FIX: Assertion Failure After Using CDaoWorkspace::Create()

• Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.1
• Microsoft Foundation Classes (MFC)

SYMPTOMS

Using a CDaoWorkspace object after calling the CDaoWorkspace::Create() function may cause an assertion failure in Daocore.cpp line 651 inside the CDaoWorkspace::Open() function.

CAUSE

When a newly created CDaoWorkspace object is used for the first time, the CDaoWorkspace::Open() function is called. This function should only be called to retrieve either a named workspace or the default workspace from the workspaces collection.

MFC relies on the value of the m_bOpen member variable to determine if the workspace object's Open() function needs to be called. This member variable is set to TRUE only inside the Open() and Append() member functions.

RESOLUTION

Call CDaoWorkspace::Append() before using a newly created workspace object.

STATUS

Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This problem was corrected in Visual C++, 32-bit Edition, version 4.2.

MORE INFORMATION

Sample Code

CDaoWorkspace wsp;
wsp.Create(_T("NewWorkspace"), _T("admin"), _T(""));
// Call Append() to set the m_bOpen flag.
// This will also append the workspace to the engine's workspaces
// collection
wsp.Append();

CDaoDatabase db(&wsp);
db.Open(_T("c:\\path\\to\\mdbfile.mdb"), FALSE, FALSE, NULL);
... 

Additional query words: kbVC400bug 4.00 4.10 vcfixlist420

Keywords : kbDAO kbDatabase kbMFC kbVC
Version : winnt:4.0,4.1; :
Platform : winnt
Issue type :