The Old New Thing

Converting between LCIDs and RFC 1766 language codes

January 5, 2006 Jan 5, 2006 01/5/06

Raymond Chen

Occasionally, I see someone ask for a function thatconverts between LCIDs (such as 0x0409 for English-US)and RFC 1766 language identifiers (such as "en-us").The rule of thumb is, if it's something a web browser would need,and it has to do with locales and languages,you should look inthe MLang library.In this case, the...

Taxes: Detecting session state changes, such as a locked workstation

January 4, 2006 Jan 4, 2006 01/4/06

Raymond Chen

Another developer tax is playing friendly with Fast User Switchingand 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 ofpainting only when your window is visible ...

Taxes: Remote Desktop Connection and painting

January 3, 2006 Jan 3, 2006 01/3/06

Raymond Chen

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

The world's slowest RET instruction

January 3, 2006 Jan 3, 2006 01/3/06

Raymond Chen

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 ...

On the abuse of properties

January 3, 2006 Jan 3, 2006 01/3/06

Raymond Chen

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

There's more to calling a function than just getting the types to match

January 3, 2006 Jan 3, 2006 01/3/06

Raymond Chen

Here's a classic novice error.You want to call a function, sayGetBinaryType.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 ...