Q199060: PRB: ATL Service Run from the IDE Doesn’t Log Events to Console

Article: Q199060
Product(s): Microsoft C Compiler
Version(s): 2.0,3.0,5.0,6.0
Operating System(s): 
Keyword(s): kbATL200 kbATL210 kbService kbVC500 kbVC600 kbATL300 kbGrpDSMFCATL
Last Modified: 26-JUL-2002

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The information in this article applies to:

- The Microsoft Active Template Library (ATL), versions 2.0, 3.0, included with:
   - Microsoft Visual C++, 32-bit Enterprise Edition, versions 5.0, 6.0 
   - Microsoft Visual C++, 32-bit Professional Edition, versions 5.0, 6.0 
   - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

Using the ATL COM AppWizard to generate an NT service may not produce code that
behaves as expected. When the AppWizard-generated service is started as a local
server, the message strings passed to CServiceModule::LogEvent() are not
displayed to the console. When started as a service, the messages are logged
into the applications' event log.

CAUSE
=====

In the generated code CServiceModule::LogEvent() calls _putts() in to write the
message to stdout, but stdout is not setup by default.

RESOLUTION
==========

To remedy this behavior, the developer should do one of the following:

- Edit CServiceModule::Start() to initialize stdout as desired (that is,
  redirect it either to a console or to a file). The code to do this is in the
  More Information section below.
- Replace _putts() with ATLTRACE().
- Redirecting the output of the application to a file, in a console window. For
  example:

  "MyApp.exe > output.txt" (without the quotation marks)

- In CServiceModule::LogEvent(), remove the "if" statement and _putts()
  statement, so that the output always goes to the application log file.

MORE INFORMATION
================

To correct this problem, the developer should edit CServiceModule::Start() as
follows:

  inline void CServiceModule::Start()
     {
         SERVICE_TABLE_ENTRY st[] =
        {
             { m_szServiceName, _ServiceMain },
             { NULL, NULL }
         };
         if (m_bService && !::StartServiceCtrlDispatcher(st))
         {
             m_bService = FALSE;
         }
         if (m_bService == FALSE)
         {
             // Allocate a new console.
             AllocConsole();
             // Redirect stdout to the console.
             freopen("CONOUT$", "wta+", stdout);
             Run();
             // Free the console.
             FreeConsole();
         }
     }

If the logs should be sent to a file, just redirect stdout to that file, without
allocating/freeing the console.

Steps to Reproduce Behavior
---------------------------

1. Create a new project with ATL COM AppWizard. In step 1, specify Server Type
  as Service(EXE).

2. Build the project.

3. Execute the project either from the command line or from the IDE.

  Notice that the message "Service started" does not appear anywhere.

4. Make the changes outlined in the first resoultion.

5. Build and run.

  You'll notice a new console displaying the message "Service started."

Additional query words:

======================================================================
Keywords          : kbATL200 kbATL210 kbService kbVC500 kbVC600 kbATL300 kbGrpDSMFCATL 
Technology        : kbVCsearch kbAudDeveloper kbATLsearch
Version           : :2.0,3.0,5.0,6.0
Issue type        : kbprb

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