January 2013 | The Old New Thing

The somewhat misguided question of whether MapViewOfFile or WriteProcessMemory is faster

Raymond ChenJanuary 31, 2013Jan 31, 201301/31/13

A customer asked, "Which is faster for copying data from one process to another; MapViewOfFile or WriteProcessMemory?" This is one of those "Huh?"-type questions, where the customer has solved half of a problem and is looking for help with the other half, the half that makes no sense. First of all, the question is...

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

Raymond ChenJanuary 30, 2013Jan 30, 201301/30/13

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...

Poisoning your own DNS for fun and profit

Raymond ChenJanuary 29, 2013Jan 29, 201301/29/13

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 ...

Please hold your head perfectly still while you write up that memo

Raymond ChenJanuary 28, 2013Jan 28, 201301/28/13

I dreamed that the original Volkswagen Beetle factory was so cramped that the office workers had to move their desks to the factory floor, with heavy equipment swinging around just inches from their faces. To prevent serious injuries, a template passed through every so often to make sure nothing was out of place...

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

Raymond ChenJanuary 28, 2013Jan 28, 201301/28/13

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 ...

When you have a SAFEARRAY, you need to know what it is a SAFEARRAY of

Raymond ChenJanuary 25, 2013Jan 25, 201301/25/13

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&, ...

STRICT_TYPED_ITEMIDS is the shell namespace version of the STRICT macro used by USER and GDI

Raymond ChenJanuary 24, 2013Jan 24, 201301/24/13

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...

Why was WHEEL_DELTA chosen to be 120 instead of a much more convenient value like 100 or even 10?

Raymond ChenJanuary 23, 2013Jan 23, 201301/23/13

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 ...

Eliot Chang’s list of things Asians hate

Raymond ChenJanuary 22, 2013Jan 22, 201301/22/13

One time, somebody asked me, "What nationality are you?" I answered, "American." "No, I mean what nationality are your parents?" "They're also American." "No, I mean where are your parents from?" "They're from New Jersey." "No, I mean before that." "North Carolina...

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