The Old New Thing

November 2014 - Page 2 of 3 - The Old New Thing

How to view the stack of a user-mode thread when its kernel stack has been paged out

November 14, 2014 Nov 14, 2014 11/14/14
Raymond Chen
Suppose you have a machine that has crashed, and your investigation shows that the reason is that there is a critical section that everybody is waiting for. While waiting for that critical section, work piles up, and eventually the machine keels over. Suppose further that this crash is given to you in the form of a kernel debugger. In case ...

When does GetTickCount consider the system to have started?

November 13, 2014 Nov 13, 2014 11/13/14
Raymond Chen
The and functions return "the number of milliseconds that have elapsed since the system was started." (The 32-bit version wraps around after around 50 days.) But when exactly is the system considered to have started? Is it when power is applied to the computer? When the BIOS completes POST? When the user picks the operating system from the ...
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How can I wait until all startup applications have finished launching?

November 12, 2014 Nov 12, 2014 11/12/14
Raymond Chen
A customer wanted to know how to detect that all startup applications have finished launching. They wanted to wait until everything settled down before proceeding with some task. What if two programs did this? Suppose two programs both wanted to detect that all startup applications have finished launching. Each one would sit there waiting ...
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A little cheat in my Tiger Beat photo homage

November 11, 2014 Nov 11, 2014 11/11/14
Raymond Chen
One thing nobody has called out in my tribute to the Bill Gates Tiger Beat photo, either because it was too subtle or too obvious, is that the photo is actually a mirror image. The arrangement of furniture in the room was not correct: The big table was on the wrong side of the room. It was also too heavy to move around, so we cheated. We ...

Kicking around a function that formats stuff

November 10, 2014 Nov 10, 2014 11/10/14
Raymond Chen
Today's "Little Program" is really a "Little Puzzle" that got out of hand. This started out as a practical question: This code fragment screams out for some sort of simplification. (I've changed the names of the classes.) Clearly, the pattern is Everything here is pretty straightforward, except for the part. Can we write a function ...
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Why does an attempt to create a SysLink control in my plug-in sometimes fail?

November 7, 2014 Nov 7, 2014 11/7/14
Raymond Chen
A customer had written a plug-in for some application, and they found that their plug-in was unable to create a SysLink control via the function. The same code in a standalone application works fine, but when the code is placed in their plug-in, the code fails. Debugging showed that the call to succeeded, but the call failed with "Cannot ...
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How do I get a handle to the primary monitor?

November 6, 2014 Nov 6, 2014 11/6/14
Raymond Chen
There are various ways of getting a monitor. You can get the monitor from a point, from a rectangle, or from a window. But how do you get the primary monitor? The primary monitor is defined to be the one which has (0, 0) as its origin. Therefore, one solution is The desktop window by convention is deemed to reside primarily on the ...
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Passing the incorrect object type for a handle, how bad is it?

November 5, 2014 Nov 5, 2014 11/5/14
Raymond Chen
A customer asked a somewhat strange question: "We are calling but passing the handle to a waitable timer. Application Verifier reports, "Incorrect object type for handle." But the code works well. We want to know the risks of passing the wrong object type to . Is the recommendation only to pass handles of type "Event" to ? Let's answer those...
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Microspeak: Line of sight

November 4, 2014 Nov 4, 2014 11/4/14
Raymond Chen
I first encountered this term in a meeting I attended. Q: We would like to be able to reverse the polarity of the neutron flow without requiring a reboot. A: Yes, that is something we've been thinking about, but we don't have line of sight to having that feature before the end of the month. From context, having line of sight to a result...