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Q124271: PRB: Heap Walker’s Object: USER LocalWalk Doesn’t Track Data

Article: Q124271
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s): 
Keyword(s): kb16bitonly
Last Modified: 06-NOV-1999

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The information in this article applies to:

- Microsoft Windows Software Development Kit (SDK) 3.1 
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SYMPTOMS
========

Using the Microsoft Windows Heap Walker application (HEAPWALK.EXE), you choose
Object:USER Localwalk(DATASEG) to do a local walk of the USER heap. After saving
the results in a file, you open the file to discover all the count and size
values are zero as in this example:

-----------------------------------------
OBJECT              COUNT      SIZE
Class                   0         0
Window                  0         0
String                  0         0
Menu                    0         0
Clipbrd                 0         0
ComboBox                0         0
Palette                 0         0
EditCtrl                0         0
WindowList              0         0
OwnerDraw               0         0
SPB                     0         0
CheckPoint              0         0
DCE                     0         0
MoveWinPos              0         0
Properties              0         0
ListBox                 0         0
Misc                    0         0
Atoms                   0         0
LockInputState          0         0
HookList                0         0
UserSeeUserDo           0         0
HotKeyList              0         0
Handle Table            0         0
-----------------------------------------

CAUSE
=====

The Heap Walker application obtains the information for the chart by walking the
USER module's local heap using the LocalFirst() and LocalNext() functions in the
ToolHelp library. The entries correspond to the wType values in the LOCALENTRY
structure of the ToolHelp library. The documentation on the LOCALENTRY structure
in the Windows SDK Help file states that these wType values are included only in
the debugging version of USER.EXE, not in the retail version. Therefore, because
Heap Walker uses ToolHelp to obtain these values, no values are found in the
retail version of Windows.

RESOLUTION
==========

Switch to the Debug version of Windows, and run the Heap Walker application.
This will produce correct results. For more information on the debugging version
of Windows and how to switch to it, search on the phrase "Windows Debugging
Version" in the Windows version 3.1 SDK Help file (WIN31WH.HLP) or refer to the
topic "Windows Debugging Version" in Appendix C of the "Programming Tools for
Windows" manual, which is part of the Visual C++ version 1.50 "Professional
Tools User's Guide."

NOTE: When you try to reproduce the same behaviour in the Heap Walker application
for GDI heap by choosing Object:GDI LocalWalk(DATASEG), you will see that the
table shows correct values for individual GDI objects. This is by design.


STATUS
======

This behavior is by design.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Run the Microsoft Windows Heap Walker application (HEAPWALK.EXE) shipped with
  the Microsoft Windows versions 3.0 and 3.1 SDK or the Visual C++ version
  1.50.

2. Choose the Object:USER Localwalk(DATASEG) menu option to do a local walk of
  the USER heap.

3. From the USER Heap(Local Walk) window, choose Heap:Save.

4. Open the file created by Heap Walker (usually \WINDOWS\HWL00.TXT) with a text
  editor, and scroll to the bottom.

5. Notice that there are columns for OBJECT, COUNT, and SIZE, but all the COUNT
  and SIZE values are zeros.

Additional query words: 3.00 3.10 heapwalker no32bit

======================================================================
Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version           : WINDOWS:3.1

=============================================================================

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