Microsoft KB Archive/152781

= FIX: Incorrect Return Values from COleDateTime Members =

Article ID: 152781

Article Last Modified on 11/21/2006

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APPLIES TO

 Microsoft Foundation Class Library 4.2, when used with:  Microsoft Visual C++ 4.0 Standard Edition

 Microsoft Visual C++ 4.1 Subscription

 Microsoft Visual C++ 4.2 Enterprise Edition

 Microsoft Visual C++ 4.2 Professional Edition</li></ul> </li></ul>

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This article was previously published under Q152781

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SYMPTOMS
When you call the COleDateTime members (SetDate, SetTime, and SetDateTime), the return value indicates failure even though the call is successful. This may cause code that checks the return value to believe incorrectly that the call failed.

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CAUSE
This behavior is caused by a problem in the COleDateTime code. COleDateTime defines the following enumeration: enum DateTimeStatus {       valid = 0, invalid = 1,   // Invalid date (out of range, etc.) null = 2,      // Literally has no value }; The problem occurs because SetDate, SetTime, and SetDateTime all return 'valid' if successful. However 'valid' is defined to be 0 in the DateTimeStatus enumeration, which translates to a Boolean FALSE. The code should check for success and return TRUE or FALSE.

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RESOLUTION
Call COleDateTime::GetStatus after each call to SetDate, SetTime, or SetDateTime. Then compare the value returned by GetStatus against 'valid' to check for success. The "More Information" section of this article provides an example.

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STATUS
Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been corrected in the Visual C++ 4.2b technology update.

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MORE INFORMATION
Because of the problem outlined previously in this article, code that checks the return value from these functions may believe that a failure has occurred when in fact the Date/Time was set correctly. For example, the following code will ASSERT even though the call was successful: COleDateTime myodt; VERIFY(myodt.SetDateTime(96,1,1,10,45,0)); To work around this problem, test the success of the call by calling the COleDateTime::GetStatus member. Compare the value returned by GetStatus against 'valid' to check for success as shown in this example: COleDateTime myodt; myodt.SetDateTime(95,6,1,23,45,0); VERIFY(myodt.GetStatus == COleDateTime.valid);

Additional query words: kbVC400bug

Keywords: kbbug kbfix kbnoupdate kbvc420fix KB152781

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