The Old New Thing
Practical development throughout the evolution of Windows.
Latest posts
The challenge of improvisational historical comedy
I dreamed that one of my friends signed me up for some sort of combination Punk'd/Thank God You're Here improv show without my knowledge, and I had to explain how her husband had unwittingly coined some nonspecific Internet meme.
Why doesn't the "Automatically move pointer to the default button in a dialog box" work for nonstandard dialog boxes, and how do I add it to my own nonstandard dialog boxes?
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 is enabled, it will center the pointer on the default button. If your application does not use the dialog manager but instead creates its own custom dialog-like windows, then naturally the code in the standard dialog manager will not run. If you want your nonstandard...
If I attach a file to an existing completion port, do I have to close the completion port handle a second time?
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 port, in addition to whatever other file handles are already associated with that port. In both cases, the return value on success is a handle to the I/O completion port, either the brand new one or the existing one. The question from a customer was, "In the case where I...
All I/O on a synchronous file handle is serialized; that's why it's called a synchronous file handle
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." Imagine if synchronous file handles were not serialized for metadata operations. First of all, it means that the documentation for synchronous file handles suddenly got a lot more complicated. "Some operations on synchronous file handles are serialized, but not others. S...
Adding a confirmation dialog to every drag/drop operation does not solve the problem
A customer wanted to know how to enable a confirmation dialog whenever the user inadvertently perform a drag/drop operation in Explorer to move files within a volume. For example, if I have an S drive mapped to \\server\share, I would like to display the confirmation dialog when users inadvertently drag and drop a file or folder within the S drive. Okay, first of all, the problem statement doesn't match the question. But that's good, because the question was misguided. The question was "How do I add a confirmation dialog to every drag/drop operation?" But the problem statement was "We have users who inadverte...
Microspeak: The train
Hop on board, don't be late, or you'll have to catch the next one.
A dream about forgetting to deploy the backup brake pads
I dreamed that that I was driving through a parking garage when my brakes suddenly failed. I tried executing turns to bleed off speed, but it was largely ineffective. I managed to avoid hitting a parked police car (which had arrived to investigate some other accident), but was unable to avoid another parked car. An insurance adjuster who was on the scene for the first accident looked at my car and discovered that my primary brake pads were completely missing, so the calipers were grabbing air. And in my panic, it never occurred to me to use my left foot to push the button which hot-installs the secondary brake p...
The tiny table sorter – or – you can write LINQ in JavaScript
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 should sort. If there is no , then I just use the cell's . (My table was constructed at runtime from an , so adding the to the date fields was not difficult.) One handy thing about the functions in the prototype is that as a rule, they do not actually require that the...
If I signal an auto-reset event and there is a thread waiting on it, is it guaranteed that the event will be reset and the waiting thread released before SetEvent returns?
Let's go straight to the question: I have two programs that take turns doing something. Right now, I manage the hand-off with two auto-reset events. In Thread A, after it finishes doing some work, it signals Event B and then immediately waits on Event A. Thread B does the converse: When its wait on Event B completes, it does some work, then signals Event A and then immediately waits on Event B. This works great, but I'm wondering if I can save myself an event and use the same event to hand control back and forth. Is it guaranteed that when Thread A signals Event ...