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Nifty Win32 tricks. (RSS)

Building a flicker free volume control

When we shipped Windows Vista, one of the really annoying UI annoyances with the volume control was that whenever you resized it, it would flicker.  To be more specific, the right side of the control would flicker – the rest didn’t flicker (which Read More...
Posted Wednesday, September 16, 2009 2:50 PM by LarryOsterman | 30 Comments

What’s the difference between GetTickCount and timeGetTime?

I’ve always believed that the most frequently used multimedia API in winmm.dll was the PlaySound API.  However I recently was working with the results of some static analysis tools that were run on the Windows 7 codebase and I realized that in fact Read More...
Posted Wednesday, September 02, 2009 2:31 PM by LarryOsterman | 26 Comments
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Delay Load is not a good way to check for functionality

On my previous post , Koro made the following comment : “Don't ever check windows versions.  Instead check for functionality being present or not." You can't always do that. Do I want to add a __try/__except to catch delay-load exceptions around Read More...
Posted Friday, March 06, 2009 12:19 PM by LarryOsterman | 15 Comments

Fixing an accessibility bug with the trackbar common control

The trackbar common control is a strange beast. The trackbar can be oriented either horizontally or vertically. On LTR language machines, when the trackbar is horizontal, it works much as you’d expect it to: The minimum value of the trackbar is on the Read More...
Posted Tuesday, January 27, 2009 5:17 PM by LarryOsterman | 9 Comments

Fixing a customer problem: “No Audio Device is Installed” when launching sndvol on Windows Vista

Yesterday someone forwarded me an email from one of our DirectShow MVPs – he was having problems playing audio on his Windows Vista machine.   Fortunately David (the MVP) had done most of the diagnostic work – the symptoms he saw were that he was Read More...
Posted Tuesday, January 06, 2009 11:26 AM by LarryOsterman | 18 Comments

What really happens when you shutdown Windows?

About a year or so ago, I wrote a post that talked about the Windows shutdown experience.   A couple of the people reading the post asked for more details, and it turns out that the performance folks have just issued this paper which describes (in Read More...
Posted Thursday, October 09, 2008 10:47 AM by LarryOsterman | 7 Comments
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The common control library sometimes sends an NMCUSTOMDRAW message for the NM_CUSTOMDRAW notification.

I just fixed a bug in our UI that was caused by a misunderstanding of the API contract for the NM_CUSTOMDRAW handler for some of the common controls. On of October 3rd, 2008 The common control documentation for the NM_CUSTOMDRAW message says: lpNMCustomDraw Read More...
Posted Friday, October 03, 2008 4:37 PM by LarryOsterman | 7 Comments
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DrawThemeText doesn’t really support the DT_CALCRECT format value

I just noticed this while working on a bug fix. We have some code that attempts to determine the size of a piece of text by calling DrawThemeText with the DT_CALCRECT format value. According to this page (as of 9/30/2008) the DT_CALCRECT option determines Read More...
Posted Tuesday, September 30, 2008 4:49 PM by LarryOsterman | 1 Comments
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Why specify SND_NODEFAULT when calling PlaySound?

Because the alternative is often much worse.   Several months ago, I got a bug report that if you launched mmsys.cpl then set the “Select” sound to a value, then cleared the sound, the reporters application would ding whenever you moved around their Read More...
Posted Thursday, September 25, 2008 2:46 PM by LarryOsterman | 5 Comments

Why call PlaySound(NULL, NULL, SND_NODEFAULT)?

Someone just wandered over to my office and he had noticed the following pattern in his code: PlaySound(NULL, NULL, SND_NODEFAULT); PlaySound( ".Default" , NULL, SND_SYSTEM | SND_ASYNC | SND_NODEFAULT); He was wondering why on earth the code Read More...
Posted Monday, September 15, 2008 5:18 PM by LarryOsterman | 5 Comments

Anatomy of a Heisenbug

I just spent a half an hour debugging a heisenbug and thought I’d pass on what was happening.   I was running my unit tests for one of my features and they were reliably failing.  Unfortunately the instant I ran the test case under the debugger, Read More...
Posted Wednesday, September 03, 2008 10:43 AM by LarryOsterman | 15 Comments
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Gotchas associated with using WM_PRINTCLIENT…

Yesterday I mentioned WM_PRINTCLIENT and how awesome it is when trying to strictly control the drawing of your application. Part of the reason it took over a week to change the drawing model is that there are a number of serious gotcha’s associated with Read More...
Posted Thursday, August 28, 2008 9:47 AM by LarryOsterman | 22 Comments
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Larry’s new favorite windows message – WM_PRINTCLIENT

As I’ve mentioned before, I’ve been fuddling around doing UI programming recently – it’s a bit different from my usual work deep in the bowels of the <insert whatever subsystem Larry happens to be working on (redirector, audio stack, POP3 server, whatever)>. Read More...
Posted Wednesday, August 27, 2008 5:51 PM by LarryOsterman | 18 Comments
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The SS_PATHELLIPSIS, SS_ENDELLIPSIS and SS_WORDELLIPSIS styles force static controls to disable word wrap.

I didn’t find this in the documentation for the static standard window so I figured I’d put it out in my blog in the hopes that someone else won’t get stuck on this problem. The Windows “static” control has a number of styles that control how the control Read More...
Posted Thursday, August 14, 2008 11:08 AM by LarryOsterman | 5 Comments
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What’s wrong with this code, Part 22 – the answers

The other day, I wrote about measuring the dimensions of a piece of text using the DrawText API . My code worked just great when I initially tested it (obviously it’s a part of a larger chunk of code that does more complicated work).  The problem Read More...
Posted Monday, August 04, 2008 1:32 PM by LarryOsterman | 14 Comments
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