delphi - How to view output of OutputDebugString?

Question

I want to use OutputDebugString() in my application and then have the option to show it in a separate viewer when the application is deployed in the field.

That is to say, I don't want to have to change a flag and rebuild my .exe to turn debugging on and off.

Googling around, it seems like DebugView should handle that, but neither it, nor TraceTool show any output from this code.

unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type
  TForm1 = class(TForm)
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}


procedure TForm1.FormCreate(Sender: TObject);
begin
   OutputDebugString(PChar('Hello, wurld'));
end;

end.

I have read the documentation, to no avail, and see that others have had similar problems, but have not posted a solution.

Is there a solution?

Answer 1

The DebugView tool works fine; only be sure to launch your application directly (without the Delphi IDE or another debugger attached).

Anyway, the natural way to view the OutputDebugString output for a Delphi application is to use the Delphi IDE and the Event Log Window.