hello world ada-ncurses new_window

hello world ada-ncurses new_window

[Alain De Vos]

Creating a window in ada-ncurses raises an exception :

Code,

with Terminal_Interface.Curses; 
use  Terminal_Interface.Curses;
....
with Ada.Exceptions; 
use  Ada.Exceptions;
with GNAT.OS_Lib;
use GNAT.OS_Lib;
with Text_IO;
use Text_IO;
with Ada.Text_IO;
use Ada.Text_IO;

procedure test01 is
begin
   W1 := New_Window (5,5,1,1);
   Delete (W1);
exception
      when Event : others =>
         Terminal_Interface.Curses.End_Windows;
         Text_IO.Put ("Exception: ");
         Text_IO.Put (Exception_Name (Event));
         Text_IO.New_Line;
         GNAT.OS_Lib.OS_Exit (1);
end test01;

Exception:
raised TERMINAL_INTERFACE.CURSES.CURSES_EXCEPTION : terminal_interface-curses.adb:117

Re: hello world ada-ncurses new_window

[J-P. Rosen]

Le 07/11/2019 à 23:05, Alain De Vos a écrit :
>          GNAT.OS_Lib.OS_Exit (1);
Package Ada.Command_Line has a procedure Set_Exit_Status. It's always
better to use standard subprograms, Ada is for portability after all!

-- 
J-P. Rosen
Adalog
2 rue du Docteur Lombard, 92441 Issy-les-Moulineaux CEDEX
Tel: +33 1 45 29 21 52, Fax: +33 1 45 29 25 00
http://www.adalog.fr

Re: hello world ada-ncurses new_window

[Simon Wright]

Alain De Vos <devosalain71@gmail.com> writes:

> Exception:
> raised TERMINAL_INTERFACE.CURSES.CURSES_EXCEPTION : terminal_interface-curses.adb:117

If you compile with -g (enable debug) and run under the debugger (start
by saying "catch exception") you will find that the first exception is
actually raised at terminal_interface-curses.adb:248, in Create:

      W := Newwin (C_Int (Number_Of_Lines),
                   C_Int (Number_Of_Columns),
                   C_Int (First_Line_Position),
                   C_Int (First_Column_Position));
      if W = Null_Window then
         raise Curses_Exception;
      end if;

A couple of points:

About the library: it'd have been easier on us if you'd said

         raise Curses_Exception with "Create: unable to create window";

About your code: when you're starting off with an experiment, why bother
to catch exceptions and report them in a way that masks any attempt by
the library writer to help you solve problems? Just let the exception
happen. With any luck you'll get a stack trace that'll quickly lead you
to the immediate cause of the problem.
In your case, the exception happened at
terminal_interface-curses.adb:117, in End_Windows:

      if Endwin = Curses_Err then
         raise Curses_Exception;
      end if;

and End_Windows was called from your exception handler! doubly masking
the reason for the exception.

====

As to why you're getting this problem, I don't know at all. Perhaps you
need to initialize ncurses? -- just guessing.

Re: hello world ada-ncurses new_window

[Simon Wright]

Simon Wright <simon@pushface.org> writes:

> About the library: it'd have been easier on us if you'd said

I meant, if the library author had said

Re: hello world ada-ncurses new_window

[Alain De Vos]

On Friday, November 8, 2019 at 2:20:00 PM UTC+1, Simon Wright wrote:
> Simon Wright <simon@pushface.org> writes:
> 
> > About the library: it'd have been easier on us if you'd said
> 
> I meant, if the library author had said

It seemed I just needed :
Init_Screen;
That was easy.

However , writing a program with just one input text form seems impossible for me.

Maybe I mus stick to Ada.Text_IO.Get_Line;

Re: hello world ada-ncurses new_window

[Dmitry A. Kazakov]

On 2019-11-09 12:25, Alain De Vos wrote:
> On Friday, November 8, 2019 at 2:20:00 PM UTC+1, Simon Wright wrote:
>> Simon Wright <simon@pushface.org> writes:
>>
>>> About the library: it'd have been easier on us if you'd said
>>
>> I meant, if the library author had said
> 
> It seemed I just needed :
> Init_Screen;
> That was easy.
> 
> However , writing a program with just one input text form seems impossible for me.
> 
> Maybe I mus stick to Ada.Text_IO.Get_Line;

Terminal interface curses [you]. Sorry, could not resist.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de