BUG: Calling CHttpFile::ErrorDlg Function Causes Errors 127 & 2

ID: Q189094

The information in this article applies to:

Microsoft Visual C++, 32-bit Editions, version 5.0
Microsoft Internet Explorer (Programming)

SYMPTOMS

Calling CHttpFile::ErrorDlg results in one of the following error messages:

Error: (127) The specified procedure could not be found.

Error: (2) The system cannot find the file specified.

CAUSE

MFC attempts to call the Unicode or American National Standards Institute (ANSI) versions of most Win32 Internet Extensions (WinInet) functions when appropriate. In the case of the ErrorDlg function, MFC attempts to call the Unicode or ANSI version of the InternetErrorDlg function. For InternetErrorDlg, Unicode and ANSI versions are not necessary (no character data is passed in) and in fact, not available. When MFC attempts to call the Unicode or ANSI version of the function, the function is not found in the DLL.

RESOLUTION

It is possible to call the InternetErrorDlg function yourself. Following is a section of the Tear sample modified to do so:


   if (dwRet == HTTP_STATUS_DENIED)
   {
       DWORD dwPrompt;

       //dwPrompt = pFile->ErrorDlg(NULL,
       //ERROR_INTERNET_INCORRECT_PASSWORD,
       //FLAGS_ERROR_UI_FLAGS_GENERATE_DATA |
       //FLAGS_ERROR_UI_FLAGS_CHANGE_OPTIONS, NULL);

       LPVOID lpEmpty;

       dwPrompt = ::InternetErrorDlg(GetDesktopWindow(), *pFile,
                                     ERROR_INTERNET_INCORRECT_PASSWORD,
                                     FLAGS_ERROR_UI_FLAGS_GENERATE_DATA
                                   | FLAGS_ERROR_UI_FLAGS_CHANGE_OPTIONS,
                                     &lpEmpty);

       if (dwPrompt != ERROR_INTERNET_FORCE_RETRY)
   ...

In some cases, you may want different parameters for InternetErrorDlg. See the WinInet documentation for InternetErrorDlg and the MFC source code for CHttpFile::ErrorDlg. Note that you must change your project setting to link with wininet.lib in order to use InternetErrorDlg.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. We are researching this bug and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

When you run the MFC Internet Tear sample, an error is reported and the program fails if the site being accessed uses Basic Authentication without allowing anonymous access and with NTLM turned off.

It is also possible to collect the User Name and Password yourself and send a new request for data, as in the following example:


   if (dwRet == HTTP_STATUS_DENIED)
   {
       cerr << "This page is password protected. " << endl;
       CHAR szUser[50]="";
       CHAR szPass[50]="";

       cerr << "User: "; cin  >> szUser;
       // This should really not show the password on the screen.
       cerr << "Pass: "; cin  >> szPass;

       // You have to read all outstanding data on the Internet handle
       // before you can resubmit the request. Just discard the data.

       CString strBuff;
       while (pFile->ReadString(strBuff))
       {
       }

       pServer->SetOption(INTERNET_OPTION_USERNAME, szUser,
                          lstrlen(szUser));
       pServer->SetOption(INTERNET_OPTION_PASSWORD, szPass,
                          lstrlen(szPass));

       pFile->SendRequest();
   ...

Notice that SetOption is being called on the CHttpConnection per the InternetSetOption documentation in Visual C++ which states the following:

Sets the user name associated with a handle returned by InternetConnect.

Calling SetOption on the CInternetSession will result in an Access violation in WinInet.dll.

REFERENCES

Additional query words: kbMFC kbVC500bug kbWinInet

Keywords : kbWinInet
Version : WINNT:5.0
Platform : winnt
Issue type : kbbug