In the Win32 SDK, versions 3.1, 3.5, 3.51, and 4.0, the system can spawn a debugger whenever an application faults. The capability is controlled by the following Registry key on Windows NT:

   HKEY_LOCAL_MACHINE\ 

             SOFTWARE\ 
            Microsoft\ 
           Windows NT\ 
       CurrentVersion\ 
              AeDebug
				

This key contains the following entries:

   Auto
   Debugger
				

These entries are also available on Windows 95. However, on Windows 95, they are contained in the Win.ini file instead of the registry. The section [aedebug] has entries that correspond to the registry.

If the value of Auto is set to "0" (zero), then the system will generate a pop-up window, and if the user chooses Cancel, spawn the debugger that is specified in the Debugger value. If the value of Auto is set to "1", then the system will automatically spawn the debugger that is specified in the Debugger value.

After installing Windows NT, the Debugger value is set to

   DRWTSN32 -p %ld -e %ld -g
				

and the Auto value is set to 1. If the Win32 SDK is installed, then the Debugger value is changed to

   <MSTOOLS>\BIN\WINDBG -p %ld -e %ld
				

and the Auto value is set to 0.

Microsoft Visual C++ version 5.0 makes the following entry for the Debugger value:

   C:\Program Files\DevStudio\SharedIDE\BIN\msdev.exe -p %ld -e %ld
				

The DRWTSN32 debugger is a post-mortem debugger similar in functionality to the Windows 3.1 Dr. Watson program. DRWTSN32 generates a log file containing fault information about the offending application. The following data is generated in the Drwtsn32.log file:

•	Exception information (exception number and name).
•	System information (machine name, user name, OS version, and so forth.
•	Task list.
•	State dump for each thread (register dump, disassembly, stack walk, symbol table).

A record of each application error is recorded in the application event log. The application error data for each crash is stored in a log file named Drwtsn32.log, which by default is placed in your Windows directory.

NOTE: You can install DRWTSN32 correctly into the registry by running

DRWTSN32 -i
				

from a command prompt (or from the Start menu, click Run).