The case of the file that won't copy because of an Invalid Handle error message

Raymond ChenOctober 31, 2014Oct 31, 201410/31/14

A customer reported that they had a file that was “haunted”
on their machine:
Explorer was unable to copy the file.
If you did a copy/paste, the copy dialog displayed an error.

1 Interrupted Action

Invalid file handle

⚿ 
Contract Proposal
Size: 110 KB
Date modified: 10/31/2013 7:00 AM

Okay,

The contents of the Start page are not programmatically accessible

Raymond ChenOctober 29, 2014Oct 29, 201410/29/14

A customer wanted to know if is possible for an application to edit the user’s Start page.
No, there is no interface for editing the user’s Start page or even knowing what is on it. The Start page is the user’s personal space and applications should not be messing with it.

A question about preventing the system from going to the idle state turns out to be misguided

Raymond ChenOctober 28, 2014Oct 28, 201410/28/14

A customer asked how they could have their program prevent the system from going to the idle state. Specifically, when the system goes idle, the application gets into a weird state where it starts leaking memory like crazy. The program normally uses around 100MB of memory,

Enumerating the ways of distributing n balls into k boxes

Raymond ChenOctober 27, 2014Oct 27, 201410/27/14

Suppose you had n indistinguishable balls
and k distinguishable boxes.
Enumerate the ways of distributing the balls into boxes.
Some boxes may be empty.

We can represent each distribution in the form of
n stars and
k − 1 vertical lines.

Debugging a hang: Chasing the wait chain inside a process

Raymond ChenOctober 24, 2014Oct 24, 201410/24/14

Today we’re going to debug a hang.
Here are some of the (redacted) stacks of the process.
I left some red herrings and other frustrations.

0: kd> !process ffffe000045ef940 7
PROCESS ffffe000045ef940
SessionId: 1 Cid: 0a50 Peb: 7ff6b661f000 ParentCid: 0a0c
DirBase: 12e5c6000 ObjectTable: ffffc0000288ae80 HandleCount: 1742.

How can I detect programmatically whether the /3GB switch is enabled?

Raymond ChenOctober 23, 2014Oct 23, 201410/23/14

A customer was doing some diagnostic work and wanted a way to detect
whether the
/3GB switch was enabled.
(Remember that the /3GB switch is
meaningful only for 32-bit versions of Windows.)

The way to detect the setting is to call
Get­System­Info and look at the
lp­Maximum­Application­Address.

How do I disable Windows 8 touch contact visualizations for my application?

Raymond ChenOctober 22, 2014Oct 22, 201410/22/14

You might have an application (like a game) where the default
touch contact visualizations are a distraction.
In WinRT, you can disable the contact visualizations by simply saying

// JavaScript
Windows.UI.Input.PointerVisualizationSettings.
getForCurrentView().
isContactFeedbackEnabled = false;
// C#
Windows.UI.Input.PointerVisualizationSettings.
GetForCurrentView().
IsContactFeedbackEnabled = false;

The great thing about regular expression languages is that there are so many to choose from!

Raymond ChenOctober 21, 2014Oct 21, 201410/21/14

Before you ask a question about regular expressions,
you should make sure you and your audience agree on
which regular expression language you are talking about.

Here is a

handy table of which features are supported by
which regular expression language.

Scripting an Internet Explorer window

Raymond ChenOctober 20, 2014Oct 20, 201410/20/14

Today’s Little Program takes a random walk through MSDN
by starting at the Create­Process page
and randomly clicking links.
The exercise is not as important as the technique it demonstrates.

function randomwalk(ie, steps) {
for (var count = 0; count <