DOCUMENT:Q128896  11-JUN-2002  [visualc]
TITLE   :PRB: Exception in Service Causes JIT Debugger to Hang Computer
PRODUCT :Microsoft C Compiler
PROD/VER::2.0,2.1,4.0,5.0,6.0
OPER/SYS:
KEYWORDS:kbDebug kbide kbVC200 kbVC210 kbVC400 kbVC500 kbVC600

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The information in this article applies to:

 - The Integrated Debugger, included with:
    - Microsoft Visual C++, 32-bit Editions, versions 2.0, 2.1, 4.0 
    - Microsoft Visual C++, 32-bit Enterprise Edition, versions 5.0, 6.0 
    - Microsoft Visual C++, 32-bit Professional Edition, versions 5.0, 6.0 
    - Microsoft Visual C++, 32-bit Learning Edition, version 6.0 
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SYMPTOMS
========

When Just-In-Time (JIT) debugging is enabled in Visual C++, applications that
cause exceptions (debuggees) bring up a dialog that will allow you to start the
debugger.

If a process running in a different context, such as a Service, causes an access
violation or another exception under Windows NT version 3.5, the dialog appears,
but the debugger never comes up and the process causes the computer to hang
(stop responding).

CAUSE
=====

When Windows NT starts the debugger after a fault, it runs in the same context
as the application that faulted. Many services run in the LocalSystem account,
which does not have access to the user desktop by default. Because the process
cannot interact with the desktop, the debugger cannot either.

RESOLUTION
==========

Beginning with version 3.5 of Windows NT, you can allow a Service to interact
with the desktop. There are two ways to do this:

 - Use the SERVICE_INTERACTIVE_PROCESS flag when calling CreateService().

   -or-

 - Start the Services control panel applet. Select the service, press the
   Startup button, and choose Allow Service to Interact with Destop.

STATUS
======

This behavior is by design in Windows NT 3.1 and 3.5. This problem does not
occur under Windows NT 3.51.

Additional query words: hung hang WorkBench

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Keywords          : kbDebug kbide kbVC200 kbVC210 kbVC400 kbVC500 kbVC600 
Technology        : kbVCsearch kbAudDeveloper kbIntegratedDebugger
Version           : :2.0,2.1,4.0,5.0,6.0
Issue type        : kbprb

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

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