Author Archives: Ofek Shilon

Presenting at Windows Platform Developers Israel User Group

Posted on August 22, 2011 by Ofek Shilon

I’ll be giving a talk at a local Windows Developers user group meeting, titled ‘Undocumented Native Debugging Tricks’.  In essence I’ll be surveying as much as time permits of my collection of lesser-known VS tricks – many of which were … Continue reading →

Posted in VC++ | Leave a comment

VC++ Version Boundaries

Posted on June 14, 2011 by Ofek Shilon

Using a binary built in VC verXXX from a binary built in VC verYYY is very dangerous. This is very obvious in retrospect, but real life recently forced us to try just that: we migrated to VS2010, and a few … Continue reading →

Posted in VC++ | 1 Comment

Breaking on Data Read

Posted on May 22, 2011 by Ofek Shilon

Edit: As of windows 10 the details and code below do not work. A working alternative is detailed at a newer post.   You’re probably familiar with Data Breakpoints, and rightfully so: It’s extremely useful to know where a value changes. … Continue reading →

Posted in Debugging, VC++, Win32 | 6 Comments

_VC80_UPGRADE and Warning RC4005 (IDR_MANIFEST Redefinition)

Posted on May 13, 2011 by Ofek Shilon

The _VC80_UPGRADE macro seems to cause some confusion around, as does the warning – ‘warning RC4005: ‘IDR_MANIFEST’ : redefinition.’ While it was tempting to try and smear these issues on two posts, fact is they are one. A disk search … Continue reading →

Posted in VC++, Visual Studio | Leave a comment

g_dwLastErrorToBreakOn: Watching Errors on VS Revisited

Posted on May 3, 2011 by Ofek Shilon

Raymond Chen posted about SetLastError recently, and an interesting discussion ensued. One comment in particular caught my eye: The easiest way to catch a specific last error value in debugger is to set ntdll!g_dwLastErrorToBreakOn to that value. A good while … Continue reading →

Posted in Debugging, Win32 | 3 Comments

Debugging Reference Count – Part 1

Posted on April 28, 2011 by Ofek Shilon

I recently dealt with a large memory leak that turned out to be a delicate reference count issue. It is a common debugging scenario, and I’ll be sharing here some suggestions about it. First I had to isolate the leaking … Continue reading →

Posted in Debugging, VC++ | Leave a comment

The Case of the ‘X’ That Didn’t Kill the App

Posted on February 7, 2011 by Ofek Shilon

One of our MFC apps recently had a weird bug: occasionally debug builds would result in a binary where the ‘X’ corner button killed the app window but not the app – it would just keep idle indefinitely until killed … Continue reading →

Posted in Debugging, VC++ | 1 Comment

AfxIsValidAddress (and Others) Don’t Work as Advertised

Posted on January 31, 2011 by Ofek Shilon

MFC exposes a some memory debugging facilities such as AfxIsValidAddress, which (for debug builds) supposedly – Tests any memory address to ensure that it is contained entirely within the program’s memory space. Or does it?   AfxIsValidAddress only delegates the call … Continue reading →

Posted in MFC, Win32 | Leave a comment

Child Breakpoints in Visual Studio

Posted on January 24, 2011 by Ofek Shilon

You often see in the breakpoints window that certain breakpoints are expandable: These are called child breakpoints, and are a strong contender to the title of most poorly documented feature of VS.  According to MSDN, child breakpoints occur – …when … Continue reading →

Posted in Debugging, Visual Studio | 1 Comment

‘Frames below may be incorrect’, or: Stack Walking Requires Symbols

Posted on December 15, 2010 by Ofek Shilon

Here’s the symptom – you stop and inspect a stack: Note the message at the second line: Frames below may be incorrect and/or missing. No symbols loaded for XXXXX.dll. Chances are you read it once years ago and ignored it … Continue reading →

Posted in Debugging, Visual Studio | 5 Comments