Showing tag results for Code

If you call on a critical section you never entered, the behavior is undefined. Critical sections are an extremly high-traffic code path. Intense work goes into making them as fast as possible. Customers like to ask questions like "Exactly how many cycles does it take to enter a critical section? We're not going to use them if they're too slow."...

The window manager distinguishes between synchronous state (the state of the world based on what messages your program has received) and asynchronous state (the actual state of the world this very instant). We saw this earlier when discussing the difference between GetKeyState and GetAsyncKeyState. Here are some other functions and their relation...

Memory access time changes the math.

If you have one of those cool swively LCD displays (or if you decided to build your own), you naturally want to tell your video card to display rotated output, so you can take advantage of the portrait orientation. And naturally you would think that calling the and using the field of the structure would do the trick. And then you would find t...

In response to my description of how you can use the #error directive to check whether the compiler even sees you, some commenters proposed alternatives. I never claimed that my technique was the only one, just that it was another option available to you. Here are some other options. scott suggested merely typing asdasdasd into the header file ...

Commenter Kevin Eshbach asks why you cannot programatically change the text centering style of an edit control after the control has been created. The edit control is one of the original window manager controls, so it comes with a lot of history. First thing to note is that the message did not exist until Windows 95. The edit control preda...

A customer asked the following question: Is it guaranteed that the events when signaled multiple times on an event object are delivered in the order in which they were signaled? For example, a thread is waiting on the event handle and performs some operation each time it is signaled. The ordering of those operations should be in the same order...

Commenter Skeets Norquist asks how to tell whether the original window procedure processed a message when you use to call the original window procedure. "CallWindowProc() always seems to return an LRESULT of 0." No, actually, returns whatever the window procedure did. If the window procedure returned zero, then returns zero. If the window pro...

Prerequisites: Experience with sort functions such as qsort. Overqualifications: Familiarity with sort algorithms. If you break the rules for sort comparison functions, then don't expect the result of a sort call to be meaningful. In fact, if you really mess it up, you can corrupt memory or go into an infinite loop. My program hangs when I...

When you subclass a window, you set the window procedure to a function of your choosing, and you remember the original window procedure so you can pass it to the CallWindowProc function when your subclass function wants to pass the message to the original window procedure. For example, if you subclass a window like this: SubclassWidgetDialog(HWN...