.eu.org/mailman/listinfo/comp.lang.ada
> 

Re: How do I end the program?

[Stephen Leake]

David Starner <dvdeug@x8b4e53cd.dhcp.okstate.edu> writes:

> How do I exit the program? It may seem like a silly question, but I'm
> trying to exit from a function called from a callback written in C, so I
> can't just return or raise an exception. glutMainLoop never returns, so
> I can't run off the end of the main function. I used
> GNAT.OS_Lib.OS_Exit. Is there a pure Ada alternative?

To exit cleanly, you need to tell the top level application to exit.
There should be a return value, or out parameter, or global variable
that says "give up and exit, please".

-- 
-- Stephe

Re: How do I end the program?

[Steve Doiel]

Yes, but it isn't pretty.

Take a look at the module: Ada.Task_Identification.

In the main procedure of your program, before entering glutMainLoop save off
the task ID of the environment task.

  env_task_id := Ada.Task_Identification.Current_Task;

When you want to kill the program call:

  Ada.Task_Identification.Abort_Task( env_task_id );

When you kill the environment task, all subordinate tasks are terminated as
well.

With GNAT 3.14p, I get the message:
  Execution terminated by abort of environment task

On the console window of my test program.

SteveD

"David Starner" <dvdeug@x8b4e53cd.dhcp.okstate.edu> wrote in message
news:a3n4mj$9qe1@news.cis.okstate.edu...
> How do I exit the program? It may seem like a silly question, but I'm
> trying to exit from a function called from a callback written in C, so I
> can't just return or raise an exception. glutMainLoop never returns, so
> I can't run off the end of the main function. I used
> GNAT.OS_Lib.OS_Exit. Is there a pure Ada alternative?
>
> --
> David Starner - starner@okstate.edu, dvdeug/jabber.com (Jabber)
> Pointless website: http://dvdeug.dhis.org
> What we've got is a blue-light special on truth. It's the hottest thing
> with the youth. -- Information Society, "Peace and Love, Inc."

Re: How do I end the program?

[Dale Stanbrough]

Steve Doiel wrote:

> In the main procedure of your program, before entering glutMainLoop save off
> the task ID of the environment task.
> 
>   env_task_id := Ada.Task_Identification.Current_Task;
> 
> When you want to kill the program call:
> 
>   Ada.Task_Identification.Abort_Task( env_task_id );
> 
> When you kill the environment task, all subordinate tasks are terminated as
> well.
> 
> With GNAT 3.14p, I get the message:
>   Execution terminated by abort of environment task
> 
> On the console window of my test program.

Well, i'm not sure that would work. What if one of the tasks is 
a library level task, i.e. declared and elaborated in a library
level package? I'm not sure that there is a "parent" task in that
case.


Dale

Re: How do I end the program?

[Martin Dowie]

> > In the main procedure of your program, before entering glutMainLoop save
off
> > the task ID of the environment task.
> >
> >   env_task_id := Ada.Task_Identification.Current_Task;
> >
> > When you want to kill the program call:
> >
> >   Ada.Task_Identification.Abort_Task( env_task_id );
> >
> > When you kill the environment task, all subordinate tasks are terminated
as
> > well.
> >
> > With GNAT 3.14p, I get the message:
> >   Execution terminated by abort of environment task
> >
> > On the console window of my test program.
>
> Well, i'm not sure that would work. What if one of the tasks is
> a library level task, i.e. declared and elaborated in a library
> level package? I'm not sure that there is a "parent" task in that
> case.

This was covered circa nov/dec 2000 and the above solution was
proposed with the slight twist of "env_task_id" being a package
level variable assigned during elaboration. The rationale then
was that all elaboration occurs within the scope of the environment
task.

Can't remember who put forward the example - I have a feeling they
had a french sounding name though! :-)

Re: How do I end the program?

[Robert A Duff]

Dale Stanbrough <dstanbro@bigpond.net.au> writes:

> Well, i'm not sure that would work. What if one of the tasks is 
> a library level task, i.e. declared and elaborated in a library
> level package? I'm not sure that there is a "parent" task in that
> case.

There was some confusion about this in Ada 83, but in Ada 95,
the library-package tasks depend on the environment task,
so aborting the env task aborts all other tasks, too.
(I believe that was the original intent of Ada 83, too,
but there was some confusing wording in the RM.)

- Bob