DOCUMENT:Q152384  07-MAY-2001  [visualc]
TITLE   :FIX: DDX for Short Causes Stack Corruption
PRODUCT :Microsoft C Compiler
PROD/VER:winnt:4.0,4.1; :
OPER/SYS:
KEYWORDS:kbMFC KbUIDesign kbVC400bug kbVC410bug kbVC420fix kbClassWizard kbGrpDSMFCATL kbNoUpdat

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The information in this article applies to:

 - Microsoft Visual C++, versions 4.0, 4.1 
 - Microsoft Foundation Classes (MFC) 
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SYMPTOMS
========

Using the Class Wizard to associate a short with a control on a dialog may
result in the following behavior:

 - Access Violation when UpdateData(TRUE) is called.

-or-

 - Other member variables of the dialog are corrupted after the call to
   UpdateData(TRUE).

CAUSE
=====

The overloaded DDX routine for short has a bug where it assumes that the
variable is of type int instead of short. This may result in stack corruption
because a short occupies less space than an int.

RESOLUTION
==========

To resolve this problem, use an int instead of a short. If you want to limit the
values to the range of values that can be represented by a short, set the
appropriate limits for the int variable.

STATUS
======

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

Additional query words: kbVC400bug 4.00 4.10 4.20 vcfixlist420 DDX_Text short DDX_FieldText MfcUI

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Keywords          : kbMFC KbUIDesign kbVC400bug kbVC410bug kbVC420fix kbClassWizard kbGrpDSMFCATL kbNoUpdate 
Technology        : kbVCsearch kbVC400 kbAudDeveloper kbMFC kbVC410
Version           : winnt:4.0,4.1; :
Issue type        : kbbug
Solution Type     : kbfix

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