PRB: CString::LoadString Fails in Console Application

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This article was previously published under Q150764

SYMPTOMS

CString::LoadString() generates an MFC assert in debug mode console applications or fails in release mode console applications.

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CAUSE

CString::LoadString() relies on MFC global resource handles that are initialized in AfxWinMain(), which is only called in MFC GUI-based applications.

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The resource string is loaded using the Win32 API ::LoadString() function. This method does not require any extra MFC initialization.

Example #1 below uses this method.

It is possible to initialize the MFC global resource handles by calling the undocumented AfxWinInit() function. In this case, it is advisable to declare an instance of a CWinApp class.

Example #2 below demonstrates this method.

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Sample Code - Example #1

   /* Compile options needed: /MT
   */ 
   #include <afx.h>
   #include <stdio.h>
   #include <conio.h>

   #define IDS_HELLO 1

   BOOL LoadStringResource(CString &cszString, UINT nID)
   {
       int nSize = 0;
       int nLen = -1;

       cszString.Empty();

       //Keep looping until we have the whole string
       while ((nLen != 0) && (nLen == nSize - 1))
       {
           //Grow buffer by 256 bytes
           nSize += 256;

           //Load String Resource
           nLen = ::LoadString( GetModuleHandle(NULL), nID,
                                cszString.GetBuffer(nSize-1), nSize);
       }
       cszString.ReleaseBuffer();

       return (BOOL) nLen;
   }

   void main(void)
   {
       AfxInitialize();

       CString cszString;

       // IDS_HELLO is a string resource attached to the console
   application
       if (LoadStringResource(cszString, IDS_HELLO))
           printf("The string was loaded\n%s\n", (LPCTSTR) cszString);
       else
           printf("Error loading string");

       getch();
   }

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Sample Code - Example #2

   /* Compile options needed: /MT
   */ 
   #include <afx.h>
   #include <afxwin.h>
   #include <conio.h>

   #define IDS_HELLO 1

   CWinApp theApp;

   void main()
   {
       if (!AfxWinInit(GetModuleHandle(NULL), NULL,
           ::GetCommandLine(), 0))
       {
           printf("Couldn't initialize MFC!\n");
           return;
       }

       CString cszString;

       // IDS_HELLO is a string resource attached to the console
   application
       if (cszString.LoadString(IDS_HELLO))
           printf("The string was loaded\n%s\n", (LPCTSTR) cszString);
       else
           printf("Error loading string");

       getch();
   }

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STATUS

This behavior is by design.

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APPLIES TO

Microsoft Foundation Class Library 4.2, when used with:

Microsoft Visual C++ 2.0 Professional Edition
Microsoft Visual C++ 2.1
Microsoft Visual C++ 2.2
Microsoft Visual C++ 4.0 Standard Edition
Microsoft Visual C++ 4.1 Subscription

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kbprb KB150764

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Retired KB Content Disclaimer

This article was written about products for which Microsoft no longer offers support. Therefore, this article is offered "as is" and will no longer be updated.

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