Q89331: Stack Traces Under Windows 3.1 SDK Debugging Kernel
Article: Q89331
Product(s): Microsoft Windows Software Development Kit
Version(s): WINDOWS:3.1
Operating System(s):
Keyword(s): kbfile kb16bitonly kbOSWin310
Last Modified: 10-DEC-1999
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The information in this article applies to:
- Microsoft Windows Software Development Kit (SDK) 3.1
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SUMMARY
=======
When a FatalExit occurs, the Microsoft Windows operating system version 3.1
Software Development Kit (SDK) debugging kernel does not display a stack trace
on the debugging monitor unless the user presses the ENTER or SPACEBAR key
immediately after the kernel displays the "Abort, Break, Ignore" message. This
behavior is different from that found in the debugging kernel for Windows
version 3.0 or prerelease versions of Windows version 3.1.
The rationale behind changing this behavior was to simplify the interface to the
debugging kernel and to speed its execution. When a FatalExit message occurs, a
stack trace is available if desired. However, the kernel does not take time to
create and display unwanted stack traces.
MORE INFORMATION
================
The following files are available for download from the Microsoft Download
Center:
Nudbwin.exe
For additional information about how to download Microsoft Support files, click
the article number below to view the article in the Microsoft Knowledge Base:
Q119591 How to Obtain Microsoft Support Files from Online Services
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In its default configuration, the Windows debugging kernel displays messages on a
serial terminal connected to the COM1 port. The kernel produces four levels of
messages: Trace, Warning, Error, and FatalExit. Appendix C of the SDK
"Programming Tools" manual and the SDK Help system documents the Windows
debugging kernel.
When the debugging kernel displays the "Abort, Retry, Ignore" message for a
FatalExit it does not display a stack trace immediately. Instead, the kernel
enters a loop, waiting for the user to respond. If the user presses the SPACEBAR
or ENTER key before the loop times out, the kernel displays the stack trace. To
continue execution after the stack trace, press the I key to ignore the
FatalExit. The other options are to press the A key to abort execution or the B
key to break into the debugger.
The Windows 3.1 SDK includes an advanced sample application called DBWIN that
provides a good user interface and some useful features to assist in debugging a
Windows-based application with the debugging kernel. If the advanced samples are
installed into the default directory, the DBWIN source code is in the
C:\WINDEV\SAMLES\DBWIN directory.
DBWIN can redirect debugging messages into a window on the main display or to a
secondary monochrome monitor. However, when DBWIN redirects messages in this
manner, the debugging kernel ignores FatalExit messages (irrespective of the
debug settings). In other words, no stack traces are available when DBWIN
redirects debug messages to a window or a secondary monochrome monitor. However,
stack traces are available when DBWIN redirects debugging information to COM1 or
COM2 as outlined above for a debugging terminal.
DBWIN ignores FatalExit messages because the system runs much faster when it
displays debugging messages in a window rather than on a serial terminal.
However, because a stack trace provides very useful information to assist in
debugging an application, this default behavior might not be considered very
useful.
The text below provides the modification to the DBWIN source code required to
provide stack traces in a window or on a secondary monochrome monitor. The
modified version of DBWIN produces a stack trace for every FatalExit message
displayed by the debugging kernel, similar to the behavior of the Windows 3.0
debugging kernel. While the system might run slowly with the modified DBWIN, the
additional debugging information might make the change worthwhile. The modified
version of DBWIN is available in the NUDBWIN file in the Software/Data Library.
The only modifications required are to the NotifyCallback function in the
DBWINDLL.C source file. Add the text in the lines that begin with NEW to the
file, as follows:
BOOL CALLBACK _export _loadds NotifyCallback(WORD id, DWORD dwData)
{
BOOL fHandled;
.
.
NEW // By default, produce stack trace at every FatalExit
NEW static BOOL fStackTrace = TRUE;
// If we're not outputting anything,
// just return FALSE to chain to next handler.
if (modeOutput == OMD_NONE)
return FALSE;
.
.
.
case NFY_INCHAR:
switch (modeOutput)
{
case OMD_COM1:
case OMD_COM2:
fHandled = (BOOL)ComIn();
break;
default:
NEW if (fStackTrace)
NEW fHandled = (BOOL)' '; // Return a SPACEBAR press
NEW // to produce stack trace
NEW else
NEW fHandled = (BOOL)'i'; // Return an I key press to
NEW // ignore the FatalExit
NEW
NEW // Do not produce the stack trace a second time at the
NEW // "Abort, Break, Ignore" message. Ignore FatalExit this time
NEW fStackTrace = !fStackTrace;
}
break;
.
.
.
Additional query words: softlib NUDBWIN.EXE kbfile
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Keywords : kbfile kb16bitonly kbOSWin310
Technology : kbAudDeveloper kbWin3xSearch kbSDKSearch kbWinSDKSearch kbWinSDK310
Version : WINDOWS:3.1
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