FIX: DDX for Short Causes Stack Corruption

 Last reviewed: September 19, 1997
Article ID: Q152384
4.00 4.10 WINDOWS NT kbprg kbbuglist kbfixlist

The information in this article applies to:

  • The Microsoft Foundation Classes (MFC), included with: Microsoft Visual C++, 32-bit Edition, version 4.0, 4.1

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.

KBCategory: kbprg kbbuglist kbfixlist
KBSubcategory: MfcUI
Additional reference words: 4.00 4.10 4.20 vcbuglist400 vcfixlist420
DDX_Text short DDX_FieldText

Keywords : MfcUI kbbuglist kbfixlist kbprg
Technology : kbMfc
Version : 4.00 4.10
Platform : NT WINDOWS
Solution Type : kbfix

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Last reviewed: September 19, 1997
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