BUG: QueryInterface Returning E_NOINTERFACE

• Microsoft Visual SourceSafe, 32-bit, for Windows versions 5.0, 6.0

SYMPTOMS

When creating OLE Automation in C that communicates with Microsoft Visual SourceSafe (VSS), if the program is created using VSS 5.0 OLE Automation and is then run on a computer that is using VSS 6.0, QueryInterface for versions can fail for the IID_IVSSVersion.

CAUSE

The VSS 6.0 Automation ignores the 5.0 IID_IVSSVersion.

RESOLUTION

If you have to create code that will run on computers using VSS 5.0 or VSS 6.0, see the following steps.

1. Follow the steps in:

   HOWTO: Write automation for computers using VSS 5 or VSS 6.




2. Create two separate programs and call the correct one based on what version of VSS the computer is using.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

Steps to Reproduce Behavior

1. Follow the steps in:

   HOWTO: Open a SourceSafe Database with OLE Automation in C++




2. Add the following code at the top of the program:

   
      #include <objbase.h>
      #include <initguid.h>
      #include <stdio.h>
   
      #define MAKEHR(iStat) MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF,(USHORT) (iStat))
     




3. Add the following code where the "// Add code here..." is:

   
      IVSSVersions* pVersions = NULL;
      IVSSVersion* pVersion = NULL;
      IVSSItem* pItem = NULL;
      IUnknown* pEnumerator = NULL;
      IEnumVARIANT* pVariant = NULL;
      Variant v;
      unsigned long actual;
      int error, nointerface;
      BSTR Root = SysAllocString(L"$/");
   
      VariantInit(&v);
      pVdb->get_VSSItem(Root, FALSE, &pItem);
      pItem->get_Versions(0, &pVersions);
      pVersions->_NewEnum(&pEnumerator);
      pEnumerator->QueryInterface(IID_IEnumVARIANT, (void **) &pVariant);
      pEnumerator->Release();
      pVariant->Next((unsigned long) 1, &v, &actual);
      error = v.pdispVal->QueryInterface(IID_IVSSVersion, (void **) &pVersion);
      nointerface = MAKEHR(E_NOINTERFACE);
      if (error == nointerface)
      printf("No Interface Error.\n"); 




4. Compile and run the program. You should get an error number returned from the QueryInterface call with IID_IVSSVersion.

Additional query words: OLE Automation

Keywords : kbAutomation kbSSafe500bug kbSSafe600bug kbDSupport
Version : WINDOWS:5.0,6.0
Platform : WINDOWS
Issue type : kbbug