What does it mean when GetQueuedCompletionStatus return ERROR_SEM_TIMEOUT?

Raymond Chen July 17, 2014 Jul 17, 2014 07/17/14

A customer asked for assistance interpreting a failure of the Get­Queued­Completion­Status function. We are observing that Get­Queued­Completion­Status is intermittently behaving as follows: That's all the information we have in our log files. We don't know the value of number­Of­Bytes or completion­...

How do I configure Windows Update programmatically?

Raymond Chen July 16, 2014 Jul 16, 2014 07/16/14

First of all, normal programs shouldn't be messing with Windows Update configuration. That's something the user (or the user's administrator) decides. If you're an IT administrator, then you can use Group Policy to configure Windows Update on your network. But maybe you're a special case where the above remarks don't apply. Say you're a ...

Enumerating integer compositions (the return of the binomial coefficients)

Raymond Chen July 14, 2014 Jul 14, 2014 07/14/14

In number theory, a composition of an integer is an ordered sequence of positive integers which sum to the target value. For example, the value 3 can be written as 3, 1+2, 2+1, or 1+1+1. You can think about the target number as a string of stars, and a composition is a way of breaking the stars into groups. For example, here are the ...

If I duplicate a handle, can I keep using the duplicate after closing the original?

Raymond Chen July 11, 2014 Jul 11, 2014 07/11/14

A customer asked whether it was okay to use a duplicated handle even after the original handle was closed. Yes. That's sort of why you would duplicate it. Duplicating a handle creates a second handle which refers to the same underlying object as the original. Once that's done, the two handles are completely equivalent. There's no way to know...

Using the REFIID/void** pattern for returning COM objects for future-proofing and to avoid problems with dependencies

Raymond Chen July 10, 2014 Jul 10, 2014 07/10/14

Suppose you have a function that creates a reference to a COM object: There are a few issues with this design. First of all, it requires that whoever uses your header file must have included shlobj.h first, since that's where IShell­Item is defined. You could solve that problem by putting #include <shlobj.h> at the top of pixie...