I am using C# and VS2010.

When I use OutputDebugString to write debug information, should it show up in the output window? I can see the output from OutputDebugString in DebugView, but I thought I would see it in Visual Studio's Output window. I have looked under Tools->Options->Debugging->General and the output is NOT being redirected to the Immediate window. I have also looked under Tools->Options->Debugging->Output Window and all General Output Settings are set to "On". Finally, I have used the drop-down list in the Output window to specify that Debug messages should appear.

If I change Tools->Options->Debugging->General to redirect the output to the Immediate window, the OutputDebugString messages do not appear in the immediate window.

Here is my entire test program:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Diagnostics;

namespace OutputDebugString
{
  class Program
  {
    [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
    public static extern void OutputDebugString(string message);

    static void Main(string[] args)
    {
      Console.WriteLine("Main - Enter - Console.WriteLine");
      Debug.WriteLine("Main - Enter - Debug.WriteLine");
      OutputDebugString("Main - Enter - OutputDebugString");
      OutputDebugString("Main - Exit - OutputDebugString");
      Debug.WriteLine("Main - Exit - Debug.WriteLine");
      Console.WriteLine("Main - Exit - Console.WriteLine");
    }
  }
}

If I run within the debugger, the Debug.WriteLine output does show up in the output window, but the OutputDebugString output does not.

If I run from a console window, both Debug.WriteLine and OutputDebugString show up in DebugView.

Why doesn't the OutputDebugString output ever show up in the output window?

Ultimately, my intent is not to write a lot of debug output with OutputDebugString, rather I will use System.Diagnostics or NLog or something similar. I am just trying to find out, if I configure a logging platform to write to OutputDebugString, will the output be visible from within the debugger.

Edit: I went back to my original program (not the simple test above) which uses TraceSources and TraceListeners configured via the app.config file. If I configure the trace sources to write to the System.Diagnostics.DefaultTraceListener (which is documented as writing to OutputDebugString), then the trace source output DOES go to the debug window. However, lines that write directly with OutputDebugString (such as in my simple example) DO NOT go to the debug window. Also, if I use a different TraceListener that writes to OutputDebugString (I got one from Ukadc.Diagnostics at codeplex), that output DOES NOT go to the debug window.

Note that I have seen these questions but they did not provide a working solution: here and here