procedure OpenLogFile(var f: TextFile; FileName: string);
begin
  Assign(f, FileName);
  {$I-}
  Append(f);
  {$I+}
  if IOREsult<>0 then 
    Rewrite(f);
end;
// contoh seting global
var LogFileName: string = 'C:\debug.log';
  
procedure WriteLog(s: string);
var f: TextFile;
    d: TDateTime;
    s2: string;
begin
  try
    d:=Now;
    s2:=FormatDateTime('yyyy-mm-dd hh:nn:ss; ',d);
    OpenLogFile(f, LogFileName);
    try
      Writeln(f, s2 + s);
    finally
      CloseFile(f);
    end;
  except
  end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Application.OnException:= AppException;
end;
procedure TForm1.AppException(Sender: TObject; E: Exception) ;
begin
  WriteLog(E.Message);
end;

@em052007: user "delphiexpert", saya sudah mencoba coding diatas dan berhasil dijalankan. Itu kan hanya menampilkan tanggal dan jenis errornya. Nah kalau saya ingin menampilkan di file log itu informasi, di form yang mana error itu terjadi ? bagaimana caranya ? dan menyimpan file log tersebut pada path yang sama dengan file exe-nya (program aplikasinya). Saya sangat mengharapkan bantuannya. terima kasih.

procedure TForm1.AppException(Sender: TObject; E: Exception) ;
begin
  WriteLog(Name+': '+ E.Message);
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  LogFileName:=ExtractFilePath(Application.ExeName)+'debug.log';
  Application.OnException:= AppException;
end;

procedure OpenLogFile(var f: TextFile; FileName: string);
begin
  Assign(f, FileName);
  {$I-}
  Append(f);
  {$I+}
  if IOREsult<>0 then 
    Rewrite(f);
end;
 
// contoh seting global
var LogFileName: string;
  
procedure WriteLog(s: string);
var f: TextFile;
    d: TDateTime;
    s2: string;
begin
  try
    d:=Now;
    s2:=FormatDateTime('yyyy-mm-dd hh:nn:ss; ',d);
    OpenLogFile(f, LogFileName);
    try
      Writeln(f, s2 + s);
    finally
      CloseFile(f);
    end;
  except
  end;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
  LogFileName:=ExtractFilePath(Application.ExeName)+'debug.log';
  Application.OnException:= AppException;
end;
 
procedure TForm1.AppException(Sender: TObject; E: Exception) ;
begin
  WriteLog(Name+': '+ E.Message); // u/ informasi lain yg di butuhkan tambahkan pada parameter
end;