FIX: COleDateTime::operator=(time_t) Breaks If Year Past 1999

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

SYMPTOMS

The function COleDateTime::operator=(const time_t& timeSrc) does not properly handle dates greater than December 31, 1999. For example, 02/05/2000 may be represented as 02/05/100. This bug can be seen in the Windows 95/Windows 98 diagnostics applet Msinfo32.exe. If the date on the computer is set to greater than December 31, 1999, the dates in the Msinfo32-generated report are not displayed properly.

CAUSE

COleDateTime::operator= calls a helper function in MFC called OleDateFromTm. This function is used to convert from the CRT time structure, which stores the year relative to 1900 (for example, 99 = 1999, 100 = 2000) to what the OLE date/time conversion functions expect. OleDateFromTm assumes that any year passed to it less than 100 is an abbreviated date relative to 1900 and adds 1900 to it. If the year is greater than 99 (that is, 100 = 2000) nothing is added. So, when 100 is passed (for 2000) to OleDateFromTm, nothing is added to it and the date comes back as 100.

STATUS

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

This bug has been fixed in patched versions of the Mfc40.dll and Mfc40u.dll. Version number is 4.1.6140. These DLLs are included as part of the Y2K updates for Windows 95 and Windows 98. Please see the Microsoft Y2K web site, http://www.microsoft.com/y2k for details. For Windows NT 4.0, a hot fix is available.

For additional information, please see the following article in the Microsoft Knowledge Base:

Q218877 Mfc40.dll Causes Programs to Display Wrong Date After 01/01/2000

MORE INFORMATION

Only applications built with Visual C++ 4.0 or 4.1 require this updated DLL. To determine if your executable is linked to the Mfc40.dll:

1. Start Windows Explorer.



2. Right-click the EXE or DLL.



3. Select Quick View.



4. Scroll down to the Import Table. The MFC DLL linked in should be listed here (that is, Mfc40.dll).

Additional query words: y2k MFC COleDateTime time_t OleDateFromTm

Keywords : kbservicepack kb2000 kbMFC kbVC400bug kbVC410bug kbVC600 kbVS600sp2 kbfaq kbVS600SP1 kbVS600sp3fix
Version : winnt:4.0,4.1
Platform : winnt
Issue type : kbbug