The Old New Win32API

This page provides a list of links to subset of posts of Raymond Chen's famous blog The Old New Thing. The subset is limited mainly to Win32API and some COM-related stuff.

The reason why I maintain this page is that it often provides information which is missing on MSDN or which is described there in a cryptic way, and also because the blog is not easily searchable.

The links here are categorized by their topic instead of a chronological order. Sometimes, when appropriate, a single post may be put into multiple categories.

In some (quite rare) cases, links to other sources are included if they are found useful.

Disclaimer: I am not claiming authorship of any linked contents. This is only about hopefully useful organization of the great articles Raymond has written over the years.

Table of Contents

• Processes and Threads
  • Processes
  • Threads
  • Thread Pools
  • Thread Affinity of Objects
  • Thread Stack
  • Fibers
• Synchronization
  • WaitOnAddress()
  • WaitForMultipleObjects() and Relatives
  • Lock-Free Patterns
• DLLs
  • DllMain()
• Resources
  • Bitmap and Icon Resources
  • Dialog Templates
  • Menu Templates and Accelerator Resources
  • String Resources
  • Version Templates
  • Data and Custom Resources
• Application (as a whole)
  • Command Line
  • Taskbar
• HWND (General Point of View)
  • Windows Hierarchy
  • Window Styles
  • Window Classes
• Top-Level Windows
  • Window Frame and Caption
  • DWM
  • Dialogs
  • Nested and Embedded Dialogs
  • Common Dialogs
  • Control Navigation
  • Dialog Manager
  • Modality
  • Property Sheets
• Controls
  • Animation Controls
  • Buttons
  • Combo Boxes
  • Edit Controls
  • List Views
  • Rich Text Controls
  • Scrollbars
  • Static Controls
  • Toolbars
  • Tooltips
  • Trackbars
  • Tree List Views
• Processing of Messages
  • Hooking
• Specific Messages
  • Notifications
  • Window Construction and Destruction
  • Window Geometry Messages
  • Window Painting Messages
  • Window Focus Messages
  • Keyboard Messages
  • Mouse Messages
  • Dialog Messages
  • Other Window Messages
  • System Messages
• GDI
  • Cursors
  • Brushes
  • Pens
  • Bitmaps
  • DIB
  • LockWindowUpdate()
  • Painting Standard Elements
  • UXTHEME.DLL
  • Multiple Monitors
• Accessibility
• COM
  • Declaring COM Interfaces
  • COM Apartments
  • COM Initialization
  • COM Static Store
  • COM Marshaling
  • COM Error Handling
  • COM Asynchronous Interfaces
  • GUIDs
  • COM Strings
  • COM Variants
  • IUnknown
  • IMoniker
  • ICallback
  • IContextMenu
  • IFileDialog
  • IMultiLanguage
  • INamespaceWalk
  • IStream
  • IVirtual­Desktop­Manager
  • Clipboard
  • Drag and Drop
  • Enumeration
  • Shell
  • Uncategorized COM Stuff
• Memory
• Input and Output
  • Asynchronous Input and Output
  • Files and Directories
  • ACL
• Security Permissions, Attributes and Identifiers
• Registry
• Strings and Locales
• NT Services
• Uncategorized

Processes and Threads

Processes

• CreateProcess does not wait for the process to start
• Why does the CreateProcess function modify its input command line?
• Why do people take a lock around CreateProcess calls?
• Disabling the program crash dialog
• How do I pass a lot of data to a process when it starts up?
• What was the purpose of the hPrevInstance parameter to WinMain?
• Is RunAsInvoker a secret, even higher UAC setting?
• How do I prevent a child process from displaying the Windows Error Reporting dialog?
• How is it that WriteProcessMemory succeeds in writing to read-only memory?
• Is it a good idea to let WriteProcessMemory manage the page protection for me?
• How can I launch an unelevated process from my elevated process, redux
• How can I check the integrity level of my process?
• Is it true that raising a structured exception from a structured exception handler terminates the process?
• A more direct and mistake-free way of creating a process in a job object

Threads

• Invalid thread and process IDs
• Why does my thread handle suddenly go bad? All I did was wait on it!
• What happens if you simply return from the thread callback passed to _beginthread and _beginthreadex?
• Why you should never suspend a thread
• The dangers of sleeping on a UI thread
• In pursuit of the message queue
• Enumerating threads in a process
• Win32 user interface work is inherently single-threaded
• How bad is it to delay closing a thread handle for a long time after the thread has exited?
• If I call GetExitCodeThread for a thread that I know for sure has exited, why does it still say STILL_ACTIVE?
• Is there a problem with Create­Remote­Thread on 64-bit systems?
• Is the Terminate­Thread function synchronous?
• Removing the Terminate­Thread from code that waits for a job object to empty
• What is the point of FreeLibraryAndExitThread?
• What happens if I give contradictory values for the stack commit and stack reserve?

Thread Pools

• What exactly does the msWindowLength parameter to SetThreadpoolTimer mean?
• What’s the difference between CreateTimerQueueTimer and SetThreadpoolTimer?
• How to avoid accessing freed memory when canceling a thread pool callback
• Avoiding deadlocks when cancelling a thread pool callback, part 1: External callback data
• Avoiding deadlocks when cancelling a thread pool callback, part 2: Referring back to the containing object
• Gotcha: A threadpool periodic timer will not wait for the previous tick to complete
• Why am I getting an exception from the thread pool during process shutdown?
• What happens to the value returned from the function passed to Queue­User­Work­Item?
• The mental model for StartThreadpoolIo
• How can I detect that a thread pool work item is taking too long?
• How can I close a thread pool and cancel all work that had been queued to it?

Thread Affinity of Objects

• Thread affinity of user interface objects, part 1: Window handles
• Thread affinity of user interface objects, part 2: Device contexts
• Thread affinity of user interface objects, part 3: Menus, icons, cursors, and accelerator tables
• Thread affinity of user interface objects, part 4: GDI objects and other notes on affinity
• Thread affinity of user interface objects, part 5: Object clean-up
• Thread affinity of user interface objects: Addendum

Thread Stack

• How can I expand my thread’s stack at runtime?
• Using fibers to expand a thread’s stack at runtime, part 1
• Using fibers to expand a thread’s stack at runtime, part 2
• Using fibers to expand a thread’s stack at runtime, part 3
• Using fibers to expand a thread’s stack at runtime, part 4
• Using fibers to expand a thread’s stack at runtime, part 5
• Using fibers to expand a thread’s stack at runtime, part 6
• Comparing fibers to threads for the purpose of expanding a thread’s stack at runtime
• Determining approximately how much stack space is available, part 1
• Determining approximately how much stack space is available, part 2

Fibers

• What happens to the fibers which ran on a thread when the thread exits?
• It's fine to use fibers, but everybody has to be on board with the plan
• Fibers aren’t useful for much any more; there’s just one corner of it that remains useful for a reason unrelated to fibers

Synchronization

• Understanding the consequences of WAIT_ABANDONED
• Windows keyed events, critical sections, and new Vista synchronization features
• Combining the work queue of distinct events, order not important, with an auto-reset event
• How fair are SRW locks, particularly when there are both readers and writers?
• You can use a file as a synchronization object, too
• Can I wait for a kernel event to become unsignaled?
• If the slim reader/writer lock (SRWLOCK) doesn’t remember who the shared lock owner is, does that mean it’s okay to acquire it recursively?

WaitOnAddress()

• WaitOnAddress lets you create a synchronization object out of any data variable, even a byte
• Implementing a synchronization barrier in terms of WaitOnAddress
• Implementing a critical section in terms of WaitOnAddress
• Extending our critical section based on WaitOnAddress to support timeouts
• Comparing WaitOnAddress with futexes (futexi? futexen?)
• Creating a semaphore from WaitOnAddress
• Creating a semaphore with a maximum count from WaitOnAddress
• Creating a manual-reset event from WaitOnAddress
• Creating an automatic-reset event from WaitOnAddress

WaitForMultipleObjects() and Relatives

• MsgWaitForMultipleObjects and the queue state
• You can call MsgWaitForMultipleObjects with zero handles
• Pumping messages while waiting for a period of time
• Waiting for all handles with MsgWaitForMultipleObjects is a bug waiting to happen
• Why does WaitForMultipleObjects return ERROR_INVALID_PARAMETER when all the parameters look valid to me?
• If more than one object causes a WaitForMultipleObjects to return, how do I find out about the other ones?
• What’s the point of passing a never-signaled event to MsgWaitForMultipleObjects?

Lock-Free Patterns

• Lock free many-producer/single-consumer patterns: A work queue with task coalescing
• Lock free many-producer/single-consumer patterns: A work queue where the last one wins
• Lock free many-producer/single-consumer patterns: A work queue of identical non-coalescable events
• Lock free many-producer/single-consumer patterns: A work queue of distinct events, order not important
• Lock free many-producer/single-consumer patterns: A work queue of distinct events, FIFO
• Lock free many-producer/single-consumer patterns: A work queue of distinct events, order not important, follow-up question

DLLs

• Don't trust the return address
• Why can't I GetProcAddress a function I dllexport'ed?
• What is the difference between HINSTANCE and HMODULE?
• Accessing the current module's HINSTANCE from a static library
• LoadLibraryEx(DONT_RESOLVE_DLL_REFERENCES) is fundamentally flawed
• Why are DLLs unloaded in the "wrong" order?
• How are DLL functions exported in 32-bit Windows?
• Exported functions that are really forwarders
• Rethinking the way DLL exports are resolved for 32-bit Windows
• Names in the import library are decorated for a reason
• What happens when you get dllimport wrong?
• Issues related to forcing a stub to be created for an imported function
• Allocating and freeing memory across module boundaries
• DLL forwarding is not the same as delay-loading
• What is DLL import hinting?
• What is DLL import binding?
• What is the point of FreeLibraryAndExitThread?
• A library loaded via LOAD_LIBRARY_AS_DATAFILE (or similar flags) doesn't get to play in any reindeer module games
• Could there be any problems with calling GetModuleFileNameEx on your own process?
• How can I specify that my DLL should resolve a DLL dependency from the same directory that the DLL is in?
• After I made my DLL delay-load another DLL, my DLL has started crashing in its process detach code
• The different kinds of DLL planting
• Why does GetModuleInfo fail to produce an entry point for executables?
• What does the SizeOfImage mean in the MODULEINFO structure?
• How do I suppress the error box that appears when a LoadLibrary fails?

DllMain()

• Some reasons not to do anything scary in your DllMain
• Another reason not to do anything scary in your DllMain: Inadvertent deadlock
• Some reasons not to do anything scary in your DllMain, part 3
• The thread that gets the DLL_PROCESS_DETACH notification is not necessarily the one that got the DLL_PROCESS_ATTACH notification
• How you might be loading a DLL during DLL_PROCESS_DETACH without even realizing it
• When DLL_PROCESS_DETACH tells you that the process is exiting, your best bet is just to return without doing anything

Resources

• The Resource Compiler defaults to CP_ACP, even in the face of subtle hints that the file is UTF-8
• The relationship between module resources and resource-derived objects in 32-bit Windows
• What's the difference between FreeResource and, say, DestroyAcceleratorTable
• PE resources must be 4-byte aligned, but that doesn't stop people from trying other alignments
• How can I tell that somebody used the MAKEINTRESOURCE macro to smuggle an integer inside a pointer?
• Horrifically nasty gotcha: FindResource and FindResourceEx

Bitmap and Icon Resources

• Why are device-independent bitmaps upside down?
• The format of bitmap resources
• The format of icon resources
• The format of icon resources, revisited
• The evolution of the ICO file format, part 1: Monochrome beginnings
• The evolution of the ICO file format, part 2: Now in color!
• The evolution of the ICO file format, part 3: Alpha-blended images
• The evolution of the ICO file format, part 4: PNG images
• How do I set the alpha channel of a GDI bitmap to 255?

Message String Resources

• Why does Format­Message say that %0 terminates the message without a trailing newline? Is it secretly adding newlines?

Dialog Templates

• On the difficulty of getting pixel-perfect layout in Win32 dialog templates
• The evolution of dialog templates - 32-bit Classic Templates
• The evolution of dialog templates - 32-bit Extended Templates
• The evolution of dialog templates - Summary
• The resource compiler will helpfully add window styles for you, but if you're building a dialog template yourself, you don't get that help

Menu Templates and Accelerator Resources

• The evolution of menu templates: Introduction
• The evolution of menu templates: 32-bit classic menus
• The evolution of menu templates: 32-bit extended menus
• The format of accelerator table resources

String Resources

• The format of string resources
• LoadString can load strings with embedded nulls, but your wrapper function might not

Version Templates

• The evolution of version resources - 32-bit version resources
• The evolution of version resources - corrupted 32-bit version resources

Data and Custom Resources

• The format of data and custom resources

Application (as a whole)

• Which windows appear in the Alt+Tab list?
• Windows Vista changed the Alt+Tab order slightly
• Win32 user interface work is inherently single-threaded
• When does STARTF_USESHOWWINDOW override the parameter passed to ShowWindow?
• WaitForInputIdle should really be called WaitForProcessStartupComplete
• WaitForInputIdle waits for any thread, which might not be the thread you care about
• What are the conventions for managing standard handles?
• Standard handles are really meant for single-threaded programs
• If only DLLs can get DllMain notifications, how can an EXE receive a notification when a thread is created (for example)?

Command Line

• The first word on the command line is the program name only by convention
• How is the CommandLineToArgvW function intended to be used?
• What's up with the strange treatment of quotation marks and backslashes by CommandLineToArgvW

Taskbar

• How do I prevent users from pinning my program to the taskbar?
• Instead of creating something and then trying to hide it, simply don't create it in the first place (tray icon)
• What if my application is really two applications bundled into a single file, and I want them collected into two groups on the taskbar in Windows 7?
• How do I customize how my application windows are grouped in the Taskbar?
• Display an overlay on the taskbar button
• Display control buttons on your taskbar preview window
• Display a custom thumbnail for your application (and while you're at it, a custom live preview)
• How can I query the location of the taskbar on secondary monitors?
• How did that program manage to pin itself to my taskbar when I installed it?
• What if I have two programs that are logically a single application, and I want them to be treated as a single group on the taskbar?
• Why does the taskbar icon for grouped windows change to something weird?

HWND (General Point of View)

• What does it mean for a window to be Unicode?
• How can I get the actual window procedure address and not a thunk?
• What are these strange values returned from GWLP_WNDPROC?
• The bonus window bytes at GWLP_USERDATA
• What is the difference between WM_DESTROY and WM_NCDESTROY?
• Sending a window a WM_DESTROY message is like prank calling somebody pretending to be the police
• The secret life of GetWindowText
• Why are the rules for GetWindowText so weird?
• Painting only when your window is visible on the screen
• Determining whether your window is covered
• Obtaining a window's size and position while it is minimized
• Why does calling SetForegroundWindow immediately followed by GetForegroundWindow not return the same window back?
• How does Windows decide whether a newly-created window should use LTR or RTL layout?

Windows Hierarchy

• What's so special about the desktop window?
• What is the window nesting limit?
• What's the difference between HWND_TOP and HWND_TOPMOST?
• A window can have a parent or an owner but not both
• Why does my control send its notifications to the wrong window after I reparent it?
• WindowFromPoint, ChildWindowFromPoint, RealChildWindowFromPoint, when will it all end?
• GetParent, just as confusing as EnumClaw, but it's an actual function! (GetAncestor(), GetWindow())
• Having an owner window from another process is tricky, but it's sometimes the right thing to do
• What is the documentation for SetParent trying to tell me about synchronizing the UI state?
• Demonstrating what happens when a parent and child window have different UI states
• Getting a parent and child window to have the same UI states

Window Styles

• Which window style bits belong to whom?
• How do I indicate that I want my window to follow right-to-left layout rules?
• Why isn't my transparent static control transparent? (WS_EX_TRANSPARENT)
• Like the cake, WS_EX_TRANSPARENT is a lie, or at least not the entire truth
• I used WS_EX_COMPOSITED to get rid of my redrawing flicker, but it resulted in sluggish response
• How can I use WS_CLIP­CHILDREN and still be able to draw a control with a transparent background?

Window Classes

• What is the HINSTANCE passed to CreateWindow and RegisterClass used for?
• Using the wrong HINSTANCE in RegisterClass is like identity theft
• If the RegisterClass function takes ownership of the custom background brush, why is it leaking?
• Changing a window class affects all windows which belong to that class
• What does CS_SAVEBITS do?
• What does the CS_OWNDC class style do?
• What does the CS_CLASSDC class style do?
• Modifying the CS_NOCLOSE style does affect all windows of the class, just not necessarily in an immediately noticeable way
• Why does PrintWindow hate CS_PARENTDC? Because EVERYBODY hates CS_PARENTDC!
• Why does PrintWindow hate CS_PARENTDC? redux
• Safer subclassing
• Private classes, superclassing, and global subclassing
• What makes RealGetWindowClass so much more real than GetClassName?
• Why does CreateWindowEx take the extended style parameter as its first parameter instead of its last?
• When should I use CS_GLOBALCLASS?
• How unique must the uIdSubclass parameter be when I call Set­Window­Subclass?

Top-Level Windows

Window Frame and Caption

• Getting a custom right-click menu for the caption icon
• Drawing an active-looking caption even when not active
• How do I suppress full window drag/resize for just one window?
• How do I switch a window between normal and fullscreen?
• How do I enable and disable the minimize, maximize, and close buttons in my caption bar?
• Getting the location of the Close button in the title bar
• Getting the location of the Close button in the title bar, from Windows 2000 or Windows XP
• Why are the dimensions of a maximized window larger than the monitor?
• Creating a window that can be resized in only one direction
• Why don't you forward WM_GETMINMAXINFO and clamp the results?

DWM

• Why doesn't my program receive the WM_DWMSENDICONICTHUMBNAIL message when I ask for an iconic representation?
• The MARGINS parameter to the DwmExtendFrameIntoClientArea function controls how far the frame extends into the client area
• How do I suppress the default animation that occurs when I hide or show a window?
• Display a custom thumbnail for your application (and while you're at it, a custom live preview)
• How can I detect that my window has been suppressed from the screen by the shell? ("window cloaking")

Dialogs

• Why can't I create my dialog box? Rookie mistake #1
• Why can't I create my dialog box? Rookie mistake #2
• Returning values from a dialog procedure
• A different type of dialog procedure
• Another different type of dialog procedure
• The default answer to every dialog box is "Cancel"
• Rotating the Z-order
• Using the TAB key to navigate in non-dialogs
• Using the TAB key to navigate in non-dialogs, redux
• Preventing edit control text from being autoselected in a dialog box
• Those who do not understand the dialog manager are doomed to reimplement it, badly
• Other tricks with WM_GETDLGCODE
• GetDialogBaseUnits is a crock
• Why isn’t MapDialogRect mapping dialog rectangles?
• Why are dialog boxes initially created hidden?
• What's the deal with the DS_SHELLFONT flag?
• Why does DS_SHELLFONT = DS_FIXEDSYS | DS_SETFONT?
• How to set focus in a dialog box
• Never leave focus on a disabled control
• A subtlety in restoring previous window position
• Things you already know: How do I wait until my dialog box is displayed before doing something?
• What does TranslateAccelerator do?
• If I have a modeless dialog box with custom accelerators, which should I call first: IsDialogMessage or TranslateAccelerator
• Gentle reminder: On a dialog box, do not give OK and Cancel accelerators
• Why are accelerators for hidden controls still active?
• How do I make my accelerators apply only when used in the main window and not when the user is using a modeless dialog?
• Why doesn't the TAB key work on controls I've marked as WS_TABSTOP?
• You can't use the WM_USER message in a dialog box
• How can I make a dialog box right-to-left at runtime?
• How does the dialog manager calculate the average width of a character?

Nested and Embedded Dialogs

• What is the DS_CONTROL style for?
• More notes on use of the DS_CONTROL style
• It's not a good idea to give multiple controls on a dialog box the same ID
• When embedding a dialog inside another, make sure you don't accidentally create duplicate control IDs
• When the default pushbutton is invoked, the invoke goes to the top-level dialog

Common Dialogs

• Why doesn't my MessageBox wrap at the right location?
• How do I customize the Favorite Links section of the File Open dialog?
• Why does the common file dialog change the current directory?
• You can filter the Common File dialog with wildcards
• How do I display the Find Printers dialog programmatically?
• Why doesn't the Open Files list in the Shared Folders snap-in show all my open files?
• A common control for associating extensions is well overdue
• Filtering the folders that appear in the Browse for Folder dialog
• Opening the classic folder browser dialog with a specific folder preselected
• Why does the common file save dialog create a temporary file and then delete it?
• Customing the standard color-picker dialog
• How do I set the initial directory of the File Open dialog to a virtual directory?
• When I select multiple files in the File Open dialog, why does the last item come first?
• I set the OFN_NONETWORKBUTTON option in the OPENFILENAME structure, but it has no effect on the network item in the navigation pane
• How do I add custom controls to the common file open or file save dialogs?
• How can I get my FileSavePicker to open in the same folder that was picked by the FileOpenPicker or FolderPicker? (win32/COM equivalent mentioned at the end of the post)

Control Navigation

• Using the TAB key to navigate in non-dialogs
• Using the TAB key to navigate in non-dialogs, redux
• Managing the UI state of accelerators and focus rectangles
• Custom navigation in dialog boxes, redux
• Dialog boxes return focus to the control that had focus when you last switched away; how do I get in on that action for my own windows?
• How can I create a non-circular tab order, or some other type of custom ordering in my Win32 dialog?

Dialog Manager

• The dialog manager, part 1: Warm-ups
• The dialog manager, part 2: Creating the frame window
• The dialog manager, part 3: Creating the controls
• The dialog manager, part 4: The dialog loop
• The dialog manager, part 5: Converting a non-modal dialog box to modal
• The dialog manager, part 6: Subtleties in message loops
• The dialog manager, part 7: More subtleties in message loops
• The dialog manager, part 8: Custom navigation in dialog boxes
• The dialog manager, part 9: Custom accelerators in dialog boxes

Modality

• The correct order for disabling and enabling windows
• Modality, part 1: UI-modality vs code-modality
• Modality, part 2: Code-modality vs UI-modality
• Modality, part 3: The WM_QUIT message
• Modality, part 4: The importance of setting the correct owner for modal UI
• Modality, part 5: Setting the correct owner for modal UI
• Modality, part 6: Interacting with a program that has gone modal
• Modality, part 7: A timed MessageBox, the cheap version
• Modality, part 8: A timed MessageBox, the better version
• Modality, part 9: Setting the correct owner for modal UI, practical exam
• Thread messages are eaten by modal loops
• Rescuing thread messages from modal loops via message filters

Property Sheets

• What other effects does DS_SHELLFONT have on property sheet pages?
• PSM_ISDIALOGMESSAGE is to modeless property sheets as IsDialogMessage is to modeless dialog boxes
• You can extend the PROPSHEETPAGE structure with your own bonus data
• The PSN_SETACTIVE notification is sent each time your wizard page is activated
• Appending additional payload to a PROPSHEETPAGE structure
• How do I pass an array of variable-sized PROPSHEETPAGE structures to PropertySheet?

Controls

• Just because you're a control doesn't mean that you're necessarily inside a dialog box

Animation Controls

• Limitations of the shell animation control
• Why does the version 6 animation control not use a background thread?

Buttons

• What's the BS_PUSHLIKE button style for? (Don't use, it's completely obsolete nowadays. Use check box or radio button instead.)

Combo Boxes

• Speeding up adding items to a combobox or listbox (WM_SETREDRAW)

Edit Controls

• What's the deal with the EM_SETHILITE message?
• Preventing edit control text from being autoselected in a dialog box
• How do I suppress the CapsLock warning on password edit controls?
• The early history of the ES_NUMBER edit control style
• How do I allow negative numbers with the ES_NUMBER edit control style?
• How do I permit a minus sign to be entered into my edit control, but only if it’s the first character?

List Views

• Positioned vs. non-positioned listview views
• Displaying infotips for folded and unfolded listview items
• Computing listview infotips in the background
• What's the difference between LVM_HITTEST and LVM_INSERTMARKHITTEST?
• Why is there an LVN_ODSTATECHANGED notification when there's already a perfectly good LVN_ITEMCHANGED notification?
• Creating a listview with checkboxes on some items but not others
• How can I programmatically resize a listview column to fit its contents?
• How do I create a disabled checkbox for a listview item?
• Speeding up adding items to a combobox or listbox (WM_SETREDRAW)

Rich Text Controls

• The history of the RichEdit control from Murray Sargent (The post is just a (broken) link to https://blogs.msdn.microsoft.com/murrays/2006/10/19/some-richedit-history/)
• How do I load an entire file into a rich text control?
• How do I put more than 32,000 characters into a rich text control?
• How do I print the contents of a rich text control?

Scrollbars

• The scratch program
• Scrollbars, part 2
• Scrollbars, part 3: Optimizing the paint cycle
• Scrollbars, part 4: Adding a proportional scrollbar
• Likely part 5: Keyboard accessibility for scrollbars
• Addendum to part 5: A subtlety in the keyboard code
• Scrollbars part 6 - The wheel
• Scrollbars part 7 - Integrality
• Scrollbars part 8 - Integral interactive resizing
• Scrollbars part 9 - Maintaining the metaphor
• Scrollbars part 10 - Towards a deeper understanding of the WM_NCCALCSIZE message
• Scrollbars part 11: Towards an even deeper understanding of the WM_NCCALCSIZE message
• Answers to exercise from Scrollbars Part 11
• Scrollbars part 12: Applying WM_NCCALCSIZE to our scrollbar sample
• Scrollbars redux: Part 12
• There are two types of scrollbars
• Why was WHEEL_DELTA chosen to be 120 instead of a much more convenient value like 100 or even 10?
• Why does setting the horizontal scroll bar range for the first time also set the vertical range, and vice versa?
• Autoscrolling on drag, part 1: Basic implementation
• Autoscrolling on drag, part 2: Why does scrolling go faster if I wiggle the mouse?
• Autoscrolling on drag, part 3: Dynamic autoscroll based on mouse position
• Autoscrolling on drag, part 4: Dynamic autoscroll based on escape velocity
• Autoscrolling on drag, part 5: Adding wiggle-to-scroll to escape velocity

Static Controls

• When will the static control automatically delete the image loaded into it, and when is it the responsibility of the application?

Tab Controls

• How should I create controls on my dialog box that has a tab control?
• How am I supposed to create children of the Win32 tab control?

Toolbars

• Why are there both TBSTYLE_EX_VERTICAL and CCS_VERT?
• How do I create a toolbar that sits in the taskbar?
• How do I create a right-aligned toolbar button?
• Creating custom tasks on a jump list

Tooltips

• Coding in-place tooltips
• Using custom-draw in tooltips to adjust the font
• Multiplexing multiple tools into one in a tooltip
• Generating tooltip text dynamically
• Why can't I display a tooltip for a disabled window?
• Over-documenting TTM_RELAYEVENT and why it results in a one-second periodic timer running as long as the tooltip is visible

Trackbars

• Adding a Ctrl+arrow accelerator for moving the trackbar by just one unit, part 1: Initial plunge
• Adding a Ctrl+arrow accelerator for moving the trackbar by just one unit, part 2: Second try
• How do I prevent users from using the mouse to drag the trackbar thumb to positions that aren’t multiples of five? Part 1: Reframe the problem
• How do I prevent users from using the mouse to drag the trackbar thumb to positions that aren’t multiples of five? Part 2: Nudging the thumb position

Tree-List Views

• The TVS_CHECKBOXES style is quirky, which is a polite way of saying that it is crazy
• Beware of the leaked image list when using the TVS_CHECKBOXES style
• Creating tree view check boxes manually: A simple state image list
• Creating tree view check boxes manually: Responding to clicks
• Creating tree view check boxes manually: Themed check boxes
• Tree view check boxes: A sordid history
• Tree view check boxes: The extended check box states

Processing of Messages

• Which message numbers belong to whom?
• The various ways of sending a message
• Broadcasting user-defined messages
• When can a thread receive window messages?
• What's the difference between GetKeyState and GetAsyncKeyState?
• Thread messages are eaten by modal loops
• Rescuing thread messages from modal loops via message filters
• The dangers of filtering window messages
• You can't simulate keyboard input with PostMessage
• Pumping messages while waiting for a period of time
• In pursuit of the message queue
• No, really, you need to pass all unhandled messages to DefWindowProc
• Even if you have code to handle a message, you're allowed to call DefWindowProc, because you were doing that anyway after all
• What were Get/SetMessageExtraInfo ever used for?
• Why is GetWindowLongPtr returning a garbage value on 64-bit Windows?
• TrackMouseEvent tracks mouse events in your window, but only if the events belong to your window
• Don't forget to include the message queue in your lock hierarchy
• What happens to a sent message when SendMessageTimeout reaches its timeout?
• Why can't I PostMessage the WM_COPYDATA message, but I can SendMessageTimeout it with a tiny timeout?
• Even though mouse-move, paint, and timer messages are generated on demand, it's still possible for one to end up in your queue
• Posted messages are processed ahead of input messages, even if they were posted later
• What kind of messages can a message-only window receive?
• If the prototypes of DispatchMessageA and DispatchMessageW are identical, why have both?
• Those who do not understand the dialog manager are doomed to reimplement it, badly
• How can I trigger a recalc of the mouse cursor after I changed some of my internal application state?
• How can I trigger a recalc of the mouse cursor after I changed some of my internal application state?, follow-up
• GetQueueStatus and the queue state

Hooking

• What is the HINSTANCE passed to SetWindowsHookEx used for?
• How can I get notified when the cursor changes?
• What does the thread parameter to Set­Windows­Hook­Ex actually mean?
• Why does SetFocus fail without telling me why?

Specific Messages

Notifications

• What's the difference between the wParam of the WM_NOTIFY message and the idFrom in the NMHDR structure.
• Restating the obvious about the WM_COMMAND message
• Restating the obvious about the WM_NOTIFY message

Window Construction and Destruction

• What is the difference between WM_DESTROY and WM_NCDESTROY?
• How can I determine the reason why my window is closing? (WM_CLOSE)

Window Geometry Messages

• Use WM_WINDOWPOSCHANGED to react to window state changes
• Use WM_WINDOWPOSCHANGING to intercept window state changes

Window Painting Messages

• Paint messages will come in as fast as you let them (WM_PAINT)
• What happens if I don't paint when I get a WM_PAINT message?
• What is the implementation of WM_PRINTCLIENT?
• There's a default implementation for WM_SETREDRAW, but you might be able to do better
• Speeding up adding items to a combobox or listbox (WM_SETREDRAW)
• Using WM_SETREDRAW to speed up adding a lot of elements to a control

Window Focus Messages

• WM_KILLFOCUS is the wrong time to do field validation
• The dangers of playing focus games when handling a WM_KILLFOCUS message
• Why doesn't the MoveWindow function generate the WM_GETMINMAXINFO message?

Keyboard Messages

• How do I respond to the WM_MENUCHAR message?

Mouse Messages

• Why is there no WM_MOUSEENTER message?
• Why do I get spurious WM_MOUSEMOVE messages?
• Sure, I can get spurious WM_MOUSEMOVE messages, but why do they keep streaming in?
• How do I get mouse messages faster than WM_MOUSEMOVE?
• Logical consequences of the way Windows converts single-clicks into double-clicks
• Implementing higher-order clicks
• How slow do you have to slow-double-click for it to be a rename?
• How can I prevent the mouse from moving in response to touch input?

Dialog Messages

• Those who do not understand the dialog manager are doomed to reimplement it, badly
• Managing the UI state of accelerators and focus rectangles (WM_CHANGEUISTATE, WM_QUERYUISTATE and WM_UPDATEUISTATE)
• Untangling the confusingly-named WM_UPDATEUISTATE and WM_CHANGEUISTATE messages
• Who sends the initial WM_UPDATEUISTATE message?
• How can I prevent the keyboard focus rectangle from appearing on a control I created?
• Other tricks with WM_GETDLGCODE
• How do I prevent multi-line edit controls from eating the Enter key?
• Why do DLGC_WANTALLKEYS and DLGC_WANTMESSAGE have the same value?

Other Window Messages

• The dangers of messing with activation when handling a WM_ACTIVATE message
• Why does my window get a WM_ACTIVATE message when it isn't active?
• A timed context menu (WM_CANCELMODE)
• Pitfalls in handling the WM_CONTEXTMENU message (WM_CONTEXTMENU)
• WM_NCHITTEST is for hit-testing, and hit-testing can happen for reasons other than the mouse being over your window
• How likely is it that a window will receive a WM_NULL message out of the blue? (WM_NULL)
• Why is there a special PostQuitMessage function? (WM_QUIT)
• How does PostQuitMessage know which thread to post the quit message to? (WM_QUIT)
• Who is responsible for destroying the font passed in the WM_SETFONT message? (WM_SETFONT)
• When I send a WM_GETFONT message to a window, why don't I get a font? (WM_GETFONT)
• If my WM_TIMER handler takes longer than the timer period, will my queue fill up with WM_TIMER messages?
• Killing a window timer prevents the WM_TIMER message from being generated for that timer, but it doesn't retroactively remove ones that were already generated

System Messages

• If one program blocks shutdown, then all programs block shutdown (WM_QUERY­END­SESSION, WM_END­SESSION)
• Why do I have to return this goofy value for WM_DEVICECHANGE? (WM_DEVICECHANGE)
• Windows doesn't close windows when a user logs off; that's your call (WM_ENDSESSION)
• Once you return from the WM_ENDSESSION message, your process can be terminated at any time (WM_ENDSESSION)

GDI

• Why are RECTs endpoint-exclusive?
• Can you create an information context for the display?
• What does the CS_OWNDC class style do?
• What does the CS_CLASSDC class style do?
• How do you detect "Large Fonts"? (DPI)
• Drawing a monochrome bitmap with transparency
• Let GDI do your RLE compression for you
• The mysterious stock bitmap: There's no way to summon it, but it shows up in various places
• Why is my icon being drawn at the wrong size when I call DrawIcon?
• You must flush GDI operations when switching between direct access and GDI access, and direct access includes other parts of GDI
• How do I get the dimensions of a cursor or icon?
• What are the dire consequences of not selecting objects out of my DC?
• Of what use is the RDW_INTERNALPAINT flag?
• Functions that return GDI regions rarely actually return regions
• Color-aware ClearType requires access to fixed background pixels, which is a problem if you don't know what the background pixels are, or if they aren't fixed
• What is the correct way of using SaveDC and RestoreDC?
• How are BitBlt raster opcodes calculated?
• Notes on DrawText and tab stops
• Why doesn’t GetTextExtentPoint return the correct extent for strings containing tabs?
• Why are there trivial functions like Copy­Rect and Equal­Rect?
• More on trivial functions like CopyRect and EqualRect
• What are the consequences of increasing the per-process GDI handle limit?
• The focus rectangle says, “I’m not orange. I’m just drawn that way.”

Cursors

• The effect of SetCursor lasts only until the next SetCursor
• What can or should I do with the cursor handle returned by SetCursor?
• What is the deal with the SM_CXCURSOR system metric?
• How do I find out the size of the mouse cursor?

Brushes

• The hollow brush
• Other uses for bitmap brushes
• What is the DC brush good for?
• I know I can change the color of the DC pen, but what about the other attributes?
• How can I extract the color from a solid color GDI brush?

Pens

• Is there a difference between creating a null pen with Create­Pen and just using the stock null pen?

Bitmaps

• How do I set the alpha channel of a GDI bitmap to 255?

DIB

• A survey of the various ways of creating GDI bitmaps with predefined data
• Blitting between color and monochrome DCs
• Manipulating the DIB color table for fun and profit
• Using DIB sections to perform bulk color mapping
• The fun and profit of manipulating the DIB color table can be done without having to modify it
• Separating the metadata from the DIB pixels: Precalculating the BITMAPINFO
• Separating the metadata from the DIB pixels: Changing the raster operation
• The disembodiment of DIBs from the DIB section
• What is the hSection parameter to CreateDIBSection for?

LockWindowUpdate()

• What does LockWindowUpdate do?
• How is LockWindowUpdate meant to be used?
• With what operations is LockWindowUpdate meant to be used?
• With what operations is LockWindowUpdate not meant to be used?
• Final remarks on LockWindowUpdate

Painting Standard Elements

• Rendering standard Windows elements
• Rendering menu glyphs is slightly trickier
• What states are possible in a DRAWITEMSTRUCT structure?

UXTHEME.DLL

• BeginBufferedPaint: It's not just for buffered painting any more
• How do IsThemeActive, IsAppThemed, and IsCompositionActive differ?
• How do I get the tabbed dialog effect on my own custom tabbed dialog?
• How do I revert a control back to its default theme?

Multiple Monitors

• For better performance, set all your monitors to the same color format
• How do I get a handle to the primary monitor?
• Why does the primary monitor have (0,0) as its upper left coordinate?
• How do I get the color depth of the screen?
• How does the window manager adjust ptMaxSize and ptMaxPosition for multiple monitors?

Accessibility

• Accessibility is not just for people with disabilities
• How to retrieve text under the cursor (mouse pointer)
• How do I set an accessible name on an unlabeled control?
• How can I get notified when some other window is destroyed?
• Using accessibility to monitor windows as they come and go
• How can I write a program that monitors another window for a title change?
• How can I write a program that monitors another window for a change in size or position?

COM

Declaring COM Interfaces

• The macros for declaring COM interfaces, revisited: C version
• The macros for declaring COM interfaces, revisited: C++ version
• The macros for declaring COM interfaces, revisited: C++ implementation
• The oracle always tells the truth, even when it is wrong: COM method calls with a user-defined type as a return value (on problems of COM interfaces called from C code)
• The COM interface contract rules exist for a reason
• Giving a single object multiple COM identities, part 1
• Giving a single object multiple COM identities, part 2
• Giving a single object multiple COM identities, part 3
• Giving a single object multiple COM identities, part 4
• How do I consume raw COM interfaces from a Windows Runtime metadata file?

COM Apartments

• The dreaded "main" threading model
• A slightly less brief introduction to COM apartments (but it’s still brief)
• Yo dawg, I hear you like COM apartments, so I put a COM apartment in your COM apartment so you can COM apartment while you COM apartment
• What kind of apartment is the private apartment I created via CLSID_Context­Switcher?
• Setting up private COM contexts to allow yourself to unload cleanly
• How do you get into a context via IContext­Callback::Context­Callback?
• Using contexts to return to a COM apartment later
• What do the output values from CoGetApartmentType mean?
• User interface code + multi-threaded apartment = death
• Other problems traced to violating COM single-threaded apartment rules in the shell
• What’s the point of APTTYPE_CURRENT? I mean, of course I’m current.
• How do I get a foothold in the neutral apartment?
• What is so special about the Application STA?
• What does it mean when a call fails with 0x8000001F = RO_E_BLOCKED_CROSS_ASTA_CALL?

COM Initialization

• What does the COINIT_SPEED_OVER_MEMORY flag to CoInitializeEx do?
• Crashing in COM after I call CoUninitialize, how can COM be running after it is uninitalized?

COM Static Store

• The COM static store, part 1: Introduction
• The COM static store, part 2: Race conditions in setting a singleton
• The COM static store, part 3: Avoiding creation of an expensive temporary when setting a singleton
• The COM static store, part 4: Aggregating into a single object
• The COM static store, part 5: Using COM weak references
• The COM static store, part 6: Using C++ weak references

COM Marshaling

• What is COM marshaling and how do I use it?
• On proper handling of buffers in COM and RPC methods
• What are the rules for CoMarshalInterThreadInterfaceInStream and CoGetInterfaceAndReleaseStream?
• What are the rules for CoMarshalInterface and CoUnmarshalInterface?
• CoGetInterfaceAndReleaseStream does not mix with smart pointers
• The COM marshaller uses the COM task allocator to allocate and free memory
• Why do I get a QueryInterface(IID_IMarshal) and then nothing?
• We batched up our COM requests and return a single stream of results, but the performance is still slow
• What are the various usage patterns for manually-marshaled interfaces?
• An initial look at the mechanics of how COM marshaling is performed
• https://devblogs.microsoft.com/oldnewthing/20220616-00/?p=106757
• Writing a marshal-by-value marshaler, part 1
• Writing a marshal-by-value marshaler, part 2
• Writing a compound marshaler
• Understanding the marshaling flags: The free-threaded marshaler

COM Error Handling

• What happens to my COM server-side object when clients die unexpectedly?
• Why does COM require output pointers to be initialized even on failure?
• How do I convert an HRESULT to a Win32 error code?
• How can I tell the WIL RETURN_IF_FAILED macro that some errors are ignorable?
• Do not overload the E_NOINTERFACE error
• What does it mean when a call fails with 0x8000001F = RO_E_BLOCKED_CROSS_ASTA_CALL?
• What does it mean when my cross-thread COM call fails with RPC_E_SYS_CALL_FAILED?
• Understanding a mysterious RPC_E_WRONG­THREAD exception when we’re on the right thread

COM Asynchronous Interfaces

• COM asynchronous interfaces, part 1: The basic pattern
• COM asynchronous interfaces, part 2: Abandoning the operation
• COM asynchronous interfaces, part 3: Abandoning the operation after a timeout
• COM asynchronous interfaces, part 4: Doing work while waiting for the asynchronous operation
• COM asynchronous interfaces, part 5: The unreliable server
• COM asynchronous interfaces, part 6: Learning about completion without polling
• COM asynchronous interfaces, part 7: Being called directly when the operation completes
• COM asynchronous interfaces, part 8: Asynchronous release, the problems
• COM asynchronous interfaces, part 9: Asynchronous release, assembling a solution

GUIDs

• What's the difference between UuidFromString, IIDFromString, CLSIDFromString, GUIDFromString...
• What is the difference between UuidToString, StringFromCLSID, StringFromIID, and StringFromGUID2?
• Why are there four functions for parsing strings into GUIDs, and why are they in three different DLLs?
• Why does COM express GUIDs in a mix of big-endian and little-endian? Why can’t it just pick a side and stick with it?

COM Strings

• Why is there a BSTR cache anyway?
• Raymond’s complete guide to HSTRING semantics
• What is the correct way of using the string buffer returned by the WindowsPreallocateStringBuffer function?

COM Variants

• What’s the difference between VARIANT and VARIANTARG?
• Nasty gotcha: VarCmp vs VariantCompare
• Why can’t VarDateFromStr parse back a Hungarian date that was generated by VarBstrFromDate?

IUnknown

• The layout of a COM object
• Under what conditions will the IUnknown::AddRef method return 0?