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?
• The ways people mess up IUnknown::QueryInterface
• The ways people mess up IUnknown::QueryInterface, episode 2
• The ways people mess up IUnknown::QueryInterface, episode 3
• The ways people mess up IUnknown::QueryInterface, episode 4
• COM object destructors are very sensitive functions
• Avoiding double-destruction when an object is released
• I’d like an IUnknown, I know you have many, I’ll take any of them
• A very brief introduction to patterns for implementing a COM object that hands out references to itself
• 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
• Reducing chattiness by querying for multiple interfaces at once, part 1
• Reducing chattiness by querying for multiple interfaces at once, part 2

IMoniker

• Pidls and monikers do roughly the same thing, just backwards

ICallback

• A very brief introduction to patterns for implementing a COM object that hands out references to itself

IContextMenu

• Why an object cannot be its own enumerator
• How to host an IContextMenu, part 1 - Initial foray
• How to host an IContextMenu, part 2 - Displaying the context menu
• How to host an IContextMenu, part 3 - Invocation location
• How to host an IContextMenu, part 4 - Key context
• How to host an IContextMenu, part 5 - Handling menu messages
• How to host an IContextMenu, part 6 - Displaying menu help
• How to host an IContextMenu, part 7 - Invoking the default verb
• How to host an IContextMenu, part 8 - Optimizing for the default command
• How to host an IContextMenu, part 9 - Adding custom commands
• How to host an IContextMenu, part 10 - Composite extensions - groundwork
• How to host an IContextMenu, part 11 - Composite extensions - composition
• Simplifying context menu extensions with IExecuteCommand
• How do I launch a file as if it were a text file, even though its extension is not .txt?
• Do not access the disk in your IContextMenu handler, no really, don't do it
• Sure, we do that: Context menu edition
• Psychic debugging: Why your IContextMenu::InvokeCommand doesn't get called even though you returned success from IContextMenu::QueryContextMenu
• Don’t forget to implement canonical names for verbs in your shell context menu extension

IFileDialog

• The SetClientGuid method of the common file and folder dialogs lets you give names to those dialogs, too (multiple contexts for open/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)
• Why does IFileDialog still show non-filesystem folders when I pass FOS_FORCE­FILE­SYSTEM?

IMultiLanguage

• Converting between LCIDs and RFC 1766 language codes
• Feel free to stop using IMultiLanguage2::DetectInputCodepage

INamespaceWalk

• How can I control which parts of the shell namespace the INamespaceWalk::Walk operation will walk into?
• How can I cancel the INamespace­Walk::Walk operation?
• Cancelling the INamespace­Walk::Walk operation a little faster

IStream

• The subtleties of Create­Stream­On­HGlobal, part 1: Introduction and basic usage
• The subtleties of Create­Stream­On­HGlobal, part 2: Suppressing the deletion of an unknown HGLOBAL
• The subtleties of Create­Stream­On­HGlobal, part 3: Suppressing the deletion of a shared HGLOBAL
• The subtleties of Create­Stream­On­HGlobal, part 4: Non-movable memory
• A practical use for GetHGlobal­FromStream when sharing was never your intention

IVirtual­Desktop­Manager

• Virtual desktops are an end-user window management feature, not a programmatic one

Clipboard

• How ownership of the Windows clipboard is tracked in Win32
• What happens when applications try to copy text by sending Ctrl+C
• How do I make it so that users can copy static text on a dialog box to the clipboard easily?
• What is the proper handling of WM_RENDERFORMAT and WM_RENDERALLFORMATS?
• Copying a file to the clipboard so you can paste it into Explorer or an email message or whatever
• Printing the contents of the clipboard as text to stdout
• Improving the performance of CF_HDROP by providing file attribute information
• What’s up with the CF_SYLK and CF_DIF clipboard formats?
• How can I wait more than 30 seconds for a delay-rendered clipboard format to become rendered?

Drag and Drop

• What a drag: Dragging text
• What a drag: Dragging a Uniform Resource Locator (URL)
• What a drag: Dragging a Uniform Resource Locator (URL) and text
• What a drag: Dragging a virtual file (HGLOBAL edition)
• What a drag: Dragging a virtual file (IStream edition)
• What a drag: Dragging a virtual file (IStorage edition)
• You can drag multiple virtual objects, you know
• Reading a contract from the other side: Simulating a drop
• Simulating a drop, part two
• What happens if I drag the mouse by exactly the amount specified by SM_CXDRAG?
• How do I accept files to be opened via IDropTarget instead of on the command line?
• How do I accept files to be opened via IDropTarget instead of on the command line? - bonus content
• Using Explorer’s fancy drag/drop effects in your own programs
• Drag/drop effects: The little drop information box
• Why isn’t my shell namespace extension getting every single DragOver mouse message?
• Why doesn’t my program get fancy drag/drop effects in high contrast mode with CLSID_Drag­Drop­Helper?

Enumeration

• Using fibers to simplify enumerators, part 1: When life is easier for the enumerator
• Using fibers to simplify enumerators, part 2: When life is easier for the caller
• Using fibers to simplify enumerators, part 3: Having it both ways
• Using fibers to simplify enumerators, part 4: Filtering
• Using fibers to simplify enumerators, part 5: Composition

Shell

• When does SHLoadInProc unload a DLL?
• What does SHGFI_USEFILEATTRIBUTES mean?
• What's the difference between SHGetMalloc, SHAlloc, CoGetMalloc, and CoTaskMemAlloc
• Querying information from an Explorer window
• Execute a file as if it were a program, even though its extension is not EXE
• How do I launch a file as if it were a text file, even though its extension is not .txt?
• What does the SEE_MASK_UNICODE flag in ShellExecuteEx actually do?
• Simple things you can do with the ShellExecuteEx function
• What were ShellExecute hooks designed for?
• Why does ShellExecute return SE_ERR_ACCESSDENIED for nearly everything?
• How do I ShellExecute a file, but with a specific program instead of the default program?
• What is the difference between CSIDL_DESKTOP and CSIDL_DESKTOPDIRECTORY?
• SHCIDS_CANONICALONLY is the moral equivalent in the shell namespace of the Unicode ordinal comparison
• Don't forget to double-null-terminate those strings you pass to SHFileOperation
• Why does SHFileOperation have internal error codes for DVD?
• Why do non-folders in my shell namespace extension show up in the folder tree view?
• SHAutoComplete giveth, and SHAutoComplete taketh away
• What is the lpClass member of SHELLEXECUTEINFO used for?
• Some known folders cannot be moved, but others can, and you'll just have to accept that
• One possible reason why ShellExecute returns SE_ERR_ACCESSDENIED and ShellExecuteEx returns ERROR_ACCESS_DENIED
• Why does SHGetSpecialFolderPath take such a long time before returning a network error?
• How do you obtain the icon for a shortcut without the shortcut overlay? (SHGetFileInfo())
• How can I get information about the items in the Recycle Bin?
• Modernizing our simple program that retrieves information about the items in the Recycle Bin
• Invoking commands on items in the Recycle Bin
• How do I perform shell file operations while avoiding shell copy hooks?
• Command line tool to manage Windows 7 Libraries, with source code (IShellLibrary)
• IShellFolder::BindToObject is a high-traffic method; don't do any heavy lifting
• Obtaining the parsing name (and pidl) for a random shell object
• Creating a simple pidl: For the times you care enough to send the very fake
• Creating a simple shell item, just as fake as a simple pidl
• Displaying a property sheet for multiple files
• How do I get a high resolution icon for a file?
• How do I extract an icon at a nonstandard size if IExtractIcon::Extract tells me to go jump in a lake?
• How do I read the "Double-click to open an item (single-click to select)" setting in Folder Options?
• The wonderful world of shell bind context strings
• Helper functions to make shell bind contexts slightly more manageable
• Customizing item enumeration with IShellItem
• Customizing item enumeration with IShellItem, the old-fashioned way
• How do I create an IShellItemArray from a bunch of file paths?
• How do I invoke a verb on an IShellItemArray?
• How does a shell namespace extension provide icons for virtual items that track the standard icons set by the user's file associations?
• How do I get the user-customed name of My Computer or Recycle Bin?
• How do I get the user-customized name of a mapped network drive?
• Enumerating all the programs that can open a particular file extension
• Enumerating all the programs that can launch a particular protocol
• How do I register a command on the desktop background context menu? (And how do I remove one I don’t like?)
• How can I get the canonical name for a known folder?
• Peeking inside an IShellItem to see what it’s made of
• Why does SHGetKnownFolderPath return E_FAIL for a known folder?
• Why does SHGetKnownFolderPath fail when impersonating?
• Why can’t I use SHSetKnownFolderPath to change the location of FOLDERID_LocalAppData?
• How do I programmatically add a folder to my Documents library?
• Why doesn’t SHGetFileInfo give me customized folder icons?
• How can I detect that a shell item refers to a virtual folder, or to a file system inside a file?
• Why is there a limit of 15 shell icon overlays?
• The case of the SHGet­Folder­Path(CSIDL_COMMON_DOCUMENTS) that returned ERROR_PATH_NOT_FOUND
• Why is the HSHELL_WINDOWDESTROYED notification raised when a window is hidden, even if it hasn’t been destroyed?
• Why am I receiving HCNE_UPDATEDIR notifications that my code never generates?
• Why am I receiving SHCNE_UPDATE­DIR notifications that my code never generates?
• How can I get the original target of a shortcut without applying any 32-bit adjustments?
• How does Explorer calculate the “Date” of a file?

Uncategorized COM Stuff

• The macros for declaring and implementing COM interfaces
• An introduction to COM connection points
• Dispatch interfaces as connection point interfaces
• Adjustor thunks
• What is the underlying object behind a COM interface pointer?
• How to turn off the exception handler that COM "helpfully" wraps around your server
• Shortcuts are serializable objects, which means that they can be stored in places other than just a file
• Why does IFileOperation skip junctions even though I passed FOFX_NOSKIPJUNCTIONS?
• Nasty gotcha: STGM_READ | STGM_WRITE does not grant read/write access
• How can I get the list of programs the same way that Programs and Features gets it?
• How do I obtain the computer manufacturer's name via C++? (IWbemClassObject)
• The stream pointer position in IDataObject::GetData and IDataObject::GetDataHere is significant
• The sad implementation history of COM component categories and why it means you have to click twice to see your newly-installed taskbar toolbar
• How do I request that my out-of-process COM server run unelevated?
• How can a desktop app use a Windows Runtime object that infers UI context from its thread? The IInitializeWithWindow pattern (IInitialize­With­Window)
• How do I protect myself against a COM call that can hang? I’m already running the server out-of-process.
• What can I do about timer build-up when waiting for COM outbound calls to complete?
• Manipulating the positions of desktop icons
• A reminder about the correct way of accessing and manipulating the position of icons on the desktop
• 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)
• Notes on COM aggregation: Obtaining a pointer to your aggregated partner without introducing a reference cycle
• Notes on COM aggregation: How do you implement tear-offs in an aggregated object?
• The theory behind the IHttpFilter interface

Memory

• Stupid memory-mapping tricks
• Creating a shared memory block that can grow in size
• Why do I have to pass a valid page protection value to VirtualAlloc even if it ignores it?
• How can I include/exclude specific memory blocks in user-mode crash dumps?
• IsBadXxxPtr should really be called CrashProgramRandomly (IsBadWritePtr() et al.)
• A closer look at the stack guard page
• The case of the stack overflow exception when the stack is nowhere near overflowing
• How to allocate address space with a custom alignment or in a custom address region

Input and Output

• Mount points, volumes, and physical drives, oh my!
• What's the difference between an asynchronous PIPE_WAIT pipe and a PIPE_NOWAIT pipe?
• Be careful when redirecting both a process's stdin and stdout to pipes, for you can easily deadlock
• Looking at the problem at the wrong level: Closing a process's stdin
• ReadDirectoryChangesW reads directory changes, but what if the directory doesn't change?
• How do FILE_FLAG_SEQUENTIAL_SCAN and FILE_FLAG_RANDOM_ACCESS affect how the operating system treats my file?
• I used FILE_FLAG_SEQUENTIAL_SCAN but it didn’t seem to speed up my sequential scanning
• You can use an OVERLAPPED structure with synchronous I/O, too
• We're currently using FILE_FLAG_NO_BUFFERING and FILE_FLAG_WRITE_THROUGH, but we would like our WriteFile to go even faster
• On using ILE_FLAG_WRITE_THROUGH and FILE_FLAG_NO_BUFFERING for memory-mapped files
• On the interaction between the FILE_FLAG_NO_BUFFERING and FILE_FLAG_WRITE_THROUGH flags
• Why does my synchronous overlapped ReadFile return FALSE when the end of the file is reached?
• Why does SetFileValidData fail even though I enabled the SE_MANAGE_VOLUME_NAME privilege?
• Is GENERIC_ALL equivalent to GENERIC_READ | GENERIC_WRITE | GENERIC_EXECUTE?
• CancelIoEx can cancel I/O on console input, which is kind of nice
• CancelIoEx can cancel synchronous I/O, which is kind of nice
• Why does IsPathRelative return FALSE for paths that are drive-relative?
• The security check happens at the acquisition of the handle
• Taking a shortcut: You can query properties from a volume, and it will forward to the physical drive
• https://devblogs.microsoft.com/oldnewthing/20201023-00/?p=104395
• How do I disassociate a thread from an I/O completion port?
• Is it okay to call Map­View­Of­File on the same mapping handle simultaneously from different threads?
• What are these dire multithreading consequences that the GetFullPathName documentation is trying to warn me about?
• How can I force a WriteFile or ReadFile to complete synchronously or hang, in order to test something?
• How can I perform a CopyFile, but also flush the file buffers before the destination handle is closed?

Asynchronous Input and Output

• Developing the method for taking advantage of the fact that the OVERLAPPED associated with asynchronous I/O is passed by address
• Ready... cancel... wait for it! (part 1)
• Ready... cancel... wait for it! (part 2)
• Ready... cancel... wait for it! (part 3)
• If you're waiting for I/O to complete, it helps if you actually have an I/O to begin with
• Why does my asynchronous I/O complete synchronously?
• If an asynchronous I/O completes synchronously, is the hEvent in the OVERLAPPED structure signaled anyway?
• You can use an OVERLAPPED structure with synchronous I/O, too
• Why does my synchronous overlapped ReadFile return FALSE when the end of the file is reached?
• If I issue a second overlapped I/O operation without waiting for the first one to complete, are they still guaranteed to complete in order?
• Why are my file write operations synchronous, even though I opened the file as FILE_FLAG_OVERLAPPED?
• File-extending writes are not always synchronous, which is entirely within the contract
• Why you might need additional control over the secret event hiding inside the file object
• Why doesn’t my asynchronous read operation complete when I close the handle?
• The mental model for StartThreadpoolIo
• How can I force a WriteFile or ReadFile to complete synchronously or hang, in order to test something?
• If I issue multiple overlapped I/O requests against the same region of a file, will they execute in the order I issued them?
• What are the potentially-erroneous results if you don’t pass NULL as the lpNumberOfBytesRead when issuing overlapped I/O?

Files and Directories

• The Definitive Guide on Win32 to NT Path Conversion
• How can I tell that a directory is really a recycle bin?
• How can I tell that a directory is weird and should be excluded from the user interface?
• How do I get information about the target of a symbolic link?
• How do I access a file without updating its last-access time?
• How do I show the contents of a directory while respecting the user's preferences for hidden and super-hidden files as well as the user's language preferences?
• You can use a file as a synchronization object, too
• How can I append to a file and know where it got written, even if the file is being updated by multiple processes?
• The FILE_FLAG_DELETE_ON_CLOSE flag applies to the handle, also known as the file object, which is not the same as the file
• How long do I have to keep the SECURITY_ATTRIBUTES and SECURITY_DESCRIPTOR structures valid after using them to create a file?
• How do I create a directory where people can create subdirectories but cannot mess with those created by other users?
• How can I tell whether a file is on a removable drive, a fixed drive, or a remote drive?
• How can I tell whether a file is on an SSD?
• Why does a non-recursive Read­Directory­ChangesW still report files created inside subdirectories?
• The early history of Windows file attributes, and why there is a gap between System and Directory
• Even if you open a file with GUID, you can still get its name, or at least one of its names (GetFinalPathNameByHandle())
• How do I get from a file path to the volume that holds it?
• How do I get from a volume to the physical disk that holds it?
• Renaming a file is a multi-step process, only one of which is changing the name of the file
• How can I recognize file systems that don’t support 64-bit unique file identifiers?
• How can I recognize whether two handles refer to the same underlying file?

ACL

• The MoveSecurityAttributes policy affects only how Explorer recalculates ACLs when a file is moved; everybody else is on their own
• How to create a folder that inherits its parent’s ACL, and then overrides part of it

Security Permissions, Attributes and Identifiers

• The security check happens at the acquisition of the handle
• What is the default security descriptor?
• How do I convert a SID between binary and string forms?
• What are these SIDs of the form S-1-15-2-xxx?
• What are these SIDs of the form S-1-15-3-xxx?
• An easy way to determine whether you have a particular file permission
• What are the access rights and privileges that control changing ownership of an object?
• How do the names in the file security dialog map to access control masks?
• If you ask for STANDARD_RIGHTS_REQUIRED, you may as well ask for the moon
• A user's SID can change, so make sure to check the SID history
• Detecting whether a SID is well-known SID
• SIDs are really just another a fancy way of creating unique IDs in a decentralized way
• What's the point of giving my unnamed object proper security attributes since unnamed objects aren't accessible outside the process anyway (or are they?)
• Is a SID with zero subauthorities a valid SID? It depends whom you ask
• What’s the difference between duplicating the handle to a token and duplicating a token?
• I called AdjustTokenPrivileges, but I was still told that a necessary privilege was not held
• I called AdjustTokenPrivileges, but I was still told that a necessary privilege was not held, redux
• The history of the EncodePointer function for obfuscating pointers
• Additional helpful pseudo-handles: The process token, the thread token, and the effective token
• How can I tell whether my process is running as SYSTEM?
• A brief summary of the various versions of the Security Descriptor Definition Language (SDDL)
• How do I free the pointers returned by functions like Get­Token­Information?
• A clarification on the multithreading constraints of the Encrypt­Message function

Registry

• Beware of non-null-terminated registry strings
• The performance cost of reading a registry key
• So how bad is it that I’m calling RegOpenKey instead of RegOpenKeyEx?
• If I simply want to create a registry key but don’t intend to do anything else with it, what security access mask should I ask for?
• How can I programmatically inspect and manipulate a registry hive file without mounting it?
• Why doesn’t RegSetKeySecurity propagate inheritable ACEs, but SetSecurityInfo does?
• Why does Reg­Notify­Change­Key­Value stop notifying once the key is deleted?
• How can I emulate the REG_NOTIFY_THREAD_AGNOSTIC flag on systems that don’t support it? part 1
• How can I emulate the REG_NOTIFY_THREAD_AGNOSTIC flag on systems that don’t support it? part 2
• How can I emulate the REG_NOTIFY_THREAD_AGNOSTIC flag on systems that don’t support it? part 3
• How can I emulate the REG_NOTIFY_THREAD_AGNOSTIC flag on systems that don’t support it? part 4
• How can I emulate the REG_NOTIFY_THREAD_AGNOSTIC flag on systems that don’t support it? part 5
• The history of passing a null pointer as the key name to Reg­Open­Key­Ex
• On the failed unrealized promise of Reg­Override­Predef­Key (i.e. don't use it.)

Strings and Locales

• TEXT vs. _TEXT vs. _T, and UNICODE vs. _UNICODE
• The sad history of Unicode printf-style format specifiers in Visual C++
• Nasty gotcha: SetThreadUILanguage cannot be used to restore the thread UI language
• How can CharUpper and CharLower guarantee that the uppercase version of a string is the same length as the lowercase version? (use LCMapStringEx() in any new code)
• Is there a code page that matches ASCII and can round trip arbitrary bytes through Unicode?
• A consequence of being the first to adopt a standard is that you may end up being the only one to adopt it: The sad story of Korean jamo
• The activeCodePage manifest element can be used for more than just setting UTF-8 as the active code page
• Feel free to stop using IMultiLanguage2::DetectInputCodepage
• On the proper care and feeding of the enigmatic Get­Distance­Of­Closest­Language­In­List function
• How can I get WideCharToMultiByte to convert strings encoded in UTF-16BE?

NT Services

• Calling ShutdownBlockReasonCreate from my service doesn't stop the user from shutting down
• What does it mean when my attempt to stop a Windows NT service fails with ERROR_BROKEN_PIPE?
• How can I configure my Windows NT service to autostart when the system gains Internet access?
• On the confusing names for the Windows service SID types

Uncategorized

• How do I determine the processor's cache line size? (GetLogicalProcessorInformation())
• Why are structure sizes checked strictly?
• What's the difference between CreateMenu and CreatePopupMenu?
• Why are HANDLE return values so inconsistent?
• How to retrieve text under the cursor (mouse pointer)
• How to detect programmatically whether you are running on 64-bit Windows
• A timed context menu
• The importance of passing the WT_EXECUTELONGFUNCTION flag to QueueUserWorkItem
• If your callback fails, it's your responsibility to set the error code
• The double-click time tells the window manager how good your reflexes are
• The cursor isn't associated with a window or a window class; it's associated with a thread group
• Menu item states are not reliable until they are shown because they aren't needed until then
• How can I display a live screenshot of a piece of another application?
• Converting from a UTC-based SYSTEMTIME directly to a local-time-based SYSTEMTIME
• Programmatically uploading a file to an FTP site
• How can you use both versions 5 and 6 of the common controls within the same module?
• How can I tell if Windows Update is waiting for the system to reboot?
• How do I call SetTimer with a timer ID that is guaranteed not to conflict with any other timer ID?
• A window can’t have two timers with the same ID, so how do I assign an ID that nobody else is using?
• What does it mean when a display change is temporary?
• How do I obtain the comment for a share?
• How accurate are the various Windows time-querying functions?
• How can I detect whether the user is logging off?
• Why are timer IDs and dialog control IDs 64-bit values on 64-bit Windows? Did you really expect people to create more than 4 billion timers or dialog controls?
• If you suppress GDI+ background thread, then you are expected to pump messages yourself
• If one program blocks shutdown, then all programs block shutdown (WM_QUERY­END­SESSION, WM_END­SESSION)
• When I ask the GetIpAddrTable function to sort the results, how are they sorted?
• How can I detect that the system is no longer showing a UAC prompt? (EVENT_SYSTEM_DESKTOP­SWITCH)
• How can I get the number of processors in the system, when there are more than 64?
• Why are some system functions exported as stubs instead as forwarders?
• How can I check whether the user has disconnected from the session?
• Why does PF_VIRT_FIRMWARE_ENABLED return false even when virtualization is enabled in the firmware?
• How can I convert between IANA time zones and Windows registry-based time zones?
• The focus rectangle says, “I’m not orange. I’m just drawn that way.”
• Why does the precise point at which I get a stack overflow exception change from run to run? (structured exception handling aka SEH)
• How do I programmatically reposition monitors in a multiple-monitor system? (ChangeDisplaySettingsEx())
• How do I upgrade a 32-bit tick count to a 64-bit one?
• The error code you get might not be the one you want
• How can I find out which processor architectures are supported via emulation by the current system?
• How can I detect whether the system has a keyboard attached? On the GetRawInputDeviceList function
• Filtering out fake keyboards from the GetRawInputDeviceList function
• How expensive is PssCaptureSnapshot? How fast is it? How much memory does it consume?
• What is the CreateExplorerShellUnelevatedTask scheduled task?
• Under what conditions can I modify the memory that I received in the form a STGMEDIUM?
• Is it true that raising a structured exception from a structured exception handler terminates the process?
• Why are many Windows user interface elements positioned at multiples of 4 or 8 pixels? (DPI, DEVICE_SCALE_FACTOR)
• A history of the fd_set, FD_SETSIZE, and how it relates to WinSock
• How can I detect programmatically whether Windows is an N or KN version?
• How should I interpret the various values of NLM_CONNECTIVITY?
• How can I find out the last time a user logged on from C++?
• How can I specify icons for my app to use on the Start menu in high contrast mode?
• How can I add an environment variable to a process launched via Shell­Execute­Ex or IContext­Menu?
• Functions that return the size of a required buffer generally return upper bounds, not tight bounds