The Old New Thing

The somewhat misguided question of whether MapViewOfFile or WriteProcessMemory is faster

January 31, 2013 Jan 31, 2013 01/31/13

Raymond Chen

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?

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...

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 ...

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&, ...

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...