April 2019 | Page 2 of 3 | The Old New Thing

Microspeak: Occupant compression

Raymond Chen April 16, 2019 Apr 16, 2019 04/16/19

This is not so much Microspeak as it is Microsoft Real Estate and Facilities-speak. The following notice was displayed in one of the buildings: Microsoft Real Estate and Facilities will be converting lab 1234 to a team space. The new space will ease occupant compression. Occupant compression? Ouch, that sounds painful. The term compression...

Today is tax day, but it’s also division meeting day, so let’s get you some forms to fill out

Raymond Chen April 15, 2019 Apr 15, 2019 04/15/19

Many years ago, there was a division-wide meeting for all of the Windows product team. A local convention center was rented out for the occasion, buses were hired to shuttle employees to and from the venue, the usual "very large meeting" nonsense. The meeting happened to be scheduled for April 15, which is the day that individual income taxes...

How can a desktop app use a Windows Runtime object that infers UI context from its thread? The IInitializeWithWindow pattern

Raymond Chen April 12, 2019 Apr 12, 2019 04/12/19

Many objects in the Windows Runtime can be used from desktop apps. For today's example, we'll use the FileOpenPicker. This is a rather artificial example because you could just use the IFileDialog interface to get equivalent functionality in a desktop app, but I just picked it for use as an example. Start with our scratch ...

How can I determine the reason why my window is closing?

Raymond Chen April 11, 2019 Apr 11, 2019 04/11/19

A customer wanted to know whether their MFC program can determine why their window is closing, similar to how WinForms does. The source code for WinForms is online. You can see how they do it, and then translate that to MFC. Many of the CloseReason values refer to actions that occurred within WinForms itself, so those are naturally ...

Even if you open a file with GUID, you can still get its name, or at least one of its names

Raymond Chen April 10, 2019 Apr 10, 2019 04/10/19

Some time ago, I showed how you could eschew file names entirely and use GUIDs to open your files. But even if you choose to open the file with a GUID, you can still get its name. Take the second program from that earlier article and make these changes: There's a catch: If the file has multiple names (say, due to hard links), then only one ...

When I select multiple files in the File Open dialog, why does the last item come first?

Raymond Chen April 9, 2019 Apr 9, 2019 04/9/19

If you have a File Open dialog that supports multiple selections, and you select multiple files, you may notice that the file you selected last is listed first. This is annoying when the order of the files in the selection is significant. Why does the last item selected become the first item listed? This is a case of a leaky abstraction. The...

Optimizing your cafeteria meal card stockpile

Raymond Chen April 8, 2019 Apr 8, 2019 04/8/19

As I noted when I told the story of getting one's paycheck from some mysterious pile of money, I had a colleague with a lot of money-related quirks. Back in the early 1990's, payment for food in the Microsoft cafeterias could be made in cash, personal check, or in the form of a voucher known as a meal card. A Microsoft meal card was a piece ...

What does it mean when my attempt to stop a Windows NT service fails with ERROR_BROKEN_PIPE?

Raymond Chen April 5, 2019 Apr 5, 2019 04/5/19

A customer reported that they had a sporadic problem: Their product includes a Windows NT service, and when their client program tries to stop the service, it sometimes fails with ERROR_BROKEN_PIPE. Their client program is written in C#, so it uses the ServiceController.Stop method to stop the service, and the failure is reported in the ...

Why do we need atomic operations on the 80386, if it doesn’t support symmetric multiprocessing anyway?

Raymond Chen April 4, 2019 Apr 4, 2019 04/4/19

The 80386 processor did not support symmetric multiprocessing, yet we discussed atomic operations when in our overview of the processor. If the processor doesn't even support symmetric multiprocessing, why does it matter? Well, one reason is that the 80386 processor does support asymmetric multiprocessing. Floating point operations are ...

Dubious security vulnerability: Code execution via LNK file

Raymond Chen April 3, 2019 Apr 3, 2019 04/3/19

A security vulnerability report arrived that claimed to have achieved code execution via a shortcut (LNK) file. The report was somewhat convoluted, but it went something like this: If you can trick the user into double-clicking an arbitrary shortcut file of your choosing, then you don't have to do all this weird special ...

The Old New Thing