YourPhone.ScreenMirroring.Managed Initializes a new instance of the class. This action launches the Android intent associated with the notification. It involves sending a message from PC to phone. Gets the number of frames in the animation. Gets the frame rate of the animation. Gets the duration of the animation. Converts a zero-based frame number to the corresponding progress value denoting the start of the frame. Returns a map from marker names to corresponding progress values. Sets the color property with the given name, or does nothing if no such property exists. Sets the scalar property with the given name, or does nothing if no such property exists. Gets the number of frames in the animation. Gets the frame rate of the animation. Gets the duration of the animation. Converts a zero-based frame number to the corresponding progress value denoting the start of the frame. Returns a map from marker names to corresponding progress values. Sets the color property with the given name, or does nothing if no such property exists. Sets the scalar property with the given name, or does nothing if no such property exists. Processes AppProxy connection events as part of the shoulder tap mechanism. Handles various operations like fetching device state, creating app icons, and managing connections. Initializes a new instance of the class. Provider for remote app client instances. Store for device data management. Lazy-loaded orchestrator to YourPhone proxy service. Provider for connection establishment senders. Factory for notification count providers. Provider for device connectivity managers. Manager for theme-related operations. Provider for hosted apps package managers. Factory for remoting device data. Manager for keep-alive operations. Thrown when any required parameter is null. Processes shoulder tap notifications based on the operation type specified in the property bag. Correlation identifier for tracking the operation. Collection of properties containing operation details. Disposes the processor and releases all resources. Factory class for creating AppProxy connection event shoulder tap processors. Implements the IShoulderTapProcessorFactory interface to create processors that handle AppProxy connection events in the background. Initializes a new instance of the class. Provider for remote app client instances. Store for device data management. Lazy-loaded orchestrator to YourPhone proxy service. Provider for connection establishment senders. Factory for notification count providers. Provider for device connectivity managers. Manager for theme-related operations. Provider for hosted apps package managers. Factory for remoting device data. Manager for keep-alive operations. Thrown when any required parameter is null. Gets the type of shoulder tap processor this factory creates. Creates a new instance of the AppProxy connection event shoulder tap processor. A new instance configured for AppProxy connection events. Represents a phone request for clipboard operations, handling transfer of clipboard content including MIME types, text values, and image data to the connected phone device. Initializes a new instance of the class. The correlation identifier for tracking this request. The MIME types of the clipboard content. The text values from the clipboard. The image data from the clipboard as byte array. Thrown when correlationId is null. Gets the unique identifier for this request. Gets the correlation identifier for this request. Builds the request message as a ValueSet containing all clipboard data. A ValueSet containing the clipboard request data. Gets the headers for this request. An empty map view as no headers are required for clipboard requests. Represents a phone request for phone apps operations, handling requests for app information such as favorite apps or currently running apps on the connected phone device. Initializes a new instance of the class. The correlation identifier for tracking this request. The type of phone apps request. Initializes a new instance of the class with phone apps data. The correlation identifier for tracking this request. The type of phone apps request. The list of phone apps to include in the request. Initializes a new instance of the class for internal creation. The correlation identifier. The device data. Gets the unique identifier for this request. Creates a phone apps request with default configuration. The device data for the target device. A new instance. Builds the request message as a ValueSet containing all phone apps request data. A ValueSet containing the phone apps request data. Gets the headers for this request. An empty map view as no headers are required for phone apps requests. Adds a remote feature configuration to the ValueSet. The ValueSet to add the configuration to. The name of the remote feature. The value of the remote feature. Defines the types of phone apps requests that can be made. Note: Only add to the end of this enum! Must stay in sync with the Android and iOS versions. Request for favorite apps. Request for currently running apps. PCAppDataTable manages the pcapp_data table and related queries. Returns all app metadata as a read-only list. Returns app metadata for a given package name. Returns app metadata for a given platform app ID. Inserts or updates a batch of app data entities in a transaction. Maps a row from the database to a PCAppDataEntity. Manages the phone_apps table and related queries. Returns the count of phone apps. Returns all phone apps ordered by name. Returns all favorite phone apps ordered by favorite rank. Returns phone apps for the given package names. Returns phone apps for the given app IDs. Returns a single phone app by package name. Returns a single phone app by app ID. Inserts or updates a batch of phone app entities. Inserts or updates a batch of phone app entities with IDs. Inserts or updates a batch of phone app entities without icons. Deletes phone apps by package names. Deletes phone apps by app IDs. Deletes phone apps where the ETag does not match. Updates the favorite rank for a phone app. Updates favorite ranks for a batch of phone apps. Removes a favorite for a phone app. Removes all favorites. Maps a row from the database to a PhoneAppEntity. Synchronizes the table with the given IDs and checksums. Manages the recent_apps table and related queries. Returns all recent apps with icons, ordered by recent_app_rank. Returns all recent main apps with icons, ordered by recent_app_rank. Returns all recent apps, ordered by recent_app_rank. Returns a recent app by its app_id. Inserts or updates a batch of recent app entities. Deletes recent apps by package names. Deletes recent apps by app IDs. Clears all recent apps. Maps a row from the database to a RecentAppEntity. Synchronizes the table with the given IDs and checksums. InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) InitializeComponent() UnloadObject(DependencyObject) Connect() DisconnectUnloadedObject(int connectionId) GetBindingConnector(int connectionId, object target) The Dependency property backing the ViewModel property Gets or sets the viewmodel the chrome binds to. InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) The Dependency property backing the ViewModel property Gets or sets the viewmodel the chrome binds to. InitializeComponent() UnloadObject(DependencyObject) Connect() DisconnectUnloadedObject(int connectionId) GetBindingConnector(int connectionId, object target) The Dependency property backing the ViewModel property Gets or sets the viewmodel the chrome binds to. InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) The Dependency property backing the ViewModel property Gets or sets the viewmodel the chrome binds to. InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) The Dependency property backing the ViewModel property Gets or sets the viewmodel the chrome binds to. The Dependency property backing the PadTitleBar property The Dependency property backing the VerticalContentShift property InitializeComponent() UnloadObject(DependencyObject) Connect() DisconnectUnloadedObject(int connectionId) GetBindingConnector(int connectionId, object target) InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. The default associated with a default instance. The source-generated options associated with this context. Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. The default associated with a default instance. The source-generated options associated with this context. InitializeComponent() Connect() GetBindingConnector(int connectionId, object target) Main class for providing metadata for the app or library GetXamlType(Type) GetXamlType(String) GetXmlnsDefinitions() Trigger audio workflow on remoting workflow start instead of inside Orchestrator since remoting workflow is the "main" workflow Manages volume of audio during app remoting Audio Streaming Returns the last saved volume for from the database. Set volume slider and mute status for all windows under , send the new volume to the phone, and save to the database. Send the last saved volume in the database for , to the phone ConnectionService owns the fundamental connection setup, initializing workflows, and setting up channels Public facing method that takes in handle requests, does handle management, and requests a connection Only one handle for each workflow can be requested at once. N+1 requests will throw InvalidOperationException Name of workflow to start token Create a new connection even if one already exists and connection handle store is empty. The correlation id to track the connection request handle to connection for the workflow This method ensures that only one connection attempt occurs at once All other invocations will wait for the main connection attempt to succeed (or fail) and will adopt that result as well Exception is thrown (and standardized to ConnectionServiceException) if the connection attempt fails or times out Name of workflow to ensure connection Token by caller for cancellation (e.g. cancel via Close) The correlation id to track the connection request Task to wait for a connection attempt to complete Actual logic to form a connection Underyling components throw if the connection attempt fails or times out Name of workflow to attempt connection Correlation ID to pass around and to Android CancellationToken to cancel the operation Task to wait for a connection attempt to complete This object adapts the Nano IClient interface to APC's IClientAdapter interface This gets a client which is already connected and maintains it. It also creates a message channel so communication is possible with the device. The message channel is for the invocation of workflows The client is the first recipient of any new channels created. It also monitors the connection (instability/close) Waits for the client to finish setting up its internal objects Exceptions thrown: - TaskCanceledException - Close is called and current operations will be canceled - OperationCanceledException - Cancellation token passed into WaitForOpenAsync has been canceled The name of the workflow that triggers the waiting for open action Cancellation token Returns when client has finished setting up internal objects This object adapts the Nano IConnect interface to APC's IConnectAdapter interface This gets the local handshake request in InitializeAsync and uses the remote handshake response in OpenAsync Initializes the p2p transport Exceptions thrown: - TaskCanceledException - Close is called and current operations will be canceled - OperationCanceledException - Cancellation token passed into InitializeAsync has been canceled - InvalidOperationException - Invalid call sequence Returns connection string to be sent to peer for handshake Using the peer's connection string, attempts to open a connection with the peer Exceptions thrown: - TaskCanceledException - Close is called and current operations will be canceled - OperationCanceledException - Cancellation token passed into InitializeAsync has been canceled - InvalidOperationException - Invalid call sequence - ConnectionServiceException - DirectConnectionTimedOut, Error, Canceled, Failed (unexpected), RemoteTransportTooOld, RemoteTransportTooNew Peer's connection string The name of the workflow that triggers the openning action Returns client object with open connection Encapsulates the workflow-level message channel. The lifetime of this object is the lifetime of the workflow Gets a value indicating whether the current connection is local. A local connection typically means that the connected device is on the same local network or within close proximity (e.g., via IP or Wi-Fi Direct), whereas a non-local connection indicates that the device is accessed over a wider network, such as the internet. Initializes and opens the workflow message channel without cancellation token (legacy solution) Throws OperationCanceledException if canceled Throws InvalidOperationException if Open is called incorrectly Task completed on Open success Initializes and opens the workflow message channel with cancellation token (platform solution) Throws InvalidOperationException if Open is called incorrectly Task completed on Open success Encapsulates logic to start a workflow Starts a workflow asynchronously WorkflowException may be fired for unexpected code issues, cancellations, or connection failures Name of workflow to start Opportunity to register listeners with the workflow message channel before open Cancel token to stop the connection while its still starting Name of activity to start Whether to force a new connection Optional message channel type override. WorkflowMessageChannel to represent the workflow connection Get last volume level that was saved in the database for Save in the database as the latest volume level Get last mute state that was saved in the database for Save in the database as the latest mute state Get the last screen layout for the given Save the for the given Used as a Stream by APC, on write of bytes we send them to AP where they are written into the actual Stream Provisions a messaging platform channel early on device connection. If a context handle is already available for the device, channel provisioning is triggered immediately. Otherwise, waits for a context handle to be published before triggering. Each new call cancels any pending wait from a prior call. Ensures the device (PL↔LTW) connection for the supplied device is established before subsequent operations that depend on it, e.g. platform channel creation. If the connectivity state is not Connected, invalidates any cached platform channel for that device, drives a reconnect, and re-verifies the state before returning. Returns successfully if is already connected. Otherwise invalidates the cached platform channel for this device and triggers a reconnect. Throws with reason LostConnection if the reconnect does not bring the state to Connected. Callers are expected to be sequenced (typically via each flow manager's per-instance ISingleRun) so concurrent invocations for the same device are rare. The gate does not deduplicate concurrent reconnect attempts; if N callers race through the disconnected branch, N ConnectAsync requests will be sent. If a future entry point can fan out concurrently without outer sequencing, add a per-device in-flight Task cache here. Ensures a messaging platform channel is available for the specified . Callers are expected to snapshot the deviceId once up front and pass it here so the decision is made against a stable device identity, not a re-read of the global selected-device state. Invalidates any cached platform channel for so the next call recreates it. Used when the underlying PL connection has been lost without propagating ChannelClosed (e.g., user-initiated Disconnect in LTW). If the cached channel is for a different device, the call is a no-op. Retires this workflow channel instance when the factory resets without disposing the underlying messaging platform channel, then detaches all event handlers so the reused platform channel stays clean for the next session. Singleton store for the persistent used across phone-mirroring workflow sessions. Lifetime semantics: - If channel creation is already in progress, returns the same in-flight to every concurrent caller. - If a valid channel already exists for the currently selected device (created but not yet opened, or currently open), it is returned immediately without starting a new creation. - Otherwise a new creation is started and its task is stored for sharing. The channel is intentionally persistent and must not be explicitly closed or disposed by callers. When the channel is opened and subsequently closed, clears the stored task and disposes the channel so the next call starts a fresh creation. Ensures a messaging platform channel is available for the specified . Stable device identifier snapshotted by the caller. Token used only when a new channel creation is initiated; ignored for shared in-flight or cached tasks. Schedules disposal of the channel produced by an in-flight creation task whose owner is abandoning the reference. Also attaches a faulted-only continuation so the task's exception is observed and does not surface as an UnobservedTaskException. Remoting session describes the time while the user is remoting into the phone This interface represents lifecycle events of the remoting workflow Called when the remoting session is starting and objects are initialized for the session Contains objects associated with a new start of the session Called when the remoting session has started Called when the remoting session has stopped Service interface for the lifecycle events of AppProxyConnection Called when the remoting session is starting and objects are initialized for the session Must be cautious about blocking calls as this is called during initialization of the module Clear caches on device change Retrieves the cached value or starts a request to fetch the value. When starting a new request, create a new cache Cache location tcsLock Returns cached result if successful, otherwise TaskCanceledException is thrown Shoulder taps then returns cached result Possible exceptions: - TaskCanceledException if shouldertap fails - TimeoutException if shouldertap times out Cache Returns cached result if successful, otherwise exception is thrown Shoulder taps for all device state Task completes on success otherwise throws Possible exceptions: - TaskCanceledException if shouldertap fails - TimeoutException if shouldertap times out Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. The default associated with a default instance. The source-generated options associated with this context. Asks Android to check the permission status type of permission to check cancellation token Returns PermissionStatus based on current permission status Asks Android to show permission so user can provide input Its possible that the permission does not show on Android because the permission is disabled type of permission to check cancellation token Returns user input from permission prompt on Android Asks Android to launch app settings so user can change the permission value Returns when the user changes the value, closes the app settings, the request times out, or a new request has been made type of permission to check cancellation token Returns user input from permission prompt on Android Triggers the appropriate audio streaming permission flow based on params provided. Set to null if multiple apps is not supported. IStateMachineWatcher listens for state changes and ensures that the target state machine does not get stuck in an unexpected state. Initialize the watcher with a target state machine. Target state machine Command to be issued if the state machine spends longer than the in an invalid state. Command details to be sent to the state machine if the timeout is reached Maximum time without any transition out of an invalid state. Exceeding the delay causes the watcher to timeout and issue the List of states which are not valid long running states. Exceeding the while in one of theses states will cause a timeout Defines the source generated JSON serialization contract metadata for a given type. Defines the source generated JSON serialization contract metadata for a given type. The default associated with a default instance. The source-generated options associated with this context. This helps coordinate the request and response of messages where the request is fire and forget and a response comes another way. The relationship between the two messages is a transaction id. This helps connect the two together so the caller can expose an async method. This starts a transaction and returns a Task that can be waited on for transaction compmletion. AsyncTransaction that allows the caller to wait and get the transaction id This completes the transaction. The task returned when the transaction was started is completed. Unique id that links to the start of the transaction Value to return in the transaction Supported is whether phone supports audio Enabled is whether PC has EXP enabled whether audio code can run This class is used to ensure that a single method will run just once However, it may run again if the method throws or the object is Reset One example of this class's use if there is a method that creates a connection. If there are multiple calls to create that connection from different sources, then only one thread should actually create the connection, while the other threads wait for that thread's completion before continuing This class is thread safe Returns the current run task so callers can check status without invoking a run Returns null if there is no current task Runs the single method if not yet run, or waits for a previous call to complete and returns on completion Returns a task to wait for completion Resets the object so that runs are canceled and threads are released Contains a module initializer for generated CsWinRT projections. The module initializer registering the current assembly via . Contains information about a system appbar message. Learn more about this API from docs.microsoft.com. Type: DWORD The size of the structure, in bytes. Read more on docs.microsoft.com. Type: HWND The handle to the appbar window. Not all messages use this member. See the individual message page to see if you need to provide an hWind value. Read more on docs.microsoft.com. Type: UINT An application-defined message identifier. The application uses the specified identifier for notification messages that it sends to the appbar identified by the hWnd member. This member is used when sending the ABM_NEW message. Read more on docs.microsoft.com. Type: UINT A value that specifies an edge of the screen. This member is used when sending one of these messages: This doc was truncated. Read more on docs.microsoft.com. Type: RECT A RECT structure whose use varies depending on the message: This doc was truncated. Read more on docs.microsoft.com. Type: LPARAM A message-dependent value. This member is used with these messages: This doc was truncated. Read more on docs.microsoft.com. Defines the initialization parameters passed to the window procedure of an application. These members are identical to the parameters of the CreateWindowEx function. (Unicode) Because the lpszClass member can contain a pointer to a local (and thus inaccessible) atom, do not obtain the class name by using this member. Use the GetClassName function instead. You should access the data represented by the lpCreateParams member using a pointer that has been declared using the UNALIGNED type, because the pointer may not be DWORD aligned. This is demonstrated in the following example: This doc was truncated. Read more on docs.microsoft.com. Type: LPVOID Contains additional data which may be used to create the window. If the window is being created as a result of a call to the CreateWindow or CreateWindowEx function, this member contains the value of the lpParam parameter specified in the function call. If the window being created is a MDI client window, this member contains a pointer to a CLIENTCREATESTRUCT structure. If the window being created is a MDI child window, this member contains a pointer to an MDICREATESTRUCT structure. If the window is being created from a dialog template, this member is the address of a SHORT value that specifies the size, in bytes, of the window creation data. The value is immediately followed by the creation data. For more information, see the following Remarks section. Read more on docs.microsoft.com. Type: HINSTANCE A handle to the module that owns the new window. Read more on docs.microsoft.com. Type: HMENU A handle to the menu to be used by the new window. Read more on docs.microsoft.com. Type: HWND A handle to the parent window, if the window is a child window. If the window is owned, this member identifies the owner window. If the window is not a child or owned window, this member is NULL. Read more on docs.microsoft.com. Type: int The height of the new window, in pixels. Read more on docs.microsoft.com. Type: int The width of the new window, in pixels. Read more on docs.microsoft.com. Type: int The y-coordinate of the upper left corner of the new window. If the new window is a child window, coordinates are relative to the parent window. Otherwise, the coordinates are relative to the screen origin. Read more on docs.microsoft.com. Type: int The x-coordinate of the upper left corner of the new window. If the new window is a child window, coordinates are relative to the parent window. Otherwise, the coordinates are relative to the screen origin. Read more on docs.microsoft.com. Type: LPCTSTR The name of the new window. Read more on docs.microsoft.com. Type: LPCTSTR A pointer to a null-terminated string or an atom that specifies the class name of the new window. Read more on docs.microsoft.com. Type: DWORD The extended window style for the new window. For a list of possible values, see Extended Window Styles. Read more on docs.microsoft.com. Contains window class information. (Unicode) > [!NOTE] > The winuser.h header defines WNDCLASSEX as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see [Conventions for Function Prototypes](/windows/win32/intl/conventions-for-function-prototypes). Read more on docs.microsoft.com. Type: UINT The size, in bytes, of this structure. Set this member to sizeof(WNDCLASSEX). Be sure to set this member before calling the GetClassInfoEx function. Read more on docs.microsoft.com. Type: UINT The class style(s). This member can be any combination of the Class Styles. Read more on docs.microsoft.com. Type: WNDPROC A pointer to the window procedure. You must use the CallWindowProc function to call the window procedure. For more information, see WindowProc. Read more on docs.microsoft.com. Type: int The number of extra bytes to allocate following the window-class structure. The system initializes the bytes to zero. Read more on docs.microsoft.com. Type: int The number of extra bytes to allocate following the window instance. The system initializes the bytes to zero. If an application uses WNDCLASSEX to register a dialog box created by using the CLASS directive in the resource file, it must set this member to DLGWINDOWEXTRA. Read more on docs.microsoft.com. Type: HINSTANCE A handle to the instance that contains the window procedure for the class. Read more on docs.microsoft.com. Type: HICON A handle to the class icon. This member must be a handle to an icon resource. If this member is NULL, the system provides a default icon. Read more on docs.microsoft.com. Type: HCURSOR A handle to the class cursor. This member must be a handle to a cursor resource. If this member is NULL, an application must explicitly set the cursor shape whenever the mouse moves into the application's window. Read more on docs.microsoft.com. Type: HBRUSH A handle to the class background brush. This member can be a handle to the brush to be used for painting the background, or it can be a color value. A color value must be one of the following standard system colors (the value 1 must be added to the chosen color). If a color value is given, you must convert it to one of the following HBRUSH types: This doc was truncated. Read more on docs.microsoft.com. Type: LPCTSTR Pointer to a null-terminated character string that specifies the resource name of the class menu, as the name appears in the resource file. If you use an integer to identify the menu, use the MAKEINTRESOURCE macro. If this member is NULL, windows belonging to this class have no default menu. Read more on docs.microsoft.com. Type: LPCTSTR A pointer to a null-terminated string or is an atom. If this parameter is an atom, it must be a class atom created by a previous call to the RegisterClass or RegisterClassEx function. The atom must be in the low-order word of lpszClassName; the high-order word must be zero. If lpszClassName is a string, it specifies the window class name. The class name can be any name registered with RegisterClass or RegisterClassEx, or any of the predefined control-class names. The maximum length for lpszClassName is 256. If lpszClassName is greater than the maximum length, the RegisterClassEx function will fail. Read more on docs.microsoft.com. Type: HICON A handle to a small icon that is associated with the window class. If this member is NULL, the system searches the icon resource specified by the hIcon member for an icon of the appropriate size to use as the small icon. Read more on docs.microsoft.com. Identifies the dots per inch (dpi) setting for a monitor. All of these settings are affected by the PROCESS_DPI_AWARENESS of your application The effective DPI. This value should be used when determining the correct scale factor for scaling UI elements. This incorporates the scale factor set by the user for this specific display. The angular DPI. This DPI ensures rendering at a compliant angular resolution on the screen. This does not include the scale factor set by the user for this specific display. The raw DPI. This value is the linear DPI of the screen as measured on the screen itself. Use this value when you want to read the pixel density and not the recommended scaling setting. This does not include the scale factor set by the user for this specific display and is not guaranteed to be a supported DPI value. The default DPI setting for a monitor is MDT_EFFECTIVE_DPI. The **HRESULT** data type is the same as the [SCODE](scode.md) data type. An **HRESULT** value consists of the following fields: - A 1-bit code indicating severity, where zero represents success and 1 represents failure. - A 4-bit reserved value. - An 11-bit code indicating responsibility for the error or warning, also known as a facility code. - A 16-bit code describing the error or warning. Most MAPI interface methods and functions return **HRESULT** values to provide detailed cause formation. **HRESULT** values are also used widely in OLE interface methods. OLE provides several macros for converting between **HRESULT** values and **SCODE** values, another common data type for error handling. > [!NOTE] > In 64-bit MAPI, **HRESULT** is still a 32-bit value. For information about the OLE use of **HRESULT** values, see the *OLE Programmer's Reference*. For more information about the use of these values in MAPI, see [Error Handling](error-handling-in-mapi.md) and any of the following interface methods: [IABLogon::GetLastError](iablogon-getlasterror.md) [IMAPISupport::GetLastError](imapisupport-getlasterror.md) [IMAPIControl::GetLastError](imapicontrol-getlasterror.md) [IMAPITable::GetLastError](imapitable-getlasterror.md) [IMAPIProp::GetLastError](imapiprop-getlasterror.md) [IMAPIViewAdviseSink::OnPrint](imapiviewadvisesink-onprint.md) Read more on docs.microsoft.com. A pointer to the IErrorInfo interface that provides more information about the error. You can specify to use the current IErrorInfo interface, or new IntPtr(-1) to ignore the current IErrorInfo interface and construct the exception just from the error code. , if it does not reflect an error. A pointer to a null-terminated, constant character string. A pointer to the first character in the string. The content should be considered readonly, as it was typed as constant in the SDK. Gets the number of characters up to the first null character (exclusive). Returns a with a copy of this character array, up to the first null character (exclusive). A , or if is . Returns a span of the characters in this string, up to the first null character (exclusive). Returns a span of the characters in this string, up to the first null character (exclusive). The RECT structure defines a rectangle by the coordinates of its upper-left and lower-right corners. The RECT structure is identical to the RECTL structure. Specifies the x-coordinate of the upper-left corner of the rectangle. Specifies the y-coordinate of the upper-left corner of the rectangle. Specifies the x-coordinate of the lower-right corner of the rectangle. Specifies the y-coordinate of the lower-right corner of the rectangle. Represents a Win32 handle that can be closed with . The MONITORINFO structure contains information about a display monitor.The GetMonitorInfo function stores information in a MONITORINFO structure or a MONITORINFOEX structure.The MONITORINFO structure is a subset of the MONITORINFOEX structure. Learn more about this API from docs.microsoft.com. The size of the structure, in bytes. Set this member to sizeof ( MONITORINFO ) before calling the GetMonitorInfo function. Doing so lets the function determine the type of structure you are passing to it. Read more on docs.microsoft.com. A RECT structure that specifies the display monitor rectangle, expressed in virtual-screen coordinates. Note that if the monitor is not the primary display monitor, some of the rectangle's coordinates may be negative values. A RECT structure that specifies the work area rectangle of the display monitor, expressed in virtual-screen coordinates. Note that if the monitor is not the primary display monitor, some of the rectangle's coordinates may be negative values. A set of flags that represent attributes of the display monitor. The following flag is defined. This doc was truncated. Read more on docs.microsoft.com. Represents a Win32 handle that can be closed with . Contains extern methods from "api-ms-win-shcore-scaling-l1-1-1.dll". Contains extern methods from "GDI32.dll". Contains extern methods from "KERNEL32.dll". Contains extern methods from "SHELL32.dll". Contains extern methods from "USER32.dll". Queries the dots per inch (dpi) of a display. Handle of the monitor being queried. The type of DPI being queried. Possible values are from the MONITOR_DPI_TYPE enumeration. The value of the DPI along the X axis. This value always refers to the horizontal edge, even when the screen is rotated. The value of the DPI along the Y axis. This value always refers to the vertical edge, even when the screen is rotated. This function returns one of the following values. This doc was truncated. This API is not DPI aware and should not be used if the calling thread is per-monitor DPI aware. For the DPI-aware version of this API, see GetDpiForWindow. When you call GetDpiForMonitor, you will receive different DPI values depending on the DPI awareness of the calling application. DPI awareness is an application-level property usually defined in the application manifest. For more information about DPI awareness values, see PROCESS_DPI_AWARENESS. The following table indicates how the results will differ based on the PROCESS_DPI_AWARENESS value of your application. This doc was truncated. Read more on docs.microsoft.com. Sent prior to the WM\_CREATE message when a window is first created. Type: **LRESULT** If an application processes this message, it should return **TRUE** to continue creation of the window. If the application returns **FALSE**, the [**CreateWindow**](/windows/win32/api/winuser/nf-winuser-createwindowa) or [**CreateWindowEx**](/windows/win32/api/winuser/nf-winuser-createwindowexa) function will return a **NULL** handle. Learn more about this API from docs.microsoft.com. Notifies a window that its nonclient area is being destroyed. The DestroyWindow function sends the WM\_NCDESTROY message to the window following the WM\_DESTROY message. Type: **LRESULT** If an application processes this message, it should return zero. This message frees any memory internally allocated for the window. Sent when the contents of the clipboard have changed. If an application processes this message, it should return zero. To register a window to receive this message, use the [**AddClipboardFormatListener**](/windows/desktop/api/Winuser/nf-winuser-addclipboardformatlistener) function. Sent when a window is being destroyed. It is sent to the window procedure of the window being destroyed after the window is removed from the screen. Type: **LRESULT** If an application processes this message, it should return zero. If the window being destroyed is part of the clipboard viewer chain (set by calling the [**SetClipboardViewer**](/windows/win32/api/winuser/nf-winuser-setclipboardviewer) function), the window must remove itself from the chain by processing the [**ChangeClipboardChain**](/windows/win32/api/winuser/nf-winuser-changeclipboardchain) function before returning from the **WM\_DESTROY** message. Sent as a signal that a window or an application should terminate. Type: **LRESULT** If an application processes this message, it should return zero. An application can prompt the user for confirmation, prior to destroying a window, by processing the **WM\_CLOSE** message and calling the [**DestroyWindow**](/windows/win32/api/winuser/nf-winuser-destroywindow) function only if the user confirms the choice. By default, the [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function calls the [**DestroyWindow**](/windows/win32/api/winuser/nf-winuser-destroywindow) function to destroy the window. Read more on docs.microsoft.com. Retrieves the bounding rectangle of the Windows taskbar. Returns **TRUE** if successful; otherwise, **FALSE**. Note that this applies only to the system taskbar. Other objects, particularly toolbars supplied with third-party software, also can be present. As a result, some of the screen area not covered by the Windows taskbar might not be visible to the user. To retrieve the area of the screen not covered by both the taskbar and other app bars the working area available to your application , use the [**GetMonitorInfo**](/windows/desktop/api/winuser/nf-winuser-getmonitorinfoa) function. The DeleteObject function deletes a logical pen, brush, font, bitmap, region, or palette, freeing all system resources associated with the object. After the object is deleted, the specified handle is no longer valid. A handle to a logical pen, brush, font, bitmap, region, or palette. If the function succeeds, the return value is nonzero. If the specified handle is not valid or is currently selected into a DC, the return value is zero. Do not delete a drawing object (pen or brush) while it is still selected into a DC. When a pattern brush is deleted, the bitmap associated with the brush is not deleted. The bitmap must be deleted independently. Read more on docs.microsoft.com. The GetDeviceCaps function retrieves device-specific information for the specified device. A handle to the DC. The return value specifies the value of the desired item. When nIndex is BITSPIXEL and the device has 15bpp or 16bpp, the return value is 16. When nIndex is SHADEBLENDCAPS: This doc was truncated. Read more on docs.microsoft.com. Closes an open object handle. A valid handle to an open object. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. If the application is running under a debugger, the function will throw an exception if it receives either a handle value that is not valid or a pseudo-handle value. This can happen if you close a handle twice, or if you call CloseHandle on a handle returned by the FindFirstFile function instead of calling the FindClose function. The CloseHandle function closes handles to the following objects: This doc was truncated. Read more on docs.microsoft.com. Frees the loaded dynamic-link library (DLL) module and, if necessary, decrements its reference count. A handle to the loaded library module. The LoadLibrary, LoadLibraryEx, GetModuleHandle, or GetModuleHandleEx function returns this handle. Read more on docs.microsoft.com. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call the GetLastError function. The system maintains a per-process reference count for each loaded module. A module that was loaded at process initialization due to load-time dynamic linking has a reference count of one. The reference count for a module is incremented each time the module is loaded by a call to LoadLibrary. The reference count is also incremented by a call to LoadLibraryEx unless the module is being loaded for the first time and is being loaded as a data or image file. The reference count is decremented each time the FreeLibrary or FreeLibraryAndExitThread function is called for the module. When a module's reference count reaches zero or the process terminates, the system unloads the module from the address space of the process. Before unloading a library module, the system enables the module to detach from the process by calling the module's DllMain function, if it has one, with the DLL_PROCESS_DETACH value. Doing so gives the library module an opportunity to clean up resources allocated on behalf of the current process. After the entry-point function returns, the library module is removed from the address space of the current process. It is not safe to call FreeLibrary from DllMain. For more information, see the Remarks section in DllMain. Calling FreeLibrary does not affect other processes that are using the same module. Use caution when calling FreeLibrary with a handle returned by GetModuleHandle. The GetModuleHandle function does not increment a module's reference count, so passing this handle to FreeLibrary can cause a module to be unloaded prematurely. A thread that must unload the DLL in which it is executing and then terminate itself should call FreeLibraryAndExitThread instead of calling FreeLibrary and ExitThread separately. Otherwise, a race condition can occur. For details, see the Remarks section of FreeLibraryAndExitThread. Read more on docs.microsoft.com. Retrieves a module handle for the specified module. The module must have been loaded by the calling process. (Unicode) The name of the loaded module (either a .dll or .exe file). If the file name extension is omitted, the default library extension .dll is appended. The file name string can include a trailing point character (.) to indicate that the module name has no extension. The string does not have to specify a path. When specifying a path, be sure to use backslashes (\\), not forward slashes (/). The name is compared (case independently) to the names of modules currently mapped into the address space of the calling process. If this parameter is NULL, GetModuleHandle returns a handle to the file used to create the calling process (.exe file). The GetModuleHandle function does not retrieve handles for modules that were loaded using the LOAD_LIBRARY_AS_DATAFILE flag. For more information, see LoadLibraryEx. Read more on docs.microsoft.com. If the function succeeds, the return value is a handle to the specified module. If the function fails, the return value is NULL. To get extended error information, call GetLastError. The returned handle is not global or inheritable. It cannot be duplicated or used by another process. If lpModuleName does not include a path and there is more than one loaded module with the same base name and extension, you cannot predict which module handle will be returned. To work around this problem, you could specify a path, use side-by-side assemblies, or use GetModuleHandleEx to specify a memory location rather than a DLL name. The GetModuleHandle function returns a handle to a mapped module without incrementing its reference count. However, if this handle is passed to the FreeLibrary function, the reference count of the mapped module will be decremented. Therefore, do not pass a handle returned by GetModuleHandle to the FreeLibrary function. Doing so can cause a DLL module to be unmapped prematurely. This function must be used carefully in a multithreaded application. There is no guarantee that the module handle remains valid between the time this function returns the handle and the time it is used. For example, suppose that a thread retrieves a module handle, but before it uses the handle, a second thread frees the module. If the system loads another module, it could reuse the module handle that was recently freed. Therefore, the first thread would have a handle to a different module than the one intended. Read more on docs.microsoft.com. Frees the specified global memory object and invalidates its handle. A handle to the global memory object. This handle is returned by either the GlobalAlloc or GlobalReAlloc function. It is not safe to free memory allocated with LocalAlloc. Read more on docs.microsoft.com. If the function succeeds, the return value is NULL. If the function fails, the return value is equal to a handle to the global memory object. To get extended error information, call GetLastError. If the process examines or modifies the memory after it has been freed, heap corruption may occur or an access violation exception (EXCEPTION_ACCESS_VIOLATION) may be generated. The GlobalFree function will free a locked memory object. A locked memory object has a lock count greater than zero. The GlobalLock function locks a global memory object and increments the lock count by one. The GlobalUnlock function unlocks it and decrements the lock count by one. To get the lock count of a global memory object, use the GlobalFlags function. If an application is running under a debug version of the system, GlobalFree will issue a message that tells you that a locked object is being freed. If you are debugging the application, GlobalFree will enter a breakpoint just before freeing a locked object. This allows you to verify the intended behavior, then continue execution. Read more on docs.microsoft.com. Allocates the specified number of bytes from the heap. (GlobalAlloc) The number of bytes to allocate. If this parameter is zero and the uFlags parameter specifies GMEM_MOVEABLE, the function returns a handle to a memory object that is marked as discarded. If the function succeeds, the return value is a handle to the newly allocated memory object. If the function fails, the return value is NULL. To get extended error information, call GetLastError. Windows memory management does not provide a separate local heap and global heap. Therefore, the GlobalAlloc and LocalAlloc functions are essentially the same. The movable-memory flags GHND and GMEM_MOVABLE add unnecessary overhead and require locking to be used safely. They should be avoided unless documentation specifically states that they should be used. New applications should use the heap functions to allocate and manage memory unless the documentation specifically states that a global function should be used. For example, the global functions are still used with Dynamic Data Exchange (DDE), the clipboard functions, and OLE data objects. If the GlobalAlloc function succeeds, it allocates at least the amount of memory requested. If the actual amount allocated is greater than the amount requested, the process can use the entire amount. To determine the actual number of bytes allocated, use the GlobalSize function. If the heap does not contain sufficient free space to satisfy the request, GlobalAlloc returns NULL. Because NULL is used to indicate an error, virtual address zero is never allocated. It is, therefore, easy to detect the use of a NULL pointer. Memory allocated with this function is guaranteed to be aligned on an 8-byte boundary. To execute dynamically generated code, use the VirtualAlloc function to allocate memory and the VirtualProtect function to grant PAGE_EXECUTE access. To free the memory, use the GlobalFree function. It is not safe to free memory allocated with GlobalAlloc using LocalFree. Read more on docs.microsoft.com. Locks a global memory object and returns a pointer to the first byte of the object's memory block. A handle to the global memory object. This handle is returned by either the GlobalAlloc or GlobalReAlloc function. Read more on docs.microsoft.com. If the function succeeds, the return value is a pointer to the first byte of the memory block. If the function fails, the return value is NULL. To get extended error information, call GetLastError. The internal data structures for each memory object include a lock count that is initially zero. For movable memory objects, GlobalLock increments the count by one, and the GlobalUnlock function decrements the count by one. Each successful call that a process makes to GlobalLock for an object must be matched by a corresponding call to GlobalUnlock. Locked memory will not be moved or discarded, unless the memory object is reallocated by using the GlobalReAlloc function. The memory block of a locked memory object remains locked until its lock count is decremented to zero, at which time it can be moved or discarded. Memory objects allocated with GMEM_FIXED always have a lock count of zero. For these objects, the value of the returned pointer is equal to the value of the specified handle. If the specified memory block has been discarded or if the memory block has a zero-byte size, this function returns NULL. Discarded objects always have a lock count of zero. Read more on docs.microsoft.com. Decrements the lock count associated with a memory object that was allocated with GMEM_MOVEABLE. A handle to the global memory object. This handle is returned by either the GlobalAlloc or GlobalReAlloc function. Read more on docs.microsoft.com. If the memory object is still locked after decrementing the lock count, the return value is a nonzero value. If the memory object is unlocked after decrementing the lock count, the function returns zero and GetLastError returns NO_ERROR. If the function fails, the return value is zero and GetLastError returns a value other than NO_ERROR. The internal data structures for each memory object include a lock count that is initially zero. For movable memory objects, the GlobalLock function increments the count by one, and GlobalUnlock decrements the count by one. For each call that a process makes to GlobalLock for an object, it must eventually call GlobalUnlock. Locked memory will not be moved or discarded, unless the memory object is reallocated by using the GlobalReAlloc function. The memory block of a locked memory object remains locked until its lock count is decremented to zero, at which time it can be moved or discarded. Memory objects allocated with GMEM_FIXED always have a lock count of zero. If the specified memory block is fixed memory, this function returns TRUE. If the memory object is already unlocked, GlobalUnlock returns FALSE and GetLastError reports ERROR_NOT_LOCKED. A process should not rely on the return value to determine the number of times it must subsequently call GlobalUnlock for a memory object. Read more on docs.microsoft.com. Sends an appbar message to the system. Type: DWORD Type: PAPPBARDATA A pointer to an APPBARDATA structure. The content of the structure on entry and on exit depends on the value set in the dwMessage parameter. See the individual message pages for specifics. Read more on docs.microsoft.com. Type: UINT_PTR This function returns a message-dependent value. For more information, see the Windows SDK documentation for the specific appbar message sent. Links to those documents are given in the See Also section. Learn more about this API from docs.microsoft.com. Opens the clipboard for examination and prevents other applications from modifying the clipboard content. Type: HWND A handle to the window to be associated with the open clipboard. If this parameter is NULL, the open clipboard is associated with the current task. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. OpenClipboard fails if another window has the clipboard open. An application should call the CloseClipboard function after every successful call to OpenClipboard. The window identified by the hWndNewOwner parameter does not become the clipboard owner unless the EmptyClipboard function is called. If an application calls OpenClipboard with hwnd set to NULL, EmptyClipboard sets the clipboard owner to NULL; this causes SetClipboardData to fail. Read more on docs.microsoft.com. Closes the clipboard. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. When the window has finished examining or changing the clipboard, close the clipboard by calling CloseClipboard. This enables other windows to access the clipboard. Do not place an object on the clipboard after calling CloseClipboard. Read more on docs.microsoft.com. Empties the clipboard and frees handles to data in the clipboard. The function then assigns ownership of the clipboard to the window that currently has the clipboard open. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. Before calling EmptyClipboard, an application must open the clipboard by using the OpenClipboard function. If the application specifies a NULL window handle when opening the clipboard, EmptyClipboard succeeds but sets the clipboard owner to NULL. Note that this causes SetClipboardData to fail. Retrieves a handle to a window whose class name and window name match the specified strings. The function searches child windows, beginning with the one following the specified child window. This function does not perform a case-sensitive search. (Unicode) Type: HWND A handle to the parent window whose child windows are to be searched. If hwndParent is NULL, the function uses the desktop window as the parent window. The function searches among windows that are child windows of the desktop. If hwndParent is HWND_MESSAGE, the function searches all message-only windows. Read more on docs.microsoft.com. Type: HWND A handle to a child window. The search begins with the next child window in the Z order. The child window must be a direct child window of hwndParent, not just a descendant window. If hwndChildAfter is NULL, the search begins with the first child window of hwndParent. Note that if both hwndParent and hwndChildAfter are NULL, the function searches all top-level and message-only windows. Read more on docs.microsoft.com. Type: LPCTSTR The class name or a class atom created by a previous call to the RegisterClass or RegisterClassEx function. The atom must be placed in the low-order word of lpszClass; the high-order word must be zero. If lpszClass is a string, it specifies the window class name. The class name can be any name registered with RegisterClass or RegisterClassEx, or any of the predefined control-class names, or it can be MAKEINTATOM(0x8000). In this latter case, 0x8000 is the atom for a menu class. For more information, see the Remarks section of this topic. Read more on docs.microsoft.com. Type: LPCTSTR The window name (the window's title). If this parameter is NULL, all window names match. Read more on docs.microsoft.com. Type: HWND If the function succeeds, the return value is a handle to the window that has the specified class and window names. If the function fails, the return value is NULL. To get extended error information, call GetLastError. The FindWindowEx function searches only direct child windows. It does not search other descendants. If the lpszWindow parameter is not NULL, FindWindowEx calls the GetWindowText function to retrieve the window name for comparison. For a description of a potential problem that can arise, see the Remarks section of GetWindowText. An application can call this function in the following way. FindWindowEx( NULL, NULL, MAKEINTATOM(0x8000), NULL ); Note that 0x8000 is the atom for a menu class. When an application calls this function, the function checks whether a context menu is being displayed that the application created. > [!NOTE] > The winuser.h header defines FindWindowEx as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see [Conventions for Function Prototypes](/windows/win32/intl/conventions-for-function-prototypes). Read more on docs.microsoft.com. Destroys the specified menu and frees any memory that the menu occupies. Type: HMENU A handle to the menu to be destroyed. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. Before closing, an application must use the DestroyMenu function to destroy a menu not assigned to a window. A menu that is assigned to a window is automatically destroyed when the application closes. DestroyMenu is recursive, that is, it will destroy the menu and all its submenus. Read more on docs.microsoft.com. Creates an overlapped, pop-up, or child window with an extended window style; otherwise, this function is identical to the CreateWindow function. (Unicode) Type: DWORD The extended window style of the window being created. For a list of possible values, see Extended Window Styles. Read more on docs.microsoft.com. Type: LPCTSTR A null-terminated string or a class atom created by a previous call to the RegisterClass or RegisterClassEx function. The atom must be in the low-order word of lpClassName; the high-order word must be zero. If lpClassName is a string, it specifies the window class name. The class name can be any name registered with RegisterClass or RegisterClassEx, provided that the module that registers the class is also the module that creates the window. The class name can also be any of the predefined system class names. Read more on docs.microsoft.com. Type: LPCTSTR The window name. If the window style specifies a title bar, the window title pointed to by lpWindowName is displayed in the title bar. When using CreateWindow to create controls, such as buttons, check boxes, and static controls, use lpWindowName to specify the text of the control. When creating a static control with the SS_ICON style, use lpWindowName to specify the icon name or identifier. To specify an identifier, use the syntax "#num". Read more on docs.microsoft.com. Type: DWORD The style of the window being created. This parameter can be a combination of the window style values, plus the control styles indicated in the Remarks section. Read more on docs.microsoft.com. Type: int The initial horizontal position of the window. For an overlapped or pop-up window, the x parameter is the initial x-coordinate of the window's upper-left corner, in screen coordinates. For a child window, x is the x-coordinate of the upper-left corner of the window relative to the upper-left corner of the parent window's client area. If x is set to CW_USEDEFAULT, the system selects the default position for the window's upper-left corner and ignores the y parameter. CW_USEDEFAULT is valid only for overlapped windows; if it is specified for a pop-up or child window, the x and y parameters are set to zero. Read more on docs.microsoft.com. Type: int The initial vertical position of the window. For an overlapped or pop-up window, the y parameter is the initial y-coordinate of the window's upper-left corner, in screen coordinates. For a child window, y is the initial y-coordinate of the upper-left corner of the child window relative to the upper-left corner of the parent window's client area. For a list box y is the initial y-coordinate of the upper-left corner of the list box's client area relative to the upper-left corner of the parent window's client area. If an overlapped window is created with the WS_VISIBLE style bit set and the x parameter is set to CW_USEDEFAULT, then the y parameter determines how the window is shown. If the y parameter is CW_USEDEFAULT, then the window manager calls ShowWindow with the SW_SHOW flag after the window has been created. If the y parameter is some other value, then the window manager calls ShowWindow with that value as the nCmdShow parameter. Read more on docs.microsoft.com. Type: int The width, in device units, of the window. For overlapped windows, nWidth is the window's width, in screen coordinates, or CW_USEDEFAULT. If nWidth is CW_USEDEFAULT, the system selects a default width and height for the window; the default width extends from the initial x-coordinates to the right edge of the screen; the default height extends from the initial y-coordinate to the top of the icon area. CW_USEDEFAULT is valid only for overlapped windows; if CW_USEDEFAULT is specified for a pop-up or child window, the nWidth and nHeight parameter are set to zero. Read more on docs.microsoft.com. Type: int The height, in device units, of the window. For overlapped windows, nHeight is the window's height, in screen coordinates. If the nWidth parameter is set to CW_USEDEFAULT, the system ignores nHeight. Read more on docs.microsoft.com. Type: HWND A handle to the parent or owner window of the window being created. To create a child window or an owned window, supply a valid window handle. This parameter is optional for pop-up windows. To create a message-only window, supply HWND_MESSAGE or a handle to an existing message-only window. Read more on docs.microsoft.com. Type: HMENU A handle to a menu, or specifies a child-window identifier, depending on the window style. For an overlapped or pop-up window, hMenu identifies the menu to be used with the window; it can be NULL if the class menu is to be used. For a child window, hMenu specifies the child-window identifier, an integer value used by a dialog box control to notify its parent about events. The application determines the child-window identifier; it must be unique for all child windows with the same parent window. Read more on docs.microsoft.com. Type: HINSTANCE A handle to the instance of the module to be associated with the window. Read more on docs.microsoft.com. Type: LPVOID Pointer to a value to be passed to the window through the CREATESTRUCT structure (lpCreateParams member) pointed to by the lParam param of the WM_CREATE message. This message is sent to the created window by this function before it returns. If an application calls CreateWindow to create a MDI client window, lpParam should point to a CLIENTCREATESTRUCT structure. If an MDI client window calls CreateWindow to create an MDI child window, lpParam should point to a MDICREATESTRUCT structure. lpParam may be NULL if no additional data is needed. Read more on docs.microsoft.com. Type: HWND If the function succeeds, the return value is a handle to the new window. If the function fails, the return value is NULL. To get extended error information, call GetLastError. This function typically fails for one of the following reasons: This doc was truncated. The CreateWindowEx function sends WM_NCCREATE, WM_NCCALCSIZE, and WM_CREATE messages to the window being created. If the created window is a child window, its default position is at the bottom of the Z-order. If the created window is a top-level window, its default position is at the top of the Z-order (but beneath all topmost windows unless the created window is itself topmost). For information on controlling whether the Taskbar displays a button for the created window, see Managing Taskbar Buttons. For information on removing a window, see the DestroyWindow function. The following predefined control classes can be specified in the lpClassName parameter. Note the corresponding control styles you can use in the dwStyle parameter. This doc was truncated. Read more on docs.microsoft.com. Destroys the specified window. Type: HWND A handle to the window to be destroyed. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. A thread cannot use DestroyWindow to destroy a window created by a different thread. If the window being destroyed is a child window that does not have the WS_EX_NOPARENTNOTIFY style, a WM_PARENTNOTIFY message is sent to the parent. Read more on docs.microsoft.com. Destroys an icon and frees any memory the icon occupied. Type: HICON A handle to the icon to be destroyed. The icon must not be in use. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. It is only necessary to call DestroyIcon for icons and cursors created with the following functions: CreateIconFromResourceEx (if called without the LR_SHARED flag), CreateIconIndirect, and CopyIcon. Do not use this function to destroy a shared icon. A shared icon is valid as long as the module from which it was loaded remains in memory. The following functions obtain a shared icon. This doc was truncated. Read more on docs.microsoft.com. Destroys a cursor and frees any memory the cursor occupied. Do not use this function to destroy a shared cursor. Type: HCURSOR A handle to the cursor to be destroyed. The cursor must not be in use. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. The DestroyCursor function destroys a nonshared cursor. Do not use this function to destroy a shared cursor. A shared cursor is valid as long as the module from which it was loaded remains in memory. The following functions obtain a shared cursor: This doc was truncated. Read more on docs.microsoft.com. Registers a window class for subsequent use in calls to the CreateWindow or CreateWindowEx function. (RegisterClassExW) Type: ATOM If the function succeeds, the return value is a class atom that uniquely identifies the class being registered. This atom can only be used by the CreateWindow, CreateWindowEx, GetClassInfo, GetClassInfoEx, FindWindow, FindWindowEx, and UnregisterClass functions and the IActiveIMMap::FilterClientWindows method. If the function fails, the return value is zero. To get extended error information, call GetLastError. If you register the window class by using RegisterClassExA, the application tells the system that the windows of the created class expect messages with text or character parameters to use the ANSI character set; if you register it by using RegisterClassExW, the application requests that the system pass text parameters of messages as Unicode. The IsWindowUnicode function enables applications to query the nature of each window. For more information on ANSI and Unicode functions, see Conventions for Function Prototypes. All window classes that an application registers are unregistered when it terminates. No window classes registered by a DLL are unregistered when the DLL is unloaded. A DLL must explicitly unregister its classes when it is unloaded. Read more on docs.microsoft.com. Unregisters a window class, freeing the memory required for the class. (Unicode) Type: LPCTSTR A null-terminated string or a class atom. If lpClassName is a string, it specifies the window class name. This class name must have been registered by a previous call to the RegisterClass or RegisterClassEx function. System classes, such as dialog box controls, cannot be unregistered. If this parameter is an atom, it must be a class atom created by a previous call to the RegisterClass or RegisterClassEx function. The atom must be in the low-order word of lpClassName; the high-order word must be zero. Read more on docs.microsoft.com. Type: HINSTANCE A handle to the instance of the module that created the class. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the class could not be found or if a window still exists that was created with the class, the return value is zero. To get extended error information, call GetLastError. Before calling this function, an application must destroy all windows created with the specified class. All window classes that an application registers are unregistered when it terminates. Class atoms are special atoms returned only by RegisterClass and RegisterClassEx. No window classes registered by a DLL are unregistered when the .dll is unloaded. > [!NOTE] > The winuser.h header defines UnregisterClass as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see [Conventions for Function Prototypes](/windows/win32/intl/conventions-for-function-prototypes). Read more on docs.microsoft.com. Places (posts) a message in the message queue associated with the thread that created the specified window and returns without waiting for the thread to process the message. (Unicode) Type: HWND A handle to the window whose window procedure is to receive the message. The following values have special meanings. This doc was truncated. Read more on docs.microsoft.com. Type: UINT The message to be posted. For lists of the system-provided messages, see System-Defined Messages. Read more on docs.microsoft.com. Type: WPARAM Additional message-specific information. Read more on docs.microsoft.com. Type: LPARAM Additional message-specific information. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. When a message is blocked by UIPI the last error, retrieved with GetLastError, is set to 5 (access denied). Messages in a message queue are retrieved by calls to the GetMessage or PeekMessage function. Applications that need to communicate using HWND_BROADCAST should use the RegisterWindowMessage function to obtain a unique message for inter-application communication. The system only does marshalling for system messages (those in the range 0 to (WM_USER-1)). To send other messages (those >= WM_USER) to another process, you must do custom marshalling. If you send a message in the range below WM_USER to the asynchronous message functions (PostMessage, SendNotifyMessage, and SendMessageCallback), its message parameters cannot include pointers. Otherwise, the operation will fail. The functions will return before the receiving thread has had a chance to process the message and the sender will free the memory before it is used. Do not post the WM_QUIT message using PostMessage; use the PostQuitMessage function. An accessibility application can use PostMessage to post WM_APPCOMMAND messages to the shell to launch applications. This functionality is not guaranteed to work for other types of applications. There is a limit of 10,000 posted messages per message queue. This limit should be sufficiently large. If your application exceeds the limit, it should be redesigned to avoid consuming so many system resources. To adjust this limit, modify the following registry key. 
HKEY_LOCAL_MACHINE SOFTWARE Microsoft Windows NT CurrentVersion Windows USERPostMessageLimit
If the function fails, call GetLastError to get extended error information. GetLastError returns ERROR_NOT_ENOUGH_QUOTA when the limit is hit. The minimum acceptable value is 4000. Read more on docs.microsoft.com. Calls the default window procedure to provide default processing for any window messages that an application does not process. (Unicode) Type: HWND A handle to the window procedure that received the message. Read more on docs.microsoft.com. Type: UINT The message. Read more on docs.microsoft.com. Type: WPARAM Additional message information. The content of this parameter depends on the value of the Msg parameter. Read more on docs.microsoft.com. Type: LPARAM Additional message information. The content of this parameter depends on the value of the Msg parameter. Read more on docs.microsoft.com. Type: LRESULT The return value is the result of the message processing and depends on the message. > [!NOTE] > The winuser.h header defines DefWindowProc as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see [Conventions for Function Prototypes](/windows/win32/intl/conventions-for-function-prototypes). Read more on docs.microsoft.com. Places data on the clipboard in a specified clipboard format. Type: UINT The clipboard format. This parameter can be a registered format or any of the standard clipboard formats. For more information, see Standard Clipboard Formats and Registered Clipboard Formats. Read more on docs.microsoft.com. Type: HANDLE A handle to the data in the specified format. This parameter can be NULL, indicating that the window provides data in the specified clipboard format (renders the format) upon request; this is known as [delayed rendering](/windows/win32/dataxchg/clipboard-operations#delayed-rendering). If a window delays rendering, it must process the [WM_RENDERFORMAT](/windows/win32/dataxchg/wm-renderformat) and [WM_RENDERALLFORMATS](/windows/win32/dataxchg/wm-renderallformats) messages. If SetClipboardData succeeds, the system owns the object identified by the hMem parameter. The application may not write to or free the data once ownership has been transferred to the system, but it can lock and read from the data until the CloseClipboard function is called. (The memory must be unlocked before the Clipboard is closed.) If the hMem parameter identifies a memory object, the object must have been allocated using the function with the GMEM_MOVEABLE flag. Read more on docs.microsoft.com. Type: HANDLE If the function succeeds, the return value is the handle to the data. If the function fails, the return value is NULL. To get extended error information, call GetLastError. Windows 8: Bitmaps to be shared with Windows Store app apps must be in the CF_BITMAP format (device-dependent bitmap). If an application calls SetClipboardData in response to WM_RENDERFORMAT or WM_RENDERALLFORMATS, the application should not use the handle after SetClipboardData has been called. If an application calls OpenClipboard with hwnd set to NULL, EmptyClipboard sets the clipboard owner to NULL; this causes SetClipboardData to fail. The system performs implicit data format conversions between certain clipboard formats when an application calls the GetClipboardData function. For example, if the CF_OEMTEXT format is on the clipboard, a window can retrieve data in the CF_TEXT format. The format on the clipboard is converted to the requested format on demand. For more information, see Synthesized Clipboard Formats. Read more on docs.microsoft.com. Creates a new image (icon, cursor, or bitmap) and copies the attributes of the specified image to the new one. If necessary, the function stretches the bits to fit the desired size of the new image. Type: HANDLE A handle to the image to be copied. Read more on docs.microsoft.com. Type: UINT Type: int The desired width, in pixels, of the image. If this is zero, then the returned image will have the same width as the original hImage. Read more on docs.microsoft.com. Type: int The desired height, in pixels, of the image. If this is zero, then the returned image will have the same height as the original hImage. Read more on docs.microsoft.com. Type: UINT Type: HANDLE If the function succeeds, the return value is the handle to the newly created image. If the function fails, the return value is NULL. To get extended error information, call GetLastError. When you are finished using the resource, you can release its associated memory by calling one of the functions in the following table. This doc was truncated. Read more on docs.microsoft.com. Enumerates the data formats currently available on the clipboard. Type: UINT A clipboard format that is known to be available. To start an enumeration of clipboard formats, set format to zero. When format is zero, the function retrieves the first available clipboard format. For subsequent calls during an enumeration, set format to the result of the previous EnumClipboardFormats call. Read more on docs.microsoft.com. Type: UINT If the function succeeds, the return value is the clipboard format that follows the specified format, namely the next available clipboard format. If the function fails, the return value is zero. To get extended error information, call GetLastError. If the clipboard is not open, the function fails. If there are no more clipboard formats to enumerate, the return value is zero. In this case, the GetLastError function returns the value ERROR_SUCCESS. This lets you distinguish between function failure and the end of enumeration. You must open the clipboard before enumerating its formats. Use the OpenClipboard function to open the clipboard. The EnumClipboardFormats function fails if the clipboard is not open. The EnumClipboardFormats function enumerates formats in the order that they were placed on the clipboard. If you are copying information to the clipboard, add clipboard objects in order from the most descriptive clipboard format to the least descriptive clipboard format. If you are pasting information from the clipboard, retrieve the first clipboard format that you can handle. That will be the most descriptive clipboard format that you can handle. The system provides automatic type conversions for certain clipboard formats. In the case of such a format, this function enumerates the specified format, then enumerates the formats to which it can be converted. For more information, see Standard Clipboard Formats and Synthesized Clipboard Formats. Read more on docs.microsoft.com. Retrieves from the clipboard the name of the specified registered format. The function copies the name to the specified buffer. (Unicode) Type: UINT The type of format to be retrieved. This parameter must not specify any of the predefined clipboard formats. Read more on docs.microsoft.com. Type: LPTSTR The buffer that is to receive the format name. Read more on docs.microsoft.com. Type: int The maximum length, in characters, of the string to be copied to the buffer. If the name exceeds this limit, it is truncated. Read more on docs.microsoft.com. Type: int If the function succeeds, the return value is the length, in characters, of the string copied to the buffer. If the function fails, the return value is zero, indicating that the requested format does not exist or is predefined. To get extended error information, call GetLastError.

Security Considerations

Using this function incorrectly might compromise the security of your program. For example, miscalculating the proper size of the lpszFormatName buffer, especially when the application is used in both ANSI and Unicode versions, can cause a buffer overflow. Also, note that the string is truncated if it is longer than the cchMaxCount parameter, which can lead to loss of information. Read more on docs.microsoft.com. Registers a new clipboard format. This format can then be used as a valid clipboard format. (Unicode) Type: LPCTSTR The name of the new format. Read more on docs.microsoft.com. Type: UINT If the function succeeds, the return value identifies the registered clipboard format. If the function fails, the return value is zero. To get extended error information, call GetLastError. If a registered format with the specified name already exists, a new format is not registered and the return value identifies the existing format. This enables more than one application to copy and paste data using the same registered clipboard format. Note that the format name comparison is case-insensitive. Registered clipboard formats are identified by values in the range 0xC000 through 0xFFFF. When registered clipboard formats are placed on or retrieved from the clipboard, they must be in the form of an HGLOBAL value. Read more on docs.microsoft.com. Retrieves the window handle of the current owner of the clipboard. Type: HWND If the function succeeds, the return value is the handle to the window that owns the clipboard. If the clipboard is not owned, the return value is NULL. To get extended error information, call GetLastError. The clipboard can still contain data even if the clipboard is not currently owned. In general, the clipboard owner is the window that last placed data in clipboard. The EmptyClipboard function assigns clipboard ownership. Read more on docs.microsoft.com. Determines whether the clipboard contains data in the specified format. Type: UINT A standard or registered clipboard format. For a description of the standard clipboard formats, see Standard Clipboard Formats . Read more on docs.microsoft.com. Type: BOOL If the clipboard format is available, the return value is nonzero. If the clipboard format is not available, the return value is zero. To get extended error information, call GetLastError. Typically, an application that recognizes only one clipboard format would call this function when processing the WM_INITMENU or WM_INITMENUPOPUP message. The application would then enable or disable the Paste menu item, depending on the return value. Applications that recognize more than one clipboard format should use the GetPriorityClipboardFormat function for this purpose. Retrieves data from the clipboard in a specified format. The clipboard must have been opened previously. Type: UINT A clipboard format. For a description of the standard clipboard formats, see Standard Clipboard Formats. Read more on docs.microsoft.com. Type: HANDLE If the function succeeds, the return value is the handle to a clipboard object in the specified format. If the function fails, the return value is NULL. To get extended error information, call GetLastError.
Caution  Clipboard data is not trusted. Parse the data carefully before using it in your application.
 
An application can enumerate the available formats in advance by using the EnumClipboardFormats function. The clipboard controls the handle that the GetClipboardData function returns, not the application. The application should copy the data immediately. The application must not free the handle nor leave it locked. The application must not use the handle after the EmptyClipboard or CloseClipboard function is called, or after the SetClipboardData function is called with the same clipboard format. The system performs implicit data format conversions between certain clipboard formats when an application calls the GetClipboardData function. For example, if the CF_OEMTEXT format is on the clipboard, a window can retrieve data in the CF_TEXT format. The format on the clipboard is converted to the requested format on demand. For more information, see Synthesized Clipboard Formats. Read more on docs.microsoft.com. Places the given window in the system-maintained clipboard format listener list. Type: HWND A handle to the window to be placed in the clipboard format listener list. Read more on docs.microsoft.com. Type: BOOL Returns TRUE if successful, FALSE otherwise. Call GetLastError for additional details. When a window has been added to the clipboard format listener list, it is posted a WM_CLIPBOARDUPDATE message whenever the contents of the clipboard have changed. Removes the given window from the system-maintained clipboard format listener list. Type: HWND A handle to the window to remove from the clipboard format listener list. Read more on docs.microsoft.com. Type: BOOL Returns TRUE if successful, FALSE otherwise. Call GetLastError for additional details. When a window has been removed from the clipboard format listener list, it will no longer receive WM_CLIPBOARDUPDATE messages. Enables the specified process to set the foreground window using the SetForegroundWindow function. The calling process must already be able to set the foreground window. For more information, see Remarks later in this topic. Type: DWORD The identifier of the process that will be enabled to set the foreground window. If this parameter is ASFW_ANY, all processes will be enabled to set the foreground window. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. The function will fail if the calling process cannot set the foreground window. To get extended error information, call GetLastError. The system restricts which processes can set the foreground window. Normally, a process can set the foreground window by calling the [**SetForegroundWindow**](nf-winuser-setforegroundwindow.md) function only if: - All of the following conditions are true: - The calling process belongs to a desktop application, not a UWP app or a Windows Store app designed for Windows 8 or 8.1. - The foreground process has not disabled calls to **SetForegroundWindow** by a previous call to the [**LockSetForegroundWindow**](nf-winuser-locksetforegroundwindow.md) function. - The foreground lock time-out has expired (see [**SPI_GETFOREGROUNDLOCKTIMEOUT** in **SystemParametersInfo**](nf-winuser-systemparametersinfoa.md#SPI_GETFOREGROUNDLOCKTIMEOUT)). - No menus are active. - Additionally, at least one of the following conditions is true: - The calling process is the foreground process. - The calling process was started by the foreground process. - There is currently no foreground window, and thus no foreground process. - The calling process received the last input event. - Either the foreground process or the calling process is being debugged. A process that can set the foreground window can enable another process to set the foreground window by calling **AllowSetForegroundWindow**. The process specified by the *dwProcessId* parameter loses the ability to set the foreground window the next time that either the user generates input, unless the input is directed at that process, or the next time a process calls **AllowSetForegroundWindow**, unless the same process is specified as in the previous call to **AllowSetForegroundWindow**. Read more on docs.microsoft.com. The MonitorFromPoint function retrieves a handle to the display monitor that contains a specified point. A POINT structure that specifies the point of interest in virtual-screen coordinates. Determines the function's return value if the point is not contained within any display monitor. If the point is contained by a display monitor, the return value is an HMONITOR handle to that display monitor. If the point is not contained by a display monitor, the return value depends on the value of dwFlags. Learn more about this API from docs.microsoft.com. The GetMonitorInfo function retrieves information about a display monitor. (Unicode) A handle to the display monitor of interest. A pointer to a MONITORINFO or MONITORINFOEX structure that receives information about the specified display monitor. You must set the cbSize member of the structure to sizeof(MONITORINFO) or sizeof(MONITORINFOEX) before calling the GetMonitorInfo function. Doing so lets the function determine the type of structure you are passing to it. The MONITORINFOEX structure is a superset of the MONITORINFO structure. It has one additional member: a string that contains a name for the display monitor. Most applications have no use for a display monitor name, and so can save some bytes by using a MONITORINFO structure. Read more on docs.microsoft.com. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. > [!NOTE] > The winuser.h header defines GetMonitorInfo as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see [Conventions for Function Prototypes](/windows/win32/intl/conventions-for-function-prototypes). Read more on docs.microsoft.com. Retrieves the specified system metric or system configuration setting. Type: int Type: int If the function succeeds, the return value is the requested system metric or configuration setting. If the function fails, the return value is 0. GetLastError does not provide extended error information. System metrics can vary from display to display. GetSystemMetrics(SM_CMONITORS) counts only visible display monitors. This is different from EnumDisplayMonitors, which enumerates both visible display monitors and invisible pseudo-monitors that are associated with mirroring drivers. An invisible pseudo-monitor is associated with a pseudo-device used to mirror application drawing for remoting or other purposes. The SM_ARRANGE setting specifies how the system arranges minimized windows, and consists of a starting position and a direction. The starting position can be one of the following values. This doc was truncated. Read more on docs.microsoft.com. Retrieves the specified system metric or system configuration setting taking into account a provided DPI. The system metric or configuration setting to be retrieved. See GetSystemMetrics for the possible values. The DPI to use for scaling the metric. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. This function returns the same result as GetSystemMetrics but scales it according to an arbitrary DPI you provide if appropriate. The GetDC function retrieves a handle to a device context (DC) for the client area of a specified window or for the entire screen. A handle to the window whose DC is to be retrieved. If this value is NULL, GetDC retrieves the DC for the entire screen. If the function succeeds, the return value is a handle to the DC for the specified window's client area. If the function fails, the return value is NULL. The GetDC function retrieves a common, class, or private DC depending on the class style of the specified window. For class and private DCs, GetDC leaves the previously assigned attributes unchanged. However, for common DCs, GetDC assigns default attributes to the DC each time it is retrieved. For example, the default font is System, which is a bitmap font. Because of this, the handle to a common DC returned by GetDC does not tell you what font, color, or brush was used when the window was drawn. To determine the font, call GetTextFace. Note that the handle to the DC can only be used by a single thread at any one time. After painting with a common DC, the ReleaseDC function must be called to release the DC. Class and private DCs do not have to be released. ReleaseDC must be called from the same thread that called GetDC. The number of DCs is limited only by available memory. Read more on docs.microsoft.com. The ReleaseDC function releases a device context (DC), freeing it for use by other applications. The effect of the ReleaseDC function depends on the type of DC. It frees only common and window DCs. It has no effect on class or private DCs. A handle to the window whose DC is to be released. A handle to the DC to be released. The return value indicates whether the DC was released. If the DC was released, the return value is 1. If the DC was not released, the return value is zero. The application must call the ReleaseDC function for each call to the GetWindowDC function and for each call to the GetDC function that retrieves a common DC. An application cannot use the ReleaseDC function to release a DC that was created by calling the CreateDC function; instead, it must use the DeleteDC function. ReleaseDC must be called from the same thread that called GetDC. Read more on docs.microsoft.com.