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• Why bother with RegisterWaitForSingleObject when you have MsgWaitForMultipleObjects?

  Commenter kokorozashi wonders why you should bother with RegisterWaitForSingleObject when you have MsgWaitForMultipleObjects already . If you want to pump messages and wait for a kernel object, then you can change all calls to PeekMessage , GetMessage Read More... Posted Monday, November 17, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• Does version 6 of the common controls support ANSI or not?

  I mentioned in passing a few years ago that version 6 of the common controls supports only Unicode . And then other people stepped in to say, "Well, XYZ uses ANSI and that works for me." So does it support ANSI or doesn't it? It does and doesn't. All Read More... Posted Thursday, November 06, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• If there's already a bug, it's not surprising that there's a possibility for error

  It's great to think about all the things that can go wrong but you also have to think about the situations that could lead to those bad things. In particular, you have to recognize when you are trying to avoid a bug that is ultimately outside your component Read More... Posted Monday, November 03, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• Working with ambiguous and invalid points in time in managed code

  Public Service Announcement: Daylight Saving Time ends in most parts of the United States this weekend. I pointed out some time ago that Win32 and .NET deal with daylight saving time differently. Specifically, Win32 always deals with the time zone you Read More... Posted Friday, October 31, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code, Time

• If you don't want to try to repair the data, then don't, but you should at least know that you have corrupted data

  When I wrote about understanding the consequences of WAIT_ABANDONED , I mentioned that one of the possible responses was to try to repair the damage, but some people are suspicious of this approach . Mind you, I'm suspicious of it, too. Repairing corruption Read More... Posted Monday, October 27, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• Sucking the trap frame out of a kernel mode stack trace

  If you are placed in the unfortunate position of having to debug a user-mode crash from kernel mode, one of the first things you have to do is get back to the exception on the user-mode side so you can see what happened. We saw earlier how you can get Read More... Posted Friday, October 24, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• Why can't you thunk between 32-bit and 64-bit Windows?

  It was possible to use generic thunks in 16-bit code to allow it to call into 32-bit code. Why can't we do the same thing to allow 32-bit code to call 64-bit code ? It's the address space. Both 16-bit and 32-bit Windows lived in a 32-bit linear address Read More... Posted Monday, October 20, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• Psychic debugging: Why your thread is spending all its time processing meaningless thread timers

  I was looking at one of those "my program is consuming 100% of the CPU and I don't know why" bugs, and upon closer investigation, the proximate reason the program was consuming 100% CPU was that one of the threads was being bombarded with WM_TIMER messages Read More... Posted Thursday, October 16, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• How do I suppress the CapsLock warning on password edit controls?

  One of the features added to version 6 of the shell common controls is a warning balloon that appears if CapsLock is on in a password control. Let's demonstrate. Take the scratch program , add a manifest that requests version 6 of the common controls Read More... Posted Friday, October 10, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• How can I increase the number of files I can open at a time?

  People who ask this question invariably under-specify the question. They just say, "How can I increase the number of files I can open at a time?" without saying how they're opening them. From the operating system's point of view, the number of files you Read More... Posted Thursday, October 09, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• Acquire and release sound like bass fishing terms, but they also apply to memory models

  Many of the normal interlocked operations come with variants called InterlockedXxxAcquire and InterlockedXxxRelease . What do the terms Acquire and Release mean here? They have to do with the memory model and how aggressively the CPU can reorder operations Read More... Posted Friday, October 03, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• Anybody can make up a generic mapping

  Each component that uses ACLs to control access has its own idea of what GENERIC_READ , GENERIC_WRITE , and GENERIC_EXECUTE mean. It's not like there's a master list that somebody can make that lists them all, because I can make up a new one right here. Read More... Posted Monday, September 29, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• ERRORLEVEL is not %ERRORLEVEL%

  The command interpreter cmd.exe has a concept known as the error level , which is the exit code of the program most recently run. You can test the error level with the IF ERRORLEVEL command: IF ERRORLEVEL 1 ECHO error level is 1 or more <sidebar> Read More... Posted Friday, September 26, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• I've seen why people steal the foreground window for their dialog box

  Now, it may very well be true that many people who use GetForegroundWindow() as the owner for a dialog box because they don't know any better, but I'm not convinced that everyone who does so did it out of ignorance; I'm sure there's some malice in there, Read More... Posted Monday, September 22, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code

• How can I tell that a directory is weird and should be excluded from the user interface?

  Last time , we looked at a customer who wanted to know how to tell whether a given folder was a Recycle Bin folder or not. We answered the question as stated, but made the mistake of not looking at the problem the customer was trying to solve. I need Read More... Posted Friday, September 19, 2008 10:00 AM from The Old New Thing : Code | (Comments Off) Filed under: Code