The Old New Thing

January 2013 - The Old New Thing

Why doesn’t HeapValidate detect corruption in the managed heap?

January 30, 2013 Jan 30, 2013 01/30/13
Raymond Chen
A customer had a program that was corrupting the managed heap by p/invoking incorrectly. The problem didn't show up until the next garbage collection pass, at which point the CLR got all freaked-out-like. "According to Knowledge Base article 286470, the GFlags tool is supposed to catch heap corruption, but it doesn't catch squat." Depending...
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Poisoning your own DNS for fun and profit

January 29, 2013 Jan 29, 2013 01/29/13
Raymond Chen
When you type a phrase into the Windows Vista Start menu's search box and click Search the Internet, then the Start menu hands the query off to your default Internet search provider. Or at least that's what the Illuminati would have you believe. A customer reported that when they typed a phrase into the Search box and clicked Search the ...

Finding a printer, and then creating a shortcut to that printer

January 28, 2013 Jan 28, 2013 01/28/13
Raymond Chen
Today's "Little Program" does two things: It looks for a printer in the Printers folder, and then once it finds it, it creates a shortcut to that printer. As is common with "Little Programs", I don't bother with error checking. I'll leave you to do that. Second part first, since it is handy on its own: Creating a shortcut to an arbitrary ...
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When you have a SAFEARRAY, you need to know what it is a SAFEARRAY *of*

January 25, 2013 Jan 25, 2013 01/25/13
Raymond Chen
A customer had a problem with SAFEARRAY, or more specifically, with CComSafeArray. CComSafeArray<VARIANT> sa; GetAwesomeArray(&sa); LONG lb = sa.GetLowerBound(); LONG ub = sa.GetUpperBound(); for (LONG i = lb; i <= ub; i++) { CComVariant item = sa.GetAt(i); ... use the item ... } The GetAt method returns a VARIANT&, ...
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STRICT_TYPED_ITEMIDS is the shell namespace version of the STRICT macro used by USER and GDI

January 24, 2013 Jan 24, 2013 01/24/13
Raymond Chen
Starting with the Windows Vista PlatformSDK, defining the symbol STRICT_TYPED_ITEM­IDS before including shell header files changes declarations that previously had simply used ITEM­ID­LIST now use one of various types which are more clear about what type of ID list is being used. Think of it as the STRICT macro for the shell...
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Why was WHEEL_DELTA chosen to be 120 instead of a much more convenient value like 100 or even 10?

January 23, 2013 Jan 23, 2013 01/23/13
Raymond Chen
We saw some time ago that the nominal mouse wheel amount for one click (known as a "detent") is specified by the constant WHEEL_DELTA, which has the value 120. Why 120? Why not a much more convenient number like 100, or even 10? Because the value 120 made it easier to create higher-resolution mouse wheels. As noted in the ...

Heads-up: Phone scammers pretending to be JPMorgan Chase MasterCard security

January 22, 2013 Jan 22, 2013 01/22/13
Raymond Chen
Recently, a round of phone scammers have been dialing through our area with a caller-ID of (000) 000-0000, which should already raise suspicions. When you answer, a synthesized voice says that they are calling from JPMorgan Chase MasterCard security. They claim that your credit card has been disabled due to suspicious activity, and in order ...