Nowadays, computers have so much memory that running out of RAM is rarely the cause for an "out of memory" error. Actually, let's try that again. For over a decade, hard drive have been so large (and cheap) that running out of swap space is rarely the cause for an "out of memory" error. In user-mode, the term memory refers to virtual memory,...
A customer had a program which performed some final I/O operations as it exited. Various C++ objects deleted files or flushed buffers as part of their destructors. The customer found that if their program was left running when the user shut down Windows, then the files never got deleted, and the buffers were never flushed. On the other hand, if the...
A customer put the following code at the start of their program: // If this assertion fires, then somebody else changed the error mode // and I just overwrote it with my error mode. ASSERT(SetErrorMode(SEM_FAILCRITICALERRORS) == 0); The customer wanted to know whether it was a valid assumption that the initial error mode for a process is zero....
Today's Little Program draws content at a fixed screen position. The idea is that the window is really a viewport into some magical world. Unfortunately, our magical world just has a sign that says "Booga booga." Creating a more interesting magical world is left as an exercise. Start with our scratch program and make these changes: void OnMov...
For motivational purposes, let's start with a program that displays a DWM thumbnail. Start with the scratch program and add the following: #include <dwmapi.h> HWND g_hwndThumbnail; HTHUMBNAIL g_hthumb; void UpdateThumbnail(HWND hwndFrame, HWND hwndTarget) { if (g_hwndThumbnail != hwndTarget) { g_hwndThumbnail = hwndTarget; if (g...
Consider this code: // Code in italics is wrong foregroundThreadId = ::GetWindowThreadProcessId(::GetForegroundWindow(), 0); myThreadId = GetCurrentThreadId(); if (foregroundThreadId != myThreadId) { AttachThreadInput(foregroundThreadId, myThreadId, TRUE); BringWindowToTop(myWindowHandle); If you try to step ov...
Today's Little Program will show a property sheet that covers multiple files, just like the one you get from Explorer if you multi-select a bunch of files and right-click them all then select Properties. In fact, that description of how you do the operation interactively maps directly to how you do the operation programmatically! #define UNICO...
Last time, we listener for window navigations. Today we'll learn about tracking window creation and destruction. The events to listen to are the DShellWindowsEvents. The WindowRegistered event fires when a new window is created, and the WindowRevoked event fires when a window is destroyed. The bad news is that the paramet...
Okay, it's been a while since we set aside our Little Program to learn a bit about connection points and using dispatch interfaces as connection point interfaces. Now we can put that knowledge to use. Internet Explorer and Explorer windows fire a group of events known as DWebBrowserEvents, so we just need to listen on those events ...
Last time, we learned about how connection points work. One special case of this is where the connection interface is a dispatch interface. Dispatch interfaces are, as the name suggests, COM interfaces based on IDispatch. The IDispatch interface is the base interface for OLE automation objects, and if you want your connection point interface to...
