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Q138993: PRB: Print Break in MFC App Running in Windows NT 3.51 Checked

Article: Q138993
Product(s): Microsoft C Compiler
Version(s): winnt:
Operating System(s): 
Keyword(s): kberrmsg kbprint kbDebug kbMFC kbOSWinNT351 kbPrinting kbVC200 kbVC400 kbGrpDSMFCATL
Last Modified: 11-SEP-2001

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The information in this article applies to:

- The Microsoft Foundation Classes (MFC), used with:
   - *EDITOR Please do not choose this product*Microsoft Visual C++ 32-bit Edition* use 241, 265, 225, versions 2.0, 2.1, 2.2, 4.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

While using the Visual C++ debugger, if you click Print or Print Preview in an
MFC application running under Windows NT version 3.51 Checked Build, a message
box appears:

In the Visual C++ 2.x debugger, the message box contains:

  Break caused by hard coded breakpoint instruction

In the Visual C++ 4.0 debugger, the message box contains:

  User breakpoint called from code at 0x<8-digit address>

The following message is also printed in the Output Window of the debugger:

  BASE: GlobalFree called with a locked object.

CAUSE
=====

MFC queries an HDEVNAMES handle for information about the printer device. This
information is obtained by making calls to GlobalLock to get a valid pointer to
the DEVNAMES structure. Under Win32, it is not technically necessary to call
GlobalUnlock for every GlobalLock, so MFC doesn't always do so.

The Checked Build of Windows NT 3.51 provides debugging information that warns
you when GlobalFree is called on an object that does not have a lock count of 0.
When this occurs, it outputs a trace message and causes a hard coded break
instruction to be executed.

RESOLUTION
==========

The message and the break can be safely ignored. To continue with execution in
the debugger, you can just click Go on the Debug menu, or press the F5 key.

STATUS
======

This behavior is by design.

Additional query words: 2.00 2.10 2.20 4.00 3.00 3.10 3.20

======================================================================
Keywords          : kberrmsg kbprint kbDebug kbMFC kbOSWinNT351 kbPrinting kbVC200 kbVC400 kbGrpDSMFCATL 
Technology        : kbAudDeveloper kbMFC
Version           : winnt:
Issue type        : kbprb

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