Showing results for Code - The Old New Thing

Another developer tax is playing friendly with Fast User Switching and Terminal Services. When the workstation is locked or disconnected, you should turn off non-essential timers, minimize background activities, and generally send your program into a quiet state. If you already used the technique of painting only when your window is visible on th...

An increasingly important developer tax is supporting Remote Desktop Connection properly. When the user is connected via a Remote Desktop Connection, video operations are transferred over the network connection to the client for display. Since networks have high latency and nowhere near the bandwidth of a local PCI or AGP bus, you need to adapt to...

Occasionally, somebody will ask I'm debugging a hang, and I see that many threads are stuck at a RET instruction. When I try to trace one instruction from that thread, the trace breakpoint never fires. It's as if the RET instruction itself is wedged! I've found the world's slowest RET instruction. (A common variation on this theme is that the th...

One thing that I see occasionally is the abuse of property syntax. IDispatch and CLR objects (and C++ objects if you want to avail yourself of a Microsoft-specific extension) support "properties", which syntactically look like fields but internally are treated as a pair of methods ("get" and "put"). An important principle is that given an object ...

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...