DOCUMENT:Q230756  05-MAY-2001  [visualc]
TITLE   :BUG: Windows CE Emulation Serial Communications Bugs
PRODUCT :Microsoft C Compiler
PROD/VER:WINDOWS:5.0,6.0
OPER/SYS:
KEYWORDS:kbAPI kbCommPort kbKernBase kbSDKWin32 kbOSWinCE200bug kbOSWinCE210bug kbFAQ

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The information in this article applies to:

 - Microsoft Windows CE Toolkit for Visual C++, versions 5.0, 6.0 
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SYMPTOMS
========

When running under the Windows CE emulator, the following are some issues you
might encounter with serial communications:

 - Using HPC Pro emulation, attempting to open a comm port with the CreateFile
   API returns INVALID_HANDLE_VALUE, and GetLastError() returns
   ERROR_ALREADY_EXISTS.

 - Using HPC emulation, attempting to open a comm port with the CreateFile API
   returns returns ERROR_INVALID_HANDLE, and GetLastError() returns 0.

 - When using the serial port in the Windows CE emulator, the serial port works
   normally for a while, but after a certain number of calls to ReadFile or
   WriteFile, future calls to ReadFile/WriteFile seems to hang.

RESOLUTION
==========

Regardless of whether you run into any of these issues, it is highly recommended
that you test and debug your application running on the actual target hardware.
Differences in timing and serial hardware such as the UART can cause enough
differences that testing on the actual target hardware is the only way to ensure
your application performs as desired.

If your CE device only has one serial port, you can debug using an Ethernet
connection so that your serial port can be used by your application. For more
information about remotely debugging over an Ethernet connection, please see the
documentation included with the Windows CE Toolkit for Visual C++.

STATUS
======

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

REFERENCES
==========

Q175029 INFO: Troubleshooting Windows CE Emulation

Additional query words:

======================================================================
Keywords          : kbAPI kbCommPort kbKernBase kbSDKWin32 kbOSWinCE200bug kbOSWinCE210bug kbFAQ 
Technology        : kbVCsearch kbAudDeveloper kbWinCETKVCSearch kbWinCESearch kbWinCETK500VC kbWinCETK600VC
Version           : WINDOWS:5.0,6.0
Issue type        : kbbug

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