Showing results for April 2011 - Page 2 of 3 - The Old New Thing

If you are using Visual Studio 2005 or later, then you don't need the weird function because Visual Studio 2005 and later automatically impose acquire semantics on reads from volatile locations. It also imposes release semantics on writes to volatile locations. In other words, you can replace the old function with the following: This is a g...

I actually came back Thursday night, but I've been too lazy to jot down some reactions until now. There are signs on the street directing you to a tram connecting the Monte Carlo hotel with the Bellagio. but once you follow the first sign (that takes you into the casino), there are no more signs telling you how to get to the tram. The tram is a l...

In addition to the loader lock, the message queue is another resource that people often forget to incorporate into their lock hierarchy. If your code runs on a UI thread, then it implicitly owns the message queue whenever it is running, because messages cannot be dispatched to a thread until it calls a message-retrieval function such as or . In o...

The last lock-free pattern for this week isn't actually lock-free, but it does run without blocking. The pattern for what I'll call try/commit/(hand off) is more complicated than the other patterns, so I'll start off by describing it in words rather than in code, because the code tends to make things more complicated. First, you take the state...

Suppose profiling reveals that a specific calculation is responsible for a significant portion of your CPU time, and instrumentation says that most of the time, it's just being asked to calculate the same thing over and over. A simple one-level cache would do the trick here. Of course, this isn't thread-safe, because if one thread is pre-empted...

A customer was looking for advice on this synchronization problem: We have a small amount of data that we need to share among multiple processes. One way to protect the data is to use a spin lock. However, that has potential for deadlock if the process which holds the spinlock doesn't get a chance to release it. For example, it might be suspend...

While on a trip to Las Vegas, I happened to overhear a woman talking on her mobile phone who, from her body language, was clearly trying to meet up with a friend. We were in the casino of one of the major hotels. She said, "I'm over here by the slot machines." Yeah, that narrows it down. I'll be heading to Vegas for the Niney Awards. If I don't ...

The singleton constructor pattern and the example we saw some time ago are really special cases of the more general pattern which I'll call try/commit/(try again). I don't know if this pattern has a real name, but that's what I'm calling it for today. The general form of this pattern goes like this: We calculate the desired new value based ...

Holding the shift key when calling up a context menu is a convention for indicating that you want to see additional advanced options which are normally hidden. One of those options is Pin to Start menu. What is this doing as an extended command? The Pin to Start menu command normally appears on the context menu of a program or a shortcut to a pr...

Letting the smart people do the work for you.