Re: Ada-kernel calls / IF & ELSE...

["Vadim Godunko" <vgodunko@vipmail.ru>]

You MUST append ASCII.Nul if you pass any string parameters direct to
imported C routines.
For passing strings to C routines better use Interfaces.C.char_array type.
In package Interfaces.C you may found needed String<=>char_array conversion
routines, that automaticaly append/remove ASCII.Nul at the end of strings.
And, in you case, may be used standard Ada-POSIX bindings, that have open,
close, read, write,... functions.
This bindings for GNAT called Florist.

Regards,
Vadim

----- Original Message -----
From: "Karl Ran" <karlran1234@yahoo.com>
Newsgroups: comp.lang.ada
Sent: Monday, March 11, 2002 10:42 PM
Subject: Ada-kernel calls / IF & ELSE...


> Hi,
> I'm just starting to understand how to make Ada-kernel calls...
>
> Has anyone compiled the Kernel Calls demo on
> http://www.vaxxine.com/pegasoft/homes/13.html#13.5.4
> ?
>
> Here is a much simpler version:
>
> -----------------------------------------------------
> with Ada.Text_IO; use Ada.Text_IO;
>
> procedure audiocd is
>
>   DevCDROM : constant string := "/dev/cdrom";
>
>   type aFileID is new integer;
>
>   procedure open( id : out aFileID;
>                   path : string;
>                   flags : integer );
>
>   pragma import( C, open, "open");
>   pragma import_valued_procedure( open );
>
>   procedure perror( prefixstr : string );
>   pragma import( C, perror, "perror");
>
>   cd : aFileID;
>
> begin
>
>   Put_Line( "Openning " & DevCDROM & "..." );
>   Open( cd, DevCDROM, 0 );
>
>   if cd < 0 then
>      perror( "IF: Error openning CDROM drive " );
>   else
>      Put_Line( "ELSE: opened CDROM drive successfully " );
>   end if;
>
> end audiocd;
> -----------------------------------------------------
>
> >gnatmake -gnatwa audiocd.adb
> gcc -c -gnatwa audiocd.adb
> gnatbind -x audiocd.ali
> gnatlink audiocd.ali
>
> >./audiocd
> Openning /dev/cdrom...
> IF: Error openning CDROM drive ELSE: opened CDROM drive successfully :
> No such file or directory
>
>
> Would someone please explain whats going on here?
>
> Is this just because of my bleeding-edge-suse71-gnat3.14p-unsupported
> system or is normal?
>
>
> Karl