DOCUMENT:Q116489  26-JUN-2001  [utilities]
TITLE   :BUG: Printing to stdout with CV /2 Can Cause Screen Corruption
PRODUCT :Microsoft Programming Utilities
PROD/VER::4.0,4.01,4.1
OPER/SYS:
KEYWORDS:kb16bitonly

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft CodeView for MS-DOS, versions 4.0, 4.01, 4.1 
-------------------------------------------------------------------------------

SYMPTOMS
========

Screen corruption occurs when printing to stdout from a DOS application, while
using CV /2 to start CodeView in a DOS session under Windows. Portions of the
screen may get blanked out and restored from old buffered screens, the mouse
position may move to the middle of the screen, or existing text may get
overwritten. Note that these problems do not occur when running outside of
Windows under native DOS.

RESOLUTION
==========

To work around the problem, you can debug under native DOS or switch to single
monitor mode.

Depending on your application, the following may also work while debugging under
Windows:

 - Clear the screen before starting CV at the DOS session prompt.

 - If you have Visual C++, start CodeView for DOS from the Workbench Tools menu.

STATUS
======

Microsoft has confirmed this to be a problem with the interaction between
Windows and CodeView for DOS while running in a Windows DOS session. We will
post more information here in the Knowledge Base as it becomes available.

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

The example program below demonstrates the problem. Once you have built the
program, run CodeView in dual monitor mode and step through the code in the
debugger, observing the changes to the VGA screen. It is best to begin with a
full screen of text before starting CodeView.

Sample Code
-----------

   /* Compile options needed: /Zi /Od */ 
   #include <stdio.h>

   void main( void )
   {
       int i;

       for( i = 0; i < 50; i++ )
       {
           fprintf( stdout,"Hello World\n" );
       }
   }

Additional query words: 4.00 4.10

======================================================================
Keywords          : kb16bitonly 
Technology        : kbAudDeveloper kbCodeView kbZNotKeyword3 kbCodeView400DOS kbCodeView401DOS kbCodeView410DOS
Version           : :4.0,4.01,4.1

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

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS
PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND.  MICROSOFT DISCLAIMS
ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  IN NO
EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR
ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL,
CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF
MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE
POSSIBILITY OF SUCH DAMAGES.  SOME STATES DO NOT ALLOW THE EXCLUSION
OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES
SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 2001.