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Q200578: BUG: Cannot Step Over Function That Contains Data Breakpoint

Article: Q200578
Product(s): Microsoft C Compiler
Version(s): 5.0,6.0
Operating System(s): 
Keyword(s): kbVC500bug kbVC600bug kbDSupportkbbuglist
Last Modified: 11-MAR-2002

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The information in this article applies to:

- Microsoft Visual C++, 32-bit Enterprise Edition, versions 5.0, 6.0, on platform(s):
   - the hardware: DEC Alpha 
- Microsoft Visual C++, 32-bit Professional Edition, versions 5.0, 6.0, on platform(s):
   - the hardware: DEC Alpha 
- Microsoft Visual C++, 32-bit Learning Edition, version 6.0, on platform(s):
   - the hardware: DEC Alpha 
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SYMPTOMS
========

If you attempt to step over a function that contains a data breakpoint anywhere
in its execution path and the data expression does not evaluate to true, the
Developer Studio debugger may step into the function or appear to hang.

CAUSE
=====

The RISC implementation of the breakpoint handler fails to differentiate between
normal breakpoints and data breakpoints, and handles the data breakpoints
incorrectly.

RESOLUTION
==========

Disable or remove all data breakpoints when stepping through code.

STATUS
======

Microsoft has confirmed this to be a problem in the Microsoft products that are
listed at the beginning of this article.

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

Data breakpoints are discouraged on Windows NT RISC platforms because most of
these architectures don't support debug breakpoint registers, resulting in
extremely poor performance.

Additional query words: WBDebug VCAlpha

======================================================================
Keywords          : kbVC500bug kbVC600bug kbDSupport kbbuglist
Technology        : kbVCsearch kbAudDeveloper kbVC32bitSearch
Version           : :5.0,6.0
Issue type        : kbbug
Solution Type     : kbpending

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