Article ID: 141417
Article Last Modified on 10/16/2002
APPLIES TO
- Microsoft Visual C++ 4.0 Standard Edition
This article was previously published under Q141417
SYMPTOMS
A problem occurs on Win32s when the user tries to open a file using the standard MFC file opening procedures. This only occurs with an MFC application running under Win32s version 1.3 that uses MFC in a shared DLL (Mfc40.dll for Win32s) and the C runtime libraries in a DLL (Msvcrt40.dll for Win32s). Note that this is the default configuration for a default AppWizard generated application.
Two known symptoms are access violation and EMM386 error #06 (Invalid opcode). Symptoms will vary depending on the condition of the call stack.
CAUSE
AfxResolveShortcut (an internal MFC function) calls SHGetFileInfo, which is not correctly implemented on Win32s. This happens as a result of the ID_FILE_OPEN command. AfxResolveShortcut is called from CDocManager::OpenDocumentFile, which is in turn called from CWinApp::OpenDocumentFile.
RESOLUTION
Derive a class from CDocManager and override the OpenDocumentFile function by copying the existing code and make some small changes. Because this fix is dependent on the internal MFC implementation, make sure you include the #if _MFC_VER == 0x400 statements.
Copy the following code into your application's .cpp file above the implementation of InitInstance. If you're looking at a paper copy of this article, note that you can find most of the code for OpenDocumentFile in Mfc\Src\Docmgr.cpp; rather than retyping the entire text, you could copy most of the code and make the change noted below:
#if _MFC_VER == 0x400
static inline BOOL IsDirSep(TCHAR ch)
{
return (ch == _T('\\') || ch == _T('/'));
}
#ifndef _MAC
BOOL AFXAPI AfxResolveShortcut(CWnd* pWnd, LPCTSTR pszShortcutFile,
LPTSTR pszPath, int cchPath);
#endif
#define _countof(array) (sizeof(array)/sizeof(array[0]))
BOOL AFXAPI AfxFullPath(LPTSTR lpszPathOut, LPCTSTR lpszFileIn);
void AFXAPI AfxGetRoot(LPCTSTR lpszPath, CString& strRoot);
class CMyDocManager : public CDocManager
{
public:
CMyDocManager() {};
virtual ~CMyDocManager() {};
virtual CDocument* OpenDocumentFile(LPCTSTR lpszFileName);
};
CDocument* CMyDocManager::OpenDocumentFile(LPCTSTR lpszFileName)
{
// find the highest confidence
POSITION pos = m_templateList.GetHeadPosition();
CDocTemplate::Confidence bestMatch = CDocTemplate::noAttempt;
CDocTemplate* pBestTemplate = NULL;
CDocument* pOpenDocument = NULL;
TCHAR szPath[_MAX_PATH];
ASSERT(lstrlen(lpszFileName) < _countof(szPath));
#ifndef _MAC
TCHAR szTemp[_MAX_PATH];
if (lpszFileName[0] == '\"')
++lpszFileName;
lstrcpyn(szTemp, lpszFileName, _MAX_PATH);
LPTSTR lpszLast = _tcsrchr(szTemp, '\"');
if (lpszLast != NULL)
*lpszLast = 0;
AfxFullPath(szPath, szTemp);
TCHAR szLinkName[_MAX_PATH];
// CHANGE: check the windows version before calling AfxResolveShortcut
if((BYTE)GetVersion() >=4 && AfxResolveShortcut(AfxGetMainWnd(),
szPath, szLinkName,_MAX_PATH))
lstrcpy(szPath, szLinkName);
#else
lstrcpyn(szPath, lpszFileName, _MAX_PATH);
WIN32_FIND_DATA fileData;
HANDLE hFind = FindFirstFile(lpszFileName, &fileData);
if (hFind != INVALID_HANDLE_VALUE)
VERIFY(FindClose(hFind));
else
fileData.dwFileType = 0; // won't match any type
#endif
while (pos != NULL)
{
CDocTemplate* pTemplate =
(CDocTemplate*)m_templateList.GetNext(pos);
ASSERT_KINDOF(CDocTemplate, pTemplate);
CDocTemplate::Confidence match;
ASSERT(pOpenDocument == NULL);
#ifndef _MAC
match = pTemplate->MatchDocType(szPath, pOpenDocument);
#else
match = pTemplate->MatchDocType(szPath,
fileData.dwFileType, pOpenDocument);
#endif
if (match > bestMatch)
{
bestMatch = match;
pBestTemplate = pTemplate;
}
if (match == CDocTemplate::yesAlreadyOpen)
break; // stop here
}
if (pOpenDocument != NULL)
{
POSITION pos = pOpenDocument->GetFirstViewPosition();
if (pos != NULL)
{
CView* pView = pOpenDocument->GetNextView(pos);
// get first one
ASSERT_VALID(pView);
CFrameWnd* pFrame = pView->GetParentFrame();
if (pFrame != NULL)
pFrame->ActivateFrame();
else
TRACE0(
"Error: Cannot find frame for document to activate.\n");
CFrameWnd* pAppFrame;
if (pFrame !=
(pAppFrame = (CFrameWnd*)AfxGetApp()->m_pMainWnd))
{
ASSERT_KINDOF(CFrameWnd, pAppFrame);
pAppFrame->ActivateFrame();
}
}
else
{
TRACE0(
"Error: Can not find view for document to activate.\n");
}
return pOpenDocument;
}
if (pBestTemplate == NULL)
{
AfxMessageBox(AFX_IDP_FAILED_TO_OPEN_DOC);
return NULL;
}
return pBestTemplate->OpenDocumentFile(szPath);
}
#endif //mfc version 4.0 workaround
Now, include the following three lines to the first part of your MyApp::InitInstance function:
#if _MFC_VER == 0x400
m_pDocManager = new CMyDocManager;
#endif
STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug was corrected in Visual C++ 4.1.
MORE INFORMATION
Steps to Reproduce Problem
- Open the scribble tutorial sample from:
\Msdev\Samples\Mfc\Tutorial\Scribble\Step6\Scribble.mdb
- Open the Project Settings dialog box. In Settings For, select Win32 Release.
- From the Project Settings dialog box, click the general tab. From the Microsoft Foundation Classes list box, select Use MFC in a shared DLL (MFC40(d).DLL). Click OK to dismiss the project settings dialog box.
- Open the default configuration dialog box, and select the Release build.
- Rebuild the program.
- Run the program under Win32s.
- Create, save, and close a scribble document.
- Try to open the document you just closed. An access violation occurs.
Additional query words: kbVC400bug 4.00 4.10 1.30
Keywords: kbbug kbfix kbnoupdate kbvc410fix kbdocview kbcode KB141417
