The Old New Thing

Code - The Old New Thing

Where is my program running from?

September 5, 2003 Sep 5, 2003 09/5/03
Raymond Chen
Another common question: "How do I find out where my program is? I want to be able to access support files in that same directory." Answer: GetModuleFileName(NULL...

Case mapping on Unicode is hard

September 5, 2003 Sep 5, 2003 09/5/03
Raymond Chen
Occasionally, I'm asked, "I have to identify strings that are identical, case-insensitively.  How do I do it?" The answer is, "Well, it depends. Whose case-mapping rules do you want to use?" Sometimes the reply is, "I want this to be language-independent." Now ...

Determining whether your window is covered

September 2, 2003 Sep 2, 2003 09/2/03
Raymond Chen
The method described in the previous coding blog entry works great if you are using the window visibility state to control painting, since you're using the paint system itself to do the heavy lifting for you. To obtain this information outside of the paint loop, use and . The HDC...

Painting only when your window is visible on the screen

August 29, 2003 Aug 29, 2003 08/29/03
Raymond Chen
Sometimes you want to perform an activity, such as updating a status window, only as long as the window is not covered by another window. The easiest way to determine this is by not actually trying to determine it. For example, here's how the taskbar clock updates itself...

What are those little overlay icons?

August 27, 2003 Aug 27, 2003 08/27/03
Raymond Chen
Windows XP ships with a number of icon overlays. The black clock is particularly baffling because you sometimes see it even if your system is not equipped with Hierarchical Storage Management. When this happens, it's because some program (...

Rotating the Z-order

August 26, 2003 Aug 26, 2003 08/26/03
Raymond Chen
Sometimes you run into a conflict where you need the controls laid out in one Z-order to get hit-testing to work, but need a different order to get keyboard TAB order working. For example, consider this dialog template, which has been simplified for expository purposes. The...

The secret life of GetWindowText

August 21, 2003 Aug 21, 2003 08/21/03
Raymond Chen
GetWindowText() is more complicated than you think. The documentation tries to explain its complexity with small words, which is great if you don't understand long words, but it also means that you're not getting the full story. Here's an attempt to give the full story. How windows ...