What kind of messages can a message-only window receive?

Raymond Chen December 18, 2017 Dec 18, 2017 12/18/17

There's this thing called a message-only window, which is a very misleading name because receiving messages is the thing a window spends all its time doing anyway. It's like calling something a water-only swimming pool or a heat-only oven. It's also a very misleading name because it doesn't receive all messages. "Wait, the name of this window...

Creating double-precision integer multiplication with a quad-precision result from single-precision multiplication with a double-precision result using intrinsics (part 3)

Raymond Chen December 15, 2017 Dec 15, 2017 12/15/17

Last time, we converted our original assembly language code for creating double-precision integer multiplication with a quad-precision result from single-precision multiplication with a double-precision result to C++ code with intrinsics working entirely in registers, thereby making the function eligible for leaf function optimizations. Our ...

Creating double-precision integer multiplication with a quad-precision result from single-precision multiplication with a double-precision result using intrinsics (part 2)

Raymond Chen December 14, 2017 Dec 14, 2017 12/14/17

Last time, we converted our original assembly language code for creating double-precision integer multiplication with a quad-precision result from single-precision multiplication with a double-precision result to C++ code with intrinsics. We observed that the compiler was able to optimize out some memory accesses by extracting the values using...

Creating double-precision integer multiplication with a quad-precision result from single-precision multiplication with a double-precision result using intrinsics (part 1)

Raymond Chen December 13, 2017 Dec 13, 2017 12/13/17

Some time ago, I derived how to create double-precision integer multiplication with a quad-precision result from single-precision multiplication with a double-precision result, but I expressed it in assembly language. This time, I'll express it in C using intrinsics. Using intrinsics rather than inline assembly language is slightly more ...

Coroutines mean that the thing that looks like a stack variable may not technically be one

Raymond Chen December 11, 2017 Dec 11, 2017 12/11/17

Some time ago, I pointed out the Get­Current­Thread­Stack­Limits function which lets you determine whether a pointer points into the stack. Note, however, that if the local variable is captured by a coroutine, The introduction of coroutines into the C++ language means that what looks like a local variable may end up being ...

How do I respond to the WM_MENUCHAR message?

Raymond Chen December 8, 2017 Dec 8, 2017 12/8/17

Today, for no particular reason, I'll demonstrate how to handle the WM_MENU­CHAR message. The system sends you the message when a menu is active and the user presses a key that does not correspond to any mnemonic or accelerator key. The typical case for needing to handle this message is when you have a bitmap menu item and want to provide...

How can I prevent the keyboard focus rectangle from appearing on a control I created?

Raymond Chen December 6, 2017 Dec 6, 2017 12/6/17

A customer wanted to prevent keyboard focus rectangles from appearing on controls they have created, like button controls. Presumably the reason is that they have customized the control's appearance to the point where the focus rectangle is no longer necessary. Drawing a focus rectangle in addition to the customized focus appearance would be ...

Tree view check boxes: The extended check box states

Raymond Chen December 5, 2017 Dec 5, 2017 12/5/17

Version 6 of the common controls in Windows Vista introduced some new check-box-related extended styles for the tree view controls. Unfortunately, the documentation for them is kind of spare. TVS_EX_PARTIAL­CHECK­BOXES Include partial checkbox state if the control has the TVS_CHECK­BOXES style. TVS_EX_DIMMED­...