Showing results for Code - The Old New Thing

Here's a classic novice error. You want to call a function, say GetBinaryType. What should you write for those question marks? Well, the prototype says that the second parameter is an LPDWORD, so let's pass it one. Hm, but that crashes. Well, maybe we can pass it an LPDWORD this way: Hm, that still crashes. Oh wait, it's because of the...

The MSDN documentation for says [T]he implementation of GetHashCode provided by the String class returns unique hash codes for unique string values. This is another case of ambiguous use of the word "unique". The intended meaning is "for each string value, the same hash code is returned". Even though "unique" means "one and only one", the...

When you're developing your debugging code, don't forget that just because it's only for debugging doesn't mean that you can forget about security. I remember one customer who asked (paraphrased) We have a service, and for testing purposes we want to be able to connect to this service and extract the private data that the service is managing, ...

One frequently-overlooked software "tax" is geopolitics. We've alread seen that the time zone and regional settings dialogs created international unrest. It appears that Google Maps failed to recognize the extremely sensitive issue of naming the body of water that lies between Korea and Japan, as well as stirring up international tensions with ...

One of the taxes I alluded to some time ago when I broached the issues of software development "taxes" is Hierarchical Storage Management. The short description of Hierarchical Storage Management is that it is a way of archiving data transparently. When a file is due for archival, it is transferred to a slower (but less expensive) storage medium,...

Unlike mutexes and critical sections, semaphores don't have owners. They merely have counts. The ReleaseSemaphore function increases the count associated with a semaphore by the specified amount. (This increase might release waiting threads.) But the thread releasing the semaphore need not be the same one that claimed it originally. This is dif...

When I saw a discussion of how to simulate retry via try/catch, using as inspiration a Ruby function that retried a network operation three times before finally giving up, I felt the need to caution against automatic retry. Your natural inclination when faced with a failure that has a good chance of being caused by a transient condition is to re...

Why is there a special PostQuitMessage function? Because it's not really a posted message. Commenter A. Skrobov asked, "What's the difference between and ?" They are not equivalent, though they may look that way at first glance. The differences are subtle but significant. Like the , , and messages, the message is not a "real" posted mess...

Some people believe that the COM rules on interfaces are needlessly strict. But the rules are there for a reason. Suppose you ship some interface in version N of your product. It's an internal interface, not documented to outsiders. Therefore, you are free to change it any time you want without having to worry about breaking compatibility w...

Some time ago, I discussed several timestamp formats you might run into. Today we'll take a logical step from that information and develop a list of special values you might encounter. Note that if you apply time zone adjustments, the actual timestamp may shift by up to a day. All of these special values have one thing in common: If you see them...