Here it is. It is plainfully simple. Just use it as follows. Place it in the uses clause in the unit where you want to use it.

   uses udebug;

Then someplace in the unit just turn on debug output with.

   Debug.DebugOn := True;

Now any place you have the text

   Debug.Write('my message');

you will get that output. As I stated if you want it to go to a log file then add

   Debug.LogFile := 'mylogfile.log';

The rest takes care of itself.

+++++++++++++++++++++++++++++++++++++++++++++
unit udebug;
{$mode delphi}
interface
uses sysutils;
type
   TDebug = class
   private
      { Private declarations }
      fLogFileName : string;
      fState : Boolean;
   public
      { Public declarations }
      constructor Create;
      procedure Write(message : string);
      property LogFile : String read fLogFileName write fLogFileName;
      property DebugOn : Boolean read fState write fState;
   end;
var
   Debug : TDebug;
implementation
constructor TDebug.Create;
begin
   fLogFileName := '';
   fState := False;   { False is off - True is on }
end;
procedure TDebug.Write(message : string);
var
   fileH  : Text;
begin
   if fState then
   begin
      Assign(fileH, fLogFileName);
      {$I-}
      if fLogFileName  '' then
         if FileExists(fLogFileName) = False then
	 begin
	    Rewrite(fileH);
	    Close(fileH);
	 end;
      Append(fileH);
      if ioresult = 0 then
         Writeln(fileH, message);
      {$I+}
      Close(fileH);
   end;
end;
initialization
   Debug := TDebug.Create;
finalization
   Debug.Free;
end.