Showing results for Code - The Old New Thing

The function takes a source rectangle and subtracts out the portion which intersects a second rectangle, returning the result in a third rectangle. But wait a second, the result of subtracting one rectangle from another need not be another rectangle. It might be an L-shape, or it might be a rectangle with a rectangular hole. How does this map bac...

Today's Little Program closes a file handle that was opened remotely. It builds on previous discussion on how to use the functions. Forcing a network file handle closed does not actually close the handle. This makes it very different from the various "force handle closed" utilities out there. Rather, forcing a network file handle closed is a...

This question was inspired by an actual customer question, but I changed a lot of it around to make for a more interesting story. (Trust me, the original story was even more boring.) A customer's background thread posted a message to the main UI thread to signal something (details not important). They found that the posted message was never rece...

We saw some time ago that the x64 calling convention in Windows reserves space for the register parameters on the stack, in case the called function wants to spill them. But can the called function use the memory for other purposes, too? You sort of already know the answer to this question. Consider this function: How would a naïve comp...

A customer wanted to know how to detect that the user has opened Notepad to view a particular file. They had come up with method based on polling and sniffing the Notepad title bar, but they found that it consumed a lot of CPU. (They hadn't noticed yet that it doesn't localize, and that it can trigger false positives since Notepad shows only the fi...

Continuing the highly-sporadic series of Win32 resource formats, today we'll look at the format of resources, which are declared in resource files as . Also the format of custom resources, which are declared in resource files by just giving the custom resource name or ordinal as the second word on the declaration. The format is very simple: It's ...

The Mouse control panel has a setting called Automatically move pointer to the default button in a dialog box, known informally as Snap to default button or simply Snap To. You may have discovered that it doesn't work for all dialog boxes. Why not? The Snap To feature is implemented by the dialog manager. When the window is shown and the setting...

There are two ways of calling the function. You can pass a null pointer as the parameter, indicating that you would like to create a brand new completion port, associated with the file handle you passed (if you passed one). Or you can pass the handle of an existing completion port, and the file handle you passed will be associated with that por...

File handles are synchronous by default. If you want asynchronous file handles, you need to pass the flag when you create the handle. And all operations on a synchronous file handle are serialized. You'd think this was a simple and obvious rule, but "Someone" finds it "very surprising that operations can block which only handle file metadata." I...

I had a little side project that displayed status information in a table, and I figured, hey, let me add sorting. And it was a lot easier than I thought. I just put the header row in the and the table contents in the , then I could use this code to sort the table: Each cell can have an optional custom attribute which specifies how the item sh...