program ExitProc_Example;
    
     const
       MyExitCode = 123;
    
     var
       OldExitProc : Pointer;
    
       procedure end;
       begin
         WriteLn('This is the end');
    
         case ExitCode of
           2: 
             begin
               WriteLn('file not found');
             end;
    
           MyExitCode:
             begin
               WriteLn('It was deliberately terminated with ', MyExitCode);
             end;
    
           else 
             begin
               WriteLn('Error: ', ExitCode);
             end;
         end;
    
         ExitProc := OldExitProc;
       end;
    
     var
       f : file;
    
     begin
       // Save old ExitProc
       OldExitProc := ExitProc;
    
       // Assign new ExitProc.
       ExitProc := @end ;
    
       // Open a file that doesn't exist
       Assign(f, 'abc.txt');
    
       // This triggers runtime error 2
       Reset(f);
    
       // Terminate with your own exit code
       Halt(MyExitCode);
     end.

var
       a : array[0 .. 3] of byte;
    
     begin
       OldExitProc := ExitProc;
       ExitProc := @end;
    
       // memory field deliberately exceeded
       a[4] := 12;

Halt(123);