The Old New Thing

Code - The Old New Thing

How do I simulate input without SendInput?

December 21, 2010 Dec 21, 2010 12/21/10
Raymond Chen
Michal Zygmunt wants to create a system where multiple applications can have focus, with different users generating input and directing them at their target applications. Attempting to simulate this by posting input messages didn't work. "Can you tell us maybe how SendInput is internally implemented so that we can use it to simulate only ...

Developing the method for taking advantage of the fact that the OVERLAPPED associated with asynchronous I/O is passed by address

December 20, 2010 Dec 20, 2010 12/20/10
Raymond Chen
You can take advantage of the fact that the associated with asynchronous I/O is passed by address, but there was some confusion about how this technique could "work" when kernel mode has no idea that you are playing this trick. Whether kernel mode is in on the trick is immaterial since it is not part of the trick. Let's start with a ...

The OVERLAPPED associated with asynchronous I/O is passed by address, and you can take advantage of that

December 17, 2010 Dec 17, 2010 12/17/10
Raymond Chen
When you issue asynchronous I/O, the completion function or the I/O completion port receives, among other things, a pointer to the structure that the I/O was originally issued against. And that is your key to golden riches. If you need to associate information with the I/O operation, there's no obvious place to put it, so some people end ...

Why does SHCOLUMNINFO have unusually tight packing?

December 16, 2010 Dec 16, 2010 12/16/10
Raymond Chen
Alternate title: News flash: Sometimes things happen by mistake rbirkby asks why the structure has 1-byte packing. "Was the expectation that there would be so many columns in a details view that the saving would be worthwhile?" Hardly anything that clever or ingenious. It's just the consequence of a mistake. When the structure was ...

There is no interface for preventing your notification icon from being hidden

December 15, 2010 Dec 15, 2010 12/15/10
Raymond Chen
Yes, it's another installment of I bet somebody got a really nice bonus for that feature. A customer had this question for the Windows 7 team: Our program creates a notification icon, and we found that on Windows 7 it is hidden. It appears properly on all previous versions of Windows. What is the API to make our icon visible? ...

How do I limit the size of the preview window used by Aero Snap?

December 10, 2010 Dec 10, 2010 12/10/10
Raymond Chen
A customer reported that the translucent preview shows by Aero Snap showed the wrong dimensions for their application window. "As you can see in the screen shot, the preview is too wide. Our application window has a maximum width, but the preview is fully half the width of the screen. How can we disable the Aero Snap feature?" Whoa there, ...

We've traced the call and it's coming from inside the house: Grid lines in list view report mode

December 9, 2010 Dec 9, 2010 12/9/10
Raymond Chen
A customer wanted to know how to remove the grid lines from a list view control in report mode. The customer was kind enough to include the source code for the relevant part of the program and drew our attention to the line in the resource file that he believed to be the source of the problem: The customer didn't know it, but that line in ...

The alignment declaration specifier is in bytes, not bits

December 2, 2010 Dec 2, 2010 12/2/10
Raymond Chen
Explicit object alignment is not something most people worry about when writing code, which means that when you decide to worry about it, you may be a bit rusty on how the declarations work. (After all, if it's something you worried about all the time, then you wouldn't have trouble remembering how to do it!) I was looking at some customer ...

The easy way out is to just answer the question: What is the current Explorer window looking at?

November 26, 2010 Nov 26, 2010 11/26/10
Raymond Chen
A customer had the following question: We have an application which copies and pastes files. Our problem is that we want to paste the files into the folder which corresponds to the currently active Windows Explorer window. Right now, we're using , but we find this method unsatisfactory because we want to replace Explorer's default file copy ...