May 2012

Charles Petzold is back with another edition of Programming Windows

Raymond Chen May 17, 2012 May 17, 2012 05/17/12

Back in the day (and perhaps still true today), Charles Petzold's Programming Windows was the definitive source for learning to program Windows. The book is so old that even I used it to learn Windows programming, back when everything was 16-bit and uphill both ways. The most recent edition is Programming Windows, 5th Edition, which was ...

How to view the stack of threads that were terminated as part of process teardown from the kernel debugger

Raymond Chen May 17, 2012 May 17, 2012 05/17/12

As we saw some time ago, process shutdown is a multi-phase affair. After you call ExitProcess, all the threads are forcibly terminated. After that's done, each DLL is sent a DLL_PROCESS_DETACH notification. You may be debugging a problem with DLL_PROCESS_DETACH handling that suggests that some of those threads were not cleaned up properly. ...

Sure, we do that: Context menu edition

Raymond Chen May 16, 2012 May 16, 2012 05/16/12

A customer reported a problem that occurred only when they installed a particular application. If they uninstalled it, then the problem went away. After installing the application, the "Run As" context menu option stopped working. The customer didn't provide any other details, but we were able to make an educated guess as to what was going on...

Microspeak: The parking lot

Raymond Chen May 15, 2012 May 15, 2012 05/15/12

Mike Dunn wonders what the Microspeak term parking lot means. I'm not familiar with this term either, and the first document I turned up during my search was a PowerPoint presentation that said "Avoid using Microsoft jargon terms, such as parking lot and dogfood." Yeah, that wasn't much help. From what I can gather, the term parking lot ...

What is the historical reason for MulDiv(1, -0x80000000, -0x80000000) returning 2?

Raymond Chen May 14, 2012 May 14, 2012 05/14/12

Commenter rs asks, "Why does Windows (historically) return 2 for MulDiv(1, -0x80000000, -0x80000000) while Wine returns zero?" The MulDiv function multiplies the first two parameters and divides by the third. Therefore, the mathematically correct answer for MulDiv(1, -0x80000000, -0x80000000) is 1, because a × b ÷ b&...

Warum deine Mutter Deutsch spricht

Raymond Chen May 11, 2012 May 11, 2012 05/11/12

This upcoming Sunday is Mother's Day in the United States. In recognition of the holiday last year, a local church displayed the following message on its message board: "God couldn't be / everywhere / so God made mothers / German speaking." This explains why your mother speaks German. POIDH The church in question has an evening ...

When you crash on a mov ebx, eax instruction, there aren't too many obvious explanations, so just try what you can

Raymond Chen May 11, 2012 May 11, 2012 05/11/12

A computer running some tests encountered a mysterious crash: A colleague of mine quickly diagnosed the proximate cause. *Something* marked the code page PAGE_READWRITE, instead of PAGE_EXECUTE_READ. I suspect a bug in a driver. FOO is just a victim here. This diagnosis was met with astonishment. "Wow! What made you think to check ...

Cheap amusement: Searching for spelling errors in the registry

Raymond Chen May 10, 2012 May 10, 2012 05/10/12

One source of cheap amusement is searching for spelling errors in the registry. For example, one program tried to register a new file extension, or at least they tried, except that they spelled Extension wrong. And they wonder why that feature never worked. My discovery was that my registry contained the mysterious key HKEY_CURRENT_USER\S...

How do I hide a window without blocking on it?

Raymond Chen May 9, 2012 May 9, 2012 05/9/12

A customer was working on improving their application startup performance. They found that if their application was launched immediately after a fresh boot, the act of dismissing their splash screen was taking over 5% of their boot time. Their code removed the splash screen by calling ShowWindow(hwndSplash, SW_HIDE). They suspect that the...

Why can't I use the file sharing wizard if I exclude inheritable permissions from a folder's parent?

Raymond Chen May 8, 2012 May 8, 2012 05/8/12

In Windows Vista and Windows Server 2008, if you go to a the advanced security settings for a directory and uncheck "include inheritable permissions from this object's parent", then go back to the Sharing tab, you'll find that the "Share" button is disabled. Why is this? We don't see this behavior on Windows 7 or Windows Server 2008 ...

The Old New Thing

May 2012 - Page 2 of 3 - The Old New Thing