Article: Q155133
Product(s): Microsoft C Compiler
Version(s): 4.2,5.0,6.0
Operating System(s):
Keyword(s): kbcode kbwizard kbMFC kbVC420 kbVC500 kbVC600 kbWinsock kbClassWizard kbGrpDSMFCATL
Last Modified: 17-APR-2002
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The information in this article applies to:
- The Microsoft Foundation Classes (MFC), used with:
- Microsoft Visual C++, 32-bit Enterprise Edition, versions 4.2, 5.0, 6.0
- Microsoft Visual C++, 32-bit Professional Edition, versions 4.2, 5.0, 6.0
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0
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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:
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Keywords : kbcode kbwizard kbMFC kbVC420 kbVC500 kbVC600 kbWinsock kbClassWizard kbGrpDSMFCATL
Technology : kbAudDeveloper kbMFC
Version : :4.2,5.0,6.0
Issue type : kbprb
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