The Old New Thing
Practical development throughout the evolution of Windows.
Latest posts
Why does my window get a WM_ACTIVATE message when it isn't active?
Say you launch a program, and for whatever reason the program takes a long time to start up, so you start doing something else, say launching Calculator and balancing your checkbook. Eventually, the program you launched a while back gets itself off the ground and creates its main window. And the window sits in the background (since the window manager won't let it steal foreground activation), but the caret is blinking in the edit control, and the program seems to think it's the active window. If you write a test program to do this, say by sticking a at the start of your , you'll see that your window gets a mes...
Just because I don't deny something doesn't make it true
There are a number of tricks people try to pull, and I hate them. Today's trick is one of the many varieties of the BCC trick (sometimes less surreptitiously—but still annoyingly—done as a CC trick). Occasionally, I will be quietly added to an email discussion, typically via BCC, without any indication as to why I was added. After reading the discussion (which can be quite lengthy), I realize that they are pulling the "Raymond didn't deny this, so I'll assume this is true" trick. They are adding me as a way of obtaining my approval for a claim made in the discussion. "The Widget does not immediatel...
The imaginary experience of dining at an underground restaurant
I dreamed that my brother complained, "Dude, you didn't leave room for my car in the garage." Well yeah, because I didn't know you were coming. We decide to go out for dinner, and I see that he squeezed a third car into our two-car garage. We back out, and I watch the car fit through a gap of two feet between my car and the garage door. We drive around and decide to eat at an underground restaurant at the home of my retired next-door neighbors (across the street in real life at my old house). At this point, my dinner partner changes to a former work colleague. Without prompting, she tilts her head back, and he...
Filtering the folders that appear in the Browse for Folder dialog
IFolderFilter.
C++ corner case: You can implement pure virtual functions in the base class
In our discussion , we saw that you can declare a pure virtual function with the syntax, and if you try to call one of these functions from the base class, you will get the dreaded R6025 - pure virtual function call error. In that article, I wrote that a pure virtual function is "a method which is declared by the base class, but for which no implementation is provided." That statement is false. You can provide an implementation for a pure virtual method in C++. "That's crazy talk," I hear you say. Okay, let's start talking crazy: What happens when the function constructs a ? Trick question, becau...
Happy 110th birthday, Professor Alyea
Professor Hubert Alyea would be 110 years old today, if he were still among us. (He passed away in 1996 at the ripe age of 93.) LIFE magazine called him the science teacher you wish you had for his engaging (and often explosive) chemistry demonstrations. He was called an "international grand master of lecture demonstrations" by Bassam Shakhashiri, noted chemist and author of several books on chemical demonstrations. I had the immense good fortune to attend one of his lectures. As he prepared his equipment, he casually popped a piece of dry ice in his mouth. (DO NOT TRY THIS AT HOME.) You can see a demonstrat...
How do I find out what size the window manager would have chosen for my window?
We saw some time ago how the window manager decides where to place a newly-created window if you pass the values when creating the window. But what if you want to filter the values first? If you pass an explicit upper left corner but pass for the width and height, then the bottom right corner will be down near the bottom right corner of the screen. Given that your code is buggy, is there a way I can ask how big you would have made the window, so I can go in and fix your mistake? If I try to resize it after the fact, there's an ugly flicker. I'm kind of disgusted that something this simple still doesn't work ...
Using the TAB key to navigate in non-dialogs, redux
You want to use the TAB key to navigate through a non-dialog, so you call in your message loop, but it doesn't work! The problem here is that you are passing the wrong window handle to . The first parameter to is the dialog-like window you want to be able to navigate through. But the code above passes the window that received the message, so you are basically telling the control to do TAB navigation within itself. And naturally, the result of that is that focus stays where it is, because if you ask a button, "Hey, could you move to your next tab stop?" the button is going to say, "Dude, I'm the only tab st...
I wrote my thesis on an airplane, for heaven's sake
As I wrote today's story, I recalled that I wrote the bulk of my thesis on an airplane. In longhand. Microsoft flew me out for an interview, so I had to endure two cross-country plane trips. I scheduled the interview on a Monday so that I would miss only one day of class, and among the things I brought with me was a notepad, which started the trip blank. I wasn't sure why I brought it, but I was sure it'd come in handy. And then I realized that I had a lot of time to kill, what with spare moments on the ground, in the air, back on the ground, waiting for my next interview, whatever. And during that time, I wro...