Terminal Control (or System calls), unix

Terminal Control (or System calls), unix

[Sven E. Anderson]

I am attempting to write a simple screen editor with Ada95 and would
like to suppress the tty echo (unix/linux).  A very simple solution
would be a system call to "stty -echo cbreak".  How might I make such
a call in Ada?

I take it that Ada does not have the equivalent of C's curses package.

-sven
anderson@cs.und.edu

Re: Terminal Control (or System calls), unix

[dennison]

In article <3703F011.1DBB143C@cs.und.edu>,
  "Sven E. Anderson" <anderson@cs.und.edu> wrote:
> I am attempting to write a simple screen editor with Ada95 and would
> like to suppress the tty echo (unix/linux).  A very simple solution
> would be a system call to "stty -echo cbreak".  How might I make such
> a call in Ada?

If its a system call, you should be able to make it from Ada. However I think
stty is typically a shell builtin, isn't it?


> I take it that Ada does not have the equivalent of C's curses package.

If your platform has curses, you should be able to write bindings to the
curses functions you want to use and link in libcurses.a. The curses routines
are just library calls that can be made from any language that knows how to
link to them. It just happens that most people use C to do that, but it
doesn't have to be that way.

T.E.D.

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Re: Terminal Control (or System calls), unix

[Jerry van Dijk]

dennison@telepath.com wrote:

: In article <3703F011.1DBB143C@cs.und.edu>,
:   "Sven E. Anderson" <anderson@cs.und.edu> wrote:

(note I careful I am about the attributions :-)

: > I am attempting to write a simple screen editor with Ada95 and would
: > like to suppress the tty echo (unix/linux).  A very simple solution
: > would be a system call to "stty -echo cbreak".  How might I make such
: > a call in Ada?

: If its a system call, you should be able to make it from Ada. However I think
: stty is typically a shell builtin, isn't it?

That does not matter, on Linux, you could use something like:

	with System;

	procedure No_Echo is

	   type Echo_Type is (On, Off);

	   procedure Set_Echo (Echo : in Echo_Type) is
   
	      procedure Execute (S : in String) is
	         procedure System (S : in System.Address);
	         pragma Import (C, System, "system");
	         C_String : constant String := S & ASCII.NUL;
	      begin
	         System (C_String'Address);
	      end Execute;
	      pragma Inline (Execute);
      
	   begin
	      if Echo = On then
	         Execute ("stty -echo cbreak");
	      else
	         Execute ("stty echo");
	      end if;
	   end Set_Echo;
   
	begin
	   null;
	end No_Echo;

--
-- Jerry van Dijk | Leiden, Holland
-- Team Ada       | jdijk@acm.org
-- see http://stad.dsl.nl/~jvandyk

Re: Terminal Control (or System calls), unix

[dennison]

In article <F9LA0u.4w@jvdsys.stuyts.nl>,
  jerry@jvdsys.stuyts.nl (Jerry van Dijk) wrote:
> dennison@telepath.com wrote:
>
> : In article <3703F011.1DBB143C@cs.und.edu>,
> :   "Sven E. Anderson" <anderson@cs.und.edu> wrote:
>
> (note I careful I am about the attributions :-)

Appreciated. :-)

>
> : If its a system call, you should be able to make it from Ada. However I
think
> : stty is typically a shell builtin, isn't it?
>
> That does not matter, on Linux, you could use something like:
>
> 	      procedure Execute (S : in String) is
> 	         procedure System (S : in System.Address);
> 	         pragma Import (C, System, "system");
> 	         C_String : constant String := S & ASCII.NUL;
> 	      begin
> 	         System (C_String'Address);
> 	      end Execute;

I suppose. But don't you have to worry that the person executing your program
might have a default shell on which stty behaves differently (or does not
exist)?

T.E.D.

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Re: Terminal Control (or System calls), unix

[dennison]

In article <7eaf43$mk2$1@nnrp1.dejanews.com>,
  dennison@telepath.com wrote:
> In article <F9LA0u.4w@jvdsys.stuyts.nl>,
>   jerry@jvdsys.stuyts.nl (Jerry van Dijk) wrote:
> > dennison@telepath.com wrote:
> >

> > : If its a system call, you should be able to make it from Ada. However I
> think
> > : stty is typically a shell builtin, isn't it?
> >
> > That does not matter, on Linux, you could use something like:
>
> I suppose. But don't you have to worry that the person executing your program
> might have a default shell on which stty behaves differently (or does not
> exist)?

OK. I just went and checked. For the two unixes I tried (AIX 4.2 and SunOS
5.3) stty is *not* a shell builtin; it is a command. So Ted, you're an idiot.
(Wow, flaming me is fun. No wonder so many do it. :-)

Also, it appears stty changes apply to a parent shell when I invoke it from a
child shell, so I suspect the "system" call method would do the trick.

However, since the original poster seemed to really want "curses"
functionality, I'd suggest they go ahead and use curses to aviod frustration
on further functionalty during the rest of the implementation process. If
they only need a few curses functions, writing a small number of "thick"
bindings by hand is really no trouble. If they want a lot, there are thin
bindings (and thin binding generators) out there.



T.E.D.

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Re: Terminal Control (or System calls), unix

[Tarjei Tj�stheim Jensen]

dennison@telepath.com wrote:

> > I suppose. But don't you have to worry that the person executing your program
> > might have a default shell on which stty behaves differently (or does not
> > exist)?
>
> OK. I just went and checked. For the two unixes I tried (AIX 4.2 and SunOS
> 5.3) stty is *not* a shell builtin; it is a command. So Ted, you're an idiot.
> (Wow, flaming me is fun. No wonder so many do it. :-)
>
> Also, it appears stty changes apply to a parent shell when I invoke it from a
> child shell, so I suspect the "system" call method would do the trick.

There are portable ways of doing this without invoking a separate program. There
are a couple of Posix calls to do this. The easiest way of finding out how to do
this is to look up the metods in various Perl FAQs. That is where I found the
answer to it last time I looked (or was it the Perl book).

Use the Posix interface so that context can be saved and restored easily without
depending on the arcane syntax of stty.


Greetings,

Re: Terminal Control (or System calls), unix

[Thomas Handler]

Sven,


Sven E. Anderson wrote:
> 
> 
> I take it that Ada does not have the equivalent of C's curses package.
> 
I guess you're not right on this one. As far as I remember J. Pfeiffer
made an Ada binding for ncurses that is distributed as part of all newer
ncurses versions. You might take a look at this one since it comes with
two or three examples that show you how to use it.

Thomas Handler