[Linux, SDL_bgi 2.6.0] Error while linking: undefined reference to 'xkbhit'

[rchastain]

Hello! Congratulations for this very nice project.

I installed on Linux SDL_bgi 2.6.0. When I try to compile an example from ubgi, I get this error:

[roland@localhost examples (master)]$ fpc -B -Fu.. exus.pas
Free Pascal Compiler version 3.2.0 [2020/07/05] for x86_64
Copyright (c) 1993-2020 by Florian Klaempfl and others
Target OS: Linux for x86-64
Compiling exus.pas
exus.pas(3,2) Note: APPTYPE is not supported by the target OS
Compiling /home/roland/Documents/pascal/sources/ubgi/ubgi.pas
Linking exus
/usr/bin/ld : /home/roland/Documents/pascal/sources/ubgi/ubgi.o : dans la fonction « UBGI_$$_KEYPRESSED$$BOOLEAN » :
ubgi.pas:(.text.n_ubgi_$$_keypressed$$boolean+0xa) : référence indéfinie vers « kbhit »
Error: Error while linking
Fatal: There were 1 errors compiling module, stopping
Fatal: Compilation aborted
Error: /usr/bin/ppcx64 returned an error exitcode

After taking a look into ubgi.pas, I tried this.

function KeyPressed(): Boolean;
begin
{$IFDEF LINUX}
  Result := XKbHit() <> 0;
{$ELSE}
  Result := KbHit() <> 0;
{$ENDIF}
end;

With that modification, I can compile the example. (But I understood later that it wasn't the correct solution. See correct solution below.)

[rchastain]

After I installed SDL_bgi 3.0.0.

With the original ubgi unit, I get the error undefined reference to kbhit. With the modified ubgi, I get undefined reference to xkbhit!

I don't know why my patch doesn't work with that version of the library.

[rchastain]

Solution for SDL_bgi 3.0.0:

(*
  Returns 1 when a key is pressed, excluding special keys
  (Ctrl, Shift, etc.); in 'slow mode', a screen refresh is performed.
  If an SDL_QUIT event occurs, QUIT is returned.
*)
function KbHit(): Integer;
  cdecl; external LIB_UBGI name LIB_FNPFX + 'k_bhit';//'kbhit';

(*
  Returns 1 when any key is pressed, including special keys
  (Ctrl, Shift, etc.) in 'slow mode', a screen refresh is performed.
  If an SDL QUIT event occurs, QUIT is returned.
*)
function XKbHit(): Integer;
  cdecl; external LIB_UBGI name LIB_FNPFX + 'xkb_hit';//'xkbhit';

{ ... }

function KeyPressed(): Boolean;
begin
//{$IFDEF LINUX}
//  Result := XKbHit() <> 0;
//{$ELSE}
  Result := KbHit() <> 0;
//{$ENDIF}
end;

[rchastain]

For 2.6.0, the solution was:

function KbHit(): Integer;
  cdecl; external LIB_UBGI name LIB_FNPFX + 'bgi_kbhit';//'kbhit';

{ ... }

function KeyPressed(): Boolean;
begin
//{$IFDEF LINUX}
//  Result := XKbHit() <> 0;
//{$ELSE}
  Result := KbHit() <> 0;
//{$ENDIF}
end;

[rchastain]

Pull request.