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On Windows 8.1 I want to port an Ada 2012 program in Julia 1.0. This program interacts with the keyboard and the Console through the system library user32.

In Ada for exemple the importation of _kbhit is successfully made on the same computer through the instructions :

pragma Linker_Options ("-luser32");
function Kbhit return Integer;
pragma Import (C, Kbhit, "_kbhit");

In Julia 1.0 the invocation of _kbhit should be done through (if I am not wrong, as I am a Julia beginner) :

t = ccall((:_kbhit, "C:/Windows/System32/user32.dll"), Int32,())

But I get the following error :

ERROR: LoadError: ccall: could not find function _kbhit in library C:/Windows/System32/user32.dll

I tried unsuccessfully several other ways to define the library path.

dlopen("user32") failed also.

So the question is : what am I doing wrong with Julia ?

Here the body of the Ada package which imports the C functions to interface with Console and keyboard :

pragma C_Pass_By_Copy (128);

with Interfaces; use Interfaces;
with Text_IO;    use Text_IO;
--with Text_IO.Integer_IO;    use Text_IO.Integer_IO;
with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
package body Nt_Console is

   pragma Linker_Options ("-luser32");

   ---------------------
   -- WIN32 INTERFACE --
   ---------------------

   Beep_Error : exception;
   Fill_Char_Error : exception;
   Cursor_Get_Error : exception;
   Cursor_Set_Error : exception;
   Cursor_Pos_Error : exception;
   Buffer_Info_Error : exception;
   Set_Attribute_Error : exception;
   Invalid_Handle_Error : exception;
   Fill_Attribute_Error : exception;
   Cursor_Position_Error : exception;

   subtype Dword is Unsigned_32;
   subtype Handle is Unsigned_32;
   subtype Word is Unsigned_16;
   subtype Short is Short_Integer;
   subtype Winbool is Integer;

   type Lpdword is access all Dword;
   pragma Convention (C, Lpdword);

   type Nibble is mod 2 ** 4;
   for Nibble'Size use 4;

   type Attribute is record
      Foreground : Nibble;
      Background : Nibble;
      Reserved   : Unsigned_8 := 0;
   end record;

   for Attribute use record
      Foreground at 0 range 0 .. 3;
      Background at 0 range 4 .. 7;
      Reserved   at 1 range 0 .. 7;
   end record;

   for Attribute'Size use 16;
   pragma Convention (C, Attribute);

   type Coord is record
      X : Short;
      Y : Short;
   end record;
   pragma Convention (C, Coord);

   type Small_Rect is record
      Left   : Short;
      Top    : Short;
      Right  : Short;
      Bottom : Short;
   end record;
   pragma Convention (C, Small_Rect);

   type Console_Screen_Buffer_Info is record
      Size       : Coord;
      Cursor_Pos : Coord;
      Attrib     : Attribute;
      Window     : Small_Rect;
      Max_Size   : Coord;
   end record;
   pragma Convention (C, Console_Screen_Buffer_Info);

   type Pconsole_Screen_Buffer_Info is access all Console_Screen_Buffer_Info;
   pragma Convention (C, Pconsole_Screen_Buffer_Info);

   type Console_Cursor_Info is record
      Size    : Dword;
      Visible : Winbool;
   end record;
   pragma Convention (C, Console_Cursor_Info);

   type Pconsole_Cursor_Info is access all Console_Cursor_Info;
   pragma Convention (C, Pconsole_Cursor_Info);

   function Getch return Integer;
   pragma Import (C, Getch, "_getch");

   function Kbhit return Integer;
   pragma Import (C, Kbhit, "_kbhit");

   function Messagebeep (Kind : Dword) return Dword;
   pragma Import (Stdcall, Messagebeep, "MessageBeep");

   function Getstdhandle (Value : Dword) return Handle;
   pragma Import (Stdcall, Getstdhandle, "GetStdHandle");

   function Getconsolecursorinfo
     (Buffer : Handle;
      Cursor : Pconsole_Cursor_Info)
      return   Winbool;
   pragma Import (Stdcall, Getconsolecursorinfo, "GetConsoleCursorInfo");

   function Setconsolecursorinfo
     (Buffer : Handle;
      Cursor : Pconsole_Cursor_Info)
      return   Winbool;
   pragma Import (Stdcall, Setconsolecursorinfo, "SetConsoleCursorInfo");

   function Setconsolecursorposition
     (Buffer : Handle;
      Pos    : Coord)
      return   Dword;
   pragma Import
     (Stdcall,
      Setconsolecursorposition,
      "SetConsoleCursorPosition");

   function Setconsoletextattribute
     (Buffer : Handle;
      Attr   : Attribute)
      return   Dword;
   pragma Import
     (Stdcall,
      Setconsoletextattribute,
      "SetConsoleTextAttribute");

   function Getconsolescreenbufferinfo
     (Buffer : Handle;
      Info   : Pconsole_Screen_Buffer_Info)
      return   Dword;
   pragma Import
     (Stdcall,
      Getconsolescreenbufferinfo,
      "GetConsoleScreenBufferInfo");

   function Fillconsoleoutputcharacter
     (Console : Handle;
      Char    : Character;
      Length  : Dword;
      Start   : Coord;
      Written : Lpdword)
      return    Dword;
   pragma Import
     (Stdcall,
      Fillconsoleoutputcharacter,
      "FillConsoleOutputCharacterA");

   function Fillconsoleoutputattribute
     (Console : Handle;
      Attr    : Attribute;
      Length  : Dword;
      Start   : Coord;
      Written : Lpdword)
      return    Dword;
   pragma Import
     (Stdcall,
      Fillconsoleoutputattribute,
      "FillConsoleOutputAttribute");

   Win32_Error          : constant Dword  := 0;
   Invalid_Handle_Value : constant Handle := -1;
   Std_Output_Handle    : constant Dword  := -11;

   Color_Value      : constant array (Color_Type) of Nibble :=
     (0,
      1,
      2,
      3,
      4,
      5,
      6,
      7,
      9,
      10,
      11,
      12,
      13,
      14,
      15);
   Color_Type_Value : constant array (Nibble) of Color_Type :=
     (Black,
      Blue,
      Green,
      Cyan,
      Red,
      Magenta,
      Brown,
      Gray,
      Black,
      Light_Blue,
      Light_Green,
      Light_Cyan,
      Light_Red,
      Light_Magenta,
      Yellow,
      White);

   -----------------------
   -- PACKAGE VARIABLES --
   -----------------------

   Output_Buffer    : Handle;
   Num_Bytes        : aliased Dword;
   Num_Bytes_Access : Lpdword                     := Num_Bytes'Access;
   Buffer_Info_Rec  : aliased Console_Screen_Buffer_Info;
   Buffer_Info      : Pconsole_Screen_Buffer_Info := Buffer_Info_Rec'Access;

   -------------------------
   -- SUPPORTING SERVICES --
   -------------------------
   procedure Get_Buffer_Info is
   begin
      if Getconsolescreenbufferinfo (Output_Buffer, Buffer_Info) =
         Win32_Error
      then
         raise Buffer_Info_Error;
      end if;
   end Get_Buffer_Info;

   --------------------
   -- CURSOR CONTROL --
   --------------------

   function Cursor_Visible return Boolean is
      Cursor : aliased Console_Cursor_Info;
   begin
      if Getconsolecursorinfo (Output_Buffer, Cursor'Unchecked_Access) =
         0
      then
         raise Cursor_Get_Error;
      end if;
      return Cursor.Visible = 1;
   end Cursor_Visible;

   procedure Set_Cursor (Visible : in Boolean) is
      Cursor : aliased Console_Cursor_Info;
   begin
      if Getconsolecursorinfo (Output_Buffer, Cursor'Unchecked_Access) =
         0
      then
         raise Cursor_Get_Error;
      end if;
      if Visible then
         Cursor.Visible := 1;
      else
         Cursor.Visible := 0;
      end if;
      if Setconsolecursorinfo (Output_Buffer, Cursor'Unchecked_Access) =
         0
      then
         raise Cursor_Set_Error;
      end if;
   end Set_Cursor;

   function Where_X return X_Pos is
   begin
      Get_Buffer_Info;
      return X_Pos (Buffer_Info_Rec.Cursor_Pos.X);
   end Where_X;

   function Where_Y return Y_Pos is
   begin
      Get_Buffer_Info;
      return Y_Pos (Buffer_Info_Rec.Cursor_Pos.Y);
   end Where_Y;

   procedure Goto_Xy
     (X : in X_Pos := X_Pos'First;
      Y : in Y_Pos := Y_Pos'First)
   is
      New_Pos : Coord := (Short (X), Short (Y));
   begin
      Get_Buffer_Info;
      if New_Pos.X > Buffer_Info_Rec.Size.X then
         New_Pos.X := Buffer_Info_Rec.Size.X;
      end if;
      if New_Pos.Y > Buffer_Info_Rec.Size.Y then
         New_Pos.Y := Buffer_Info_Rec.Size.Y;
      end if;
      if Setconsolecursorposition (Output_Buffer, New_Pos) =
         Win32_Error
      then
         raise Cursor_Pos_Error;
      end if;
   end Goto_Xy;

   -------------------
   -- COLOR CONTROL --
   -------------------

   function Get_Foreground return Color_Type is
   begin
      Get_Buffer_Info;
      return Color_Type_Value (Buffer_Info_Rec.Attrib.Foreground);
   end Get_Foreground;

   function Get_Background return Color_Type is
   begin
      Get_Buffer_Info;
      return Color_Type_Value (Buffer_Info_Rec.Attrib.Background);
   end Get_Background;

   procedure Set_Foreground (Color : in Color_Type := Gray) is
      Attr : Attribute;
   begin
      Get_Buffer_Info;
      Attr.Foreground := Color_Value (Color);
      Attr.Background := Buffer_Info_Rec.Attrib.Background;
      if Setconsoletextattribute (Output_Buffer, Attr) = Win32_Error then
         raise Set_Attribute_Error;
      end if;
   end Set_Foreground;

   procedure Set_Background (Color : in Color_Type := Black) is
      Attr : Attribute;
   begin
      Get_Buffer_Info;
      Attr.Foreground := Buffer_Info_Rec.Attrib.Foreground;
      Attr.Background := Color_Value (Color);
      if Setconsoletextattribute (Output_Buffer, Attr) = Win32_Error then
         raise Set_Attribute_Error;
      end if;
   end Set_Background;

   --------------------
   -- SCREEN CONTROL --
   --------------------

   procedure screen_dimension is
   begin
      Get_Buffer_Info;
--        wx:=integer(buffer_info_rec.size.x);
--        wy:=integer(buffer_info_rec.size.y);
      wx:=integer(buffer_info_rec.window.right - buffer_info_rec.window.left + 1);
      wy:=integer(buffer_info_rec.window.Bottom - buffer_info_rec.window.top + 1);
   end screen_dimension;

   procedure Clear_Screen (Color : in Color_Type := Black) is
      Length : Dword;
      Attr   : Attribute;
      Home   : constant Coord := (0, 0);
   begin
      Get_Buffer_Info;
      Length          := Dword (Buffer_Info_Rec.Size.X) *
                         Dword (Buffer_Info_Rec.Size.Y);
      Attr.Background := Color_Value (Color);
      Attr.Foreground := Buffer_Info_Rec.Attrib.Foreground;
      if Setconsoletextattribute (Output_Buffer, Attr) = Win32_Error then
         raise Set_Attribute_Error;
      end if;
      if Fillconsoleoutputattribute
            (Output_Buffer,
             Attr,
             Length,
             Home,
             Num_Bytes_Access) =
         Win32_Error
      then
         raise Fill_Attribute_Error;
      end if;
      if Fillconsoleoutputcharacter
            (Output_Buffer,
             ' ',
             Length,
             Home,
             Num_Bytes_Access) =
         Win32_Error
      then
         raise Fill_Char_Error;
      end if;
      if Setconsolecursorposition (Output_Buffer, Home) = Win32_Error then
         raise Cursor_Position_Error;
      end if;
   end Clear_Screen;

   -------------------
   -- SOUND CONTROL --
   -------------------
   procedure Bleep is
   begin
      if Messagebeep (16#FFFFFFFF#) = Win32_Error then
         raise Beep_Error;
      end if;
   end Bleep;

   -------------------
   -- INPUT CONTROL --
   -------------------

   function Get_Key return Character is
      Temp : Integer;
   begin
      Temp := Getch;
      if Temp = 16#00E0# then
         Temp := 0;
      end if;
      return Character'Val (Temp);
   end Get_Key;

   function Key_Available return Boolean is
   begin
      if Kbhit = 0 then
         return False;
      else
         return True;
      end if;
   end Key_Available;

   protected body Screen is

      -------------
      -- Goto_XY --
      -------------

      entry Goto_XY (X : in Integer; Y : Integer) when True is
      begin
         --  Generated stub: replace with real body!
         NT_Console.Goto_XY (X, Y);
         --   raise Program_Error;
      end Goto_XY;

      -----------------
      -- clearscreen --
      -----------------

      entry clearscreen when True is
      begin
         --  Generated stub: replace with real body!
         NT_Console.Clear_Screen;
         --   raise Program_Error;
      end clearscreen;

      entry Ecritcolor
        (X  : Integer;
         Y  : Integer;
         S1 : String;
         S2 : String) when True
      is
      begin
         NT_Console.Goto_XY (X, Y);
         Set_Foreground (Magenta);
         Put (S1);
         Put (S2);
         Set_Foreground (White);
      end Ecritcolor;

      entry Ecrit
        (X  : Integer;
         Y  : Integer;
         S1 : String;
         S2 : String) when True
      is
      begin
         NT_Console.Goto_XY (x, y);
         Put (s1);
         Put (s2);
      end Ecrit;

   end Screen;

begin

   --------------------------
   -- WIN32 INITIALIZATION --
   --------------------------

   Output_Buffer := Getstdhandle (Std_Output_Handle);
   if Output_Buffer = Invalid_Handle_Value then
      raise Invalid_Handle_Error;
   end if;

--     begin
      screen_dimension;
      put(wx);put("   "); put(wy);
   delay 1.0;

end Nt_Console;
Schemer
  • 137
  • 7
  • Is the difference `_khbit` != `Khbit`relevant? I.e. did you try combinations of removing the "_" and the capitalisation? – Yunnosch Aug 23 '18 at 06:11
  • I haven't looked recently, but my recollection is that there's nothing like a kbhit in user32.dll. Pretty sure the Ada import is for a non-C-standard library function. Perhaps Borland or Watcom? It's been a long while, my memory could be faulty. – jwdonahue Aug 23 '18 at 07:04
  • I would add that the user32.dll dependency of the Ada program is not related to the `pragma Import (C, Kbhit, "_kbhit");` line. – jwdonahue Aug 23 '18 at 07:18
  • This is interesting: https://stackoverflow.com/questions/18672923/python-kbhit-problems – jwdonahue Aug 23 '18 at 07:21
  • And so is this: https://stackoverflow.com/questions/983354/how-do-i-make-python-to-wait-for-a-pressed-key – jwdonahue Aug 23 '18 at 07:23
  • With Kbhit instead of _kbhit I get the same kind of error : ERROR: LoadError: ccall: could not find function Kbhit in library C:/Windows/System32/user32.dll – Schemer Aug 23 '18 at 07:24
  • Possible duplicate of [How do I make python to wait for a pressed key](https://stackoverflow.com/questions/983354/how-do-i-make-python-to-wait-for-a-pressed-key) – jwdonahue Aug 23 '18 at 07:24
  • You are right : the user32.dll dependency of the Ada program is not related to the pragma Import (C, Kbhit, "_kbhit"); line. If I comment the line --pragma Linker_Options ("-luser32"); in the Ada program, it compiles and run properly ! But there is no other Linker_Option statement in the Ada Program, so it should be implicit for the GNAT compiler. – Schemer Aug 23 '18 at 07:39
  • I have added in the main message, the code of the body of Ada package which shows all the elements which are imported (and that I should import now in Julia). _kbhit wàs just an example. – Schemer Aug 23 '18 at 07:52
  • _kbhit() is not implemented by user32.dll, it is a C runtime library function in the Microsoft CRT. Many to choose from, consider msvcrt.dll – Hans Passant Aug 23 '18 at 08:58
  • Here we are : ccall((:_getch, "msvcrt.dll ") and ccall((:_kbhit, "msvcrt.dll ") work fine ! Thank you. – Schemer Aug 23 '18 at 09:43
  • I have now to manage to retrieve the size of the Console and to position the cursor ... – Schemer Aug 23 '18 at 09:46
  • Certainly using an interface to Kernel32.dll – Schemer Aug 23 '18 at 10:29

0 Answers0