PRB: Assertion Failed: WINAPP.CPP, APPCORE.CPP, or WINMAIN.CPP (85496)


The information in this article applies to:

  • The Microsoft Foundation Classes (MFC), when used with:
    • Microsoft Visual C++ for Windows, 16-bit edition 1.0
    • Microsoft Visual C++ for Windows, 16-bit edition 1.5
    • Microsoft Visual C++, 32-bit Editions 1.0
    • Microsoft Visual C++, 32-bit Editions 2.0
    • Microsoft Visual C++, 32-bit Editions 2.1
    • Microsoft Visual C++, 32-bit Editions 4.0
This article was previously published under Q85496

SYMPTOMS

Running a Microsoft Foundation Classes (MFC) application developed with Microsoft C/C++ version 7.0 or Visual C++ for Windows may cause one of the following error messages to be displayed:
Assertion failed - <unknown application>:File winapp.cpp, Line 258
-or-
Assertion failed - <unknown application>:File appcore.cpp, Line 602
Running a MFC application developed with Visual C++, 32-bit Edition, version 1.0 may cause the following error message to be displayed:
Assertion failed - <unknown application>:File appcore.cpp, Line 559
Running a MFC application developed with Visual C++, 32-bit Edition, version 2.x, may cause the following error message to be displayed:
Assertion failed - <unknown application>:File winmain.cpp, Line 40
Running a MFC application developed with Visual C++, 32-bit Edition, version 4.0, may cause the following error message to be displayed:
Debug Assertion Failed!

Program: <program_name>
File: winmain.cpp
Line: 34
NOTE: In Visual C++, 32-bit Edition, versions 2.0 and above, the assertion will be followed by an Application Error.

CAUSE

The assertion that fails is the check to see whether an application object exists. Without the application object, the program cannot run.

RESOLUTION

Define an object of a class derived from the CWinApp class.

MORE INFORMATION

An example of this error may be seen by commenting out the file scoped statement of any MFC application that defines the CWinApp-derived object. This statement will look similar to the following: 
   CMyWinApp  MyWinApp;
where CMyWinApp is defined as follows: 
   class CMyWinApp : public CWinApp
   {
      //...
   };
For an example MFC application, see the HELLOAPP sample program included with any of the Microsoft products listed above. Chapter 3 of the "Microsoft C Class Libraries User's Guide," provided with Microsoft C/C++ version 7.0, and chapter 1 of the "Programming with MFC: Overview," included in the Visual C++ Books Online, contain additional information on CWinApp and on the fundamentals of using the Microsoft Foundation Classes to build an application for Windows.
Modification Type:MinorLast Reviewed:7/5/2005
Keywords:kbprb KB85496
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