PRB: ClassWizard Doesn't Bring in Proper Header File

• The Microsoft Foundation Classes (MFC), included with:
  • Microsoft Visual C++, 32-bit Editions, versions 4.2, 5.0, 6.0

SYMPTOMS

After creating a new class derived from either CSocket or CAsyncSocket using the ClassWizard, one of the following errors occur during compilation:

   error C2504: 'CSocket' : base class undefined
   error C2504: 'CAsyncSocket' : base class undefined 

CAUSE

ClassWizard allows you to derive a class directly from CSocket or CAsyncSocket; however, it does not pull in the required header file where these classes are declared. Therefore, the compiler displays an error message reflecting that CSocket or CAsyncSocket was not defined.

RESOLUTION

Include the header file, afxsock.h, into your project, preferably in your project's StdAfx.h header file:

     ...
     #include <afxsock.h>  //MFC support for Sockets
     ... 

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

The header file, afxsock.h, contains the class definitions for CAsyncSocket and CSocket. If you are using these classes or any classes that are derived from these classes, you must make sure to include afxsock.h in your project. Also note that if you use AppWizard to start your project and select the Socket Support option on the fourth page of the wizard, you will automatically get afxsock.h inserted into your StdAfx.h file. In addition, you will get the function call, AfxSocketInit(), inserted into your project. This is very important because you must make a call to AfxSocketInit() if you want to use Sockets in your MFC application. This function is usually called from your InitInstance() method of your CWinApp derived object.

   BOOL CMyApp::InitInstance()
   {

        if (!AfxSocketInit())
        {
             AfxMessageBox("Socket Initialization Failed");
             return FALSE;
        }

        ...
   } 

Additional query words:

Keywords : kbcode kbMFC kbVC kbVC420 kbVC500 kbVC600 kbWinsock
Version : 4.2 5.0 6.0
Platform : NT WINDOWS
Issue type : kbprb