Thursday, August 25, 2011

DBH: How the Debugger Help utility can help.

My work in servicing Windows usually results in a bunch of "This component is crashing, please investigate it" questions. One of the first things I always need to do is locate the source code for that component. Lately, I've been using a nice little utility, dbh.exe to accomplish this.

dbh.exe is included with the Windows Debugging tools and it basically provides a command line interface to the dbghelp.dll. For code-finding purposes I'll use the "src" option.

Here's the output on a small utility I'm working on (it's much more useful for large source bases (like Windows) where the code is spread out in many separate source code depots):
c:\>dbh d:\data\projects\base\windd\Debug\windd.exe src *.c*

I had to cut off some more of the display because this is on a development machine with private Windows symbols -- it displays all the source paths for the Visual Studio CRT, Windows source files that define various GUIDs used by my application, and other miscellaneous junk.

The most important thing I tell people to answer the "Where does the code for XYZ live?" question is: "Check out dbh.exe in the debugging tools." If you have the symbols to your code it's amazing what you can do with the default tools. There are a few features I'd like to see (disassembly of a function with line data, etc...) and perhaps I'll be making my own version of dbh.exe shortly.

There's so much to dbh.exe and I haven't even scratched the surface with this post. I hope you find it as useful as I do.

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