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

This article was previously published under Q225140
This article has been archived. It is offered "as is" and will no longer be updated.
The function COleDateTime::operator=(const time_t& timeSrc) does not properly handle dates later 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 later than December 31, 1999, the dates in the Msinfo32-generated report are not displayed properly.
COleDateTime::operator= calls a helper function in MFC named 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 that is passed to it that is 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. Therefore, when 100 is passed (for 2000) to OleDateFromTm, nothing is added to it and the date comes back as 100.
Microsoft has confirmed that this is a bug in the Microsoft products that are 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. For Windows NT 4.0, a hot fix is available.

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:
218877 Mfc40.dll Causes Programs to Display Wrong Date After 01/01/2000
This bug was corrected in Visual Studio 6.0 Service Pack 3. For additional information about Visual Studio service packs, click the article numbers below to view the articles in the Microsoft Knowledge Base:
194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why
194295 HOWTO: Tell That Visual Studio 6.0 Service Packs Are Installed
Only applications that are built with Visual C++ 4.0 or 4.1 require this updated DLL. To determine whether your executable is linked to the Mfc40.dll, follow these steps:
  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).
y2k MFC COleDateTime time_t OleDateFromTm

Article ID: 225140 - Last Review: 10/20/2013 22:44:50 - Revision: 2.1

Microsoft Foundation Class Library 4.2

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