YourPhone.Utilities Converts an ILogger state object into a set of key-value pairs (That can be send to a EventSource) This method register special magic with the provided window handle to enable the DirectLaunch/Speed of light Launch feature in Windows. This speeds up protocol launches as it means we don't need to spin up a new process, find the main process, and redirect the activation which all add delays. Instead Windows will seend a special message to our window with the uri so we can handle it directly in our already running process. The window handle that will receive the special mesages. The protocol to register for DirectLaunch. NOTE: only some protocol are allowed. The id that will be set inside a WM_COPYDATA message to identity the DirectLaunch payload. The window merssage that will be send for tile activation. A disposable that when disposed unregisters the protocol. Find first descendant control of a specified type. Type to search for. Parent element. Descendant control or null if not found. Ensures that an async operation that is not await'ed logs and continues on failures. Ensures that an async operation that is not await'ed logs and continues on failures When using await in a ContinueWith, the return is a Task{Task} and it needs to be unwrapped. Ensures that an async operation that is not await'ed FailsFast on failures Ensures that an async operation that is not await'ed FailsFast on failures When using await in a ContinueWith, the return is a Task{Task} and it needs to be unwrapped. Throws the exception on the ThreadPool. The exception to propagate. The target context on which to propagate the exception. Null to use the ThreadPool. Replaces any unknown parameter with asterisks to remove PII Workaround for WinUI Bug 37947822: [Fulltrust]: Clicking on notification toast, resizes YP window Value type tag. Checks if this has an empty or null value Get the MSA user id (PUID) for the current Phone Link user in hexadecimal format Get the MSA user id (PUID) for the current Phone Link user in hexadecimal format with the "p:" prefix We use this method to convert the YP rings to OCV audience groups NOTE: Calling this can have compliance impact. Unless you have explicit approval to call this do not call this under any circumstances. NOTE: Calling this can have compliance impact. Unless you have explicit approval to call this do not call this under any circumstances. This class will keep track of components requesting the app to stay alive. The app stays alive if any of the following conditions are met: - A device is setup. Or - The app is running in the foreground. Or - The app is being activated. Or - There are active OutOfProc Com servers Wait for 30 seconds after the list of alive tasks gets to zero, before attempting to close the process. During debugging the delay is skipped to find races faster. Gets the running instance of the ETW provider. This event sends Product and Service usage data about Ratings features in the Your Phone App to improve the user experience and feature quality. Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Package that this action is for, can be empty List of app packages displayed on flyout at the time of the action, can be emptyy This event sends Product and Service usage data about Ratings features in the Your Phone App to improve the user experience and feature quality. Correlation for the page 1 - the flyout is shown, 2, the flyout is hidden This event sends Product and Service performance data for the Your Phone app about unknown toast arguments to improve feature quality. Toast activation argument Correlation Id used to correlate with other telemetry Product and Service performance data for the Your Phone app when it received an unexpected response command type. Product and Service performance data for the Your Phone app when a processor is unexpectedly initialized. Product and Service performance data for the Phone Link app when the EnRNearInactivityOrUnreadWhatsNew toast is shown. This event sends Product and Service performance data about the badge manager component to improve the user experience and feature quality. This event sends data regarding the final staus of an ANCS attribute request event result result detail TraceContext for the operation This event is emitted when the Bluetooth wake setup flow is entered and logs how the user entered the flow (entryPoint). The entrypoint that brought the user to the Bluetooth wake setup. Session id for the setup flow session. Additional details pertaining to this event This event is emitted when the Bluetooth wake setup flow is completed successfully. Session id for the setup flow session. Additional details pertaining to this event Product and Service performance data for the Your Phone app offering warning when the communication layer gets a message but is disposed. Unique ID which represents all operations related to the operation's initial trigger (e.g. a GUID generated when the user pressed a button) Correlation ID handed down by incoming message Correlation ID for the response Which user or device action prompted this request? What are we trying to accomplish? Product and Service performance data for the Your Phone app offering warning when the communication layer gets a message with no apparent author. Unique ID which represents all operations related to the operation's initial trigger (e.g. a GUID generated when the user pressed a button) Correlation ID handed down by incoming message Correlation ID for the response Which user or device action prompted this request? What are we trying to accomplish? Product and Service performance data for the Your Phone app offering warning when the communication layer gets a message with no apparent author. Unique ID which represents all operations related to the operation's initial trigger (e.g. a GUID generated when the user pressed a button) Correlation ID handed down by incoming message Correlation ID for the response Which user or device action prompted this request? What are we trying to accomplish? Product and Service performance data for the Your Phone app offering warning when the app blocks an outgoing message attempt because the user is not present. Unique ID which represents all operations related to the operation's initial trigger (e.g. a GUID generated when the user pressed a button) Correlation ID handed down by outgoing message Correlation ID for the request Which user or device action prompted this request? What are we trying to accomplish? Product and Service performance data for the Your Phone app offering warning when the app blocks an outgoing message attempt because the using the app is blocked. Unique ID which represents all operations related to the operation's initial trigger (e.g. a GUID generated when the user pressed a button) Correlation ID handed down by outgoing message Correlation ID for the request Which user or device action prompted this request? What are we trying to accomplish? Product and Service performance data for the Your Phone app offering warning when the app blocks an outgoing message attempt because the using the app is incompatible. Unique ID which represents all operations related to the operation's initial trigger (e.g. a GUID generated when the user pressed a button) Correlation ID handed down by outgoing message Correlation ID for the request Which user or device action prompted this request? What are we trying to accomplish? Product and Service performance data for the Your Phone app about the Platform Trust Migration scenario. Operation-specific info that doesn't map to the above Update/Send (Type: enum Telemetry.ActivityStatus) [1, 2, 3] - Indicates Start / Stop / StopIgnore Result of the activity Detailed status or error that may still be aggregated Correlation Id that is used correlate between Start and Stop event This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about contact store updates to improve the user experience and feature quality. Id of the contact saved This event sends Product and Service performance data for the Your Phone app about contact store updates to improve the user experience and feature quality. This event sends Product and Service performance data for the Your Phone app about contact store updates to improve the user experience and feature quality. This event sends Product and Service performance data for the Your Phone app about contact store updates to improve the user experience and feature quality. Id of the contact error message This event sends Product and Service performance data for the Your Phone app about contact store updates to improve the user experience and feature quality. Id of the contact error message This event sends Product and Service performance data for the Your Phone app about contact store updates to improve the user experience and feature quality. Id of the contact error message This event sends Product and Service performance data for the Your Phone app about contact store updates to improve the user experience and feature quality. Id of the contact error message This event sends Product and Service performance data for the Your Phone app about contact store updates to improve the user experience and feature quality. Id of the contact error message Gets the running instance of the ETW provider. Product and Service performance data for the Your Phone app about the Device Status scenario. Operation-specific info that doesn't map to the above Update/Send (Type: enum Telemetry.ActivityStatus) [1, 2, 3] - Indicates Start / Stop / StopIgnore Result of the activity Detailed status or error that may still be aggregated Correlation Id that is used correlate between Start and Stop event This event sends Product and Service performance data for the Your Phone app about unknown toast arguments to improve feature quality. RemoteDevice count This event is emitted when the Your Phone app onboarding experience is entered, and logs how the user entered the experience (organic vs. campaign). Used for campaign conversion. Why FRE is running: FirstRun (1), DeviceNotOptedIn (2), NoDevicesFound (3). An enum representing what brought the user to the FRE. Represents whether the users started from, Campaign = 5, Launch = 0, Phone = 2, Protocol = 4, Search = 1, Toast = 1010 Correlation id for the FRE session. Page summary. This telemetry event is emitted when we detect a user has completed onboarding their mobile phone to sync with the Your Phone app on PC. Used for campaign segmentation and conversion. This telemetry event is emitted when we detect a user has canceled onboarding their mobile phone to sync with the Your Phone app on PC. Used for campaign segmentation and conversion. Correlation for the FRE session. Page summary. This event is emitted when the Instant Hotspot FTU setup flow is entered and logs how the user entered the flow (entryPoint). The entrypoint that brought the user to the Instant Hotspot setup. Session id for the setup flow session. Additional details pertaining to this event This event is emitted when the Instant Hotspot FTU setup flow is completed successfully. Session id for the setup flow session. Additional details pertaining to this event This event is emitted when the Instant Hotspot Crypto work has failed Session id for the crypto flow session Referrer that created the event Additional details pertaining to this event Traces an info event if an attachment fails to be added. Type of attachment. Traces an info event if an attempt to retrieve GIF images fails. HTTP Response Code. Response reason. This event sends Product and Service performance data for the Your Phone app about a user-initiated request to send a message to improve the user experience and feature quality. Identifier for the message Id of the thread this message is sent in Unique identifier for the draft message Boolean value indicating whether this message is a retry of a previously failed message Correlation Id that is used to correlate between other Message events Id of sim used to send outgoing message This event sends Product and Service performance data for the Your Phone app about a user-initiated request to send a message to improve the user experience and feature quality. Identifier for the message Id of the thread this message is sent in Unique identifier for the draft message Status of the outgoing message, which maps to UI state Kind of message: SMS (1) or MMS (2) This event sends Product and Service performance data for the Your Phone app about a user-initiated request to send a message to improve the user experience and feature quality. Identifier for the message Id of the thread this message is sent in Unique identifier for the draft message Status of the outgoing message, which maps to UI state Kind of message: SMS (1) or MMS (2) This event sends Product and Service usage data about the user's usage of multiple subscriptions. This is needed to improve the user experience and feature quality. Boolean value indicating whether multiple subscriptions are present. This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about UI changes when conversations are synced to improve the user experience and feature quality. Android's unique identifier for the conversation This event sends Product and Service performance data for the Your Phone app about UI changes when conversations are synced to improve the user experience and feature quality. Android's unique identifier for the conversation Index of the temporary conversation that is being replaced This event sends Product and Service performance data for the Your Phone app about toast notifications related to new messages to improve the user experience and feature quality. Correlation ID for current sync transaction Boolean value indicating whether the toast is displayed Enum mapped to the reason why the toast is NOT displayed. If the toast is displayed, this value is 0. Unique identifier for the toast notification so it can be tracked in ActionCenter telemetry This event sends Product and Service performance data for the Your Phone app about toast notifications related to failed messages to improve the user experience and feature quality. Correlation ID for current sync transaction Boolean value indicating whether the toast is displayed Enum mapped to the reason why the toast is NOT displayed. If the toast is displayed, this value is 0. Unique identifier for the toast notification so it can be tracked in ActionCenter telemetry This event sends Product and Service usage data about MMS attachment content types to improve the user experience and feature quality. The id of the message The content type of the attachment This event sends Product and Service usage data about MMS attachment size to improve the user experience and feature quality. The id of the message The size of the attachment This event sends Product and Service usage data about media messages to improve the user experience and feature quality. The id of the message This event sends Product and Service usage data about MMS attachment content types to improve the user experience and feature quality. The id of the message The id of the attachment The content type of the attachment This event sends Product and Service usage data about MMS attachment size to improve the user experience and feature quality. The id of the message The id of the attachment The size of the attachment This sends Product and Service performance data for the Your Phone app about missing recipients for synced conversations to improve the user experience and feature quality. Kind of message: SMS (1) or MMS (2) Android's unique identifier for the conversation Android's identifier for the message This sends Product and Service performance data for the Your Phone app about ChatNotificationObserver events to improve the user experience and feature quality. This sends Product and Service performance data for the Your Phone app about missing recipients for synced conversations to improve the user experience and feature quality. This event sends Product and Service performance data for the Your Phone app about the message syncing process to improve the user experience and feature quality. Android's identifier for the message The action to take on the synced content. For a full sync the action is sync (-1). For an incremental sync it can be create (0), update (1), or delete (2). Correlation ID for current sync transaction This event sends Product and Service performance data for the Your Phone app about the message syncing process to improve the user experience and feature quality. Android's identifier for the message The action to take on the synced content. For a full sync the action is sync (-1). For an incremental sync it can be create (0), update (1), or delete (2). Correlation ID for current sync transaction This event sends Product and Service performance data for the Your Phone app about the message syncing process to improve the user experience and feature quality. Android's identifier for the message The action to take on the synced content. For a full sync the action is sync (-1). For an incremental sync it can be create (0), update (1), or delete (2). Correlation ID for current sync transaction This event sends Product and Service performance data for the Your Phone app about the message syncing process to improve the user experience and feature quality. Android's identifier for the message The action to take on the synced content. For a full sync the action is sync (-1). For an incremental sync it can be create (0), update (1), or delete (2). Correlation ID for current sync transaction This event sends Product and Service performance data for the Your Phone app about the subscription syncing process to improve the user experience and feature quality. Android's identifier for the subscription The action to take on the synced content. For a full sync the action is sync (-1). For an incremental sync it can be create (0), update (1), or delete (2). Correlation ID for current sync transaction This event sends Product and Service performance data for the Your Phone app about the status of sent messages to improve the user experience and feature quality. Number of messages finished sending. This sends Product and Service performance data for the Your Phone app about missing recipients for synced conversations to improve the user experience and feature quality. Identifier for the missing recipient This event sends Product and Service usage data for Your Phone app when the first batch of the first message sync is completed. This event is necessary for the MMX business KPIs and campaign conversion analytics. Number of conversations that was synced from phone This event sends Product and Service usage data for Your Phone app when all the batches of the first messages sync is completed. This event is necessary for the MMX business KPIs and campaign conversion analytics. Number of conversations synced from the phone including RCS conversations Number of items synced from the phone. This includes conversations, SMS, MMS, MMS Part, Subscriptions, RCS chats, RCS Conversations Size of the payload that was synced. This event sends Product and Service usage data for Your Phone app about invalid message timestamps This event sends Product and Service usage data for Your Phone app when messages are first shown to the user. This event is necessary for the MMX business KPIs and campaign conversion analytics. This event sends Product and Service performance data for the Your Phone app about UI changes when conversations are synced to improve the user experience and feature quality. Android's unique identifier for the conversation This event sends Product and Service performance data for the Your Phone app about changes in the status of conversation attributes to improve the user experience and feature quality. to improve the user experience and feature quality. New pinned position to be written to the DB Android's identifier for the thread Current pinned position Current muted state Current hidden state This event sends Product and Service performance data for the Your Phone app about changes in the status of conversation attributes to improve the user experience and feature quality. to improve the user experience and feature quality. New is_hidden status to be written to the DB Android's identifier for the thread Current pinned position Current muted state Current hidden state This event sends Product and Service performance data for the Your Phone app about changes in the status of conversation attributes to improve the user experience and feature quality. to improve the user experience and feature quality. New is_muted status to be written to the DB Android's identifier for the thread Current pinned position Current muted state Current hidden state This event sends Product and Service performance data for the Your Phone app about database table updates to improve the user experience and feature quality. Number of rows updated This event sends Product and Service performance data for the Your Phone app about UI changes when conversations are synced to improve the user experience and feature quality. The database operation being performed: delete, insert, update Android's unique identifier for the conversation Android's unique identifier for rich text conversation Pinned location of a conversation Details if a conversation is muted Details if a conversation is hidden This transactional telemetry is similar to the above Activity telemetry pattern, but should be used in cases where your feature is looking to return success / result breakdown. The main difference from the Activity pattern is that this telemetry only has a single event as opposed to a Start and Stop event. (Type: TraceContext - Trace context for scenario (Type: string optional - Dimension 1 to help differentiate feature activities (Type: string optional - Dimension 2 to help differentiate feature activities (Type: string optional - Dimension 3 to help differentiate feature activities (Type: Signed int) - Indicates status code. 0 or positive for success. Negative for failure. (Type: string) - indicates detailed status or error that may still be aggregated (Type: string optional) - JSON blob of dynamic data / scenario-specific data that is serialized into string. This is not aggregated automatically, but serve as bread crumbs and details for debuggability / investigation This event sends Product and Service usage data for Your Phone app about Toasts Failures on Notifications Feature "Correlation Id that is used to correlate events" "Was the toast shown to the user" "The reason why YourPhone did not show a toast to the user" This sends Product and Service performance data for the Your Phone app about a specific error scenario where the notification could not be found. The scenario in which the notification could not be found The specific parameter for the scenario The status code for the Notifications scenario Optional details Correlation ID that is used to correlated between other Notifications events Optional additional details This event sends Product and Service health data for Your Phone app Toasts on Notifications about the toast shown and toast id of the toast to correlate wiht the AC toasts data Correlation Id that is used to correlate events Was the toast shown to the user The reason why YourPhone did not show a toast to the user Toast Id used to correlate the events from AC data The summary. This event locally logs usage data for Your Phone app about Toasts that are not shown on Photos Feature "Correlation Id that is used to correlate events" The page name. The reason we did not show the toast. This event sends Product and Service performance data for the Your Phone app about a control's reliability Width of control Height of control Diagnostic event that occurred Send Product and Service performance data for the Your Phone app about the health of the operation that processes received shared content to improve the user experience and feature quality. Type: enum Telemetry.ActivityStatus [1, 2] - Indicates Start / Stop TraceContext for the operation The status code for the result Detailed result This event sends Product and Service performance data for the Your Phone app about the launch URI processing status to improve the user experience This field describe the status of the sharing process CorrelationId corresponds to current session This event sends Product and Service performance data for the Your Phone app about Launch URI request initialization to improve the user experience Correlation Id used to correlate with This event sends Product and Service performance data for the Your Phone app telling if the device was linked before starting share target page to improve the user experience Correlation Id used to correlate with This event sends Product and Service usage data about if the remote device and the app are compatible. This is needed to improve the user experience and feature quality. Contract version of the app Contract version of the active device This event sends Product and Service usage data about app and/or YPP version compatibility. This is needed to improve the user experience and feature quality. Type of incompatibility. Will be one of (LTWContractVersionIncompatible, YPCContractVersionIncompatible, YPContractVersionIncompatible) Contract compatibility as determined previously by ContractVersion.CheckCompatibility() YPP version of the linked device YPP capabilities of the linked device This event sends Product and Service usage data about app and/or YPP version compatibility. This is needed to improve the user experience and feature quality. The version of the local device", The version of the remote device This event sends Product and Service performance data avout if a device is in a state that it sync data. This is needed to improve the user experience and feature quality. The trigger that would result in the connection. The reason the operation was blocked. The correlation id from the trace context. This event sends Product and Service performance data when establishing a connection to the phone is skipped This is needed to improve the user experience and feature quality. This event sends Product and Service usage data about if the remote device and the app are compatible. This is needed to improve the user experience and feature quality. Id of the active device that was candidate for migration Indicates if the request had a payoad TraceContext for the operation This event sends Product and Service usage data if the QR code image fails to load This is needed to aid debuggability Reason for the failure Product and Service performance data for the Your Phone app offering notice that a migration activity occurred for critical mapping protocol between app and platform Unique ID which represents all operations related to the operation's initial trigger (e.g. a GUID generated when the user pressed a button) Correlation ID handed down by outgoing message Correlation ID for the request Include counts for debugging This event sends Product and Service Performance data for the Your Phone app to measure the quality of the background task used to populate information for bluetoothLE scan. [publish, subscribe] The mode of the discovery [foreground, background] Health state details needed for problem diagnosis Result of the activity Detailed status or error that may still be aggregated Correlation Id that is used correlate between Start and Stop event NOTE: This event is raised when APpData is inaccessible. Therefore we can't call into anything that calls into AppData including RemoteConfiguration.GetCurrentRingFromCache. NOTE: DO NOT ACCESS ANY DATA OTHER THAN PASSED IN. This event is used to track the app being in a bad state. We cannot assume anything else is setup. That includes exp. This event sends Product and Service performance data of the Audio Control feature of Your Phone App to help improve the feature quality. Correlation Id that is used to correlate respective Start and Stop events for a given Activity (Type: enum Telemetry.ActivityStatus) [1, 2] - Indicates Start / Stop Indicates status code. 0 or positive for success. Negative for failure. indicates detailed status or error that may still be aggregated Optional dimension1 to help differentiate feature activities Optional dimension2 to help differentiate feature activities Optional dimension3 to help differentiate feature activities Trace context to provide parentId, traceId, and tracestate correlation id that's used to associate with a parent event Blob of dynamic data / scenario-specific data that is serialized into string. This is not aggregated automatically, but serve as breadcrumbs and details for debuggability / investigation This event sends Product and Service performance data of the Calling feature of Your Phone App to help improve the feature quality. Setup event name detail 1 Setup event name detail 2 Setup event name detail 3 event result result detail More information for debuggability/investigation Correlation Id that is used correlate between Start and Stop event This event sends Product and Service performance data of anomalies in PBAP sync to help improve the feature quality. This event sends data regarding the final staus of an ANCS attribute request event result result detail TraceContext for the operation This event sends Product and Service Performance data for the Your Phone app to measure the quality of the background task used to populate contact information for PC calls. [Dial, Origin, Dismissed, TextReply] The stage of the call Details about the particular stage Health state details needed for problem diagnosis (Type: enum Telemetry.ActivityStatus) [1, 2, 3] - Indicates Start / Stop / StopIgnore Result of the activity Detailed status or error that may still be aggregated Correlation Id that is used correlate between Start and Stop event TraceContext for the operation This event sends Product and Service performance data of the Calling feature of Your Phone App to help improve the feature quality. Setup event name detail 1 Setup event name detail 2 Setup event name detail 3 event result result detail More information for debuggability/investigation Correlation Id that is used correlate between Start and Stop event This event sends Product and Service performance data of the Calling feature of Your Phone App to help improve the feature quality. correlation id that's used to associate with a parent event Setup stage/activity name detail 1 start (1) or stop (2) Result of the activity result detail TraceContext containing scenario trigger, type, and correlationId More information for debuggability/investigation Gets the running instance of the ETW provider. This event sends Product and Service Performance data for the Your Phone app related to sync over metered connections to improve the user experience and feature quality The operation TraceContext The string to log The correlation id This event sends Product and Service Performance data for the Your Phone app about requests to toggle SyncOverMeteredConnection to improve the user experience and feature quality The operation TraceContext Whether this is a start (1) or stop (2) event Result of the activity (optional) detailed result (optional) other activity specific data This event sends Product and Service Performance data for the Your Phone app about requests to toggle LTW to improve the user experience and feature quality The operation TraceContext Whether this is a start (1) or stop (2) event Result of the activity (optional) detailed result (optional) other activity specific data This event sends Product and Service Performance data for the Your Phone app related to Device Permissions Request sync'ing. to improve the user experience and feature quality The operation TraceContext The string to log The correlation id This event sends Product and Service Performance data for the Your Phone app about the remote control to improve the user experience and feature quality Whether this is a start (1) or stop (2) event The operation TraceContext Correlation Id that is used correlate between Start and Stop event The remote control type Result of the command More information for debuggability/investigation This event sends Product and Service usage data for the Your Phone app about File Explorer Health Data File Explorer activity name detail 1 File Explorer activity name detail 2 start (1) or stop (2) More information for debuggability/investigation Result of the activity Correlation Id that is used correlate between Start and Stop event The event is emitted when a user interacts with the feedback experience. This event is necessary for the MMX business KPIs and campaign conversion analytics. TraceContext for the operation This event sends Product and Service usage data for the Your Phone app about the Messaging Send Message scenario start (1) or stop (2) Result of the activity Correlation Id that is used correlate between Start and Stop event Session Id that is used to correlate between other app events More information for debuggability/investigation This event sends Product and Service usage data for the Your Phone app about the Messaging Mark as Ready scenario start (1) or stop (2) Correlation Id that is used correlate between Start and Stop event Session Id that is used to correlate between other app events More information for debuggability/investigation This transactional telemetry will support the primary way to measure success rate and latency of your feature code. Telemetry events that follow this pattern should expect to be included in centralized processing and measures. (Type: TraceContext - Trace context for scenario (Type: enum Telemetry.ActivityStatus) [1, 2] - Indicates Start / Stop (Type: string optional) - Dimension 1 to help differentiate feature activities (Type: string optional) - Dimension 2 to help differentiate feature activities (Type: string optional) - Dimension 3 to help differentiate feature activities (Type: Signed int) - Indicates status code. 0 or positive for success. Negative for failure. (Type: string) - indicates detailed status or error that may still be aggregated (Type: string optional) - bread crumbs and details for debuggability / investigation This event is to record information about the processing of incoming messages. (Type: string - What are we trying to accomplish? (Type: string - What caused this event? (Type: string) - indicates detailed status or error that may still be aggregated (Type: string optional) - JSON blob of dynamic data / scenario-specific data that is serialized into string. This is not aggregated automatically, but serve as bread crumbs and details for debuggability / investigation This sends Product and Service performance data for the Your Phone app about missing recipients for synced conversationsto improve the user experience and feature quality. Kind of message: SMS (1) or MMS (2) message mailbox type This event is to record information about the visibility of the summarize recent messages button. (Type: string - What are we trying to accomplish? (Type: string - What caused this event? (Type: string) - indicates detailed status or error that may still be aggregated (Type: string optional) - JSON blob of dynamic data / scenario-specific data that is serialized into string. This is not aggregated automatically, but serve as bread crumbs and details for debuggability / investigation This event sends Product and Service usage data for the Your Phone app about the Messaging Download Attachment scenario start (1) or stop (2) Correlation Id that is used correlate between Start and Stop event Session Id that is used to correlate between other app events More information for debuggability/investigation This sends Product and Service performance data for the Your Phone app about missing recipients for synced conversations to improve the user experience and feature quality. Extension of the file added as an attachment This sends Product and Service performance data for the Your Phone app about a specific error scenario where notifications data is incomplete to improve the user experience and feature quality. The length of the notification operations array that was synced from phone The length of the notification keys array that was synced from phone The length of the notification json array that was synced from phone Correlation Id used to correlate with other telemetry for this transfer This event sends Product and Service health data for Your Phone app on the new notification that arrived to the PC. Correlation Id that is used to correlate events Page name for telemetry purposes Details of the telemetry event. This event sends Product and Service performance data for the Your Phone app about Photos Actions (Type: string optional - Dimension 1 to help differentiate feature activities (Type: string optional - Dimension 2 to help differentiate feature activities (Type: string optional - Dimension 3 to help differentiate feature activities (Type: enum Telemetry.ActivityStatus) [1, 2] - Indicates Start / Stop (Type: Signed int) - Indicates status code. 0 or positive for success. Negative for failure. (Type: string) - indicates detailed status or error that may still be aggregated Correlation Id that is used correlate between Start and Stop event Session Id that is used to correlate between other app events (Type: string optional) - JSON blob of dynamic data / scenario-specific data that is serialized into string. This is not aggregated automatically, but serve as bread crumbs and details for debuggability / investigation This event sends Product and Service performance data about retrieving media content in the Your Phone app from your phone. (Type: string optional - The type of media being requested (thumbnails or images) (Type: enum Telemetry.ActivityStatus) [1, 2] - Indicates Start / Stop The status code for the request Optional result details Correlation Id that is used correlate between Start and Stop event Optional details This sends Product and Service performance data for the Your Phone app about the health of File Transfer feature to improve the user experience and feature quality. File Transfer activity name detail 1 File Transfer activity name detail 2 start (1) or stop (2) JSON value of more information for debuggability/investigation Status code of the activity result. failed(-1), start(0), sending(1), succeed(2) Result detail of the activity Correlation Id that is used correlate between Start and Stop event Correlation Id corresponding to the parent operation that spawned this operation Correlation Id corresponds to the root operation. Does not change for lifetime of operation Key-value set that contains vendor/node specific information, delimited with a single comma (no space) Reports the state of the YourPhone startupTask that starts the app on sign-in. The state of the startupTask. The number of devices in the devices store. Boolean indicating if the user disabled startup. Reports the change in state of the YourPhone startupTask that starts the app on sign-in. The old state of the startupTask. The new state of the startupTask. The number of devices in the devices store. Boolean indicating if the user disabled startup. This event sends Product and Service performance data for the Your Phone app's taskbar icon. The taskbar scenario The entry point of this scenario Result of the event Detailed status or error that may still be aggregated Correlation Id that is used correlate with nearby events Correlation Id used to correlate with the parent activity Gets the running instance of the ETW provider. This event sends Product and Service usage data about Your Phone App to improve the user experience and feature quality. Census start time Census end time Schema version of underlying data set JSON string of the setting values Reason why the event was sent This event sends Product and Service usage data about navigating to and from Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data about navigating to and from Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data about navigating to and from Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page Name of the referrer page Correlation Id corresponds to the root operation. Does not change for lifetime of operation. Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data about AppFrame features in the Your Phone App to improve the user experience and feature quality. Correlation for the FRE page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data about AppFrame features in the Your Phone App to improve the user experience and feature quality. Correlation for the FRE page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data about AppFrame features in the Your Phone App to improve the user experience and feature quality. Correlation for the FRE page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Name of the referrer page Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data about navigating to and from Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data about PhoneScreenAppsAction features in the Your Phone App to improve the user experience and feature quality. Correlation for the YP page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data about Audio features in the Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page The previous page Additional details pertaining to this view event This event sends Product and Service usage data about Audio features in the Your Phone App to improve the user experience and feature quality. Trace context for the event Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Additional details pertaining to this view event This event sends Product and Service usage data about the Bluetooth wake feature in the Phone Link App. This event fires when a page is shown to the user related to the feature. Session Id for the current page being shown Related session Id for the session Whether this is a start (1) or stop (2) event Name of the current page Additional details pertaining to this event This event sends Product and Service usage data about the Bluetooth wake feature in the Phone Link App. This event fires when the user performs an action specific to the feature. Session Id for the current page being shown Related session Id for the session Type of action being performed on the target The UI item that the action was performed on Name of the current page Additional details pertaining to this event This event sends Product and Service usage data about Browser History features in the Your Phone App to improve the user experience and feature quality. Correlation for the page The page name this action is performed on Type of action being performed on the target The UI item that the action was perfomed on Package that this action is for, can be empty This event sends Product and Service usage data about Browser History Viewed And Synced From LTW to improve the user experience and feature quality. Correlation for the page The page name this action is performed on Type of action being performed on the target The UI item that the action was perfomed on Package that this action is for, can be empty This event sends Product and Service usage data about navigating to and from Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page The previous page Additional details pertaining to this view event The trace context for the operation This event sends Product and Service usage data about AppFrame features in the Your Phone App to improve the user experience and feature quality. Correlation for the FRE page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Additional details pertaining to this view event The trace context for the operation This event sends Product and Service usage data about phone calls in Your Phone to understand user success setting up phone calls. This event is necessary for the MMX business KPIS and campaign convesion analytics. Correlation for the calls setup pages Whether this is a start (1) or stop (2) event Name of the current calls setup page Name of the current calls setup subpage Additional details pertaining to this view event This event sends Product and Service usage data about phone calls in Your Phone to understand user success setting up phone calls. This event is necessary for the MMX business KPIS and campaign convesion analytics. Correlation for the calls setup pages User action that was taken in UX User item that action was taken on Name of the current calls setup page Name of the current calls setup subpage Additional details pertaining to this action event This event sends Product and Service usage data about COntacts features in the Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page The previous page Additional details pertaining to this view event This event sends Product and Service usage data about Contacts features in the Your Phone App to improve the user experience and feature quality. Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Additional details pertaining to this view event Gets the running instance of the ETW provider. This event sends Product and Service usage data about the connectivity card features in the Your Phone App to improve the user experience and feature quality. Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Name of the page Name of the sub page Additional details pertaining to this view event Summary version This event sends Product and Service usage data when a user has seen and/or acted on a particular UX within the connectivity card in the Your Phone App to improve the user experience and feature quality. Correlation for the page Whether this is a start (1) or stop (2) event Name of the page Name of the sub page Correlation Id corresponds to the root operation. Does not change for lifetime of operation. Additional details pertaining to this view event Summary version This event sends Product and Service usage data about Phone Files In File Explorer features in the Your Phone App.This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page The previous page Additional details pertaining to this view event This event sends Product and Service usage data about Phone Files In File Explorer features to improve the user experience and feature quality. Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Additional details pertaining to this view event This event sends Product and Service usage data about Flyouts features in the Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page The previous page Additional details pertaining to this view event This event sends Product and Service usage data about Flyouts features in the Your Phone App to improve the user experience and feature quality. Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Additional details pertaining to this view event The event is emitted when a user interacts with a UI control within first run experience (FRE) pages. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation for the FRE page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the current first run experience sub-page, if any Name of the previous page. Additional details pertaining to this view event The event is emitted when a user interacts with the warmup experience. This event is necessary for the MMX business KPIs and campaign conversion analytics. Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Additional details pertaining to this view event Name of the sub page The event sends Product and Service usage data for the Your Phone app when a user views a Warmup section post FRE for the device. This event is necessary for the MMX business KPIs and campaign conversion analytics. Whether this is a start (1) or stop (2) event Name of the current Warmup section Name of the current subtype of Warmup section Additional details pertaining to this view event The event sends Product and Service usage data for the Your Phone app when a user views the What's New feed. This event is necessary for the MMX business KPIs and campaign conversion analytics. Whether this is a start (1) or stop (2) event Name of the current Share target page Additional details pertaining to this view event The event is emitted when a user interacts with the warmup experience. This event is necessary for the MMX business KPIs and campaign conversion analytics. Type of action being performed on the target The UI item that the action was perfomed on Name of the current page - LinkToFeature or LinkToTutorial Name of the feature / tutorial Additional details pertaining to this view event This event sends Product and Service usage data about the Instant Hotspot feature in the Phone Link App. This event fires when a page is shown to the user related to the feature. Session Id for the current page being shown Related session Id for the session Whether this is a start (1) or stop (2) event Name of the current page Additional details pertaining to this event This event sends Product and Service usage data about the Instant Hotspot feature in the Phone Link App. This event fires when the user performs an action specific to the feature. Session Id for the current page being shown Related session Id for the session Type of action being performed on the target The UI item that the action was performed on Name of the current page Additional details pertaining to this event This telemetry describes when a user has seen and acted on a particular UX. It functionally works similar to the Activity telemetry as it defines a Start and Stop ActivityStatus. This helps provide centralized processing a means to determine the time spent in a particular page. (Type string) - GUID that corresponds to current session (i.e. each new view would have its own session) (Type: enum Telemetry.ActivityStatus) - Start (1) / Stop (2) for View which enables calculation of duration. None (0) for case where a single View is fired without matching Stop. (Type string) - Identifier for page (Type string) - JSON blob of dynamic data / scenario-specific data that may be incorporated in batching. Included in CRITICAL event (Type string optional) - Identifier for subpage (Type string) - The page where the user came from This telemetry describes when a user has taken action on a clickable item (button, menu, etc) on some particular UX. (Type string) - GUID that corresponds to current session, this should match the sessionId of the associated view (Type string) - User action that was taken in UX (Type string) - UX item that action was taken on (Type string) - Identifier for page (Type string) - JSON blob of dynamic data / scenario-specific data that may be incorporated in batching. Included in CRITICAL event (Type string optional) - Identifier for subpage The event sends Product and Service usage data for the Your Phone app when a user views the notifications pane. This event is necessary for the MMX business KPIs and campaign conversion analytics. Whether this is a start (1) or stop (2) event Name of the subpage Name of the previous page before navigating to this view Additional details pertaining to this view event The event is emitted when a user interacts with the notifications UI. This event is necessary for the MMX business KPIs and campaign conversion analytics. Type of action being performed on the target The UI item that the action was perfomed on Name of the subpage Additional details pertaining to this view event The correlation id for the view. The event sends Product and Service usage data for the Your Phone app when a user views the notifications pane. This event is necessary for the MMX business KPIs and campaign conversion analytics. Whether this is a start (1) or stop (2) event Name of the subpage Page summary. Correlation id for the view. The event is emitted when a user interacts with the notifications UI. This event is necessary for the MMX business KPIs and campaign conversion analytics. Type of action being performed on the target The UI item that the action was perfomed on Name of the subpage Additional details pertaining to this view event This event sends Product and Service usage data about Photos features in the Your Phone App. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page The previous page Additional details pertaining to this view event This event sends Product and Service usage data about Photos features in the Your Phone App to improve the user experience and feature quality. Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Additional details pertaining to this view event This event sends Product and Service usage data about navigating to and from the Ratings node. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page The previous page Additional details pertaining to this view event This event sends Product and Service usage data about Ratings features in the Your Phone App to improve the user experience and feature quality. Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Additional details pertaining to this view event This event sends Product and Service usage data about navigating to and from the Settings node. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page The previous page Additional details pertaining to this view event This event sends Product and Service usage data about Settings features in the Your Phone App to improve the user experience and feature quality. Correlation for the page Type of action being performed on the target The UI item that the action was perfomed on Name of the current page Name of the sub page Additional details pertaining to this view event The event sends Product and Service usage data for the Your Phone app when a user tries to share a weblink using the your phone app share charm. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation for the Share Target pag Whether this is a start (1) or stop (2) event Name of the current Share target page Version of the page summary Additional details pertaining to this view event This event sends Product and Service usage data for the Your Phone app when a user any action on Share Target Page. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation for the Share Target page Type of action performed on target if applicable Start, Retry or Close Share Target Page Name of the current Share target page Version of the page summary if applicable Additional details pertaining to this view event if applicable The event sends Product and Service usage data for the Your Phone app when a user tries to share files using the your phone app share charm. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation for the File Transfer page Whether this is a start (1) or stop (2) event Name of the current File Transfer page Name of the sub File Transfer page Identifying name of the page the user came from. Version of the page summary if applicable Additional details pertaining to this view event if applicable This event sends Product and Service usage data for the Your Phone app when a user any action on File Transfer Page. This event is necessary for the MMX business KPIs and campaign conversion analytics. Correlation for the File Transfer page Type of action performed on target if applicable The UI item that the action was perfomed on Name of the current File Transfer page Identifying name of the page the user came from. Version of the page summary if applicable Additional details pertaining to this view event if applicable This event sends Product and Service usage data about navigating to and from Your Phone App. This event is necessary for the MMX business KPIs. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page Additional details pertaining to this view event This event sends Product and Service usage data about banners shown in Your Phone App. This event is necessary for the MMX business KPIs. Correlation Id for the current node session Whether this is a start (1) or stop (2) event Name of the current page Name of the sub page Version of the page summary Additional details pertaining to this view event This telemetry describes when a user has seen and acted on a particular UX. It functionally works similar to the Activity telemetry as it defines a Start and Stop ActivityStatus. This helps provide centralized processing a means to determine the time spent in a particular page. (Type string) - GUID that corresponds to current session (i.e. each new view would have its own session) (Type: enum Telemetry.ActivityStatus) - Start (1) / Stop (2) for View which enables calculation of duration. None (0) for case where a single View is fired without matching Stop. (Type string) - Identifier for page (Type string) - JSON blob of dynamic data / scenario-specific data that may be incorporated in batching. Included in CRITICAL event (Type string optional) - Identifier for subpage (Type string) - The page where the user came from This telemetry describes when a user taken action on a clickable item (button, menu, etc) on some particular UX. (Type string) - GUID that corresponds to current session, this should match the sessionId of the associated view (Type string) - User action that was taken in UX (Type string) - UX item that action was taken on (Type string) - Identifier for page (Type string) - JSON blob of dynamic data / scenario-specific data that may be incorporated in batching. Included in CRITICAL event (Type string optional) - Identifier for subpage Identifier for the window, to be used for storage and telemetry. Class to be used to find the window associated with an element as long as WindowHelper.CreateWindow was used to create the window. We require this to be DesktopWindow instead of Window, as various logic in this class requires special handling of certain Window messages as done by DesktopWindow. Ensure the app is kept alive to properly process the Unloaded event on the window content when the window is closed. Contains extern methods from "ADVAPI32.dll". Contains extern methods from "api-ms-win-appmodel-runtime-l1-1-1.dll". Contains extern methods from "api-ms-win-shcore-scaling-l1-1-1.dll". Contains extern methods from "dwmapi.dll". Contains extern methods from "GDI32.dll". Contains extern methods from "KERNEL32.dll". Contains extern methods from "MSIMG32.dll". Contains extern methods from "OLE32.dll". Contains extern methods from "OLEAUT32.dll". Contains extern methods from "PROPSYS.dll". Contains extern methods from "SHELL32.dll". Contains extern methods from "USER32.dll". Opens the access token associated with a thread. A handle to the thread whose access token is opened. Specifies an access mask that specifies the requested types of access to the access token. These requested access types are reconciled against the token's discretionary access control list (DACL) to determine which accesses are granted or denied. For a list of access rights for access tokens, see Access Rights for Access-Token Objects. Read more on docs.microsoft.com. TRUE if the access check is to be made against the process-level security context. FALSE if the access check is to be made against the current security context of the thread calling the OpenThreadToken function. The OpenAsSelf parameter allows the caller of this function to open the access token of a specified thread when the caller is impersonating a token at SecurityIdentification level. Without this parameter, the calling thread cannot open the access token on the specified thread because it is impossible to open executive-level objects by using the SecurityIdentification impersonation level. Read more on docs.microsoft.com. A pointer to a variable that receives the handle to the newly opened access token. 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 token has the anonymous impersonation level, the token will not be opened and OpenThreadToken sets ERROR_CANT_OPEN_ANONYMOUS as the error. Tokens with the anonymous impersonation level cannot be opened. Close the access token handle returned through the TokenHandle parameter by calling CloseHandle. Read more on docs.microsoft.com. Closes a handle to the specified registry key. A handle to the open key to be closed. The handle must have been opened by the RegCreateKeyEx, RegCreateKeyTransacted, RegOpenKeyEx, RegOpenKeyTransacted, or RegConnectRegistry function. Read more on docs.microsoft.com. If the function succeeds, the return value is ERROR_SUCCESS. If the function fails, the return value is a nonzero error code defined in Winerror.h. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error. The handle for a specified key should not be used after it has been closed, because it will no longer be valid. Key handles should not be left open any longer than necessary. The RegCloseKey function does not necessarily write information to the registry before returning; it can take as much as several seconds for the cache to be flushed to the hard disk. If an application must explicitly write registry information to the hard disk, it can use the RegFlushKey function. RegFlushKey, however, uses many system resources and should be called only when necessary. Read more on docs.microsoft.com. Notifies the caller about changes to the attributes or contents of a specified registry key. A handle to an open registry key. This handle is returned by the RegCreateKeyEx or RegOpenKeyEx function. It can also be one of the following predefined keys: HKEY_CLASSES_ROOT HKEY_CURRENT_CONFIG HKEY_CURRENT_USER HKEY_LOCAL_MACHINE HKEY_USERS This parameter must be a local handle. If RegNotifyChangeKeyValue is called with a remote handle, it returns ERROR_INVALID_HANDLE. The key must have been opened with the KEY_NOTIFY access right. For more information, see Registry Key Security and Access Rights. Read more on docs.microsoft.com. If this parameter is TRUE, the function reports changes in the specified key and its subkeys. If the parameter is FALSE, the function reports changes only in the specified key. A handle to an event. If the fAsynchronous parameter is TRUE, the function returns immediately and changes are reported by signaling this event. If fAsynchronous is FALSE, hEvent is ignored. If this parameter is TRUE, the function returns immediately and reports changes by signaling the specified event. If this parameter is FALSE, the function does not return until a change has occurred. If hEvent does not specify a valid event, the fAsynchronous parameter cannot be TRUE. Read more on docs.microsoft.com. If the function succeeds, the return value is ERROR_SUCCESS. If the function fails, the return value is a nonzero error code defined in Winerror.h. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error. This function detects a single change. After the caller receives a notification event, it should call the function again to receive the next notification.
Note  On Windows NT, Windows 2000, and Windows XP calling RegNotifyChangeKeyValue for a particular key handle causes change notifications to continue to occur for as long as the key handle is valid. This causes a second call to RegNotifyChangeKeyValue to return immediately, if any changes have occurred in the interim period between the first and second calls. If the API is being used asynchronously, the passed event handle will be signaled immediately if any interim changes have occurred.
 
This function cannot be used to detect changes to the registry that result from using the RegRestoreKey function. If the specified key is closed, the event is signaled. This means that an application should not depend on the key being open after returning from a wait operation on the event. The REG_NOTIFY_THREAD_AGNOSTIC flag introduced in Windows 8 enables the use of RegNotifyChangeKeyValue for ThreadPool threads. If the thread that called RegNotifyChangeKeyValue exits, the event is signaled. To continue to monitor additional changes in the value of the key, call RegNotifyChangeKeyValue again from another thread. With the exception of RegNotifyChangeKeyValue calls with REG_NOTIFY_THREAD_AGNOSTIC set, this function must be called on persistent threads. If the calling thread is from a thread pool and it is not persistent, the event is signaled every time the thread terminates, not just when there is a registry change. To ensure accurate results, run the thread pool work in a persistent thread by using the SetThreadpoolCallbackPersistent function, or create your own thread using the CreateThread function. (For the original thread pool API, specify WT_EXECUTEINPERSISTENTTHREAD using the QueueUserWorkItem function.) This function should not be called multiple times with the same value for the hKey but different values for the bWatchSubtree and dwNotifyFilter parameters. The function will succeed but the changes will be ignored. To change the watch parameters, you must first close the key handle by calling RegCloseKey, reopen the key handle by calling RegOpenKeyEx, and then call RegNotifyChangeKeyValue with the new parameters. Each time a process calls RegNotifyChangeKeyValue with the same set of parameters, it establishes another wait operation, creating a resource leak. Therefore, check that you are not calling RegNotifyChangeKeyValue with the same parameters until the previous wait operation has completed. To monitor registry operations in more detail, see Registry. Windows XP/2000:  When RegNotifyChangeKeyValue is called for a particular key handle, change notifications occur for as long as the key handle is valid. This causes a second call to RegNotifyChangeKeyValue to return immediately, if any changes occur in the interim between the first and second calls. If the function is being used asynchronously, the passed event handle will be signaled immediately if any changes occur in the interim. Read more on docs.microsoft.com. Opens the specified registry key. Note that key names are not case sensitive. (Unicode) A handle to an open registry key. This handle is returned by the RegCreateKeyEx or RegOpenKeyEx function, or it can be one of the following predefined keys: HKEY_CLASSES_ROOT HKEY_CURRENT_CONFIG HKEY_CURRENT_USER HKEY_LOCAL_MACHINE HKEY_USERS Read more on docs.microsoft.com. The name of the registry subkey to be opened. Key names are not case sensitive. If the lpSubKey parameter is NULL or a pointer to an empty string, and if hKey is a predefined key, then the system refreshes the predefined key, and phkResult receives the same hKey handle passed into the function. Otherwise, phkResult receives a new handle to the opened key. For more information, see Registry Element Size Limits. Read more on docs.microsoft.com. Specifies the option to apply when opening the key. Set this parameter to zero or the following: This doc was truncated. Read more on docs.microsoft.com. A mask that specifies the desired access rights to the key to be opened. The function fails if the security descriptor of the key does not permit the requested access for the calling process. For more information, see Registry Key Security and Access Rights. Read more on docs.microsoft.com. A pointer to a variable that receives a handle to the opened key. If the key is not one of the predefined registry keys, call the RegCloseKey function after you have finished using the handle. Read more on docs.microsoft.com. If the function succeeds, the return value is ERROR_SUCCESS. If the function fails, the return value is a nonzero error code defined in Winerror.h. You can use the FormatMessage function with the FORMAT_MESSAGE_FROM_SYSTEM flag to get a generic description of the error. Unlike the RegCreateKeyEx function, the RegOpenKeyEx function does not create the specified key if the key does not exist in the registry. Certain registry operations perform access checks against the security descriptor of the key, not the access mask specified when the handle to the key was obtained. For example, even if a key is opened with a samDesired of KEY_READ, it can be used to create registry keys if the key's security descriptor permits. In contrast, the RegSetValueEx function specifically requires that the key be opened with the KEY_SET_VALUE access right. If your service or application impersonates different users, do not use this function with HKEY_CURRENT_USER. Instead, call the RegOpenCurrentUser function. Note that operations that access certain registry keys are redirected. For more information, see Registry Virtualization and 32-bit and 64-bit Application Data in the Registry. Read more on docs.microsoft.com. Gets the package family name for the specified token. Type: HANDLE A token that contains the package identity. Read more on docs.microsoft.com. Type: UINT32* On input, the size of the packageFamilyName buffer, in characters. On output, the size of the package family name returned, in characters, including the null-terminator. Read more on docs.microsoft.com. Type: PWSTR The package family name. Read more on docs.microsoft.com. Type: LONG If the function succeeds it returns ERROR_SUCCESS. Otherwise, the function returns an error code. The possible error codes include the following. This doc was truncated. For info about string size limits, see Identity constants. 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. Default window procedure for Desktop Window Manager (DWM) hit testing within the non-client area. A handle to the window procedure that received the message. The message. Specifies additional message information. The content of this parameter depends on the value of the msg parameter. Specifies additional message information. The content of this parameter depends on the value of the msg parameter. A pointer to an LRESULT value that, when this method returns successfully,receives the result of the hit test. TRUE if DwmDefWindowProc handled the message; otherwise, FALSE. When creating custom frames that include the standard caption buttons, WM_NCHITTEST and other non-client hit test messages should first be passed to the DwmDefWindowProc function. This enables the DWM to provide hit testing for the captions buttons. If DwmDefWindowProc does not handle the non-client hit test messages, further processing of these messages might be necessary. Extends the window frame into the client area. The handle to the window in which the frame will be extended into the client area. A pointer to a MARGINS structure that describes the margins to use when extending the frame into the client area. If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This function must be called whenever Desktop Window Manager (DWM) composition is toggled. Handle the WM_DWMCOMPOSITIONCHANGED message for composition change notification. Use negative margin values to create the "sheet of glass" effect where the client area is rendered as a solid surface with no window border. Read more on docs.microsoft.com. Sets the value of Desktop Window Manager (DWM) non-client rendering attributes for a window. The handle to the window for which the attribute value is to be set. A flag describing which value to set, specified as a value of the [DWMWINDOWATTRIBUTE](/windows/desktop/api/dwmapi/ne-dwmapi-dwmwindowattribute) enumeration. This parameter specifies which attribute to set, and the *pvAttribute* parameter points to an object containing the attribute value. A pointer to an object containing the attribute value to set. The type of the value set depends on the value of the *dwAttribute* parameter. The [**DWMWINDOWATTRIBUTE**](/windows/desktop/api/Dwmapi/ne-dwmapi-dwmwindowattribute) enumeration topic indicates, in the row for each flag, what type of value you should pass a pointer to in the *pvAttribute* parameter. The size, in bytes, of the attribute value being set via the *pvAttribute* parameter. The type of the value set, and therefore its size in bytes, depends on the value of the *dwAttribute* parameter. Type: **[HRESULT](/windows/desktop/com/structure-of-com-error-codes)** If the function succeeds, it returns **S_OK**. Otherwise, it returns an [**HRESULT**](/windows/desktop/com/structure-of-com-error-codes) [error code](/windows/desktop/com/com-error-codes-10). If Desktop Composition has been disabled (Windows 7 and earlier), then this function returns **DWM_E_COMPOSITIONDISABLED**. It's not valid to call this function with the *dwAttribute* parameter set to **DWMWA_NCRENDERING_ENABLED**. To enable or disable non-client rendering, you should use the **DWMWA_NCRENDERING_POLICY** attribute, and set the desired value. For more info, and a code example, see [Controlling non-client region rendering](/windows/desktop/dwm/composition-ovw#controlling-non-client-region-rendering). Broadcast to every window following a theme change event. Examples of theme change events are the activation of a theme, the deactivation of a theme, or a transition from one theme to another. Type: **LRESULT** If an application processes this message, it should return zero. A window receives this message through its [**WindowProc**](/previous-versions/windows/desktop/legacy/ms633573(v=vs.85)) function. > [!Note] > This message is posted by the operating system. Applications typically do not send this message. Themes are specifications for the appearance of controls, so that the visual element of a control is treated separately from its functionality. To release an existing theme handle, call [**CloseThemeData**](/windows/win32/api/uxtheme/nf-uxtheme-closethemedata). To acquire a new theme handle, use [**OpenThemeData**](/windows/win32/api/uxtheme/nf-uxtheme-openthemedata). Following the **WM\_THEMECHANGED** broadcast, any existing theme handles are invalid. A theme-aware window should release and reopen any of its pre-existing theme handles when it receives the **WM\_THEMECHANGED** message. If the [**OpenThemeData**](/windows/win32/api/uxtheme/nf-uxtheme-openthemedata) function returns **NULL**, the window should paint unthemed. Read more on docs.microsoft.com. 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. The WM\_QUERYENDSESSION message is sent when the user chooses to end the session or when an application calls one of the system shutdown functions. Applications should respect the user's intentions and return **TRUE**. By default, the [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function returns **TRUE** for this message. If shutting down would corrupt the system or media that is being burned, the application can return **FALSE**. However, it is good practice to respect the user's actions. When an application returns **TRUE** for this message, it receives the [**WM\_ENDSESSION**](wm-endsession.md) message, regardless of how the other applications respond to the **WM\_QUERYENDSESSION** message. Each application should return **TRUE** or **FALSE** immediately upon receiving this message, and defer any cleanup operations until it receives the **WM\_ENDSESSION** message. Applications can display a user interface prompting the user for information at shutdown, however it is not recommended. After five seconds, the system displays information about the applications that are preventing shutdown and allows the user to terminate them. For example, Windows XP displays a dialog box, while Windows Vista displays a full screen with additional information about the applications blocking shutdown. If your application must block or postpone system shutdown, use the [**ShutdownBlockReasonCreate**](/windows/desktop/api/Winuser/nf-winuser-shutdownblockreasoncreate) function. For more information, see [Shutdown Changes for Windows Vista](shutdown-changes-for-windows-vista.md). Console applications can use the [**SetConsoleCtrlHandler**](/windows/console/setconsolectrlhandler) function to receive shutdown notification. Service applications can use the [**RegisterServiceCtrlHandlerEx**](/windows/win32/api/winsvc/nf-winsvc-registerservicectrlhandlerexa) function to receive shutdown notifications in a handler routine. Read more on docs.microsoft.com. The WM\_ENDSESSION message is sent to an application after the system processes the results of the WM\_QUERYENDSESSION message. The WM\_ENDSESSION message informs the application whether the session is ending. If an application processes this message, it should return zero. Applications that have unsaved data could save the data to a temporary location and restore it the next time the application starts. It is recommended that applications save their data and state frequently; for example, automatically save data between save operations initiated by the user to reduce the amount of data to be saved at shutdown. The application need not call the [**DestroyWindow**](/windows/win32/api/winuser/nf-winuser-destroywindow) or [**PostQuitMessage**](/windows/win32/api/winuser/nf-winuser-postquitmessage) function when the session is ending. Read more on docs.microsoft.com. Sent when an application requests that a window be created by calling the CreateWindowEx or CreateWindow function. Type: **LRESULT** If an application processes this message, it should return zero to continue creation of the window. If the application returns –1, the window is destroyed and the [**CreateWindowEx**](/windows/win32/api/winuser/nf-winuser-createwindowexa) or [**CreateWindow**](/windows/win32/api/winuser/nf-winuser-createwindowa) function returns a **NULL** handle. Learn more about this API from docs.microsoft.com. Sent when the size and position of a window's client area must be calculated. By processing this message, an application can control the content of the window's client area when the size or position of the window changes. Type: **LRESULT** If the *wParam* parameter is **FALSE**, the application should return zero. If *wParam* is **TRUE**, the application should return zero or a combination of the following values. If *wParam* is **TRUE** and an application returns zero, the old client area is preserved and is aligned with the upper-left corner of the new client area. | Return code/value | Description | |-------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| |
**WVR\_ALIGNTOP**
0x0010
| Specifies that the client area of the window is to be preserved and aligned with the top of the new position of the window. For example, to align the client area to the upper-left corner, return the WVR\_ALIGNTOP and **WVR\_ALIGNLEFT** values.
| |
**WVR\_ALIGNRIGHT**
0x0080
| Specifies that the client area of the window is to be preserved and aligned with the right side of the new position of the window. For example, to align the client area to the lower-right corner, return the **WVR\_ALIGNRIGHT** and WVR\_ALIGNBOTTOM values.
| |
**WVR\_ALIGNLEFT**
0x0020
| Specifies that the client area of the window is to be preserved and aligned with the left side of the new position of the window. For example, to align the client area to the lower-left corner, return the **WVR\_ALIGNLEFT** and **WVR\_ALIGNBOTTOM** values.
| |
**WVR\_ALIGNBOTTOM**
0x0040
| Specifies that the client area of the window is to be preserved and aligned with the bottom of the new position of the window. For example, to align the client area to the top-left corner, return the WVR\_ALIGNTOP and **WVR\_ALIGNLEFT** values.
| |
**WVR\_HREDRAW**
0x0100
| Used in combination with any other values, except **WVR\_VALIDRECTS**, causes the window to be completely redrawn if the client rectangle changes size horizontally. This value is similar to [CS\_HREDRAW](about-window-classes.md) class style
| |
**WVR\_VREDRAW**
0x0200
| Used in combination with any other values, except **WVR\_VALIDRECTS**, causes the window to be completely redrawn if the client rectangle changes size vertically. This value is similar to [CS\_VREDRAW](about-window-classes.md) class style
| |
**WVR\_REDRAW**
0x0300
| This value causes the entire window to be redrawn. It is a combination of **WVR\_HREDRAW** and **WVR\_VREDRAW** values.
| |
**WVR\_VALIDRECTS**
0x0400
| This value indicates that, upon return from [**WM\_NCCALCSIZE**](wm-nccalcsize.md), the rectangles specified by the **rgrc**\[1\] and **rgrc**\[2\] members of the [**NCCALCSIZE\_PARAMS**](/windows/win32/api/winuser/ns-winuser-nccalcsize_params) structure contain valid destination and source area rectangles, respectively. The system combines these rectangles to calculate the area of the window to be preserved. The system copies any part of the window image that is within the source rectangle and clips the image to the destination rectangle. Both rectangles are in parent-relative or screen-relative coordinates. This flag cannot be combined with any other flags.
This return value allows an application to implement more elaborate client-area preservation strategies, such as centering or preserving a subset of the client area.
| The window may be redrawn, depending on whether the [CS\_HREDRAW](about-window-classes.md) or CS\_VREDRAW class style is specified. This is the default, backward-compatible processing of this message by the [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function (in addition to the usual client rectangle calculation described in the preceding table). When *wParam* is **TRUE**, simply returning 0 without processing the [**NCCALCSIZE\_PARAMS**](/windows/win32/api/winuser/ns-winuser-nccalcsize_params) rectangles will cause the client area to resize to the size of the window, including the window frame. This will remove the window frame and caption items from your window, leaving only the client area displayed. Starting with Windows Vista, removing the standard frame by simply returning 0 when the *wParam* is **TRUE** does not affect frames that are extended into the client area using the [**DwmExtendFrameIntoClientArea**](/windows/win32/api/dwmapi/nf-dwmapi-dwmextendframeintoclientarea) function. Only the standard frame will be removed. Read more on docs.microsoft.com. Sent to a window in order to determine what part of the window corresponds to a particular screen coordinate. The return value of the [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function is one of the following values, indicating the position of the cursor hot spot. | Return code/value | Description | |------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------| |
**HTBORDER**
18
| In the border of a window that does not have a sizing border.
| |
**HTBOTTOM**
15
| In the lower-horizontal border of a resizable window (the user can click the mouse to resize the window vertically).
| |
**HTBOTTOMLEFT**
16
| In the lower-left corner of a border of a resizable window (the user can click the mouse to resize the window diagonally).
| |
**HTBOTTOMRIGHT**
17
| In the lower-right corner of a border of a resizable window (the user can click the mouse to resize the window diagonally).
| |
**HTCAPTION**
2
| In a title bar.
| |
**HTCLIENT**
1
| In a client area.
| |
**HTCLOSE**
20
| In a **Close** button.
| |
**HTERROR**
-2
| On the screen background or on a dividing line between windows (same as **HTNOWHERE**, except that the [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function produces a system beep to indicate an error).
| |
**HTGROWBOX**
4
| In a size box (same as **HTSIZE**).
| |
**HTHELP**
21
| In a **Help** button.
| |
**HTHSCROLL**
6
| In a horizontal scroll bar.
| |
**HTLEFT**
10
| In the left border of a resizable window (the user can click the mouse to resize the window horizontally).
| |
**HTMENU**
5
| In a menu.
| |
**HTMAXBUTTON**
9
| In a **Maximize** button.
| |
**HTMINBUTTON**
8
| In a **Minimize** button.
| |
**HTNOWHERE**
0
| On the screen background or on a dividing line between windows.
| |
**HTREDUCE**
8
| In a **Minimize** button.
| |
**HTRIGHT**
11
| In the right border of a resizable window (the user can click the mouse to resize the window horizontally).
| |
**HTSIZE**
4
| In a size box (same as **HTGROWBOX**).
| |
**HTSYSMENU**
3
| In a window menu or in a **Close** button in a child window.
| |
**HTTOP**
12
| In the upper-horizontal border of a window.
| |
**HTTOPLEFT**
13
| In the upper-left corner of a window border.
| |
**HTTOPRIGHT**
14
| In the upper-right corner of a window border.
| |
**HTTRANSPARENT**
-1
| In a window currently covered by another window in the same thread (the message will be sent to underlying windows in the same thread until one of them returns a code that is not **HTTRANSPARENT**).
| |
**HTVSCROLL**
7
| In the vertical scroll bar.
| |
**HTZOOM**
9
| In a **Maximize** button.
| Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Sent to a window when the SetWindowLong function is about to change one or more of the window's styles. Type: **LRESULT** An application should return zero if it processes this message. Learn more about this API from docs.microsoft.com. Posted when the user double-clicks the left mouse button while the cursor is in the client area of a window. If an application processes this message, it should return zero. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted when the user releases the left mouse button while the cursor is in the client area of a window. If an application processes this message, it should return zero. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted when the user presses the middle mouse button while the cursor is in the client area of a window. If an application processes this message, it should return zero. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted when the user double-clicks the middle mouse button while the cursor is in the client area of a window. If an application processes this message, it should return zero. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted when the user releases the middle mouse button while the cursor is in the client area of a window. If an application processes this message, it should return zero. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted to a window when the cursor hovers over the client area of the window for the period of time specified in a prior call to TrackMouseEvent. If an application processes this message, it should return zero. Hover tracking stops when **WM\_MOUSEHOVER** is generated. The application must call [**TrackMouseEvent**](/windows/win32/api/winuser/nf-winuser-trackmouseevent) again if it requires further tracking of mouse hover behavior. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted to a window when the cursor leaves the client area of the window specified in a prior call to TrackMouseEvent. If an application processes this message, it should return zero. All tracking requested by [**TrackMouseEvent**](/windows/win32/api/winuser/nf-winuser-trackmouseevent) is canceled when this message is generated. The application must call **TrackMouseEvent** when the mouse reenters its window if it requires further tracking of mouse hover behavior. Posted to a window when the cursor moves. If the mouse is not captured, the message is posted to the window that contains the cursor. Otherwise, the message is posted to the window that has captured the mouse. If an application processes this message, it should return zero. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted when the user presses the right mouse button while the cursor is in the client area of a window. If an application processes this message, it should return zero. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted when the user double-clicks the right mouse button while the cursor is in the client area of a window. If an application processes this message, it should return zero. Only windows that have the **CS\_DBLCLKS** style can receive **WM\_RBUTTONDBLCLK** messages, which the system generates whenever the user presses, releases, and again presses the right mouse button within the system's double-click time limit. Double-clicking the right mouse button actually generates four messages: [**WM\_RBUTTONDOWN**](wm-rbuttondown.md), [**WM\_RBUTTONUP**](wm-rbuttonup.md), **WM\_RBUTTONDBLCLK**, and **WM\_RBUTTONUP** again. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted when the user releases the right mouse button while the cursor is in the client area of a window. If an application processes this message, it should return zero. Use the following code to obtain the horizontal and vertical position: This doc was truncated. Read more on docs.microsoft.com. Posted when the user presses the left mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. The [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function tests the specified point to find the location of the cursor and performs the appropriate action. If appropriate, **DefWindowProc** sends the [**WM\_SYSCOMMAND**](/windows/desktop/menurc/wm-syscommand) message to the window. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted when the user double-clicks the left mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted when the user releases the left mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. The [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function tests the specified point to find out the location of the cursor and performs the appropriate action. If appropriate, **DefWindowProc** sends the [**WM\_SYSCOMMAND**](/windows/desktop/menurc/wm-syscommand) message to the window. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted when the user presses the middle mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted when the user double-clicks the middle mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. A window need not have the **CS\_DBLCLKS** style to receive **WM\_NCMBUTTONDBLCLK** messages. The system generates a **WM\_NCMBUTTONDBLCLK** message when the user presses, releases, and again presses the middle mouse button within the system's double-click time limit. Double-clicking the middle mouse button actually generates four messages: [**WM\_NCMBUTTONDOWN**](wm-ncmbuttondown.md), [**WM\_NCMBUTTONUP**](wm-ncmbuttonup.md), **WM\_NCMBUTTONDBLCLK**, and **WM\_NCMBUTTONUP** again. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted when the user releases the middle mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted to a window when the cursor hovers over the nonclient area of the window for the period of time specified in a prior call to TrackMouseEvent. If an application processes this message, it should return zero. Hover tracking stops when this message is generated. The application must call [**TrackMouseEvent**](/windows/win32/api/winuser/nf-winuser-trackmouseevent) again if it requires further tracking of mouse hover behavior. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted to a window when the cursor leaves the nonclient area of the window specified in a prior call to TrackMouseEvent. If an application processes this message, it should return zero. All tracking requested by [**TrackMouseEvent**](/windows/win32/api/winuser/nf-winuser-trackmouseevent) is canceled when this message is generated. The application must call **TrackMouseEvent** when the mouse reenters its window if it requires further tracking of mouse hover behavior. Posted to a window when the cursor is moved within the nonclient area of the window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. If it is appropriate to do so, the system sends the [**WM\_SYSCOMMAND**](/windows/desktop/menurc/wm-syscommand) message to the window. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted when the user presses the right mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted when the user double-clicks the right mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. A window need not have the **CS\_DBLCLKS** style to receive **WM\_NCRBUTTONDBLCLK** messages. The system generates a **WM\_NCRBUTTONDBLCLK** message when the user presses, releases, and again presses the right mouse button within the system's double-click time limit. Double-clicking the right mouse button actually generates four messages: [**WM\_NCRBUTTONDOWN**](wm-ncrbuttondown.md), [**WM\_NCRBUTTONUP**](wm-ncrbuttonup.md), **WM\_NCRBUTTONDBLCLK**, and **WM\_NCRBUTTONUP** again. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. This doc was truncated. Read more on docs.microsoft.com. Posted when the user releases the right mouse button while the cursor is within the nonclient area of a window. This message is posted to the window that contains the cursor. If a window has captured the mouse, this message is not posted. If an application processes this message, it should return zero. You can also use the [**GET\_X\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_x_lparam) and [**GET\_Y\_LPARAM**](/windows/desktop/api/windowsx/nf-windowsx-get_y_lparam) macros to extract the values of the x- and y- coordinates from *lParam*. 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 to a window if the mouse causes the cursor to move within a window and mouse input is not captured. If an application processes this message, it should return **TRUE** to halt further processing or **FALSE** to continue. The [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowprocw) function passes the **WM\_SETCURSOR** message to a parent window before processing. If the parent window returns **TRUE**, further processing is halted. Passing the message to a window's parent window gives the parent window control over the cursor's setting in a child window. The **DefWindowProc** function also uses this message to set the cursor to an arrow if it is not in the client area, or to the registered class cursor if it is in the client area. If the low-order word of the *lParam* parameter is **HTERROR** and the high-order word of *lParam* specifies that one of the mouse buttons is pressed, **DefWindowProc** calls the [**MessageBeep**](/windows/desktop/api/winuser/nf-winuser-messagebeep) function. Sent to a window when the size or position of the window is about to change. An application can use this message to override the window's default maximized size and position, or its default minimum or maximum tracking size. Type: **LRESULT** If an application processes this message, it should return zero. The maximum tracking size is the largest window size that can be produced by using the borders to size the window. The minimum tracking size is the smallest window size that can be produced by using the borders to size the window. Sent to a window when the window is about to be hidden or shown. Type: **LRESULT** If an application processes this message, it should return zero. The [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function hides or shows the window, as specified by the message. If a window has the [**WS\_VISIBLE**](window-styles.md) style when it is created, the window receives this message after it is created, but before it is displayed. A window also receives this message when its visibility state is changed by the [**ShowWindow**](/windows/win32/api/winuser/nf-winuser-showwindow) or [**ShowOwnedPopups**](/windows/win32/api/winuser/nf-winuser-showownedpopups) function. The **WM\_SHOWWINDOW** message is not sent under the following circumstances: - When a top-level, overlapped window is created with the [**WS\_MAXIMIZE**](window-styles.md) or **WS\_MINIMIZE** style. - When the **SW\_SHOWNORMAL** flag is specified in the call to the [**ShowWindow**](/windows/win32/api/winuser/nf-winuser-showwindow) function. Read more on docs.microsoft.com. Sent to both the window being activated and the window being deactivated. If an application processes this message, it should return zero. If the window is being activated and is not minimized, the [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function sets the keyboard focus to the window. If the window is activated by a mouse click, it also receives a [**WM\_MOUSEACTIVATE**](wm-mouseactivate.md) message. The WM\_PAINT message is sent when the system or another application makes a request to paint a portion of an application's window. An application returns zero if it processes this message. The **WM\_PAINT** message is generated by the system and should not be sent by an application. To force a window to draw into a specific device context, use the [**WM\_PRINT**](wm-print.md) or [**WM\_PRINTCLIENT**](wm-printclient.md) message. Note that this requires the target window to support the **WM\_PRINTCLIENT** message. Most common controls support the **WM\_PRINTCLIENT** message. The [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function validates the update region. The function may also send the [**WM\_NCPAINT**](wm-ncpaint.md) message to the window procedure if the window frame must be painted and send the [**WM\_ERASEBKGND**](../winmsg/wm-erasebkgnd.md) message if the window background must be erased. The system sends this message when there are no other messages in the application's message queue. [**DispatchMessage**](/windows/win32/api/winuser/nf-winuser-dispatchmessage) determines where to send the message; [**GetMessage**](/windows/win32/api/winuser/nf-winuser-getmessage) determines which message to dispatch. **GetMessage** returns the **WM\_PAINT** message when there are no other messages in the application's message queue, and **DispatchMessage** sends the message to the appropriate window procedure. A window may receive internal paint messages as a result of calling [**RedrawWindow**](/windows/desktop/api/Winuser/nf-winuser-redrawwindow) with the RDW\_INTERNALPAINT flag set. In this case, the window may not have an update region. An application may call the [**GetUpdateRect**](/windows/desktop/api/Winuser/nf-winuser-getupdaterect) function to determine whether the window has an update region. If **GetUpdateRect** returns zero, the application need not call the [**BeginPaint**](/windows/desktop/api/Winuser/nf-winuser-beginpaint) and [**EndPaint**](/windows/desktop/api/Winuser/nf-winuser-endpaint) functions. An application must check for any necessary internal painting by looking at its internal data structures for each **WM\_PAINT** message, because a **WM\_PAINT** message may have been caused by both a non-NULL update region and a call to [**RedrawWindow**](/windows/desktop/api/Winuser/nf-winuser-redrawwindow) with the RDW\_INTERNALPAINT flag set. The system sends an internal **WM\_PAINT** message only once. After an internal **WM\_PAINT** message is returned from [**GetMessage**](/windows/win32/api/winuser/nf-winuser-getmessage) or [**PeekMessage**](/windows/win32/api/winuser/nf-winuser-peekmessagea) or is sent to a window by [**UpdateWindow**](/windows/desktop/api/Winuser/nf-winuser-updatewindow), the system does not post or send further **WM\_PAINT** messages until the window is invalidated or until [**RedrawWindow**](/windows/desktop/api/Winuser/nf-winuser-redrawwindow) is called again with the RDW\_INTERNALPAINT flag set. For some common controls, the default **WM\_PAINT** message processing checks the *wParam* parameter. If *wParam* is non-NULL, the control assumes that the value is an HDC and paints using that device context. Read more on docs.microsoft.com. Sent when the effective dots per inch (dpi) for a window has changed. If an application processes this message, it should return zero. This message is only relevant for **PROCESS\_PER\_MONITOR\_DPI\_AWARE** applications or **DPI\_AWARENESS\_PER\_MONITOR\_AWARE** threads. It may be received on certain DPI changes if your top-level window or process is running as **DPI unaware** or **system DPI aware**, but in those situations it can be safely ignored. For more information about the different types of awareness, see [**PROCESS\_DPI\_AWARENESS**](/windows/desktop/api/ShellScalingApi/ne-shellscalingapi-process_dpi_awareness) and [**DPI\_AWARENESS**](/windows/desktop/api/windef/ne-windef-dpi_awareness). Older versions of Windows required DPI awareness to be tied at the level of an application. Those apps use **PROCESS\_DPI\_AWARENESS**. Currently, DPI awareness is tied to threads and individual windows rather than the entire application. These apps use **DPI\_AWARENESS**. You only need to use either the X-axis or the Y-axis value when scaling your application since they are the same. In order to handle this message correctly, you will need to resize and reposition your window based on the suggestions provided by *lParam* and using [**SetWindowPos**](/windows/desktop/api/winuser/nf-winuser-setwindowpos). If you do not do this, your window will grow or shrink with respect to everything else on the new monitor. For example, if a user is using multiple monitors and drags your window from a 96 DPI monitor to a 192 DPI monitor, your window will appear to be half as large with respect to other items on the 192 DPI monitor. The base value of DPI is defined as **USER\_DEFAULT\_SCREEN\_DPI** which is set to 96. To determine the scaling factor for a monitor, take the DPI value and divide by **USER\_DEFAULT\_SCREEN\_DPI**. The following table provides some sample DPI values and associated scaling factors. | DPI value | Scaling percentage | |-----------|--------------------| | 96 | 100% | | 120 | 125% | | 144 | 150% | | 192 | 200% | The following example provides a sample DPI change handler. This doc was truncated. Read more on docs.microsoft.com. 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. Indicates a request to terminate an application, and is generated when the application calls the PostQuitMessage function. This message causes the GetMessage function to return zero. Type: **LRESULT** This message does not have a return value because it causes the message loop to terminate before the message is sent to the application's window procedure. The **WM\_QUIT** message is not associated with a window and therefore will never be received through a window's window procedure. It is retrieved only by the [**GetMessage**](/windows/win32/api/winuser/nf-winuser-getmessage) or [**PeekMessage**](/windows/win32/api/winuser/nf-winuser-peekmessagea) functions. Do not post the **WM\_QUIT** message using the [**PostMessage**](/windows/win32/api/winuser/nf-winuser-postmessagea) function; use [**PostQuitMessage**](/windows/win32/api/winuser/nf-winuser-postquitmessage). 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. Double-pointed arrow cursor pointing north and south. Learn more about this API from docs.microsoft.com. Standard arrow cursor. Learn more about this API from docs.microsoft.com. Sent to a window whose size, position, or place in the Z order is about to change as a result of a call to the SetWindowPos function or another window-management function. Type: **LRESULT** If an application processes this message, it should return zero. For a window with the [**WS\_OVERLAPPED**](window-styles.md) or **WS\_THICKFRAME** style, the [**DefWindowProc**](/windows/desktop/api/winuser/nf-winuser-defwindowproca) function sends the [**WM\_GETMINMAXINFO**](wm-getminmaxinfo.md) message to the window. This is done to validate the new size and position of the window and to enforce the [CS\_BYTEALIGNCLIENT](about-window-classes.md) and CS\_BYTEALIGNWINDOW client styles. By not passing the **WM\_WINDOWPOSCHANGING** message to the **DefWindowProc** function, an application can override these defaults. While this message is being processed, modifying any of the values in [**WINDOWPOS**](/windows/win32/api/winuser/ns-winuser-windowpos) affects the window's new size, position, or place in the Z order. An application can prevent changes to the window by setting or clearing the appropriate bits in the **flags** member of **WINDOWPOS**. Read more on docs.microsoft.com. A window receives this message when the user chooses a command from the Window menu (formerly known as the system or control menu) or when the user chooses the maximize button, minimize button, restore button, or close button. An application should return zero if it processes this message. To obtain the position coordinates in screen coordinates, use the following code: This doc was truncated. Read more on docs.microsoft.com. Used to define private messages for use by private window classes, usually of the form WM\_USER+x, where x is an integer value. The following are the ranges of message numbers. | Range | Meaning | |--------------------------------------------------------------|----------------------------------------------------------------| | 0 through **WM\_USER** –1
| Messages reserved for use by the system.
| | **WM\_USER** through 0x7FFF
| Integer messages for use by private window classes.
| | [**WM\_APP**](wm-app.md) (0x8000) through 0xBFFF
| Messages available for use by applications.
| | 0xC000 through 0xFFFF
| String messages for use by applications.
| | Greater than 0xFFFF
| Reserved by the system.
| Message numbers in the first range (0 through **WM\_USER** –1) are defined by the system. Values in this range that are not explicitly defined are reserved by the system. Message numbers in the second range (**WM\_USER** through 0x7FFF) can be defined and used by an application to send messages within a private window class. These values cannot be used to define messages that are meaningful throughout an application because some predefined window classes already define values in this range. For example, predefined control classes such as **BUTTON**, **EDIT**, **LISTBOX**, and **COMBOBOX** may use these values. Messages in this range should not be sent to other applications unless the applications have been designed to exchange messages and to attach the same meaning to the message numbers. Message numbers in the third range (0x8000 through 0xBFFF) are available for applications to use as private messages. Messages in this range do not conflict with system messages. Message numbers in the fourth range (0xC000 through 0xFFFF) are defined at run time when an application calls the [**RegisterWindowMessage**](/windows/win32/api/winuser/nf-winuser-registerwindowmessagea) function to retrieve a message number for a string. All applications that register the same string can use the associated message number for exchanging messages. The actual message number, however, is not a constant and cannot be assumed to be the same between different sessions. Message numbers in the fifth range (greater than 0xFFFF) are reserved by the system. Read more on docs.microsoft.com. 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 GetStockObject function retrieves a handle to one of the stock pens, brushes, fonts, or palettes. If the function succeeds, the return value is a handle to the requested logical object. If the function fails, the return value is NULL. It is not recommended that you employ this method to obtain the current font used by dialogs and windows. Instead, use the SystemParametersInfo function with the SPI_GETNONCLIENTMETRICS parameter to retrieve the current font. SystemParametersInfo will take into account the current theme and provides font information for captions, menus, and message dialogs. Use the DKGRAY_BRUSH, GRAY_BRUSH, and LTGRAY_BRUSH stock objects only in windows with the CS_HREDRAW and CS_VREDRAW styles. Using a gray stock brush in any other style of window can lead to misalignment of brush patterns after a window is moved or sized. The origins of stock brushes cannot be adjusted. The HOLLOW_BRUSH and NULL_BRUSH stock objects are equivalent. It is not necessary (but it is not harmful) to delete stock objects by calling DeleteObject. Both DC_BRUSH and DC_PEN can be used interchangeably with other stock objects like BLACK_BRUSH and BLACK_PEN. For information on retrieving the current pen or brush color, see GetDCBrushColor and GetDCPenColor. See Setting the Pen or Brush Color for an example of setting colors. The GetStockObject function with an argument of DC_BRUSH or DC_PEN can be used interchangeably with the SetDCPenColor and SetDCBrushColor functions. Read more on docs.microsoft.com. The CreateDIBSection function creates a DIB that applications can write to directly. A handle to a device context. If the value of iUsage is DIB_PAL_COLORS, the function uses this device context's logical palette to initialize the DIB colors. A pointer to a BITMAPINFO structure that specifies various attributes of the DIB, including the bitmap dimensions and colors. The type of data contained in the bmiColors array member of the BITMAPINFO structure pointed to by pbmi (either logical palette indexes or literal RGB values). The following values are defined. This doc was truncated. Read more on docs.microsoft.com. A pointer to a variable that receives a pointer to the location of the DIB bit values. A handle to a file-mapping object that the function will use to create the DIB. This parameter can be NULL. If hSection is not NULL, it must be a handle to a file-mapping object created by calling the CreateFileMapping function with the PAGE_READWRITE or PAGE_WRITECOPY flag. Read-only DIB sections are not supported. Handles created by other means will cause CreateDIBSection to fail. If hSection is not NULL, the CreateDIBSection function locates the bitmap bit values at offset dwOffset in the file-mapping object referred to by hSection. An application can later retrieve the hSection handle by calling the GetObject function with the HBITMAP returned by CreateDIBSection. If hSection is NULL, the system allocates memory for the DIB. In this case, the CreateDIBSection function ignores the dwOffset parameter. An application cannot later obtain a handle to this memory. The dshSection member of the DIBSECTION structure filled in by calling the GetObject function will be NULL. Read more on docs.microsoft.com. The offset from the beginning of the file-mapping object referenced by hSection where storage for the bitmap bit values is to begin. This value is ignored if hSection is NULL. The bitmap bit values are aligned on doubleword boundaries, so dwOffset must be a multiple of the size of a DWORD. If the function succeeds, the return value is a handle to the newly created DIB, and *ppvBits points to the bitmap bit values. If the function fails, the return value is NULL, and *ppvBits is NULL. To get extended error information, call GetLastError. GetLastError can return the following value: This doc was truncated. As noted above, if hSection is NULL, the system allocates memory for the DIB. The system closes the handle to that memory when you later delete the DIB by calling the DeleteObject function. If hSection is not NULL, you must close the hSection memory handle yourself after calling DeleteObject to delete the bitmap. You cannot paste a DIB section from one application into another application. CreateDIBSection does not use the BITMAPINFOHEADER parameters biXPelsPerMeter or biYPelsPerMeter and will not provide resolution information in the BITMAPINFO structure. You need to guarantee that the GDI subsystem has completed any drawing to a bitmap created by CreateDIBSection before you draw to the bitmap yourself. Access to the bitmap must be synchronized. Do this by calling the GdiFlush function. This applies to any use of the pointer to the bitmap bit values, including passing the pointer in calls to functions such as SetDIBits. ICM: No color management is done. Read more on docs.microsoft.com. The CreateCompatibleDC function creates a memory device context (DC) compatible with the specified device. A handle to an existing DC. If this handle is NULL, the function creates a memory DC compatible with the application's current screen. If the function succeeds, the return value is the handle to a memory DC. If the function fails, the return value is NULL. A memory DC exists only in memory. When the memory DC is created, its display surface is exactly one monochrome pixel wide and one monochrome pixel high. Before an application can use a memory DC for drawing operations, it must select a bitmap of the correct width and height into the DC. To select a bitmap into a DC, use the CreateCompatibleBitmap function, specifying the height, width, and color organization required. When a memory DC is created, all attributes are set to normal default values. The memory DC can be used as a normal DC. You can set the attributes; obtain the current settings of its attributes; and select pens, brushes, and regions. The CreateCompatibleDC function can only be used with devices that support raster operations. An application can determine whether a device supports these operations by calling the GetDeviceCaps function. When you no longer need the memory DC, call the DeleteDC function. We recommend that you call DeleteDC to delete the DC. However, you can also call DeleteObject with the HDC to delete the DC. If hdc is NULL, the thread that calls CreateCompatibleDC owns the HDC that is created. When this thread is destroyed, the HDC is no longer valid. Thus, if you create the HDC and pass it to another thread, then exit the first thread, the second thread will not be able to use the HDC. ICM: If the DC that is passed to this function is enabled for Image Color Management (ICM), the DC created by the function is ICM-enabled. The source and destination color spaces are specified in the DC. Read more on docs.microsoft.com. The DeleteDC function deletes the specified device context (DC). A handle to the device context. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. An application must not delete a DC whose handle was obtained by calling the GetDC function. Instead, it must call the ReleaseDC function to free the DC. The SelectObject function selects an object into the specified device context (DC). The new object replaces the previous object of the same type. A handle to the DC. A handle to the object to be selected. The specified object must have been created by using one of the following functions. This doc was truncated. Read more on docs.microsoft.com. If the selected object is not a region and the function succeeds, the return value is a handle to the object being replaced. If the selected object is a region and the function succeeds, the return value is one of the following values. This doc was truncated. This function returns the previously selected object of the specified type. An application should always replace a new object with the original, default object after it has finished drawing with the new object. An application cannot select a single bitmap into more than one DC at a time. ICM: If the object being selected is a brush or a pen, color management is performed. 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. Retrieves a pseudo handle for the calling thread. The return value is a pseudo handle for the current thread. A pseudo handle is a special constant that is interpreted as the current thread handle. The calling thread can use this handle to specify itself whenever a thread handle is required. Pseudo handles are not inherited by child processes. This handle has the THREAD_ALL_ACCESS access right to the thread object. For more information, see Thread Security and Access Rights. Windows Server 2003 and Windows XP:  This handle has the maximum access allowed by the security descriptor of the thread to the primary token of the process. The function cannot be used by one thread to create a handle that can be used by other threads to refer to the first thread. The handle is always interpreted as referring to the thread that is using it. A thread can create a "real" handle to itself that can be used by other threads, or inherited by other processes, by specifying the pseudo handle as the source handle in a call to the DuplicateHandle function. The pseudo handle need not be closed when it is no longer needed. Calling the CloseHandle function with this handle has no effect. If the pseudo handle is duplicated by DuplicateHandle, the duplicate handle must be closed. Do not create a thread while impersonating a security context. The call will succeed, however the newly created thread will have reduced access rights to itself when calling GetCurrentThread. The access rights granted this thread will be derived from the access rights the impersonated user has to the process. Some access rights including THREAD_SET_THREAD_TOKEN and THREAD_GET_CONTEXT may not be present, leading to unexpected failures. Read more on docs.microsoft.com. Retrieves information about the geographical location of the user. For more information, see Table of Geographical Locations. Geographical location class to return. Possible values are defined by the SYSGEOCLASS enumeration. Returns the geographical location identifier of the user if SetUserGeoID has been called before to set the identifier. If no geographical location identifier has been set for the user, the function returns GEOID_NOT_AVAILABLE. Learn more about this API from docs.microsoft.com. Gets the application user model ID for the current process. On input, the size of the applicationUserModelId buffer, in wide characters. On success, the size of the buffer used, including the null terminator. A pointer to a buffer that receives the application user model ID. If the function succeeds it returns ERROR_SUCCESS. Otherwise, the function returns an error code. The possible error codes include the following. This doc was truncated. For info about string size limits, see Identity constants. The AlphaBlend function displays bitmaps that have transparent or semitransparent pixels. A handle to the destination device context. The x-coordinate, in logical units, of the upper-left corner of the destination rectangle. The y-coordinate, in logical units, of the upper-left corner of the destination rectangle. The width, in logical units, of the destination rectangle. The height, in logical units, of the destination rectangle. A handle to the source device context. The x-coordinate, in logical units, of the upper-left corner of the source rectangle. The y-coordinate, in logical units, of the upper-left corner of the source rectangle. The width, in logical units, of the source rectangle. The height, in logical units, of the source rectangle. The alpha-blending function for source and destination bitmaps, a global alpha value to be applied to the entire source bitmap, and format information for the source bitmap. The source and destination blend functions are currently limited to AC_SRC_OVER. See the BLENDFUNCTION and EMRALPHABLEND structures. If the function succeeds, the return value is TRUE. If the function fails, the return value is FALSE. If the source rectangle and destination rectangle are not the same size, the source bitmap is stretched to match the destination rectangle. If the SetStretchBltMode function is used, the iStretchMode value is automatically converted to COLORONCOLOR for this function (that is, BLACKONWHITE, WHITEONBLACK, and HALFTONE are changed to COLORONCOLOR). The destination coordinates are transformed by using the transformation currently specified for the destination device context. The source coordinates are transformed by using the transformation currently specified for the source device context. An error occurs (and the function returns FALSE) if the source device context identifies an enhanced metafile device context. If destination and source bitmaps do not have the same color format, AlphaBlend converts the source bitmap to match the destination bitmap. AlphaBlend does not support mirroring. If either the width or height of the source or destination is negative, this call will fail. When rendering to a printer, first call GetDeviceCaps with SHADEBLENDCAPS to determine if the printer supports blending with AlphaBlend. Note that, for a display DC, all blending operations are supported and these flags represent whether the operations are accelerated. If the source and destination are the same surface, that is, they are both the screen or the same memory bitmap and the source and destination rectangles overlap, an error occurs and the function returns FALSE. The source rectangle must lie completely within the source surface, otherwise an error occurs and the function returns FALSE. AlphaBlend fails if the width or height of the source or destination is negative. The SourceConstantAlpha member of BLENDFUNCTION specifies an alpha transparency value to be used on the entire source bitmap. The SourceConstantAlpha value is combined with any per-pixel alpha values. If SourceConstantAlpha is 0, it is assumed that the image is transparent. Set the SourceConstantAlpha value to 255 (which indicates that the image is opaque) when you only want to use per-pixel alpha values. Read more on docs.microsoft.com. Creates a single uninitialized object of the class associated with a specified CLSID. The CLSID associated with the data and code that will be used to create the object. If NULL, indicates that the object is not being created as part of an aggregate. If non-NULL, pointer to the aggregate object's IUnknown interface (the controlling IUnknown). Context in which the code that manages the newly created object will run. The values are taken from the enumeration CLSCTX. A reference to the identifier of the interface to be used to communicate with the object. Address of pointer variable that receives the interface pointer requested in riid. Upon successful return, *ppv contains the requested interface pointer. Upon failure, *ppv contains NULL. This function can return the following values. This doc was truncated. The CoCreateInstance function provides a convenient shortcut by connecting to the class object associated with the specified CLSID, creating a default-initialized instance, and releasing the class object. As such, it encapsulates the following functionality: This doc was truncated. Read more on docs.microsoft.com. Enables the server to impersonate the client of the current call for the duration of the call. This function supports the standard return values, including S_OK. This method allows the server to impersonate the client of the current call for the duration of the call. If you do not call CoRevertToSelf, COM reverts automatically for you. This function will fail unless the object is being called with RPC_C_AUTHN_LEVEL_CONNECT or higher authentication in effect (which is any authentication level except RPC_C_AUTHN_LEVEL_NONE). This function encapsulates the following sequence of common calls (error handling excluded): This doc was truncated. Read more on docs.microsoft.com. Restores the authentication information on a thread of execution. This function supports the standard return values, including S_OK to indicate success. CoRevertToSelf, which is a helper function that calls IServerSecurity::RevertToSelf, restores the authentication information on a thread to the authentication information on the thread before impersonation began. CoRevertToSelf encapsulates the following common sequence of calls (error handling excluded): This doc was truncated. Read more on docs.microsoft.com. Deallocates a string allocated previously by SysAllocString, SysAllocStringByteLen, SysReAllocString, SysAllocStringLen, or SysReAllocStringLen. The previously allocated string. If this parameter is NULL, the function simply returns. Learn more about this API from docs.microsoft.com. Initializes a PROPVARIANT structure from a specified string vector. Type: PCWSTR* Pointer to a buffer that contains the source string vector. Read more on docs.microsoft.com. Type: ULONG The number of vector elements in prgsz. Read more on docs.microsoft.com. Type: PROPVARIANT* When this function returns, contains the initialized PROPVARIANT structure. Read more on docs.microsoft.com. Type: HRESULT If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates an in-memory property store. Type: REFIID Reference to the requested interface ID. Read more on docs.microsoft.com. Type: void** When this function returns, contains a pointer to the desired interface, typically IPropertyStore or IPersistSerializedPropStorage. Read more on docs.microsoft.com. Type: HRESULT If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This function creates an in-memory property store object that implements IPropertyStore, INamedPropertyStore, IPropertyStoreCache, IPersistStream, IPropertyBag, and IPersistSerializedPropStorage. The memory property store does not correspond to a file and is designed for use as a cache. IPropertyStore::Commit is a no-op, and the data stored in the object persists only as long as the object does. The memory property store is thread safe. It aggregates the free-threaded marshaller and uses critical sections to protect its data members. 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. Retrieves an object that represents a specific window's collection of properties, which allows those properties to be queried or set. Type: HWND A handle to the window whose properties are being retrieved. Read more on docs.microsoft.com. Type: REFIID A reference to the IID of the property store object to retrieve through ppv. This is typically IID_IPropertyStore. Read more on docs.microsoft.com. Type: void** When this function returns, contains the interface pointer requested in riid. This is typically IPropertyStore. Read more on docs.microsoft.com. Type: HRESULT If this function succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. An application can use this function to obtain access to a window's property store so that it can set an explicit Application User Model ID (AppUserModelID) in the System.AppUserModel.ID property. A window's properties must be removed before the window is closed. If this is not done, the resources used by those properties are not returned to the system. A property is removed by setting it to the PROPVARIANT type VT_EMPTY. When a call is made to IPropertyStore::SetValue on the object retrieved through ppv, the properties and values are immediately stored on the window. Therefore, no call to IPropertyStore::Commit is needed. No error occurs if it is called, but it has no effect. An application sets AppUserModelIDs on individual windows to control the application's taskbar grouping and Jump List contents. For instance, a suite application might want to provide a different taskbar button for each of its subfeatures, with the windows relating to that subfeature grouped under that button. Without window-level AppUserModelIDs, those windows would all be grouped together under the main process. Applications should also use this property store to set these relaunch properties so that the system can return the application to that state. This doc was truncated. Read more on docs.microsoft.com. Retrieves or sets the value of one of the system-wide parameters. (Unicode) Type: UINT The system-wide parameter to be retrieved or set. The possible values are organized in the following tables of related parameters: This doc was truncated. Read more on docs.microsoft.com. Type: UINT A parameter whose usage and format depends on the system parameter being queried or set. For more information about system-wide parameters, see the uiAction parameter. If not otherwise indicated, you must specify zero for this parameter. Read more on docs.microsoft.com. Type: PVOID A parameter whose usage and format depends on the system parameter being queried or set. For more information about system-wide parameters, see the uiAction parameter. If not otherwise indicated, you must specify NULL for this parameter. For information on the PVOID datatype, see Windows Data Types. Read more on docs.microsoft.com. Type: UINT If a system parameter is being set, specifies whether the user profile is to be updated, and if so, whether the WM_SETTINGCHANGE message is to be broadcast to all top-level windows to notify them of the change. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is a nonzero value. If the function fails, the return value is zero. To get extended error information, call GetLastError. This function is intended for use with applications that allow the user to customize the environment. A keyboard layout name should be derived from the hexadecimal value of the language identifier corresponding to the layout. For example, U.S. English has a language identifier of 0x0409, so the primary U.S. English layout is named "00000409". Variants of U.S. English layout, such as the Dvorak layout, are named "00010409", "00020409" and so on. For a list of the primary language identifiers and sublanguage identifiers that make up a language identifier, see the MAKELANGID macro. There is a difference between the High Contrast color scheme and the High Contrast Mode. The High Contrast color scheme changes the system colors to colors that have obvious contrast; you switch to this color scheme by using the Display Options in the control panel. The High Contrast Mode, which uses SPI_GETHIGHCONTRAST and SPI_SETHIGHCONTRAST, advises applications to modify their appearance for visually-impaired users. It involves such things as audible warning to users and customized color scheme (using the Accessibility Options in the control panel). For more information, see HIGHCONTRAST. For more information on general accessibility features, see Accessibility. During the time that the primary button is held down to activate the Mouse ClickLock feature, the user can move the mouse. After the primary button is locked down, releasing the primary button does not result in a WM_LBUTTONUP message. Thus, it will appear to an application that the primary button is still down. Any subsequent button message releases the primary button, sending a WM_LBUTTONUP message to the application, thus the button can be unlocked programmatically or through the user clicking any button. 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 SystemParametersInfoForDPI. For more information on DPI awareness, see the Windows High DPI documentation. Read more on docs.microsoft.com. Enables or disables mouse and keyboard input to the specified window or control. When input is disabled, the window does not receive input such as mouse clicks and key presses. When input is enabled, the window receives all input. Type: HWND A handle to the window to be enabled or disabled. Read more on docs.microsoft.com. Type: BOOL Indicates whether to enable or disable the window. If this parameter is TRUE, the window is enabled. If the parameter is FALSE, the window is disabled. Read more on docs.microsoft.com. Type: BOOL If the window was previously disabled, the return value is nonzero. If the window was not previously disabled, the return value is zero. If the window is being disabled, the system sends a WM_CANCELMODE message. If the enabled state of a window is changing, the system sends a WM_ENABLE message after the WM_CANCELMODE message. (These messages are sent before EnableWindow returns.) If a window is already disabled, its child windows are implicitly disabled, although they are not sent a WM_ENABLE message. A window must be enabled before it can be activated. For example, if an application is displaying a modeless dialog box and has disabled its main window, the application must enable the main window before destroying the dialog box. Otherwise, another window will receive the keyboard focus and be activated. If a child window is disabled, it is ignored when the system tries to determine which window should receive mouse messages. By default, a window is enabled when it is created. To create a window that is initially disabled, an application can specify the WS_DISABLED style in the CreateWindow or CreateWindowEx function. After a window has been created, an application can use EnableWindow to enable or disable the window. An application can use this function to enable or disable a control in a dialog box. A disabled control cannot receive the keyboard focus, nor can a user gain access to it. Read more on docs.microsoft.com. Changes the size, position, and Z order of a child, pop-up, or top-level window. These windows are ordered according to their appearance on the screen. The topmost window receives the highest rank and is the first window in the Z order. Type: HWND A handle to the window. Read more on docs.microsoft.com. Type: HWND Type: int The new position of the left side of the window, in client coordinates. Read more on docs.microsoft.com. Type: int The new position of the top of the window, in client coordinates. Read more on docs.microsoft.com. Type: int The new width of the window, in pixels. Read more on docs.microsoft.com. Type: int The new height of the window, in pixels. Read more on docs.microsoft.com. Type: UINT 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. As part of the Vista re-architecture, all services were moved off the interactive desktop into Session 0. hwnd and window manager operations are only effective inside a session and cross-session attempts to manipulate the hwnd will fail. For more information, see The Windows Vista Developer Story: Application Compatibility Cookbook. If you have changed certain window data using SetWindowLong, you must call SetWindowPos for the changes to take effect. Use the following combination for uFlags: SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED. A window can be made a topmost window either by setting the hWndInsertAfter parameter to HWND_TOPMOST and ensuring that the SWP_NOZORDER flag is not set, or by setting a window's position in the Z order so that it is above any existing topmost windows. When a non-topmost window is made topmost, its owned windows are also made topmost. Its owners, however, are not changed. If neither the SWP_NOACTIVATE nor SWP_NOZORDER flag is specified (that is, when the application requests that a window be simultaneously activated and its position in the Z order changed), the value specified in hWndInsertAfter is used only in the following circumstances. This doc was truncated. Read more on docs.microsoft.com. Retrieves the dimensions of the bounding rectangle of the specified window. The dimensions are given in screen coordinates that are relative to the upper-left corner of the screen. Type: HWND A handle to the window. Read more on docs.microsoft.com. Type: LPRECT A pointer to a RECT structure that receives the screen coordinates of the upper-left and lower-right corners of the 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. To get extended error information, call GetLastError. In conformance with conventions for the RECT structure, the bottom-right coordinates of the returned rectangle are exclusive. In other words, the pixel at (right, bottom) lies immediately outside the rectangle. GetWindowRect is virtualized for DPI. In Windows Vista and later, the Window Rect now includes the area occupied by the drop shadow. Calling GetWindowRect will have different behavior depending on whether the window has ever been shown or not. If the window has not been shown before, GetWindowRect will not include the area of the drop shadow. To get the window bounds excluding the drop shadow, use DwmGetWindowAttribute, specifying DWMWA_EXTENDED_FRAME_BOUNDS. Note that unlike the Window Rect, the DWM Extended Frame Bounds are not adjusted for DPI. Getting the extended frame bounds can only be done after the window has been shown at least once. Read more on docs.microsoft.com. Returns the dots per inch (dpi) value for the specified window. The window that you want to get information about. The DPI for the window, which depends on the [DPI_AWARENESS](/windows/win32/api/windef/ne-windef-dpi_awareness) of the window. See the **Remarks** section for more information. An invalid *hwnd* value will result in a return value of 0. The following table indicates the return value of GetDpiForWindow based on the [DPI_AWARENESS](/windows/win32/api/windef/ne-windef-dpi_awareness) of the provided *hwnd*. This doc was truncated. Read more on docs.microsoft.com. Determines whether a window is maximized. Type: HWND A handle to the window to be tested. Read more on docs.microsoft.com. Type: BOOL If the window is zoomed, the return value is nonzero. If the window is not zoomed, the return value is zero. Learn more about this API from docs.microsoft.com. Passes message information to the specified window procedure. (Unicode) Type: WNDPROC The previous window procedure. If this value is obtained by calling the GetWindowLong function with the nIndex parameter set to GWL_WNDPROC or DWL_DLGPROC, it is actually either the address of a window or dialog box procedure, or a special internal value meaningful only to CallWindowProc. Read more on docs.microsoft.com. Type: HWND A handle to the window procedure to receive the message. Read more on docs.microsoft.com. Type: UINT The message. Read more on docs.microsoft.com. Type: WPARAM Additional message-specific information. The contents of this parameter depend on the value of the Msg parameter. Read more on docs.microsoft.com. Type: LPARAM Additional message-specific information. The contents of this parameter depend on the value of the Msg parameter. Read more on docs.microsoft.com. Type: LRESULT The return value specifies the result of the message processing and depends on the message sent. Use the CallWindowProc function for window subclassing. Usually, all windows with the same class share one window procedure. A subclass is a window or set of windows with the same class whose messages are intercepted and processed by another window procedure (or procedures) before being passed to the window procedure of the class. The SetWindowLong function creates the subclass by changing the window procedure associated with a particular window, causing the system to call the new window procedure instead of the previous one. An application must pass any messages not processed by the new window procedure to the previous window procedure by calling CallWindowProc. This allows the application to create a chain of window procedures. If STRICT is defined, the lpPrevWndFunc parameter has the data type WNDPROC. The WNDPROC type is declared as follows: This doc was truncated. 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. 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 ClientToScreen function converts the client-area coordinates of a specified point to screen coordinates. A handle to the window whose client area is used for the conversion. A pointer to a POINT structure that contains the client coordinates to be converted. The new screen coordinates are copied into this structure if the function succeeds. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. The ClientToScreen function replaces the client-area coordinates in the POINT structure with the screen coordinates. The screen coordinates are relative to the upper-left corner of the screen. Note, a screen-coordinate point that is above the window's client area has a negative y-coordinate. Similarly, a screen coordinate to the left of a client area has a negative x-coordinate. All coordinates are device coordinates. Read more on docs.microsoft.com. The ScreenToClient function converts the screen coordinates of a specified point on the screen to client-area coordinates. A handle to the window whose client area will be used for the conversion. A pointer to a POINT structure that specifies the screen coordinates to be converted. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. The function uses the window identified by the hWnd parameter and the screen coordinates given in the POINT structure to compute client coordinates. It then replaces the screen coordinates with the client coordinates. The new coordinates are relative to the upper-left corner of the specified window's client area. The ScreenToClient function assumes the specified point is in screen coordinates. All coordinates are in device units. Do not use ScreenToClient when in a mirroring situation, that is, when changing from left-to-right layout to right-to-left layout. Instead, use MapWindowPoints. For more information, see "Window Layout and Mirroring" in Window Features. Read more on docs.microsoft.com. Sends the specified message to a window or windows. The SendMessage function calls the window procedure for the specified window and does not return until the window procedure has processed the message. (SendMessageW) Type: HWND A handle to the window whose window procedure will receive the message. If this parameter is HWND_BROADCAST ((HWND)0xffff), the message is sent to all top-level windows in the system, including disabled or invisible unowned windows, overlapped windows, and pop-up windows; but the message is not sent to child windows. Message sending is subject to UIPI. The thread of a process can send messages only to message queues of threads in processes of lesser or equal integrity level. Read more on docs.microsoft.com. Type: UINT The message to be sent. 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: LRESULT The return value specifies the result of the message processing; it depends on the message sent. When a message is blocked by UIPI the last error, retrieved with GetLastError, is set to 5 (access denied). 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 the specified window was created by the calling thread, the window procedure is called immediately as a subroutine. If the specified window was created by a different thread, the system switches to that thread and calls the appropriate window procedure. Messages sent between threads are processed only when the receiving thread executes message retrieval code. The sending thread is blocked until the receiving thread processes the message. However, the sending thread will process incoming nonqueued messages while waiting for its message to be processed. To prevent this, use SendMessageTimeout with SMTO_BLOCK set. For more information on nonqueued messages, see Nonqueued Messages. An accessibility application can use SendMessage to send WM_APPCOMMAND messages to the shell to launch applications. This functionality is not guaranteed to work for other types of applications. 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. Loads the specified cursor resource from the executable (.EXE) file associated with an application instance. (Unicode) Type: HINSTANCE A handle to an instance of the module whose executable file contains the cursor to be loaded. Read more on docs.microsoft.com. Type: LPCTSTR The name of the cursor resource to be loaded. Alternatively, this parameter can consist of the resource identifier in the low-order word and zero in the high-order word. The MAKEINTRESOURCE macro can also be used to create this value. To use one of the predefined cursors, the application must set the hInstance parameter to NULL and the lpCursorName parameter to one the following values. This doc was truncated. Read more on docs.microsoft.com. Type: HCURSOR If the function succeeds, the return value is the handle to the newly loaded cursor. If the function fails, the return value is NULL. To get extended error information, call GetLastError. The LoadCursor function loads the cursor resource only if it has not been loaded; otherwise, it retrieves the handle to the existing resource. This function returns a valid cursor handle only if the lpCursorName parameter is a pointer to a cursor resource. If lpCursorName is a pointer to any type of resource other than a cursor (such as an icon), the return value is not NULL, even though it is not a valid cursor handle. The LoadCursor function searches the cursor resource most appropriate for the cursor for the current display device. The cursor resource can be a color or monochrome bitmap.

DPI Virtualization

This API does not participate in DPI virtualization. The output returned is not affected by the DPI of the calling thread. Read more on docs.microsoft.com. Sets the cursor shape. Type: HCURSOR A handle to the cursor. The cursor must have been created by either the CreateCursor or the CreateIconIndirect function, or loaded by either the LoadCursor or the LoadImage function. If this parameter is NULL, the cursor is removed from the screen. Read more on docs.microsoft.com. Type: HCURSOR The return value is the handle to the previous cursor, if there was one. If there was no previous cursor, the return value is NULL. The cursor is set only if the new cursor is different from the previous cursor; otherwise, the function returns immediately. The cursor is a shared resource. A window should set the cursor shape only when the cursor is in its client area or when the window is capturing mouse input. In systems without a mouse, the window should restore the previous cursor before the cursor leaves the client area or before it relinquishes control to another window. If your application must set the cursor while it is in a window, make sure the class cursor for the specified window's class is set to NULL. If the class cursor is not NULL, the system restores the class cursor each time the mouse is moved. The cursor is not shown on the screen if the internal cursor display count is less than zero. This occurs if the application uses the ShowCursor function to hide the cursor more times than to show the cursor. 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. Sets the opacity and transparency color key of a layered window. Type: HWND A handle to the layered window. A layered window is created by specifying WS_EX_LAYERED when creating the window with the CreateWindowEx function or by setting WS_EX_LAYERED via SetWindowLong after the window has been created. Windows 8:  The WS_EX_LAYERED style is supported for top-level windows and child windows. Previous Windows versions support WS_EX_LAYERED only for top-level windows. Read more on docs.microsoft.com. Type: COLORREF A COLORREF structure that specifies the transparency color key to be used when composing the layered window. All pixels painted by the window in this color will be transparent. To generate a COLORREF, use the RGB macro. Read more on docs.microsoft.com. Type: BYTE Alpha value used to describe the opacity of the layered window. Similar to the SourceConstantAlpha member of the BLENDFUNCTION structure. When bAlpha is 0, the window is completely transparent. When bAlpha is 255, the window is opaque. Read more on docs.microsoft.com. Type: DWORD 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. Note that once SetLayeredWindowAttributes has been called for a layered window, subsequent UpdateLayeredWindow calls will fail until the layering style bit is cleared and set again. For more information, see Using Layered Windows. 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. Retrieves the cursor position for the last message retrieved by the GetMessage function. Type: DWORD The return value specifies the x- and y-coordinates of the cursor position. The x-coordinate is the low order short and the y-coordinate is the high-order short. As noted above, the x-coordinate is in the low-order short of the return value; the y-coordinate is in the high-order short (both represent signed values because they can take negative values on systems with multiple monitors). If the return value is assigned to a variable, you can use the MAKEPOINTS macro to obtain a POINTS structure from the return value. You can also use the GET_X_LPARAM or GET_Y_LPARAM macro to extract the x- or y-coordinate.
Important  Do not use the LOWORD or HIWORD macros to extract the x- and y- coordinates of the cursor position because these macros return incorrect results on systems with multiple monitors. Systems with multiple monitors can have negative x- and y- coordinates, and LOWORD and HIWORD treat the coordinates as unsigned quantities.
 
 Read more on docs.microsoft.com. Retrieves the status of the specified virtual key. The status specifies whether the key is up, down, or toggled (on, off�alternating each time the key is pressed). Type: int A virtual key. If the desired virtual key is a letter or digit (A through Z, a through z, or 0 through 9), nVirtKey must be set to the ASCII value of that character. For other keys, it must be a virtual-key code. If a non-English keyboard layout is used, virtual keys with values in the range ASCII A through Z and 0 through 9 are used to specify most of the character keys. For example, for the German keyboard layout, the virtual key of value ASCII O (0x4F) refers to the "o" key, whereas VK_OEM_1 refers to the "o with umlaut" key. Read more on docs.microsoft.com. Type: SHORT The return value specifies the status of the specified virtual key, as follows: This doc was truncated. The key status returned from this function changes as a thread reads key messages from its message queue. The status does not reflect the interrupt-level state associated with the hardware. Use the GetAsyncKeyState function to retrieve that information. An application calls GetKeyState in response to a keyboard-input message. This function retrieves the state of the key when the input message was generated. To retrieve state information for all the virtual keys, use the GetKeyboardState function. An application can use the virtual key code constants VK_SHIFT, VK_CONTROL, and VK_MENU as values for the nVirtKey parameter. This gives the status of the SHIFT, CTRL, or ALT keys without distinguishing between left and right. An application can also use the following virtual-key code constants as values for nVirtKey to distinguish between the left and right instances of those keys: VK_LSHIFT VK_RSHIFT VK_LCONTROL VK_RCONTROL VK_LMENU VK_RMENU These left- and right-distinguishing constants are available to an application only through the GetKeyboardState, SetKeyboardState, GetAsyncKeyState, GetKeyState, and MapVirtualKey functions. Read more on docs.microsoft.com. Posts messages when the mouse pointer leaves a window or hovers over a window for a specified amount of time. Type: LPTRACKMOUSEEVENT A pointer to a TRACKMOUSEEVENT structure that contains tracking information. Read more on docs.microsoft.com. Type: BOOL If the function succeeds, the return value is nonzero . If the function fails, return value is zero. To get extended error information, call GetLastError. The mouse pointer is considered to be hovering when it stays within a specified rectangle for a specified period of time. Call SystemParametersInfo. and use the values SPI_GETMOUSEHOVERWIDTH, SPI_GETMOUSEHOVERHEIGHT, and SPI_GETMOUSEHOVERTIME to retrieve the size of the rectangle and the time. The function can post the following messages. This doc was truncated. Read more on docs.microsoft.com. The MonitorFromRect function retrieves a handle to the display monitor that has the largest area of intersection with a specified rectangle. A pointer to a RECT structure that specifies the rectangle of interest in virtual-screen coordinates. Determines the function's return value if the rectangle does not intersect any display monitor. If the rectangle intersects one or more display monitor rectangles, the return value is an HMONITOR handle to the display monitor that has the largest area of intersection with the rectangle. If the rectangle does not intersect a display monitor, the return value depends on the value of dwFlags. Learn more about this API from docs.microsoft.com. The MonitorFromWindow function retrieves a handle to the display monitor that has the largest area of intersection with the bounding rectangle of a specified window. A handle to the window of interest. Determines the function's return value if the window does not intersect any display monitor. If the window intersects one or more display monitor rectangles, the return value is an HMONITOR handle to the display monitor that has the largest area of intersection with the window. If the window does not intersect a display monitor, the return value depends on the value of dwFlags. If the window is currently minimized, MonitorFromWindow uses the rectangle of the window before it was minimized. 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 show state and the restored, minimized, and maximized positions of the specified window. Type: HWND A handle to the window. Read more on docs.microsoft.com. Type: WINDOWPLACEMENT* A pointer to the WINDOWPLACEMENT structure that receives the show state and position information. Before calling GetWindowPlacement, set the length member to sizeof(WINDOWPLACEMENT). GetWindowPlacement fails if lpwndpl-> length is not set correctly. 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 flags member of WINDOWPLACEMENT retrieved by this function is always zero. If the window identified by the hWnd parameter is maximized, the showCmd member is SW_SHOWMAXIMIZED. If the window is minimized, showCmd is SW_SHOWMINIMIZED. Otherwise, it is SW_SHOWNORMAL. The length member of WINDOWPLACEMENT must be set to sizeof(WINDOWPLACEMENT). If this member is not set correctly, the function returns FALSE. For additional remarks on the proper use of window placement coordinates, see WINDOWPLACEMENT. Read more on docs.microsoft.com. Sets the show state and the restored, minimized, and maximized positions of the specified window. Type: HWND A handle to the window. Read more on docs.microsoft.com. Type: const WINDOWPLACEMENT* A pointer to a WINDOWPLACEMENT structure that specifies the new show state and window positions. Before calling SetWindowPlacement, set the length member of the WINDOWPLACEMENT structure to sizeof(WINDOWPLACEMENT). SetWindowPlacement fails if the length member is not set correctly. 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. If the information specified in WINDOWPLACEMENT would result in a window that is completely off the screen, the system will automatically adjust the coordinates so that the window is visible, taking into account changes in screen resolution and multiple monitor configuration. The length member of WINDOWPLACEMENT must be set to sizeof(WINDOWPLACEMENT). If this member is not set correctly, the function returns FALSE. For additional remarks on the proper use of window placement coordinates, see WINDOWPLACEMENT. Read more on docs.microsoft.com. Sets the specified window's show state. Type: HWND A handle to the window. Read more on docs.microsoft.com. Type: int Type: BOOL If the window was previously visible, the return value is nonzero. If the window was previously hidden, the return value is zero. To perform certain special effects when showing or hiding a window, use AnimateWindow. The first time an application calls ShowWindow, it should use the WinMain function's nCmdShow parameter as its nCmdShow parameter. Subsequent calls to ShowWindow must use one of the values in the given list, instead of the one specified by the WinMain function's nCmdShow parameter. As noted in the discussion of the nCmdShow parameter, the nCmdShow value is ignored in the first call to ShowWindow if the program that launched the application specifies startup information in the structure. In this case, ShowWindow uses the information specified in the STARTUPINFO structure to show the window. On subsequent calls, the application must call ShowWindow with nCmdShow set to SW_SHOWDEFAULT to use the startup information provided by the program that launched the application. This behavior is designed for the following situations: This doc was truncated. Read more on docs.microsoft.com. The UpdateWindow function updates the client area of the specified window by sending a WM_PAINT message to the window if the window's update region is not empty. Handle to the window to be updated. If the function succeeds, the return value is nonzero. If the function fails, the return value is zero. Learn more about this API from docs.microsoft.com. Activates a window. The window must be attached to the calling thread's message queue. Type: HWND A handle to the top-level window to be activated. Read more on docs.microsoft.com. Type: HWND If the function succeeds, the return value is the handle to the window that was previously active. If the function fails, the return value is NULL. To get extended error information, call GetLastError. The SetActiveWindow function activates a window, but not if the application is in the background. The window will be brought into the foreground (top of Z-Order) if its application is in the foreground when the system activates the window. If the window identified by the hWnd parameter was created by the calling thread, the active window status of the calling thread is set to hWnd. Otherwise, the active window status of the calling thread is set to NULL. Read more on docs.microsoft.com. Brings the thread that created the specified window into the foreground and activates the window. Type: HWND A handle to the window that should be activated and brought to the foreground. Read more on docs.microsoft.com. Type: BOOL If the window was brought to the foreground, the return value is nonzero. If the window was not brought to the foreground, the return value is zero. The system restricts which processes can set the foreground window. A process can set the foreground window by calling **SetForegroundWindow** 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. It is possible for a process to be denied the right to set the foreground window even if it meets these conditions. An application cannot force a window to the foreground while the user is working with another window. Instead, Windows flashes the taskbar button of the window to notify the user. A process that can set the foreground window can enable another process to set the foreground window by calling the [**AllowSetForegroundWindow**](nf-winuser-allowsetforegroundwindow.md) function. The process specified by the *dwProcessId* parameter to **AllowSetForegroundWindow** 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**. The foreground process can disable calls to SetForegroundWindow by calling the [**LockSetForegroundWindow**](nf-winuser-locksetforegroundwindow.md) function. Read more on docs.microsoft.com. Adds a new entry or changes an existing entry in the property list of the specified window. (Unicode) Type: HWND A handle to the window whose property list receives the new entry. Read more on docs.microsoft.com. Type: LPCTSTR A null-terminated string or an atom that identifies a string. If this parameter is an atom, it must be a global atom created by a previous call to the GlobalAddAtom function. The atom must be placed in the low-order word of lpString; the high-order word must be zero. Read more on docs.microsoft.com. Type: HANDLE A handle to the data to be copied to the property list. The data handle can identify any value useful to the application. Read more on docs.microsoft.com. Type: BOOL If the data handle and string are added to the property list, the return value is nonzero. If the function fails, the return value is zero. To get extended error information, call GetLastError. Before a window is destroyed (that is, before it returns from processing the WM_NCDESTROY message), an application must remove all entries it has added to the property list. The application must use the RemoveProp function to remove the entries. SetProp is subject to the restrictions of User Interface Privilege Isolation (UIPI). A process can only call this function on a window belonging to a process of lesser or equal integrity level. When UIPI blocks property changes, GetLastError will return 5. Read more on docs.microsoft.com. Determines whether the specified window is minimized (iconic). Type: HWND A handle to the window to be tested. Read more on docs.microsoft.com. Type: BOOL If the window is iconic, the return value is nonzero. If the window is not iconic, the return value is zero. Learn more about this API from docs.microsoft.com. 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. Determines whether the specified window handle identifies an existing window. Type: HWND A handle to the window to be tested. Read more on docs.microsoft.com. Type: BOOL If the window handle identifies an existing window, the return value is nonzero. If the window handle does not identify an existing window, the return value is zero. A thread should not use IsWindow for a window that it did not create because the window could be destroyed after this function was called. Further, because window handles are recycled the handle could even point to a different window. Determines the visibility state of the specified window. Type: HWND A handle to the window to be tested. Read more on docs.microsoft.com. Type: BOOL If the specified window, its parent window, its parent's parent window, and so forth, have the WS_VISIBLE style, the return value is nonzero. Otherwise, the return value is zero. Because the return value specifies whether the window has the WS_VISIBLE style, it may be nonzero even if the window is totally obscured by other windows. The visibility state of a window is indicated by the WS_VISIBLE style bit. When WS_VISIBLE is set, the window is displayed and subsequent drawing into it is displayed as long as the window has the WS_VISIBLE style. Any drawing to a window with the WS_VISIBLE style will not be displayed if the window is obscured by other windows or is clipped by its parent window. Read more on docs.microsoft.com. The BeginPaint function prepares the specified window for painting and fills a PAINTSTRUCT structure with information about the painting. Handle to the window to be repainted. Pointer to the PAINTSTRUCT structure that will receive painting information. If the function succeeds, the return value is the handle to a display device context for the specified window. If the function fails, the return value is NULL, indicating that no display device context is available. The BeginPaint function automatically sets the clipping region of the device context to exclude any area outside the update region. The update region is set by the InvalidateRect or InvalidateRgn function and by the system after sizing, moving, creating, scrolling, or any other operation that affects the client area. If the update region is marked for erasing, BeginPaint sends a WM_ERASEBKGND message to the window. An application should not call BeginPaint except in response to a WM_PAINT message. Each call to BeginPaint must have a corresponding call to the EndPaint function. If the caret is in the area to be painted, BeginPaint automatically hides the caret to prevent it from being erased. If the window's class has a background brush, BeginPaint uses that brush to erase the background of the update region before returning.

DPI Virtualization

This API does not participate in DPI virtualization. The output returned is always in terms of physical pixels. Read more on docs.microsoft.com. The EndPaint function marks the end of painting in the specified window. This function is required for each call to the BeginPaint function, but only after painting is complete. Handle to the window that has been repainted. Pointer to a PAINTSTRUCT structure that contains the painting information retrieved by BeginPaint. The return value is always nonzero. If the caret was hidden by BeginPaint, EndPaint restores the caret to the screen. EndPaint releases the display device context that BeginPaint retrieved. Read more on docs.microsoft.com. Retrieves the coordinates of a window's client area. Type: HWND A handle to the window whose client coordinates are to be retrieved. Read more on docs.microsoft.com. Type: LPRECT A pointer to a RECT structure that receives the client coordinates. The left and top members are zero. The right and bottom members contain the width and height of the 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. To get extended error information, call GetLastError. In conformance with conventions for the RECT structure, the bottom-right coordinates of the returned rectangle are exclusive. In other words, the pixel at (right, bottom) lies immediately outside the rectangle. Dispatches incoming nonqueued messages, checks the thread message queue for a posted message, and retrieves the message (if any exist). (Unicode) Type: LPMSG A pointer to an MSG structure that receives message information. Read more on docs.microsoft.com. Type: HWND A handle to the window whose messages are to be retrieved. The window must belong to the current thread. If hWnd is NULL, PeekMessage retrieves messages for any window that belongs to the current thread, and any messages on the current thread's message queue whose hwnd value is NULL (see the MSG structure). Therefore if hWnd is NULL, both window messages and thread messages are processed. If hWnd is -1, PeekMessage retrieves only messages on the current thread's message queue whose hwnd value is NULL, that is, thread messages as posted by PostMessage (when the hWnd parameter is NULL) or PostThreadMessage. Read more on docs.microsoft.com. Type: UINT The value of the first message in the range of messages to be examined. Use WM_KEYFIRST (0x0100) to specify the first keyboard message or WM_MOUSEFIRST (0x0200) to specify the first mouse message. If wMsgFilterMin and wMsgFilterMax are both zero, PeekMessage returns all available messages (that is, no range filtering is performed). Read more on docs.microsoft.com. Type: UINT The value of the last message in the range of messages to be examined. Use WM_KEYLAST to specify the last keyboard message or WM_MOUSELAST to specify the last mouse message. If wMsgFilterMin and wMsgFilterMax are both zero, PeekMessage returns all available messages (that is, no range filtering is performed). Read more on docs.microsoft.com. Type: UINT Type: BOOL If a message is available, the return value is nonzero. If no messages are available, the return value is zero. PeekMessage retrieves messages associated with the window identified by the hWnd parameter or any of its children as specified by the IsChild function, and within the range of message values given by the wMsgFilterMin and wMsgFilterMax parameters. Note that an application can only use the low word in the wMsgFilterMin and wMsgFilterMax parameters; the high word is reserved for the system. Note that PeekMessage always retrieves WM_QUIT messages, no matter which values you specify for wMsgFilterMin and wMsgFilterMax. During this call, the system dispatches (DispatchMessage) pending, nonqueued messages, that is, messages sent to windows owned by the calling thread using the SendMessage, SendMessageCallback, SendMessageTimeout, or SendNotifyMessage function. Then the first queued message that matches the specified filter is retrieved. The system may also process internal events. If no filter is specified, messages are processed in the following order: This doc was truncated. 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. Translates virtual-key messages into character messages. The character messages are posted to the calling thread's message queue, to be read the next time the thread calls the GetMessage or PeekMessage function. Type: const MSG* A pointer to an MSG structure that contains message information retrieved from the calling thread's message queue by using the GetMessage or PeekMessage function. Read more on docs.microsoft.com. Type: BOOL If the message is translated (that is, a character message is posted to the thread's message queue), the return value is nonzero. If the message is WM_KEYDOWN, WM_KEYUP, WM_SYSKEYDOWN, or WM_SYSKEYUP, the return value is nonzero, regardless of the translation. If the message is not translated (that is, a character message is not posted to the thread's message queue), the return value is zero. The TranslateMessage function does not modify the message pointed to by the lpMsg parameter. WM_KEYDOWN and WM_KEYUP combinations produce a WM_CHAR or WM_DEADCHAR message. WM_SYSKEYDOWN and WM_SYSKEYUP combinations produce a WM_SYSCHAR or WM_SYSDEADCHAR message. TranslateMessage produces WM_CHAR messages only for keys that are mapped to ASCII characters by the keyboard driver. If applications process virtual-key messages for some other purpose, they should not call TranslateMessage. For instance, an application should not call TranslateMessage if the TranslateAccelerator function returns a nonzero value. Note that the application is responsible for retrieving and dispatching input messages to the dialog box. Most applications use the main message loop for this. However, to permit the user to move to and to select controls by using the keyboard, the application must call IsDialogMessage. For more information, see Dialog Box Keyboard Interface. Read more on docs.microsoft.com. Dispatches a message to a window procedure. It is typically used to dispatch a message retrieved by the GetMessage function. (DispatchMessageW) Type: const MSG* A pointer to a structure that contains the message. Read more on docs.microsoft.com. Type: LRESULT The return value specifies the value returned by the window procedure. Although its meaning depends on the message being dispatched, the return value generally is ignored. The MSG structure must contain valid message values. If the lpmsg parameter points to a WM_TIMER message and the lParam parameter of the WM_TIMER message is not NULL, lParam points to a function that is called instead of the window procedure. Note that the application is responsible for retrieving and dispatching input messages to the dialog box. Most applications use the main message loop for this. However, to permit the user to move to and to select controls by using the keyboard, the application must call IsDialogMessage. For more information, see Dialog Box Keyboard Interface. Read more on docs.microsoft.com. Describes a pointer. Learn more about this API from docs.microsoft.com. Pointer to a function. Pointer to a variable, constant, or data member. The ITypeComp that binds the pointer. The BLOB structure (nspapi.h), which is derived from Binary Large Object, contains information about a block of data. The structure name BLOB comes from the acronym BLOB, which stands for Binary Large Object. This structure does not describe the nature of the data pointed to by pBlobData.
Note  Windows Sockets defines a similar BLOB structure in Wtypes.h. Using both header files in the same source code file creates redefinition–compile time errors.
 
 Read more on docs.microsoft.com. Size of the block of data pointed to by pBlobData, in bytes. Pointer to a block of data. Retrieves a specified number of STATSTG structures, that follow in the enumeration sequence. The number of STATSTG structures requested. An array of STATSTG structures returned. The number of STATSTG structures retrieved in the rgelt parameter. This method supports the following return values: This doc was truncated. Learn more about this API from docs.microsoft.com. Skips a specified number of STATSTG structures in the enumeration sequence. The number of STATSTG structures to skip. This method supports the following return values: | Return code | Description | |----------------|---------------| | S_OK | The specified number of **STATSTG** structures that were successfully skipped. | | S_FALSE | The number of **STATSTG** structures skipped is less than the *celt* parameter. | Learn more about this API from docs.microsoft.com. Resets the enumeration sequence to the beginning of the STATSTG structure array. This method supports the S_OK return value. This doc was truncated. Learn more about this API from docs.microsoft.com. Creates a new enumerator that contains the same enumeration state as the current STATSTG structure enumerator. A pointer to the variable that receives the IEnumSTATSTG interface pointer. If the method is unsuccessful, the value of the ppenum parameter is undefined. Read more on docs.microsoft.com. This method supports the following return values. This doc was truncated. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {0000000d-0000-0000-c000-000000000046} The IID guid for this interface. {22f55882-280b-11d0-a8a9-00a0c90c2004} Creates and opens a stream object with the specified name contained in this storage object. A pointer to a wide character null-terminated Unicode string that contains the name of the newly created stream. The name can be used later to open or reopen the stream. The name must not exceed 31 characters in length, not including the string terminator. The 000 through 01f characters, serving as the first character of the stream/storage name, are reserved for use by OLE. This is a compound file restriction, not a structured storage restriction. Specifies the access mode to use when opening the newly created stream. For more information and descriptions of the possible values, see STGM Constants. Reserved for future use; must be zero. Reserved for future use; must be zero. On return, pointer to the location of the new IStream interface pointer. This is only valid if the operation is successful. When an error occurs, this parameter is set to NULL. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The new stream was successfully created.| |E_PENDING | Asynchronous Storage only: Part or all of the necessary data is currently unavailable. | |STG_E_ACCESSDENIED | Not enough permissions to create stream.| |STG_E_FILEALREADYEXISTS | The name specified for the stream already exists in the storage object and the *grfMode* parameter includes the value STGM_FAILIFTHERE.| |STG_E_INSUFFICIENTMEMORY | The stream was not created due to a lack of memory.| |STG_E_INVALIDFLAG | The value specified for the *grfMode* parameter is not a valid **STGM** constants value.| |STG_E_INVALIDFUNCTION | The specified combination of flags in the *grfMode* parameter is not supported; for example, when this method is called without the STGM_SHARE_EXCLUSIVE flag.| |STG_E_INVALIDNAME | Invalid value for *pwcsName*.| |STG_E_INVALIDPOINTER | The pointer specified for the stream object was invalid.| |STG_E_INVALIDPARAMETER | One of the parameters was invalid.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| |STG_E_TOOMANYOPENFILES | The stream was not created because there are too many open files.| If a stream with the name specified in the pwcsName parameter already exists and the grfMode parameter includes the STGM_CREATE flag, the existing stream is replaced by a newly created one. Both the destruction of the old stream and the creation of the new stream object are subject to the transaction mode on the parent storage object. The COM-provided compound file implementation of the IStorage::CreateStream method does not support the following behaviors: This doc was truncated. Read more on docs.microsoft.com. Opens an existing stream object within this storage object in the specified access mode. A pointer to a wide character null-terminated Unicode string that contains the name of the stream to open. The 000 through 01f characters, serving as the first character of the stream/storage name, are reserved for use by OLE. This is a compound file restriction, not a structured storage restriction. Reserved for future use; must be NULL. Specifies the access mode to be assigned to the open stream. For more information and descriptions of possible values, see STGM Constants. Other modes you choose must at least specify STGM_SHARE_EXCLUSIVE when calling this method in the compound file implementation. Reserved for future use; must be zero. A pointer to IStream pointer variable that receives the interface pointer to the newly opened stream object. If an error occurs, *ppstm must be set to NULL. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The stream was successfully opened.| |E_PENDING | Asynchronous Storage only: Part or all of the stream data is currently unavailable. | |STG_E_ACCESSDENIED | Not enough permissions to open stream.| |STG_E_FILENOTFOUND | The stream with specified name does not exist.| |STG_E_INSUFFICIENTMEMORY | The stream was not opened due to a lack of memory.| |STG_E_INVALIDFLAG | The value specified for the *grfMode* parameter is not a valid **STGM** constants value.| |STG_E_INVALIDFUNCTION | The specified combination of flags in the *grfMode* parameter is not supported; for example, when this method is called without the STGM_SHARE_EXCLUSIVE flag.| |STG_E_INVALIDNAME | Invalid value for *pwcsName*.| |STG_E_INVALIDPOINTER | The pointer specified for the stream object was not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| |STG_E_TOOMANYOPENFILES | The stream was not opened because there are too many open files.| IStorage::OpenStream opens an existing stream object within this storage object in the access mode specified in grfMode. There are restrictions on the permissions that can be given in grfMode. For example, the permissions on this storage object restrict the permissions on its streams. In general, access restrictions on streams need to be stricter than those on their parent storages. Compound-file streams must be opened with STGM_SHARE_EXCLUSIVE. Opens an existing storage object with the specified name in the specified access mode. A pointer to a wide character null-terminated Unicode string that contains the name of the storage object to open. The 000 through 01f characters, serving as the first character of the stream/storage name, are reserved for use by OLE. This is a compound file restriction, not a structured storage restriction. It is ignored if pstgPriority is non-NULL. Must be NULL. A non-NULL value will return STG_E_INVALIDPARAMETER. Specifies the access mode to use when opening the storage object. For descriptions of the possible values, see STGM Constants. Other modes you choose must at least specify STGM_SHARE_EXCLUSIVE when calling this method. Must be NULL. A non-NULL value will return STG_E_INVALIDPARAMETER. Reserved for future use; must be zero. When successful, pointer to the location of an IStorage pointer to the opened storage object. This parameter is set to NULL if an error occurs. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The storage object was opened successfully.| |E_PENDING | Asynchronous Storage only: Part or all of the storage's data is currently unavailable. | |STG_E_ACCESSDENIED | Not enough permissions to open storage object.| |STG_E_FILENOTFOUND | The storage object with the specified name does not exist.| |STG_E_INSUFFICIENTMEMORY | The storage object was not opened due to a lack of memory.| |STG_E_INVALIDFLAG | The value specified for the *grfMode* parameter is not a valid **STGM** constants value.| |STG_E_INVALIDFUNCTION | The specified combination of flags in the *grfMode* parameter is not supported.| |STG_E_INVALIDNAME | Not a valid value for *pwcsName*.| |STG_E_INVALIDPOINTER | The pointer specified for the storage object was not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| |STG_E_TOOMANYOPENFILES | The storage object was not created because there are too many open files.| |STG_S_CONVERTED | The existing stream with the specified name was replaced with a new storage object containing a single stream called CONTENTS. In direct mode, the new storage is immediately written to disk. In transacted mode, the new storage is written to a temporary storage in memory and later written to disk when it is committed.| If the pstgPriority parameter is NULL, it is ignored. If the pstgPriority parameter is not NULL, it is an IStorage pointer to a previous opening of an element of the storage object, usually one that was opened in priority mode. The storage object should be closed and reopened according to grfMode. When the IStorage::OpenStorage method returns, pstgPriority is no longer valid. Use the value supplied in the ppstg parameter. Storage objects can be opened with STGM_DELETEONRELEASE, in which case the object is destroyed when it receives its final release. This is useful for creating temporary storage objects. Read more on docs.microsoft.com. Copies the entire contents of an open storage object to another storage object. The number of elements in the array pointed to by rgiidExclude. If rgiidExclude is NULL, then ciidExclude is ignored. An array of interface identifiers (IIDs) that either the caller knows about and does not want copied or that the storage object does not support, but whose state the caller will later explicitly copy. The array can include IStorage, indicating that only stream objects are to be copied, and IStream, indicating that only storage objects are to be copied. An array length of zero indicates that only the state exposed by the IStorage object is to be copied; all other interfaces on the object are to be ignored. Passing NULL indicates that all interfaces on the object are to be copied. Read more on docs.microsoft.com. A string name block (refer to SNB) that specifies a block of storage or stream objects that are not to be copied to the destination. These elements are not created at the destination. If IID_IStorage is in the rgiidExclude array, this parameter is ignored. This parameter may be NULL. Read more on docs.microsoft.com. A pointer to the open storage object into which this storage object is to be copied. The destination storage object can be a different implementation of the IStorage interface from the source storage object. Thus, IStorage::CopyTo can use only publicly available methods of the destination storage object. If pstgDest is open in transacted mode, it can be reverted by calling its IStorage::Revert method. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The storage object was successfully copied.| |E_PENDING | Asynchronous Storage only: Part or all of the data to be copied is currently unavailable. | |STG_E_ACCESSDENIED | The destination storage object is a child of the source storage object.| |STG_E_INSUFFICIENTMEMORY | The copy was not completed due to a lack of memory.| |STG_E_INVALIDPOINTER | The pointer specified for the storage object was not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| |STG_E_TOOMANYOPENFILES | The copy was not completed because there are too many open files.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| |STG_E_MEDIUMFULL | The copy was not completed because the storage medium is full.| This method merges elements contained in the source storage object with those already present in the destination. The layout of the destination storage object may differ from the source storage object. The copy process is recursive, invoking IStorage::CopyTo and IStream::CopyTo on the elements nested inside the source. When copying a stream on top of an existing stream with the same name, the existing stream is first removed and then replaced with the source stream. When copying a storage on top of an existing storage with the same name, the existing storage is not removed. As a result, after the copy operation, the destination IStorage contains older elements, unless they were replaced by newer ones with the same names. A storage object may expose interfaces other than IStorage, including IRootStorage, IPropertyStorage, or IPropertySetStorage. The rgiidExclude parameter permits the exclusion of any or all of these additional interfaces from the copy operation. A caller with a newer or more efficient copy of an existing substorage or stream object may want to exclude the current versions of these objects from the copy operation. The snbExclude and rgiidExclude parameters provide two ways of excluding a storage objects existing storages or streams.

Note to Callers

The most common way to use the IStorage::CopyTo method is to copy everything from the source to the destination, as in most full-save and save-as operations. The following example code shows how to copy everything from the source storage object to the destination storage object. This doc was truncated. Read more on docs.microsoft.com. The MoveElementTo method copies or moves a substorage or stream from this storage object to another storage object. Pointer to a wide character null-terminated Unicode string that contains the name of the element in this storage object to be moved or copied. IStorage pointer to the destination storage object. Pointer to a wide character null-terminated unicode string that contains the new name for the element in its new storage object. Specifies whether the operation should be a move (STGMOVE_MOVE) or a copy (STGMOVE_COPY). See the STGMOVE enumeration. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The storage object was successfully copied or moved.| |E_PENDING | Asynchronous Storage only: Part or all of the element's data is currently unavailable. | |STG_E_ACCESSDENIED | The destination storage object is a child of the source storage object. Or, the destination object and element name are the same as the source object and element name. In other words, you cannot move an element to itself.| |STG_E_FILENOTFOUND | The element with the specified name does not exist.| |STG_E_FILEALREADYEXISTS | The specified file already exists.| |STG_E_INSUFFICIENTMEMORY | The copy or move was not completed due to a lack of memory.| |STG_E_INVALIDFLAG | The value for the *grfFlags* parameter is not valid.| |STG_E_INVALIDNAME | Not a valid value for *pwcsName*.| |STG_E_INVALIDPOINTER | The pointer specified for the storage object was not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| |STG_E_TOOMANYOPENFILES | The copy or move was not completed because there are too many open files.| The IStorage::MoveElementTo method is typically the same as invoking the IStorage::CopyTo method on the indicated element and then removing the source element. In this case, the MoveElementTo method uses only the publicly available functions of the destination storage object to carry out the move. If the source and destination storage objects have special knowledge about each other's implementation (they could, for example, be different instances of the same implementation), this method can be implemented more efficiently. Before calling this method, the element to be moved must be closed, and the destination storage must be open. Also, the destination object and element cannot be the same storage object/element name as the source of the move. That is, you cannot move an element to itself. Read more on docs.microsoft.com. The Commit method ensures that any changes made to a storage object open in transacted mode are reflected in the parent storage. Controls how the changes are committed to the storage object. See the STGC enumeration for a definition of these values. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | Changes to the storage object were successfully committed to the parent level. If STGC_CONSOLIDATE was specified, the storage was successfully consolidated, or the storage was already too compact to consolidate further.| |STG_S_MULTIPLEOPENS | The commit operation succeeded, but the storage could not be consolidated because it had been opened multiple times using the STGM_NOSNAPSHOT flag.| |STG_S_CANNOTCONSOLIDATE | The commit operation succeeded, but the storage could not be consolidated due to an incorrect storage mode. For compound files, the storage may have been opened using the STGM_NOSCRATCH flag, or the storage may not be the outermost transacted level.| |STG_S_CONSOLIDATIONFAILED | The commit operation succeeded, but the storage could not be consolidated due to an internal error (for example, a memory allocation failure).| |E_PENDING | Asynchronous storage only: Part or all of the data to be committed is currently unavailable.| |STG_E_INVALIDFLAG | The value for the *grfCommitFlags* parameter is not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| |STG_E_NOTCURRENT | Another open instance of the storage object has committed changes. As a result, the current commit operation may overwrite previous changes.| |STG_E_MEDIUMFULL | No space left on device to commit.| |STG_E_TOOMANYOPENFILES | The commit operation could not be completed because there are too many open files.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| IStorage::Commit makes permanent changes to a storage object that is in transacted mode, in which changes are accumulated in a buffer, and not reflected in the storage object until there is a call to this method. The alternative is to open an object in direct mode, in which changes are immediately reflected in the storage object. An object opened in the direct mode does not require calling IStorage::Commit to make permanent changes in the storage object. Calling the IStorage::Commit method on a nonroot storage opened in direct mode has no effect. Opening a root storage object in direct mode ensures that changes in memory buffers are written to the underlying storage device. The commit operation publishes the current changes in this storage object and its children to the next level up in the storage hierarchy. To undo current changes before committing them, call IStorage::Revert to roll back to the last-committed version. Calling IStorage::Commit has no effect on currently opened nested elements of this storage object. They remain valid and can be used. However, the IStorage::Commit method does not automatically commit changes to these nested elements. The commit operation publishes only known changes to the next higher level in the storage hierarchy. Thus, transactions to nested levels must be committed to this storage object before they can be committed to higher levels. In commit operations, you need to take steps to ensure that data is protected during the commit process: This doc was truncated. Read more on docs.microsoft.com. The Revert method discards all changes that have been made to the storage object since the last commit operation. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The revert operation was successful.| |E_PENDING | Asynchronous Storage only: Part or all of the storage's data is currently unavailable. | |STG_E_INSUFFICIENTMEMORY | The revert operation could not be completed due to a lack of memory.| |STG_E_TOOMANYOPENFILES | The revert operation could not be completed because there are too many open files.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| For storage objects opened in transacted mode, the IStorage::Revert method discards any uncommitted changes to this storage object or changes that have been committed to this storage object from nested elements. After this method returns, any existing elements (substorages or streams) that were opened from the reverted storage object are invalid and can no longer be used. Specifying these reverted elements in any call except IUnknown::Release returns the error STG_E_REVERTED This method has no effect on storage objects opened in direct mode. Read more on docs.microsoft.com. The EnumElements method retrieves a pointer to an enumerator object that can be used to enumerate the storage and stream objects contained within this storage object. Reserved for future use; must be zero. Reserved for future use; must be NULL. Reserved for future use; must be zero. Pointer to IEnumSTATSTG* pointer variable that receives the interface pointer to the new enumerator object. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The enumerator object was successfully returned.| |E_PENDING | Asynchronous Storage only: Part or all of the element's data is currently unavailable.| |STG_E_INSUFFICIENTMEMORY | The enumerator object could not be created due to lack of memory.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| The enumerator object returned by this method implements the IEnumSTATSTG interface, one of the standard enumerator interfaces that contain the Next, Reset, Clone, and Skip methods. IEnumSTATSTG enumerates the data stored in an array of STATSTG structures. The storage object must be open in read mode to allow the enumeration of its elements. The enumerator object is permitted to enumerate the elements in any order. The enumerator object is also permitted to treat the enumeration as a snapshot or to have the enumeration reflect the current state of the storage object. Read more on docs.microsoft.com. The RenameElement method renames the specified substorage or stream in this storage object. Pointer to a wide character null-terminated Unicode string that contains the name of the substorage or stream to be changed.
Note  The pwcsName, created in CreateStorage or CreateStream must not exceed 31 characters in length, not including the string terminator.
 
 Read more on docs.microsoft.com. Pointer to a wide character null-terminated unicode string that contains the new name for the specified substorage or stream.
Note  The pwcsName, created in CreateStorage or CreateStream must not exceed 31 characters in length, not including the string terminator.
 
 Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The element was successfully renamed.| |E_PENDING | Asynchronous Storage only: Part or all of the element's data is currently unavailable.| |STG_E_ACCESSDENIED | The caller does not have enough permissions for renaming the element.| |STG_E_FILENOTFOUND | The element with the specified old name does not exist.| |STG_E_FILEALREADYEXISTS | The element specified by the new name already exists.| |STG_E_INSUFFICIENTMEMORY | The element was not renamed due to a lack of memory.| |STG_E_INVALIDNAME | Invalid value for one of the names.| |STG_E_INVALIDPOINTER | The pointer specified for the element was not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| |STG_E_TOOMANYOPENFILES | The element was not renamed because there are too many open files.| IStorage::RenameElement renames the specified substorage or stream in this storage object. An element in a storage object cannot be renamed while it is open. The rename operation is subject to committing the changes if the storage is open in transacted mode. The IStorage::RenameElement method is not guaranteed to work in low memory with storage objects open in transacted mode. It may work in direct mode. Read more on docs.microsoft.com. The SetElementTimes method sets the modification, access, and creation times of the specified storage element, if the underlying file system supports this method. The name of the storage object element whose times are to be modified. If NULL, the time is set on the root storage rather than one of its elements. Either the new creation time for the element or NULL if the creation time is not to be modified. Either the new access time for the element or NULL if the access time is not to be modified. Either the new modification time for the element or NULL if the modification time is not to be modified. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The time values were successfully set.| |E_PENDING | Asynchronous Storage only: Part or all of the element's data is currently unavailable.| |STG_E_ACCESSDENIED | The caller does not have enough permissions for changing the element.| |STG_E_FILENOTFOUND | The element with the specified name does not exist.| |STG_E_INSUFFICIENTMEMORY | The element was not changed due to a lack of memory.| |STG_E_INVALIDNAME | Not a valid value for the element name.| |STG_E_INVALIDPOINTER | The pointer specified for the element was not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| |STG_E_TOOMANYOPENFILES | The element was not changed because there are too many open files.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| SetElementTimes sets time statistics for the specified storage element within this storage object. Not all file systems support all the time values. This method sets those times that are supported and ignores the rest. Each time-value parameter can be NULL; indicating that no modification should occur. Call the IStorage::Stat method to retrieve these time values. Read more on docs.microsoft.com. The SetClass method assigns the specified class identifier (CLSID) to this storage object. The CLSID that is to be associated with the storage object. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The CLSID was successfully assigned.| |E_PENDING | Asynchronous Storage only: Part or all of the storage's data is currently unavailable.| |STG_E_ACCESSDENIED | The caller does not have enough permissions for assigning a CLSID to the storage object.| |STG_E_MEDIUMFULL | Not enough space was left on device to complete the operation.| |STG_E_REVERTED | The storage object has been invalidated by a revert operation above it in the transaction tree.| When first created, a storage object has an associated CLSID of CLSID_NULL. Call SetClass to assign a CLSID to the storage object. Call the IStorage::Stat method to retrieve the current CLSID of a storage object. Read more on docs.microsoft.com. The SetStateBits method stores up to 32 bits of state information in this storage object. Specifies the new values of the bits to set. No legal values are defined for these bits; they are all reserved for future use and must not be used by applications. A binary mask indicating which bits in grfStateBits are significant in this call. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The state information was successfully set.| |E_PENDING | Asynchronous Storage only: Part or all of the storage's data is currently unavailable. | |STG_E_ACCESSDENIED | The caller does not have enough permissions for changing this storage object.| |STG_E_INVALIDFLAG | The value for the grfStateBits or *grfMask* parameter is not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| The values for the state bits are not currently defined. The Stat method retrieves the STATSTG structure for this open storage object. On return, pointer to a STATSTG structure where this method places information about the open storage object. This parameter is NULL if an error occurs. Read more on docs.microsoft.com. Specifies that some of the members in the STATSTG structure are not returned, thus saving a memory allocation operation. Values are taken from the STATFLAG enumeration. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The STATSTG structure was successfully returned at the specified location.| |E_PENDING | Asynchronous Storage only: Part or all of the storage's data is currently unavailable.| |STG_E_ACCESSDENIED | The caller does not have enough permissions for accessing statistics for this storage object.| |STG_E_INSUFFICIENTMEMORY | The STATSTG structure was not returned due to a lack of memory.| |STG_E_INVALIDFLAG | The value for the *grfStateFlag* parameter is not valid.| |STG_E_INVALIDPARAMETER | One of the parameters was not valid.| IStorage::Stat retrieves the STATSTG structure for the current storage object. The STATSTG structure contains statistical information about the storage object. IStorage::EnumElements returns a pointer to an enumerator object. The enumerator object returned by this method implements the IEnumSTATSTG interface, through which the data stored in the array of the STATSTG structures is enumerated. Read more on docs.microsoft.com. The IID guid for this interface. {0000000b-0000-0000-c000-000000000046} The PROPVARIANT structure is used in the ReadMultiple and WriteMultiple methods of IPropertyStorage to define the type tag and the value of a property in a property set. The PROPVARIANT structure can also hold a value of VT_DECIMAL: This doc was truncated. Read more on docs.microsoft.com. Identifies the calling convention used by a member function described in the METHODDATA structure. Learn more about this API from docs.microsoft.com. Values that are used in activation calls to indicate the execution contexts in which an object is to be run. Values from the CLSCTX enumeration are used in activation calls (CoCreateInstance, CoCreateInstanceEx, CoGetClassObject, and so on) to indicate the preferred execution contexts (in-process, local, or remote) in which an object is to be run. They are also used in calls to CoRegisterClassObject to indicate the set of execution contexts in which a class object is to be made available for requests to construct instances (IClassFactory::CreateInstance). To indicate that more than one context is acceptable, you can combine multiple values with Boolean ORs. The contexts are tried in the order in which they are listed. Given a set of CLSCTX flags, the execution context to be used depends on the availability of registered class codes and other parameters according to the following algorithm. This doc was truncated. Read more on docs.microsoft.com. The code that creates and manages objects of this class is a DLL that runs in the same process as the caller of the function specifying the class context. The code that manages objects of this class is an in-process handler. This is a DLL that runs in the client process and implements client-side structures of this class when instances of the class are accessed remotely. The EXE code that creates and manages objects of this class runs on same machine but is loaded in a separate process space. Obsolete. A remote context. The LocalServer32 or LocalService code that creates and manages objects of this class is run on a different computer. Obsolete. Reserved. Reserved. Reserved. Reserved. Disables the downloading of code from the directory service or the Internet. This flag cannot be set at the same time as CLSCTX_ENABLE_CODE_DOWNLOAD. Reserved. Specify if you want the activation to fail if it uses custom marshalling. Enables the downloading of code from the directory service or the Internet. This flag cannot be set at the same time as CLSCTX_NO_CODE_DOWNLOAD. The CLSCTX_NO_FAILURE_LOG can be used to override the logging of failures in CoCreateInstanceEx. If the ActivationFailureLoggingLevel is created, the following values can determine the status of event logging: This doc was truncated. Read more on docs.microsoft.com. Disables activate-as-activator (AAA) activations for this activation only. This flag overrides the setting of the EOAC_DISABLE_AAA flag from the EOLE_AUTHENTICATION_CAPABILITIES enumeration. This flag cannot be set at the same time as CLSCTX_ENABLE_AAA. Any activation where a server process would be launched under the caller's identity is known as an activate-as-activator (AAA) activation. Disabling AAA activations allows an application that runs under a privileged account (such as LocalSystem) to help prevent its identity from being used to launch untrusted components. Library applications that use activation calls should always set this flag during those calls. This helps prevent the library application from being used in an escalation-of-privilege security attack. This is the only way to disable AAA activations in a library application because the EOAC_DISABLE_AAA flag from the EOLE_AUTHENTICATION_CAPABILITIES enumeration is applied only to the server process and not to the library application. Windows 2000:  This flag is not supported. Read more on docs.microsoft.com. Enables activate-as-activator (AAA) activations for this activation only. This flag overrides the setting of the EOAC_DISABLE_AAA flag from the EOLE_AUTHENTICATION_CAPABILITIES enumeration. This flag cannot be set at the same time as CLSCTX_DISABLE_AAA. Any activation where a server process would be launched under the caller's identity is known as an activate-as-activator (AAA) activation. Enabling this flag allows an application to transfer its identity to an activated component. Windows 2000:  This flag is not supported. Read more on docs.microsoft.com. Begin this activation from the default context of the current apartment. Activate or connect to a 32-bit version of the server; fail if one is not registered. Activate or connect to a 64 bit version of the server; fail if one is not registered. When this flag is specified, COM uses the impersonation token of the thread, if one is present, for the activation request made by the thread. When this flag is not specified or if the thread does not have an impersonation token, COM uses the process token of the thread's process for the activation request made by the thread. Windows Vista or later:  This flag is supported. Read more on docs.microsoft.com. Indicates activation is for an app container.
Note  This flag is reserved for internal use and is not intended to be used directly from your code.
 
 Read more on docs.microsoft.com. Specify this flag for Interactive User activation behavior for As-Activator servers. A strongly named Medium IL Windows Store app can use this flag to launch an "As Activator" COM server without a strong name. Also, you can use this flag to bind to a running instance of the COM server that's launched by a desktop application. The client must be Medium IL, it must be strongly named, which means that it has a SysAppID in the client token, it can't be in session 0, and it must have the same user as the session ID's user in the client token. If the server is out-of-process and "As Activator", it launches the server with the token of the client token's session user. This token won't be strongly named. If the server is out-of-process and RunAs "Interactive User", this flag has no effect. If the server is out-of-process and is any other RunAs type, the activation fails. This flag has no effect for in-process servers. Off-machine activations fail when they use this flag. Read more on docs.microsoft.com. Used for loading Proxy/Stub DLLs.
Note  This flag is reserved for internal use and is not intended to be used directly from your code.
 
 Read more on docs.microsoft.com. The CY structure is useful for calculations involving money, or for any fixed-point calculation where accuracy is particularly important. Identifies the type description being bound to. Learn more about this API from docs.microsoft.com. No match was found. A FUNCDESC was returned. A VARDESC was returned. A TYPECOMP was returned. An IMPLICITAPPOBJ was returned. The end of the enum. Contains the arguments passed to a method or property. Learn more about this API from docs.microsoft.com. An array of arguments. **Note**: these arguments appear in reverse order Read more on docs.microsoft.com. The dispatch IDs of the named arguments. The number of arguments. The number of named arguments. The ELEMDESC structure contains the type description and process-transfer information for a variable, a function, or a function parameter. (ELEMDESC) The type of the element. Describes an exception that occurred during IDispatch::Invoke. Use the pfnDeferredFillIn field to enable an object to defer filling in the bstrDescription, bstrHelpFile, and dwHelpContext fields until they are needed. This field might be used, for example, if loading the string for the error is a time-consuming operation. To use deferred fill-in, the object puts a function pointer in this slot and does not fill any of the other fields except wCode, which is required. To get additional information, the caller passes the EXCEPINFO structure back to the pexcepinfo callback function, which fills in the additional information. When the ActiveX object and the ActiveX client are in different processes, the ActiveX object calls pfnDeferredFillIn before returning to the controller. Read more on docs.microsoft.com. The error code. Error codes should be greater than 1000. Either this field or the scode field must be filled in; the other must be set to 0. Reserved. Should be 0. The name of the exception source. Typically, this is an application name. This field should be filled in by the implementer of IDispatch. The exception description to display. If no description is available, use null. The fully qualified help file path. If no Help is available, use null. The help context ID. Reserved. Must be null. Provides deferred fill-in. If deferred fill-in is not desired, this field should be set to null. A return value that describes the error. Either this field or wCode (but not both) must be filled in; the other must be set to 0. (16-bit Windows versions only.) Describes a function. (FUNCDESC) The cParams field specifies the total number of required and optional parameters. The cParamsOpt field specifies the form of optional parameters accepted by the function, as follows: This doc was truncated. Read more on docs.microsoft.com. The function member ID. The status code. Description of the element. Indicates the type of function (virtual, static, or dispatch-only). The invocation type. Indicates whether this is a property function, and if so, which type. The calling convention. The total number of parameters. The number of optional parameters. For FUNC_VIRTUAL, specifies the offset in the VTBL. The number of possible return values. The function return type. The function flags. See FUNCFLAGS. Specifies function flags. FUNCFLAG_FHIDDEN means that the property should never be shown in object browsers, property browsers, and so on. This function is useful for removing items from an object model. Code can bind to the member, but the user will never know that the member exists. FUNCFLAG_FNONBROWSABLE means that the property should not be displayed in a properties browser. It is used in circumstances in which an error would occur if the property were shown in a properties browser. FUNCFLAG_FRESRICTED means that macro-oriented programmers should not be allowed to access this member. These members are usually treated as _FHIDDEN by tools such as Visual Basic, with the main difference being that code cannot bind to those members. Read more on docs.microsoft.com. The function should not be accessible from macro languages. This flag is intended for system-level functions or functions that type browsers should not display. The function returns an object that is a source of events. The function that supports data binding. When set, any call to a method that sets the property results first in a call to IPropertyNotifySink::OnRequestEdit. The implementation of OnRequestEdit determines if the call is allowed to set the property. The function that is displayed to the user as bindable. FUNC_FBINDABLE must also be set. The function that best represents the object. Only one function in a type information can have this attribute. The function should not be displayed to the user, although it exists and is bindable. The function supports GetLastError. If an error occurs during the function, the caller can call GetLastError to retrieve the error code. Permits an optimization in which the compiler looks for a member named xyz on the type of abc. If such a member is found and is flagged as an accessor function for an element of the default collection, then a call is generated to that member function. Permitted on members in dispinterfaces and interfaces; not permitted on modules. For more information, refer to defaultcollelem in Type Libraries and the Object Description Language. The type information member is the default member for display in the user interface. The property appears in an object browser, but not in a properties browser. Tags the interface as having default behaviors. Mapped as individual bindable properties. Specifies the function type. Learn more about this API from docs.microsoft.com. The function is accessed the same as PUREVIRTUAL, except the function has an implementation. The function is accessed through the virtual function table (VTBL), and takes an implicit this pointer. The function is accessed by static address and takes an implicit this pointer. The function is accessed by static address and does not take an implicit this pointer. The function can be accessed only through IDispatch. Retrieves the number of type information interfaces that an object provides (either 0 or 1). The number of type information interfaces provided by the object. If the object provides type information, this number is 1; otherwise the number is 0. This method can return one of these values. This doc was truncated. The method may return zero, which indicates that the object does not provide any type information. In this case, the object may still be programmable through IDispatch or a VTBL, but does not provide run-time type information for browsers, compilers, or other programming tools that access type information. This can be useful for hiding an object from browsers. Retrieves the type information for an object, which can then be used to get the type information for an interface. The type information to return. Pass 0 to retrieve type information for the IDispatch implementation. The locale identifier for the type information. An object may be able to return different type information for different languages. This is important for classes that support localized member names. For classes that do not support localized member names, this parameter can be ignored. The requested type information object. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Maps a single member and an optional set of argument names to a corresponding set of integer DISPIDs, which can be used on subsequent calls to Invoke. Reserved for future use. Must be IID_NULL. The array of names to be mapped. The count of the names to be mapped. The locale context in which to interpret the names. Caller-allocated array, each element of which contains an identifier (ID) corresponding to one of the names passed in the rgszNames array. The first element represents the member name. The subsequent elements represent each of the member's parameters. This method can return one of these values. This doc was truncated. An IDispatch implementation can associate any positive integer ID value with a given name. Zero is reserved for the default, or Value property; –1 is reserved to indicate an unknown name; and other negative values are defined for other purposes. For example, if GetIDsOfNames is called, and the implementation does not recognize one or more of the names, it returns DISP_E_UNKNOWNNAME, and the rgDispId array contains DISPID_UNKNOWN for the entries that correspond to the unknown names. The member and parameter DISPIDs must remain constant for the lifetime of the object. This allows a client to obtain the DISPIDs once, and cache them for later use. When GetIDsOfNames is called with more than one name, the first name (rgszNames[0]) corresponds to the member name, and subsequent names correspond to the names of the member's parameters. The same name may map to different DISPIDs, depending on context. For example, a name may have a DISPID when it is used as a member name with a particular interface, a different ID as a member of a different interface, and different mapping for each time it appears as a parameter. GetIDsOfNames is used when an IDispatch client binds to names at run time. To bind at compile time instead, an IDispatch client can map names to DISPIDs by using the type information interfaces described in Type Description Interfaces. This allows a client to bind to members at compile time and avoid calling GetIDsOfNames at run time. For a description of binding at compile time, see Type Description Interfaces. The implementation of GetIDsOfNames is case insensitive. Users that need case-sensitive name mapping should use type information interfaces to map names to DISPIDs, rather than call GetIDsOfNames.
Caution  You cannot use this method to access values that have been added dynamically, such as values added through JavaScript. Instead, use the GetDispID of the IDispatchEx interface. For more information, see the IDispatchEx interface.
 
 Read more on docs.microsoft.com. Provides access to properties and methods exposed by an object. Identifies the member. Use GetIDsOfNames or the object's documentation to obtain the dispatch identifier. Reserved for future use. Must be IID_NULL. The locale context in which to interpret arguments. The lcid is used by the GetIDsOfNames function, and is also passed to Invoke to allow the object to interpret its arguments specific to a locale. Applications that do not support multiple national languages can ignore this parameter. For more information, refer to Supporting Multiple National Languages and Exposing ActiveX Objects. Read more on docs.microsoft.com. Flags describing the context of the Invoke call. This doc was truncated. Read more on docs.microsoft.com. Pointer to a DISPPARAMS structure containing an array of arguments, an array of argument DISPIDs for named arguments, and counts for the number of elements in the arrays. Pointer to the location where the result is to be stored, or NULL if the caller expects no result. This argument is ignored if DISPATCH_PROPERTYPUT or DISPATCH_PROPERTYPUTREF is specified. Pointer to a structure that contains exception information. This structure should be filled in if DISP_E_EXCEPTION is returned. Can be NULL. The index within rgvarg of the first argument that has an error. Arguments are stored in pDispParams->rgvarg in reverse order, so the first argument is the one with the highest index in the array. This parameter is returned only when the resulting return value is DISP_E_TYPEMISMATCH or DISP_E_PARAMNOTFOUND. This argument can be set to null. For details, see Returning Errors. This method can return one of these values. This doc was truncated. Generally, you should not implement Invoke directly. Instead, use the dispatch interface to create functions CreateStdDispatch and DispInvoke. For details, refer to CreateStdDispatch, DispInvoke, Creating the IDispatch Interface and Exposing ActiveX Objects. If some application-specific processing needs to be performed before calling a member, the code should perform the necessary actions, and then call ITypeInfo::Invoke to invoke the member. ITypeInfo::Invoke acts exactly like Invoke. The standard implementations of Invoke created by CreateStdDispatch and DispInvoke defer to ITypeInfo::Invoke. In an ActiveX client, Invoke should be used to get and set the values of properties, or to call a method of an ActiveX object. The dispIdMember argument identifies the member to invoke. The DISPIDs that identify members are defined by the implementer of the object and can be determined by using the object's documentation, the IDispatch::GetIDsOfNames function, or the ITypeInfo interface. When you use IDispatch::Invoke() with DISPATCH_PROPERTYPUT or DISPATCH_PROPERTYPUTREF, you have to specially initialize the cNamedArgs and rgdispidNamedArgs elements of your DISPPARAMS structure with the following: This doc was truncated. Read more on docs.microsoft.com. The IID guid for this interface. {00020400-0000-0000-c000-000000000046} The IEnumString::Next (objidlbase.h) method retrieves the specified number of items in the enumeration sequence. The number of items to be retrieved. If there are fewer than the requested number of items left in the sequence, this method retrieves the remaining elements. An array of enumerated items. The enumerator is responsible for allocating any memory, and the caller is responsible for freeing it. If celt is greater than 1, the caller must also pass a non-NULL pointer passed to pceltFetched to know how many pointers to release. Read more on docs.microsoft.com. The number of items that were retrieved. This parameter is always less than or equal to the number of items requested. If the method retrieves the number of items requested, the return value is S_OK. Otherwise, it is S_FALSE. Learn more about this API from docs.microsoft.com. The IEnumString::Skip (objidlbase.h) method skips over the specified number of items in the enumeration sequence. The number of items to be skipped. If the method skips the number of items requested, the return value is S_OK. Otherwise, it is S_FALSE. Learn more about this API from docs.microsoft.com. The IEnumString::Reset (objidlbase.h) method resets the enumeration sequence to the beginning. The return value is S_OK. There is no guarantee that the same set of objects will be enumerated after the reset operation has completed. A static collection is reset to the beginning, but it can be too expensive for some collections, such as files in a directory, to guarantee this condition. The IEnumString::Clone (objidlbase.h) method creates a new enumerator that contains the same enumeration state as the current one. A pointer to the cloned enumerator object. This method can return the standard return values E_INVALIDARG, E_OUTOFMEMORY, E_UNEXPECTED, and S_OK. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {00000101-0000-0000-c000-000000000046} The IEnumUnknown::Next (objidlbase.h) method retrieves the specified number of items in the enumeration sequence. The number of items to be retrieved. If there are fewer than the requested number of items left in the sequence, this method retrieves the remaining elements. An array of enumerated items. The enumerator is responsible for calling AddRef, and the caller is responsible for calling Release through each pointer enumerated. If celt is greater than 1, the caller must also pass a non-NULL pointer passed to pceltFetched to know how many pointers to release. Read more on docs.microsoft.com. The number of items that were retrieved. This parameter is always less than or equal to the number of items requested. If the method retrieves the number of items requested, the return value is S_OK. Otherwise, it is S_FALSE. Learn more about this API from docs.microsoft.com. The IEnumUnknown::Skip (objidlbase.h) method skips over the specified number of items in the enumeration sequence. The number of items to be skipped. If the method skips the number of items requested, the return value is S_OK. Otherwise, it is S_FALSE. Learn more about this API from docs.microsoft.com. The IEnumUnknown::Reset (objidlbase.h) method resets the enumeration sequence to the beginning. The return value is S_OK. There is no guarantee that the same set of objects will be enumerated after the reset operation has completed. A static collection is reset to the beginning, but it can be too expensive for some collections, such as files in a directory, to guarantee this condition. The IEnumUnknown::Clone (objidlbase.h) method creates a new enumerator that contains the same enumeration state as the current one. A pointer to the cloned enumerator object. This method can return the standard return values E_INVALIDARG, E_OUTOFMEMORY, E_UNEXPECTED, and S_OK. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {00000100-0000-0000-c000-000000000046} Adds an error for the specified property to the error log. The address of the name of the property to read. This cannot be NULL. Pointer to an array of [EXCEPINFO](ns-oaidl-excepinfo.md) structures. The IID guid for this interface. {3127ca40-446e-11ce-8135-00aa004bb851} Specifies the way a function is invoked. In C, value assignment is written as *pobj1 = *pobj2, while reference assignment is written as pobj1 = pobj2. Other languages have other syntactic conventions. A property or data member can support only a value assignment, a reference assignment, or both. The INVOKEKIND enumeration constants are the same constants that are passed to IDispatch::Invoke to specify the way in which a function is invoked. The member is called using a normal function invocation syntax. The function is invoked using a normal property-access syntax. The function is invoked using a property value assignment syntax. Syntactically, a typical programming language might represent changing a property in the same way as assignment. For example: object.property : = value. The function is invoked using a property reference assignment syntax. Reads a specified number of bytes from the stream object into memory, starting at the current seek pointer. A pointer to the buffer which the stream data is read into. The number of bytes of data to read from the stream object. A pointer to a ULONG variable that receives the actual number of bytes read from the stream object.
Note  The number of bytes read may be zero.
 
 Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | All of the requested data was successfully read from the stream object; the number of bytes requested in *cb* is the same as the number of bytes returned in *pcbRead*.| |S_FALSE | The value returned in *pcbRead* is less than the number of bytes requested in *cb*. This indicates the end of the stream has been reached. The number of bytes read indicates how much of the *pv* buffer has been filled.| |E_PENDING | Asynchronous storage only: Part or all of the data to be read is currently unavailable. | |STG_E_ACCESSDENIED | The caller does not have permissions required to read this stream object.| |STG_E_INVALIDPOINTER | One of the pointer values is invalid.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| This method reads bytes from this stream object into memory. The stream object must be opened in STGM_READ mode. This method adjusts the seek pointer by the actual number of bytes read. The number of bytes actually read is also returned in the pcbRead parameter.

Notes to Callers

The actual number of bytes read can be less than the number of bytes requested if an error occurs or if the end of the stream is reached during the read operation. The number of bytes returned should always be compared to the number of bytes requested. If the number of bytes returned is less than the number of bytes requested, it usually means the Read method attempted to read past the end of the stream. The application should handle both a returned error and S_OK return values on end-of-stream read operations. Read more on docs.microsoft.com. Writes a specified number of bytes into the stream object starting at the current seek pointer. A pointer to the buffer that contains the data that is to be written to the stream. A valid pointer must be provided for this parameter even when cb is zero. The number of bytes of data to attempt to write into the stream. This value can be zero. A pointer to a ULONG variable where this method writes the actual number of bytes written to the stream object. The caller can set this pointer to NULL, in which case this method does not provide the actual number of bytes written. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The data was successfully written to the stream object.| |E_PENDING | Asynchronous Storage only: Part or all of the data to be written is currently unavailable.| |STG_E_MEDIUMFULL | The write operation failed because there is no space left on the storage device.| |STG_E_ACCESSDENIED | The caller does not have the required permissions for writing to this stream object.| |STG_E_CANTSAVE | Data cannot be written for reasons other than improper access or insufficient space.| |STG_E_INVALIDPOINTER | One of the pointer values is not valid. The *pv* parameter must contain a valid pointer even if *cb* is zero.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| |STG_E_WRITEFAULT | The write operation failed due to a disk error. This value is also returned when this method attempts to write to a stream that was opened in simple mode (using the STGM_SIMPLE flag).| ISequentialStream::Write writes the specified data to a stream object. The seek pointer is adjusted for the number of bytes actually written. The number of bytes actually written is returned in the pcbWritten parameter. If the byte count is zero bytes, the write operation has no effect. If the seek pointer is currently past the end of the stream and the byte count is nonzero, this method increases the size of the stream to the seek pointer and writes the specified bytes starting at the seek pointer. The fill bytes written to the stream are not initialized to any particular value. This is the same as the end-of-file behavior in the MS-DOS FAT file system. With a zero byte count and a seek pointer past the end of the stream, this method does not create the fill bytes to increase the stream to the seek pointer. In this case, you must call the IStream::SetSize method to increase the size of the stream and write the fill bytes. The pcbWritten parameter can have a value even if an error occurs. In the COM-provided implementation, stream objects are not sparse. Any fill bytes are eventually allocated on the disk and assigned to the stream. Read more on docs.microsoft.com. The IID guid for this interface. {0c733a30-2a1c-11ce-ade5-00aa0044773d} Changes the seek pointer to a new location. The new location is relative to either the beginning of the stream, the end of the stream, or the current seek pointer. The displacement to be added to the location indicated by the dwOrigin parameter. If dwOrigin is STREAM_SEEK_SET, this is interpreted as an unsigned value rather than a signed value. The origin for the displacement specified in dlibMove. The origin can be the beginning of the file (STREAM_SEEK_SET), the current seek pointer (STREAM_SEEK_CUR), or the end of the file (STREAM_SEEK_END). For more information about values, see the STREAM_SEEK enumeration. A pointer to the location where this method writes the value of the new seek pointer from the beginning of the stream. You can set this pointer to NULL. In this case, this method does not provide the new seek pointer. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The seek pointer was successfully adjusted.| |E_PENDING | Asynchronous Storage only: Part or all of the stream data is currently unavailable. | |STG_E_INVALIDPOINTER | Indicates that *plibNewPosition* points to invalid memory, because *plibNewPosition* is not read.| |STG_E_INVALIDFUNCTION | The *dwOrigin* parameter contains an invalid value, or the *dlibMove* parameter contains a bad offset value. For example, the result of the seek pointer is a negative offset value.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| IStream::Seek changes the seek pointer so that subsequent read and write operations can be performed at a different location in the stream object. It is an error to seek before the beginning of the stream. It is not, however, an error to seek past the end of the stream. Seeking past the end of the stream is useful for subsequent write operations, as the stream byte range will be extended to the new seek position immediately before the write is complete. You can also use this method to obtain the current value of the seek pointer by calling this method with the dwOrigin parameter set to STREAM_SEEK_CUR and the dlibMove parameter set to 0 so that the seek pointer is not changed. The current seek pointer is returned in the plibNewPosition parameter. Read more on docs.microsoft.com. Changes the size of the stream object. Specifies the new size, in bytes, of the stream. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The size of the stream object was successfully changed.| |E_PENDING | Asynchronous Storage only: Part or all of the stream's data is currently unavailable.| |STG_E_MEDIUMFULL | The stream size is not changed because there is no space left on the storage device.| |STG_E_INVALIDFUNCTION | The value of the *libNewSize* parameter is not supported by the implementation. Not all streams support greater than 232 bytes. If a stream does not support more than 232 bytes, the high DWORD data type of *libNewSize* must be zero. If it is nonzero, the implementation may return STG_E_INVALIDFUNCTION. In general, COM-based implementations of the IStream interface do not support streams larger than 232 bytes.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| IStream::SetSize changes the size of the stream object. Call this method to preallocate space for the stream. If the libNewSize parameter is larger than the current stream size, the stream is extended to the indicated size by filling the intervening space with bytes of undefined value. This operation is similar to the ISequentialStream::Write method if the seek pointer is past the current end of the stream. If the libNewSize parameter is smaller than the current stream, the stream is truncated to the indicated size. The seek pointer is not affected by the change in stream size. Calling IStream::SetSize can be an effective way to obtain a large chunk of contiguous space. Read more on docs.microsoft.com. Copies a specified number of bytes from the current seek pointer in the stream to the current seek pointer in another stream. A pointer to the destination stream. The stream pointed to by pstm can be a new stream or a clone of the source stream. The number of bytes to copy from the source stream. A pointer to the location where this method writes the actual number of bytes read from the source. You can set this pointer to NULL. In this case, this method does not provide the actual number of bytes read. A pointer to the location where this method writes the actual number of bytes written to the destination. You can set this pointer to NULL. In this case, this method does not provide the actual number of bytes written. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The stream object was successfully copied.| |E_PENDING | Asynchronous Storage only: Part or all of the data to be copied is currently unavailable. | |STG_E_INVALIDPOINTER | The value of one of the pointer parameters is invalid.| |STG_E_MEDIUMFULL | The stream is not copied because there is no space left on the storage device.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| The CopyTo method copies the specified bytes from one stream to another. It can also be used to copy a stream to itself. The seek pointer in each stream instance is adjusted for the number of bytes read or written. This method is equivalent to reading cb bytes into memory using ISequentialStream::Read and then immediately writing them to the destination stream using ISequentialStream::Write, although IStream::CopyTo will be more efficient. The destination stream can be a clone of the source stream created by calling the IStream::Clone method. If IStream::CopyTo returns an error, you cannot assume that the seek pointers are valid for either the source or destination. Additionally, the values of pcbRead and pcbWritten are not meaningful even though they are returned. If IStream::CopyTo returns successfully, the actual number of bytes read and written are the same. To copy the remainder of the source from the current seek pointer, specify the maximum large integer value for the cb parameter. If the seek pointer is the beginning of the stream, this operation copies the entire stream. Read more on docs.microsoft.com. The Commit method ensures that any changes made to a stream object open in transacted mode are reflected in the parent storage. Controls how the changes for the stream object are committed. See the STGC enumeration for a definition of these values. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | Changes to the stream object were successfully committed to the parent level.| |E_PENDING | Asynchronous Storage only: Part or all of the stream's data is currently unavailable. | |STG_E_MEDIUMFULL | The commit operation failed due to lack of space on the storage device.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| The Commit method ensures that changes to a stream object opened in transacted mode are reflected in the parent storage. Changes that have been made to the stream since it was opened or last committed are reflected to the parent storage object. If the parent is opened in transacted mode, the parent may revert at a later time, rolling back the changes to this stream object. The compound file implementation does not support the opening of streams in transacted mode, so this method has very little effect other than to flush memory buffers. For more information, see IStream - Compound File Implementation. If the stream is open in direct mode, this method ensures that any memory buffers have been flushed out to the underlying storage object. This is much like a flush in traditional file systems. The IStream::Commit method is useful on a direct mode stream when the implementation of the IStream interface is a wrapper for underlying file system APIs. In this case, IStream::Commit would be connected to the file system's flush call. Read more on docs.microsoft.com. The Revert method discards all changes that have been made to a transacted stream since the last IStream::Commit call. On streams open in direct mode and streams using the COM compound file implementation of IStream::Revert, this method has no effect. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The stream was successfully reverted to its previous version.| |E_PENDING | Asynchronous Storage only: Part or all of the stream's data is currently unavailable. | The Revert method discards changes made to a transacted stream since the last commit operation. The LockRegion method restricts access to a specified range of bytes in the stream. Integer that specifies the byte offset for the beginning of the range. Integer that specifies the length of the range, in bytes, to be restricted. Specifies the restrictions being requested on accessing the range. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The specified range of bytes was locked.| |E_PENDING | Asynchronous Storage only: Part or all of the stream's data is currently unavailable. | |STG_E_INVALIDFUNCTION | Locking is not supported at all or the specific type of lock requested is not supported.| |STG_E_LOCKVIOLATION | Requested lock is supported, but cannot be granted because of an existing lock.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| The byte range of the stream can be extended. Locking an extended range for the stream is useful as a method of communication between different instances of the stream without changing data that is actually part of the stream. Three types of locking can be supported: locking to exclude other writers, locking to exclude other readers or writers, and locking that allows only one requester to obtain a lock on the given range, which is usually an alias for one of the other two lock types. A given stream instance might support either of the first two types, or both. The lock type is specified by dwLockType, using a value from the LOCKTYPE enumeration. Any region locked with IStream::LockRegion must later be explicitly unlocked by calling IStream::UnlockRegion with exactly the same values for the libOffset, cb, and dwLockType parameters. The region must be unlocked before the stream is released. Two adjacent regions cannot be locked separately and then unlocked with a single unlock call.

Notes to Callers

Since the type of locking supported is optional and can vary in different implementations of IStream, you must provide code to deal with the STG_E_INVALIDFUNCTION error. The LockRegion method has no effect in the compound file implementation, because the implementation does not support range locking.

Notes to Implementers

Support for this method is optional for implementations of stream objects since it may not be supported by the underlying file system. The type of locking supported is also optional. The STG_E_INVALIDFUNCTION error is returned if the requested type of locking is not supported. Read more on docs.microsoft.com. The UnlockRegion method removes the access restriction on a range of bytes previously restricted with IStream::LockRegion. Specifies the byte offset for the beginning of the range. Specifies, in bytes, the length of the range to be restricted. Specifies the access restrictions previously placed on the range. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The byte range was unlocked.| |E_PENDING | Asynchronous Storage only: Part or all of the stream's data is currently unavailable.| |STG_E_INVALIDFUNCTION | Locking is not supported at all or the specific type of lock requested is not supported.| |STG_E_LOCKVIOLATION | The requested unlock operation cannot be granted.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| IStream::UnlockRegion unlocks a region previously locked with the IStream::LockRegion method. Locked regions must later be explicitly unlocked by calling IStream::UnlockRegion with exactly the same values for the libOffset, cb, and dwLockType parameters. The region must be unlocked before the stream is released. Two adjacent regions cannot be locked separately and then unlocked with a single unlock call. Read more on docs.microsoft.com. The Stat method retrieves the STATSTG structure for this stream. Pointer to a STATSTG structure where this method places information about this stream object. Read more on docs.microsoft.com. Specifies that this method does not return some of the members in the STATSTG structure, thus saving a memory allocation operation. Values are taken from the STATFLAG enumeration. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The STATSTG structure was successfully returned at the specified location.| |E_PENDING | Asynchronous Storage only: Part or all of the stream's data is currently unavailable. | |STG_E_ACCESSDENIED | The caller does not have enough permissions for accessing statistics for this storage object.| |STG_E_INSUFFICIENTMEMORY | The STATSTG structure was not returned due to a lack of memory.| |STG_E_INVALIDFLAG | The value for the *grfStateFlag* parameter is not valid.| |STG_E_INVALIDPOINTER | The *pStatStg* pointer is not valid.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| IStream::Stat retrieves a pointer to the STATSTG structure that contains information about this open stream. When this stream is within a structured storage and IStorage::EnumElements is called, it creates an enumerator object with the IEnumSTATSTG interface on it, which can be called to enumerate the storages and streams through the STATSTG structures associated with each of them. Read more on docs.microsoft.com. The Clone method creates a new stream object with its own seek pointer that references the same bytes as the original stream. When successful, pointer to the location of an IStream pointer to the new stream object. If an error occurs, this parameter is NULL. Read more on docs.microsoft.com. This method can return one of these values. | Return code | Description | |----------------|---------------| |S_OK | The stream was successfully cloned.| |E_PENDING | Asynchronous Storage only: Part or all of the stream's data is currently unavailable. | |STG_E_INSUFFICIENTMEMORY | The stream was not cloned due to a lack of memory.| |STG_E_INVALIDPOINTER | The ppStm pointer is not valid.| |STG_E_REVERTED | The object has been invalidated by a revert operation above it in the transaction tree.| The Clone method creates a new stream object for accessing the same bytes but using a separate seek pointer. The new stream object sees the same data as the source-stream object. Changes written to one object are immediately visible in the other. Range locking is shared between the stream objects. The initial setting of the seek pointer in the cloned stream instance is the same as the current setting of the seek pointer in the original stream at the time of the clone operation. Read more on docs.microsoft.com. The IID guid for this interface. {0000000c-0000-0000-c000-000000000046} Maps a name to a member of a type, or binds global variables and functions contained in a type library. The name to be bound. The hash value for the name computed by LHashValOfNameSys. One or more of the flags defined in the INVOKEKIND enumeration. Specifies whether the name was referenced as a method or a property. When binding to a variable, specify the flag INVOKE_PROPERTYGET. Specify zero to bind to any type of member. If a FUNCDESC or VARDESC was returned, then ppTInfo points to a pointer to the type description that contains the item to which it is bound. Indicates whether the name bound to is a VARDESC, FUNCDESC, or TYPECOMP. If there was no match, DESCKIND_NONE. The bound-to VARDESC, FUNCDESC, or ITypeComp interface. This method can return one of these values. This doc was truncated. Use Bind for binding to the variables and methods of a type, or for binding to the global variables and methods in a type library. The returned DESCKIND pointer pDescKind indicates whether the name was bound to a VARDESC, a FUNCDESC, or to an ITypeComp instance. The returned pBindPtr points to the VARDESC, FUNCDESC, or ITypeComp. If a data member or method is bound to, then ppTInfopoints to the type description that contains the method or data member. If Bind binds the name to a nested binding context, it returns a pointer to an ITypeComp instance in pBindPtr and a null type description pointer in ppTInfo. For example, if the name of a type description is passed for a module (TKIND_MODULE), enumeration (TKIND_ENUM), or coclass (TKIND_COCLASS), Bind returns the ITypeComp instance of the type description for the module, enumeration, or coclass. This feature supports languages such as Visual Basic that allow references to members of a type description to be qualified by the name of the type description. For example, a function in a module can be referenced by modulename.functionname. The members of TKIND_ENUM, TKIND_MODULE, and TKIND_COCLASS types marked as Application objects can be bound to directly from ITypeComp, without specifying the name of the module. The ITypeComp of a coclass defers to the ITypeComp of its default interface. As with other methods of ITypeComp, ITypeInfo, and ITypeInfo, the calling code is responsible for releasing the returned object instances or structures. If a VARDESC or FUNCDESC is returned, the caller is responsible for deleting it with the returned type description and releasing the type description instance itself. Otherwise, if an ITypeComp instance is returned, the caller must release it. Special rules apply if you call a type library's Bind method, passing it the name of a member of an Application object class (a class that has the TYPEFLAG_FAPPOBJECT flag set). In this case, Bind returns DESCKIND_IMPLICITAPPOBJ in pDescKind, a VARDESC that describes the Application object in pBindPtr, and the ITypeInfo of the Application object class in ppTInfo. To bind to the object, ITypeInfo::GetTypeComp must make a call to get the ITypeComp of the Application object class, and then reinvoke its Bind method with the name initially passed to the type library's ITypeComp. The caller should use the returned ITypeInfo pointer (ppTInfo) to get the address of the member.
Note  The wflags parameter is the same as the wflags parameter in IDispatch::Invoke.
 
 Read more on docs.microsoft.com. Binds to the type descriptions contained within a type library. The name to be bound. The hash value for the name computed by LHashValOfName. An ITypeInfo of the type to which the name was bound. Passes a valid pointer, such as the address of an ITypeComp variable. This method can return one of these values. This doc was truncated. Use the function BindType for binding a type name to the ITypeInfo that describes the type. This function is invoked on the ITypeComp that is returned by ITypeLib::GetTypeComp to bind to types defined within that library. It can also be used in the future for binding to nested types. The IID guid for this interface. {00020403-0000-0000-c000-000000000046} Retrieves a TYPEATTR structure that contains the attributes of the type description. The attributes of this type description. This method can return one of these values. This doc was truncated. To free the TYPEATTR structure, use ITypeInfo::ReleaseTypeAttr. Retrieves the ITypeComp interface for the type description, which enables a client compiler to bind to the type description's members. The ITypeComp of the containing type library. This method can return one of these values. This doc was truncated. A client compiler can use the ITypeComp interface to bind to members of the type. Retrieves the FUNCDESC structure that contains information about a specified function. The index of the function whose description is to be returned. The index should be in the range of 0 to 1 less than the number of functions in this type. A FUNCDESC structure that describes the specified function. This method can return one of these values. This doc was truncated. The function ITypeInfo::GetFuncDesc provides access to a FUNCDESC structure that describes the function with the specified index. The FUNCDESC structure should be freed with ITypeInfo::ReleaseFuncDesc. The number of functions in the type is one of the attributes contained in the TYPEATTR structure. Retrieves a VARDESC structure that describes the specified variable. The index of the variable whose description is to be returned. The index should be in the range of 0 to 1 less than the number of variables in this type. A VARDESC that describes the specified variable. This method can return one of these values. This doc was truncated. To free the VARDESC structure, use ReleaseVarDesc. Retrieves the variable with the specified member ID or the name of the property or method and the parameters that correspond to the specified function ID. The ID of the member whose name (or names) is to be returned. The caller-allocated array. On return, each of the elements contains the name (or names) associated with the member. The length of the passed-in rgBstrNames array. The number of names in the rgBstrNames array. This method can return one of these values. This doc was truncated. The caller must release the returned BSTR array. If the member ID identifies a property that is implemented with property functions, the property name is returned. For property get functions, the names of the function and its parameters are always returned. For property put and put reference functions, the right side of the assignment is unnamed. If cMaxNames is less than is required to return all of the names of the parameters of a function, then only the names of the first cMaxNames - 1 parameters are returned. The names of the parameters are returned in the array in the same order that they appear elsewhere in the interface (for example, the same order in the parameter array associated with the FUNCDESC enumeration). If the type description inherits from another type description, this function is recursive to the base type description, if necessary, to find the item with the requested member ID. Read more on docs.microsoft.com. If a type description describes a COM class, it retrieves the type description of the implemented interface types. The index of the implemented type whose handle is returned. The valid range is 0 to the cImplTypes field in the TYPEATTR structure. A handle for the implemented interface (if any). This handle can be passed to ITypeInfo::GetRefTypeInfo to get the type description. This method can return one of these values. This doc was truncated. If the TKIND_DISPATCH type description is for a dual interface, the TKIND_INTERFACE type description can be obtained by calling GetRefTypeOfImplType with an index of –1, and by passing the returned pRefTypehandle to GetRefTypeInfo to retrieve the type information. Retrieves the IMPLTYPEFLAGS enumeration for one implemented interface or base interface in a type description. The index of the implemented interface or base interface for which to get the flags. The IMPLTYPEFLAGS enumeration value. This method can return one of these values. This doc was truncated. The flags are associated with the act of inheritance, and not with the inherited interface. Maps between member names and member IDs, and parameter names and parameter IDs. An array of names to be mapped. The count of the names to be mapped. Caller-allocated array in which name mappings are placed. This method can return one of these values. This doc was truncated. The function GetIDsOfNames maps the name of a member (rgszNames[0]) and its parameters (rgszNames[1] ...rgszNames[cNames- 1]) to the ID of the member (pMemId[0]), and to the IDs of the specified parameters (pMemId[1] ... pMemId[cNames- 1]). The IDs of parameters are 0 for the first parameter in the member function's argument list, 1 for the second, and so on. If the type description inherits from another type description, this function is recursive to the base type description, if necessary, to find the item with the requested member ID. Read more on docs.microsoft.com. Invokes a method, or accesses a property of an object, that implements the interface described by the type description. An instance of the interface described by this type description. The interface member. Flags describing the context of the invoke call. This doc was truncated. Read more on docs.microsoft.com. An array of arguments, an array of DISPIDs for named arguments, and counts of the number of elements in each array. The result. Should be null if the caller does not expect any result. If wFlags specifies DISPATCH_PROPERTYPUT or DISPATCH_PROPERTYPUTREF, pVarResultis is ignored. An exception information structure, which is filled in only if DISP_E_EXCEPTION is returned. If pExcepInfo is null on input, only an HRESULT error will be returned. If Invoke returns DISP_E_TYPEMISMATCH, puArgErr indicates the index (within rgvarg) of the argument with incorrect type. If more than one argument returns an error, puArgErr indicates only the first argument with an error. Arguments in pDispParams->rgvarg appear in reverse order, so the first argument is the one having the highest index in the array. This parameter cannot be null. This doc was truncated. Use the function ITypeInfo::Invoke to access a member of an object or invoke a method that implements the interface described by this type description. For objects that support the IDispatch interface, you can use Invoke to implement IDispatch::Invoke. ITypeInfo::Invoke takes a pointer to an instance of the class. Otherwise, its parameters are the same as IDispatch::Invoke, except that ITypeInfo::Invoke omits the refiid and lcid parameters. When called, ITypeInfo::Invoke performs the actions described by the IDispatch::Invoke parameters on the specified instance. For VTBL interface members, ITypeInfo::Invoke passes the LCID of the type information into parameters tagged with the lcid attribute, and the returned value into the retval attribute. If the type description inherits from another type description, this function recurses on the base type description to find the item with the requested member ID. Read more on docs.microsoft.com. Retrieves the documentation string, the complete Help file name and path, and the context ID for the Help topic for a specified type description. The ID of the member whose documentation is to be returned. The name of the specified item. If the caller does not need the item name, pBstrName can be null. The documentation string for the specified item. If the caller does not need the documentation string, pBstrDocString can be null. The Help localization context. If the caller does not need the Help context, it can be null. The fully qualified name of the file containing the DLL used for Help file. If the caller does not need the file name, it can be null. This method can return one of these values. This doc was truncated. The function GetDocumentation provides access to the documentation for the member specified by the memid parameter. If the passed-in memid is MEMBERID_NIL, then the documentation for the type description is returned. If the type description inherits from another type description, this function is recursive to the base type description, if necessary, to find the item with the requested member ID. The caller should use SysFreeString to free the BSTRs referenced by pBstrName, pBstrDocString, and pBstrHelpFile. Read more on docs.microsoft.com. Retrieves a description or specification of an entry point for a function in a DLL. The ID of the member function whose DLL entry description is to be returned. The kind of member identified by memid. This is important for properties, because one memid can identify up to three separate functions. If not null, the function sets pBstrDllName to the name of the DLL. If not null, the function sets pBstrName to the name of the entry point. If the entry point is specified by an ordinal, this argument is null. If not null, and if the function is defined by an ordinal, the function sets pwOrdinal to the ordinal. This method can return one of these values. This doc was truncated. The caller passes in a member ID, which represents the member function whose entry description is desired. If the function has a DLL entry point, the name of the DLL that contains the function, as well as its name or ordinal identifier, are placed in the passed-in pointers allocated by the caller. If there is no DLL entry point for the function, an error is returned. If the type description inherits from another type description, this function is recursive to the base type description, if necessary, to find the item with the requested member ID. The caller should use SysFreeString to free the BSTRs referenced by pBstrName and pBstrDllName. Read more on docs.microsoft.com. If a type description references other type descriptions, it retrieves the referenced type descriptions. A handle to the referenced type description to return. The referenced type description. This method can return one of these values. This doc was truncated. On return, the second parameter contains a pointer to a pointer to a type description that is referenced by this type description. A type description must have a reference to each type description that occurs as the type of any of its variables, function parameters, or function return types. For example, if the type of a data member is a record type, the type description for that data member contains the hRefType of a referenced type description. To get a pointer to the type description, the reference is passed to GetRefTypeInfo. Retrieves the addresses of static functions or variables, such as those defined in a DLL. The member ID of the static member whose address is to be retrieved. The member ID is defined by the DISPID. Indicates whether the member is a property, and if so, what kind. The static member. This method can return one of these values. This doc was truncated. The addresses are valid until the caller releases its reference to the type description. The invKind parameter can be ignored unless the address of a property function is being requested. If the type description inherits from another type description, this function is recursive to the base type description, if necessary, to find the item with the requested member ID. Read more on docs.microsoft.com. Creates a new instance of a type that describes a component object class (coclass). The controlling IUnknown. If Null, then a stand-alone instance is created. If valid, then an aggregate object is created. An ID for the interface that the caller will use to communicate with the resulting object. An instance of the created object. This doc was truncated. For types that describe a component object class (coclass), CreateInstance creates a new instance of the class. Normally, CreateInstance calls CoCreateInstance with the type description's GUID. For an Application object, it first calls GetActiveObject. If the application is active, GetActiveObject returns the active object; otherwise, if GetActiveObject fails, CreateInstance calls CoCreateInstance. Retrieves marshaling information. The member ID that indicates which marshaling information is needed. The opcode string used in marshaling the fields of the structure described by the referenced type description, or null if there is no information to return. This method can return one of these values. This doc was truncated. If the passed-in member ID is MEMBERID_NIL, the function returns the opcode string for marshaling the fields of the structure described by the type description. Otherwise, it returns the opcode string for marshaling the function specified by the index. If the type description inherits from another type description, this function recurses on the base type description, if necessary, to find the item with the requested member ID. Read more on docs.microsoft.com. Retrieves the containing type library and the index of the type description within that type library. The containing type library. The index of the type description within the containing type library. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Releases a TYPEATTR previously returned by ITypeInfo::GetTypeAttr. The TYPEATTR to be freed. Learn more about this API from docs.microsoft.com. Releases a FUNCDESC previously returned by ITypeInfo::GetFuncDesc. The FUNCDESC to be freed. Learn more about this API from docs.microsoft.com. Releases a VARDESC previously returned by ITypeInfo::GetVarDesc. The VARDESC to be freed. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {00020401-0000-0000-c000-000000000046} Provides the number of type descriptions that are in a type library. The number of type descriptions in the type library. Learn more about this API from docs.microsoft.com. Retrieves the specified type description in the library. The index of the interface to be returned. If successful, returns a pointer to the pointer to the ITypeInfo interface. This method can return one of these values. This doc was truncated. For dual interfaces, GetTypeInfo returns only the TKIND_DISPATCH type information. To get the TKIND_INTERFACE type information, GetRefTypeOfImplType can be called on the TKIND_DISPATCH type information, passing an index of –1. Then, the returned type information handle can be passed to GetRefTypeInfo. Retrieves the type of a type description. The index of the type description within the type library. The TYPEKIND enumeration value for the type description. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Retrieves the type description that corresponds to the specified GUID. The GUID of the type description. The ITypeInfo interface. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Retrieves the structure that contains the library's attributes. The library's attributes. This method can return one of these values. This doc was truncated. Use ITypeLib::ReleaseTLibAttr to free the memory occupied by the TLIBATTR structure. Enables a client compiler to bind to the types, variables, constants, and global functions for a library. The ITypeComp instance for this ITypeLib. A client compiler uses the methods in the ITypeComp interface to bind to types in ITypeLib, as well as to the global functions, variables, and constants defined in ITypeLib This method can return one of these values. This doc was truncated. The Bind function of the returned TypeComp binds to global functions, variables, constants, enumerated values, and coclass members. The Bind function also binds the names of the TYPEKIND enumerations of TKIND_MODULE, TKIND_ENUM, and TKIND_COCLASS. These names shadow any global names defined within the type information. The members of TKIND_ENUM, TKIND_MODULE, and TKIND_COCLASS types marked as Application objects can be directly bound to from ITypeComp without specifying the name of the module. ITypeComp::Bind and ITypeComp::BindType accept only unqualified names. ITypeLib::GetTypeComp returns a pointer to the ITypeComp interface, which is then used to bind to global elements in the library. The names of some types (TKIND_ENUM, TKIND_MODULE, and TKIND_COCLASS) share the name space with variables, functions, constants, and enumerators. If a member requires qualification to differentiate it from other items in the name space, GetTypeComp can be called successively for each qualifier in order to bind to the desired member. This allows programming language compilers to access members of modules, enumerations, and coclasses, even though the member can't be bound to with a qualified name. Read more on docs.microsoft.com. Retrieves the documentation string for the library, the complete Help file name and path, and the context identifier for the library Help topic in the Help file. The index of the type description whose documentation is to be returned. If index is -1, then the documentation for the library itself is returned. The name of the specified item. If the caller does not need the item name, then pBstrName can be null. The documentation string for the specified item. If the caller does not need the documentation string, then pBstrDocString can be null.. The Help context identifier (ID) associated with the specified item. If the caller does not need the Help context ID, then pdwHelpContext can be null. The fully qualified name of the Help file. If the caller does not need the Help file name, then pBstrHelpFile can be null. This method can return one of these values. This doc was truncated. The caller should free the parameters pBstrName, pBstrDocString, and pBstrHelpFile. Indicates whether a passed-in string contains the name of a type or member described in the library. The string to test. If this method is successful, szNameBuf is modified to match the case (capitalization) found in the type library. The hash value of szNameBuf. True if szNameBuf was found in the type library; otherwise false. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Finds occurrences of a type description in a type library. This may be used to quickly verify that a name exists in a type library. The name to search for. A hash value to speed up the search, computed by the LHashValOfNameSys function. If lHashVal = 0, a value is computed. An array of pointers to the type descriptions that contain the name specified in szNameBuf. This parameter cannot be null. An array of the found items; rgMemId[i] is the MEMBERID that indexes into the type description specified by ppTInfo[i]. This parameter cannot be null. On entry, indicates how many instances to look for. For example, *pcFound = 1 can be called to find the first occurrence. The search stops when one is found. On exit, indicates the number of instances that were found. If the in and out values of *pcFound are identical, there may be more type descriptions that contain the name. Read more on docs.microsoft.com. This method can return one of these values. This doc was truncated. Passing *pcFound = n indicates that there is enough room in the ppTInfo and rgMemId arrays for n (ptinfo, memid) pairs. The function returns MEMBERID_NIL in rgMemId[i], if the name in szNameBuf is the name of the type information in ppTInfo[i]. Releases the TLIBATTR originally obtained from GetLibAttr. The TLIBATTR to be freed. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {00020402-0000-0000-c000-000000000046} Increments the reference count for an interface pointer to a COM object. You should call this method whenever you make a copy of an interface pointer. The method returns the new reference count. This value is intended to be used only for test purposes. A COM object uses a per-interface reference-counting mechanism to ensure that the object doesn't outlive references to it. You use **AddRef** to stabilize a copy of an interface pointer. It can also be called when the life of a cloned pointer must extend beyond the lifetime of the original pointer. The cloned pointer must be released by calling [IUnknown::Release](/windows/desktop/api/unknwn/nf-unknwn-iunknown-queryinterface(refiid_void)) on it. The internal reference counter that **AddRef** maintains should be a 32-bit unsigned integer. Read more on docs.microsoft.com. Decrements the reference count for an interface on a COM object. The method returns the new reference count. This value is intended to be used only for test purposes. When the reference count on an object reaches zero, **Release** must cause the interface pointer to free itself. When the released pointer is the only (formerly) outstanding reference to an object (whether the object supports single or multiple interfaces), the implementation must free the object. Note that aggregation of objects restricts the ability to recover interface pointers. Read more on docs.microsoft.com. The IID guid for this interface. {00000000-0000-0000-c000-000000000046} The LOCKTYPE enumeration values indicate the type of locking requested for the specified range of bytes. The values are used in the ILockBytes::LockRegion and IStream::LockRegion methods. Learn more about this API from docs.microsoft.com. If this lock is granted, the specified range of bytes can be opened and read any number of times, but writing to the locked range is prohibited except for the owner that was granted this lock. If this lock is granted, writing to the specified range of bytes is prohibited except by the owner that was granted this lock. If this lock is granted, no other LOCK_ONLYONCE lock can be obtained on the range. Usually this lock type is an alias for some other lock type. Thus, specific implementations can have additional behavior associated with this lock type. Represents a safe array. The array rgsabound is stored with the left-most dimension in rgsabound[0] and the right-most dimension in rgsabound[cDims - 1]. If an array was specified in a C-like syntax as a [2][5], it would have two elements in the rgsabound vector. Element 0 has an lLbound of 0 and a cElements of 2. Element 1 has an lLbound of 0 and a cElements of 5. The fFeatures flags describe attributes of an array that can affect how the array is released. The fFeatures field describes what type of data is stored in the SAFEARRAY and how the array is allocated. This allows freeing the array without referencing its containing variant. Read more on docs.microsoft.com. The number of dimensions. Flags. This doc was truncated. Read more on docs.microsoft.com. The size of an array element. The number of times the array has been locked without a corresponding unlock. The data. One bound for each dimension. Computes the amount of memory that must be allocated to store this struct, including the specified number of elements in the variable length inline array at the end. Represents the bounds of one dimension of the array. Learn more about this API from docs.microsoft.com. The number of elements in the dimension. The lower bound of the dimension. Contains statistical data about an open storage, stream, or byte-array object. Learn more about this API from docs.microsoft.com. A pointer to a NULL-terminated Unicode string that contains the name. Space for this string is allocated by the method called and freed by the caller (for more information, see CoTaskMemFree). To not return this member, specify the STATFLAG_NONAME value when you call a method that returns a STATSTG structure, except for calls to IEnumSTATSTG::Next, which provides no way to specify this value. Read more on docs.microsoft.com. Indicates the type of storage object. This is one of the values from the STGTY enumeration. Read more on docs.microsoft.com. Specifies the size, in bytes, of the stream or byte array. Indicates the last modification time for this storage, stream, or byte array. Indicates the creation time for this storage, stream, or byte array. Indicates the last access time for this storage, stream, or byte array. Indicates the access mode specified when the object was opened. This member is only valid in calls to Stat methods. Read more on docs.microsoft.com. Indicates the class identifier for the storage object; set to CLSID_NULL for new storage objects. This member is not used for streams or byte arrays. Indicates the current state bits of the storage object; that is, the value most recently set by the IStorage::SetStateBits method. This member is not valid for streams or byte arrays. Read more on docs.microsoft.com. Reserved for future use. Flags that indicate conditions for creating and deleting the object and access modes for the object. You can combine these flags, but you can only choose one flag from each group of related flags. Typically one flag from each of the access and sharing groups must be specified for all functions and methods which use these constants. Flags from other groups are optional. Identifies the target operating system platform. Learn more about this API from docs.microsoft.com. The target operating system for the type library is 16-bit Windows. By default, data members are packed. The target operating system for the type library is 32-bit Windows. By default, data members are naturally aligned (for example, 2-byte integers are aligned on even-byte boundaries; 4-byte integers are aligned on quad-word boundaries, and so on). The target operating system for the type library is Apple Macintosh. By default, all data members are aligned on even-byte boundaries. The target operating system for the type library is 64-bit Windows. Contains information about a type library. Information from this structure is used to identify the type library and to provide national language support for member names. Learn more about this API from docs.microsoft.com. The globally unique identifier. The locale identifier. The target hardware platform. The major version number. The minor version number. The library flags. Contains attributes of a type. Learn more about this API from docs.microsoft.com. The GUID of the type information. The locale of member names and documentation strings. Reserved. The constructor ID, or MEMBERID_NIL if none. The destructor ID, or MEMBERID_NIL if none. Reserved. The size of an instance of this type. The kind of type. The number of functions. The number of variables or data members. The number of implemented interfaces. The size of this type's VTBL. The byte alignment for an instance of this type. A value of 0 indicates alignment on the 64K boundary; 1 indicates no special alignment. For other values, n indicates aligned on byte n. The type flags. See TYPEFLAGS. The major version number. The minor version number. If typekind is TKIND_ALIAS, specifies the type for which this type is an alias. The IDL attributes of the described type. Describes the type of a variable, the return type of a function, or the type of a function parameter. If the variable is VT_SAFEARRAY or VT_PTR, the union portion of the TYPEDESC contains a pointer to a TYPEDESC that specifies the element type. The variant type. Specifies a type. Learn more about this API from docs.microsoft.com. A set of enumerators. A structure with no methods. A module that can only have static functions and data (for example, a DLL). A type that has virtual and pure functions. A set of methods and properties that are accessible through IDispatch::Invoke. By default, dual interfaces return TKIND_DISPATCH. A set of implemented component object interfaces. A type that is an alias for another type. A union, all of whose members have an offset of zero. End of enum marker. Describes a variable, constant, or data member. Learn more about this API from docs.microsoft.com. The member ID. Reserved. The variable type. The variable flags. See VARFLAGS. The variable type. Specifies variable flags. Learn more about this API from docs.microsoft.com. Assignment to the variable should not be allowed. The variable returns an object that is a source of events. The variable supports data binding. When set, any attempt to directly change the property results in a call to IPropertyNotifySink::OnRequestEdit. The implementation of OnRequestEdit determines if the change is accepted. The variable is displayed to the user as bindable. VARFLAG_FBINDABLE must also be set. The variable is the single property that best represents the object. Only one variable in type information can have this attribute. The variable should not be displayed to the user in a browser, although it exists and is bindable. The variable should not be accessible from macro languages. This flag is intended for system-level variables or variables that you do not want type browsers to display. Permits an optimization in which the compiler looks for a member named "xyz" on the type of abc. If such a member is found and is flagged as an accessor function for an element of the default collection, then a call is generated to that member function. Permitted on members in dispinterfaces and interfaces; not permitted on modules. The variable is the default display in the user interface. The variable appears in an object browser, but not in a properties browser. Tags the interface as having default behaviors. The variable is mapped as individual bindable properties. Specifies the variable type. Learn more about this API from docs.microsoft.com. The variable is a field or member of the type. It exists at a fixed offset within each instance of the type. There is only one instance of the variable. The VARDESC describes a symbolic constant. There is no memory associated with it. The variable can only be accessed through IDispatch::Invoke. Describes an array, its element type, and its dimension. Learn more about this API from docs.microsoft.com. The element type. The dimension count. A variable-length array containing one element for each dimension. Computes the amount of memory that must be allocated to store this struct, including the specified number of elements in the variable length inline array at the end. Initializes a new instance of a record. An instance of a record. This method can return one of these values. This doc was truncated. The caller must allocate the memory of the record by its appropriate size using the GetSize method. RecordInit sets all contents of the record to 0 and the record should hold no resources. Read more on docs.microsoft.com. Releases object references and other values of a record without deallocating the record. The record to be cleared. This method can return one of these values. This doc was truncated. RecordClear releases memory blocks held by VT_PTR or VT_SAFEARRAY instance fields. The caller needs to free the instance fields memory, RecordClear will do nothing if there are no resources held. Copies an existing record into the passed in buffer. The current record instance. The destination where the record will be copied. This method can return one of these values. This doc was truncated. RecordCopy will release the resources in the destination first. The caller is responsible for allocating sufficient memory in the destination by calling GetSize or RecordCreate. If RecordCopy fails to copy any of the fields then all fields will be cleared, as though RecordClear had been called. Gets the GUID of the record type. The class GUID of the TypeInfo that describes the UDT. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Gets the name of the record type. The name. This method can return one of these values. This doc was truncated. The caller must free the BSTR by calling SysFreeString. Gets the number of bytes of memory necessary to hold the record instance. The size of a record instance, in bytes. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Retrieves the type information that describes a UDT or safearray of UDTs. The information type of the record. This method can return one of these values. This doc was truncated. AddRef is called on the pointer ppTypeInfo. Returns a pointer to the VARIANT containing the value of a given field name. The instance of a record. The field name. The VARIANT that you want to hold the value of the field name, szFieldName. On return, places a copy of the field's value in the variant. This method can return one of these values. This doc was truncated. The VARIANT that you pass in contains a copy of the field's value upon return. If you modify the VARIANT then the underlying record field does not change. The caller allocates memory of the VARIANT. The method VariantClear is called for pvarField before copying. Read more on docs.microsoft.com. Returns a pointer to the value of a given field name without copying the value and allocating resources. The instance of a record. The name of the field. The VARIANT that will contain the UDT upon return. Receives the value of the field upon return. This method can return one of these values. This doc was truncated. Upon return, the VARIANT you pass contains a direct pointer to the record's field, ppvDataCArray. If you modify the VARIANT, then the underlying record field will change. The caller allocates memory of the VARIANT, but does not own the memory so cannot free pvarField. This method calls VariantClear for pvarField before filling in the requested field. Read more on docs.microsoft.com. Puts a variant into a field. The only legal values for the wFlags parameter is INVOKE_PROPERTYPUT or INVOKE_PROPERTYPUTREF. If INVOKE_PROPERTYPUTREF is passed in then PutField just assigns the value of the variant that is passed in to the field using normal coercion rules. If INVOKE_PROPERTYPUT is passed in then specific rules apply. If the field is declared as a class that derives from IDispatch and the field's value is NULL then an error will be returned. If the field's value is not NULL then the variant will be passed to the default property supported by the object referenced by the field. If the field is not declared as a class derived from IDispatch then an error will be returned. If the field is declared as a variant of type VT_Dispatch then the default value of the object is assigned to the field. Otherwise, the variant's value is assigned to the field. Read more on docs.microsoft.com. The pointer to an instance of the record. The name of the field of the record. The pointer to the variant. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Passes ownership of the data to the assigned field by placing the actual data into the field. The only legal values for the wFlags parameter is INVOKE_PROPERTYPUT or INVOKE_PROPERTYPUTREF. An instance of the record described by IRecordInfo. The name of the field of the record. The variant to be put into the field. This method can return one of these values. This doc was truncated. Learn more about this API from docs.microsoft.com. Gets the names of the fields of the record. The number of names to return. The name of the array of type BSTR. If the rgBstrNames parameter is NULL, then pcNames is returned with the number of field names. It the rgBstrNames parameter is not NULL, then the string names contained in rgBstrNames are returned. If the number of names in pcNames and rgBstrNames are not equal then the lesser number of the two is the number of returned field names. The caller needs to free the BSTRs inside the array returned in rgBstrNames. Read more on docs.microsoft.com. This method can return one of these values. This doc was truncated. The caller should allocate memory for the array of BSTRs. If the array is larger than needed, set the unused portion to 0. On return, the caller will need to free each contained BSTR using SysFreeString. In case of out of memory, pcNames points to error code. Read more on docs.microsoft.com. Determines whether the record that is passed in matches that of the current record information. The information of the record. This doc was truncated. Learn more about this API from docs.microsoft.com. Allocates memory for a new record, initializes the instance and returns a pointer to the record. This method returns a pointer to the created record. The memory is set to zeros before it is returned. The records created must be freed by calling RecordDestroy. Read more on docs.microsoft.com. Creates a copy of an instance of a record to the specified location. An instance of the record to be copied. The new record with data copied from pvSource. This method can return one of these values. This doc was truncated. The records created must be freed by calling RecordDestroy. Releases the resources and deallocates the memory of the record. An instance of the record to be destroyed. This method can return one of these values. This doc was truncated. RecordClear is called to release the resources held by the instance of a record without deallocating memory.
Note  This method can only be called on records allocated through RecordCreate and RecordCreateCopy. If you allocate the record yourself, you cannot call this method.
 
 Read more on docs.microsoft.com. The IID guid for this interface. {0000002f-0000-0000-c000-000000000046} Contains information needed for transferring a structure element, parameter, or function return value between processes. Learn more about this API from docs.microsoft.com. The default value for the parameter, if PARAMFLAG_FHASDEFAULT is specified in wParamFlags. The parameter flags. See PARAMFLAG Constants. Contains information about the default value of a parameter. Learn more about this API from docs.microsoft.com. The size of the structure. The default value of the parameter. Specifies the variant types. The following table shows where these values can be used. This doc was truncated. Read more on docs.microsoft.com. Not specified. Null. A 2-byte integer. A 4-byte integer. A 4-byte real. An 8-byte real. Currency. A date. A string. An IDispatch pointer. An SCODE value. A Boolean value. True is -1 and false is 0. A variant pointer. An IUnknown pointer. A 16-byte fixed-pointer value. A character. An unsigned character. An unsigned short. An unsigned long. A 64-bit integer. A 64-bit unsigned integer. An integer. An unsigned integer. A C-style void. An HRESULT value. A pointer type. A safe array. Use VT_ARRAY in VARIANT. A C-style array. A user-defined type. A null-terminated string. A wide null-terminated string. A user-defined type. A signed machine register size width. An unsigned machine register size width. A FILETIME value. Length-prefixed bytes. The name of the stream follows. The name of the storage follows. The stream contains an object. The storage contains an object. The blob contains an object. A clipboard format. A class ID. A stream with a GUID version. Reserved. A simple counted array. A SAFEARRAY pointer. A void pointer for local use. VARIANTARG describes arguments passed within DISPPARAMS, and VARIANT to specify variant data that cannot be passed by reference. Learn more about this API from docs.microsoft.com. 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. Gets the DataTransferManager instance for the specified window. The window whose DataTransferManager instance is to be retrieved. The requested interface ID of the DataTransferManager instance. If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This method is equivalent to the DataTransferManager.GetForCurrentView method, except that you specify a window from a multi-window Windows Store app. Displays the UI for sharing content for the specified window. The window to show the share UI for. If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This method is equivalent to the DataTransferManager.ShowShareUI method, except that you specify a window from a multi-window Windows Store app. The IID guid for this interface. {3a3dcd6c-3eab-43dc-bcde-45671ce800c8} 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 information about a window's maximized size and position and its minimum and maximum tracking size. For systems with multiple monitors, the ptMaxSize and ptMaxPosition members describe the maximized size and position of the window on the primary monitor, even if the window ultimately maximizes onto a secondary monitor. In that case, the window manager adjusts these values to compensate for differences between the primary monitor and the monitor that displays the window. Thus, if the user leaves ptMaxSize untouched, a window on a monitor larger than the primary monitor maximizes to the size of the larger monitor. Type: POINT Reserved; do not use. Read more on docs.microsoft.com. Type: POINT The maximized width (x member) and the maximized height (y member) of the window. For top-level windows, this value is based on the width of the primary monitor. Read more on docs.microsoft.com. Type: POINT The position of the left side of the maximized window (x member) and the position of the top of the maximized window (y member). For top-level windows, this value is based on the position of the primary monitor. Read more on docs.microsoft.com. Type: POINT The minimum tracking width (x member) and the minimum tracking height (y member) of the window. This value can be obtained programmatically from the system metrics SM_CXMINTRACK and SM_CYMINTRACK (see the GetSystemMetrics function). Read more on docs.microsoft.com. Type: POINT The maximum tracking width (x member) and the maximum tracking height (y member) of the window. This value is based on the size of the virtual screen and can be obtained programmatically from the system metrics SM_CXMAXTRACK and SM_CYMAXTRACK (see the GetSystemMetrics function). Read more on docs.microsoft.com. Contains message information from a thread's message queue. Learn more about this API from docs.microsoft.com. Type: HWND A handle to the window whose window procedure receives the message. This member is NULL when the message is a thread message. Read more on docs.microsoft.com. Type: UINT The message identifier. Applications can only use the low word; the high word is reserved by the system. Read more on docs.microsoft.com. Type: WPARAM Additional information about the message. The exact meaning depends on the value of the message member. Read more on docs.microsoft.com. Type: LPARAM Additional information about the message. The exact meaning depends on the value of the message member. Read more on docs.microsoft.com. Type: DWORD The time at which the message was posted. Read more on docs.microsoft.com. Type: POINT The cursor position, in screen coordinates, when the message was posted. Read more on docs.microsoft.com. Contains information that an application can use while processing the WM_NCCALCSIZE message to calculate the size, position, and valid contents of the client area of a window. Learn more about this API from docs.microsoft.com. Type: RECT[3] An array of rectangles. The meaning of the array of rectangles changes during the processing of the WM_NCCALCSIZE message. When the window procedure receives the WM_NCCALCSIZE message, the first rectangle contains the new coordinates of a window that has been moved or resized, that is, it is the proposed new window coordinates. The second contains the coordinates of the window before it was moved or resized. The third contains the coordinates of the window's client area before the window was moved or resized. If the window is a child window, the coordinates are relative to the client area of the parent window. If the window is a top-level window, the coordinates are relative to the screen origin. When the window procedure returns, the first rectangle contains the coordinates of the new client rectangle resulting from the move or resize. The second rectangle contains the valid destination rectangle, and the third rectangle contains the valid source rectangle. The last two rectangles are used in conjunction with the return value of the WM_NCCALCSIZE message to determine the area of the window to be preserved. Read more on docs.microsoft.com. Type: PWINDOWPOS A pointer to a WINDOWPOS structure that contains the size and position values specified in the operation that moved or resized the window. Read more on docs.microsoft.com. Contains the styles for a window. The styles in styleOld and styleNew can be either the window styles (WS_*) or the extended window styles (WS_EX_*), depending on the wParam of the message that includes STYLESTRUCT. The styleOld and styleNew members indicate the styles through their bit pattern. Note that several styles are equal to zero; to detect these styles, test for the negation of their inverse style. For example, to see if WS_EX_LEFT is set, you test for ~WS_EX_RIGHT. Read more on docs.microsoft.com. Type: DWORD The previous styles for a window. For more information, see the Remarks. Read more on docs.microsoft.com. Type: DWORD The new styles for a window. For more information, see the Remarks. Read more on docs.microsoft.com. Contains information about the placement of a window on the screen. If the window is a top-level window that does not have the WS_EX_TOOLWINDOW window style, then the coordinates represented by the following members are in workspace coordinates: ptMinPosition, ptMaxPosition, and rcNormalPosition. Otherwise, these members are in screen coordinates. Workspace coordinates differ from screen coordinates in that they take the locations and sizes of application toolbars (including the taskbar) into account. Workspace coordinate (0,0) is the upper-left corner of the workspace area, the area of the screen not being used by application toolbars. The coordinates used in a WINDOWPLACEMENT structure should be used only by the GetWindowPlacement and SetWindowPlacement functions. Passing workspace coordinates to functions which expect screen coordinates (such as SetWindowPos) will result in the window appearing in the wrong location. For example, if the taskbar is at the top of the screen, saving window coordinates using GetWindowPlacement and restoring them using SetWindowPos causes the window to appear to "creep" up the screen. Read more on docs.microsoft.com. Type: UINT The length of the structure, in bytes. Before calling the GetWindowPlacement or SetWindowPlacement functions, set this member to sizeof(WINDOWPLACEMENT). GetWindowPlacement and SetWindowPlacement fail if this member is not set correctly. Read more on docs.microsoft.com. Type: UINT Type: POINT The coordinates of the window's upper-left corner when the window is minimized. Read more on docs.microsoft.com. Type: POINT The coordinates of the window's upper-left corner when the window is maximized. Read more on docs.microsoft.com. Type: RECT The window's coordinates when the window is in the restored position. Read more on docs.microsoft.com. Contains information about the size and position of a window. Learn more about this API from docs.microsoft.com. Type: HWND A handle to the window. Read more on docs.microsoft.com. Type: HWND The position of the window in Z order (front-to-back position). This member can be a handle to the window behind which this window is placed, or can be one of the special values listed with the SetWindowPos function. Read more on docs.microsoft.com. Type: int The position of the left edge of the window. Read more on docs.microsoft.com. Type: int The position of the top edge of the window. Read more on docs.microsoft.com. Type: int The window width, in pixels. Read more on docs.microsoft.com. Type: int The window height, in pixels. Read more on docs.microsoft.com. Type: UINT 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. Contains information about the high contrast accessibility feature. (Unicode) An application uses this structure when calling the[SystemParametersInfoW function](nf-winuser-systemparametersinfow.md) with the SPI_GETHIGHCONTRAST or SPI_SETHIGHCONTRAST value. When using SPI_GETHIGHCONTRAST, an application must specify the cbSize member of the HIGHCONTRAST structure; the SystemParametersInfo function fills the remaining members. An application must specify all structure members when using the SPI_SETHIGHCONTRAST value. > [!NOTE] > The winuser.h header defines HIGHCONTRAST 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 Specifies the size, in bytes, of this structure. Read more on docs.microsoft.com. Type: DWORD Type: LPTSTR Points to a string that contains the name of the color scheme that will be set to the default scheme. The system allocates this buffer, free it with LocalFree. Read more on docs.microsoft.com. Returned by the GetThemeMargins function to define the margins of windows that have visual styles applied. Learn more about this API from docs.microsoft.com. Type: int Width of the left border that retains its size. Read more on docs.microsoft.com. Type: int Width of the right border that retains its size. Read more on docs.microsoft.com. Type: int Height of the top border that retains its size. Read more on docs.microsoft.com. Type: int Height of the bottom border that retains its size. 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. Used by the TrackMouseEvent function to track when the mouse pointer leaves a window or hovers over a window for a specified amount of time. The system default hover time-out is initially the menu drop-down time, which is 400 milliseconds. You can call SystemParametersInfo and use SPI_GETMOUSEHOVERTIME to retrieve the default hover time-out. The system default hover rectangle is the same as the double-click rectangle. You can call SystemParametersInfo and use SPI_GETMOUSEHOVERWIDTH and SPI_GETMOUSEHOVERHEIGHT to retrieve the size of the rectangle within which the mouse pointer has to stay for TrackMouseEvent to generate a WM_MOUSEHOVER message. Read more on docs.microsoft.com. Type: DWORD The size of the TRACKMOUSEEVENT structure, in bytes. Read more on docs.microsoft.com. Type: DWORD Type: HWND A handle to the window to track. Read more on docs.microsoft.com. Type: DWORD The hover time-out (if TME_HOVER was specified in dwFlags), in milliseconds. Can be HOVER_DEFAULT, which means to use the system default hover time-out. Read more on docs.microsoft.com. A BITMAPINFOHEADER structure that contains information about the dimensions of color format. . Read more on docs.microsoft.com. The bmiColors member contains one of the following: This doc was truncated. Read more on docs.microsoft.com. Computes the amount of memory that must be allocated to store this struct, including the specified number of elements in the variable length inline array at the end. The BITMAPINFOHEADER structure contains information about the dimensions and color format of a device-independent bitmap (DIB).

Color Tables

The BITMAPINFOHEADER structure may be followed by an array of palette entries or color masks. The rules depend on the value of biCompression. This doc was truncated. Read more on docs.microsoft.com. Specifies the number of bytes required by the structure. This value does not include the size of the color table or the size of the color masks, if they are appended to the end of structure. See Remarks. Specifies the width of the bitmap, in pixels. For information about calculating the stride of the bitmap, see Remarks. Specifies the height of the bitmap, in pixels. This doc was truncated. Read more on docs.microsoft.com. Specifies the number of planes for the target device. This value must be set to 1. Specifies the number of bits per pixel (bpp). For uncompressed formats, this value is the average number of bits per pixel. For compressed formats, this value is the implied bit depth of the uncompressed image, after the image has been decoded. For compressed video and YUV formats, this member is a FOURCC code, specified as a DWORD in little-endian order. For example, YUYV video has the FOURCC 'VYUY' or 0x56595559. For more information, see FOURCC Codes. For uncompressed RGB formats, the following values are possible: This doc was truncated. Read more on docs.microsoft.com. Specifies the size, in bytes, of the image. This can be set to 0 for uncompressed RGB bitmaps. Specifies the horizontal resolution, in pixels per meter, of the target device for the bitmap. Specifies the vertical resolution, in pixels per meter, of the target device for the bitmap. Specifies the number of color indices in the color table that are actually used by the bitmap. See Remarks for more information. Specifies the number of color indices that are considered important for displaying the bitmap. If this value is zero, all colors are important. The BLENDFUNCTION structure controls blending by specifying the blending functions for source and destination bitmaps. When the AlphaFormat member is AC_SRC_ALPHA, the source bitmap must be 32 bpp. If it is not, the AlphaBlend function will fail. When the BlendOp member is AC_SRC_OVER, the source bitmap is placed over the destination bitmap based on the alpha values of the source pixels. If the source bitmap has no per-pixel alpha value (that is, AC_SRC_ALPHA is not set), the SourceConstantAlpha value determines the blend of the source and destination bitmaps, as shown in the following table. Note that SCA is used for SourceConstantAlpha here. Also, SCA is divided by 255 because it has a value that ranges from 0 to 255. This doc was truncated. Read more on docs.microsoft.com. The source blend operation. Currently, the only source and destination blend operation that has been defined is AC_SRC_OVER. For details, see the following Remarks section. Must be zero. Specifies an alpha transparency value to be used on the entire source bitmap. The SourceConstantAlpha value is combined with any per-pixel alpha values in the source bitmap. If you set SourceConstantAlpha to 0, it is assumed that your image is transparent. Set the SourceConstantAlpha value to 255 (opaque) when you only want to use per-pixel alpha values. This member controls the way the source and destination bitmaps are interpreted. AlphaFormat has the following value. This doc was truncated. Read more on docs.microsoft.com. 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. The MONITORINFOEX structure contains information about a display monitor.The GetMonitorInfo function stores information into a MONITORINFOEX structure or a MONITORINFO structure.The MONITORINFOEX structure is a superset of the MONITORINFO structure. (Unicode) > [!NOTE] > The winuser.h header defines MONITORINFOEX 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. A string that specifies the device name of the monitor being used. Most applications have no use for a display monitor name, and so can save some bytes by using a MONITORINFO structure. The PAINTSTRUCT structure contains information for an application. This information can be used to paint the client area of a window owned by that application. Learn more about this API from docs.microsoft.com. A handle to the display DC to be used for painting. Indicates whether the background must be erased. This value is nonzero if the application should erase the background. The application is responsible for erasing the background if a window class is created without a background brush. For more information, see the description of the hbrBackground member of the WNDCLASS structure. A RECT structure that specifies the upper left and lower right corners of the rectangle in which the painting is requested, in device units relative to the upper-left corner of the client area. Reserved; used internally by the system. Reserved; used internally by the system. Reserved; used internally by the system. The RGBQUAD structure describes a color consisting of relative intensities of red, green, and blue. The bmiColors member of the BITMAPINFO structure consists of an array of RGBQUAD structures. The intensity of blue in the color. The intensity of green in the color. The intensity of red in the color. This member is reserved and must be zero. Flags used by the [DwmGetWindowAttribute](/windows/desktop/api/dwmapi/nf-dwmapi-dwmgetwindowattribute) and [DwmSetWindowAttribute](/windows/desktop/api/dwmapi/nf-dwmapi-dwmsetwindowattribute) functions. Learn more about this API from docs.microsoft.com. Use with DwmGetWindowAttribute. Discovers whether non-client rendering is enabled. The retrieved value is of type BOOL. TRUE if non-client rendering is enabled; otherwise, FALSE. Use with DwmSetWindowAttribute. Sets the non-client rendering policy. The pvAttribute parameter points to a value from the DWMNCRENDERINGPOLICY enumeration. Use with DwmSetWindowAttribute. Enables or forcibly disables DWM transitions. The pvAttribute parameter points to a value of type BOOL. TRUE to disable transitions, or FALSE to enable transitions. Use with DwmSetWindowAttribute. Enables content rendered in the non-client area to be visible on the frame drawn by DWM. The pvAttribute parameter points to a value of type BOOL. TRUE to enable content rendered in the non-client area to be visible on the frame; otherwise, FALSE. Use with DwmGetWindowAttribute. Retrieves the bounds of the caption button area in the window-relative space. The retrieved value is of type RECT. If the window is minimized or otherwise not visible to the user, then the value of the **RECT** retrieved is undefined. You should check whether the retrieved **RECT** contains a boundary that you can work with, and if it doesn't then you can conclude that the window is minimized or otherwise not visible. Use with DwmSetWindowAttribute. Specifies whether non-client content is right-to-left (RTL) mirrored. The pvAttribute parameter points to a value of type BOOL. TRUE if the non-client content is right-to-left (RTL) mirrored; otherwise, FALSE. Use with DwmSetWindowAttribute. Forces the window to display an iconic thumbnail or peek representation (a static bitmap), even if a live or snapshot representation of the window is available. This value is normally set during a window's creation, and not changed throughout the window's lifetime. Some scenarios, however, might require the value to change over time. The pvAttribute parameter points to a value of type BOOL. TRUE to require a iconic thumbnail or peek representation; otherwise, FALSE. Use with DwmSetWindowAttribute. Sets how Flip3D treats the window. The pvAttribute parameter points to a value from the DWMFLIP3DWINDOWPOLICY enumeration. Use with DwmGetWindowAttribute. Retrieves the extended frame bounds rectangle in screen space. The retrieved value is of type RECT. Use with DwmSetWindowAttribute. The window will provide a bitmap for use by DWM as an iconic thumbnail or peek representation (a static bitmap) for the window. DWMWA_HAS_ICONIC_BITMAP can be specified with DWMWA_FORCE_ICONIC_REPRESENTATION. DWMWA_HAS_ICONIC_BITMAP normally is set during a window's creation and not changed throughout the window's lifetime. Some scenarios, however, might require the value to change over time. The pvAttribute parameter points to a value of type BOOL. TRUE to inform DWM that the window will provide an iconic thumbnail or peek representation; otherwise, FALSE. Windows Vista and earlier: This value is not supported. Read more on docs.microsoft.com. Use with DwmSetWindowAttribute. Do not show peek preview for the window. The peek view shows a full-sized preview of the window when the mouse hovers over the window's thumbnail in the taskbar. If this attribute is set, hovering the mouse pointer over the window's thumbnail dismisses peek (in case another window in the group has a peek preview showing). The pvAttribute parameter points to a value of type BOOL. TRUE to prevent peek functionality, or FALSE to allow it. Windows Vista and earlier: This value is not supported. Read more on docs.microsoft.com. Use with DwmSetWindowAttribute. Prevents a window from fading to a glass sheet when peek is invoked. The pvAttribute parameter points to a value of type BOOL. TRUE to prevent the window from fading during another window's peek, or FALSE for normal behavior. Windows Vista and earlier: This value is not supported. Read more on docs.microsoft.com. Use with DwmSetWindowAttribute. Cloaks the window such that it is not visible to the user. The window is still composed by DWM. Using with DirectComposition: Use the DWMWA_CLOAK flag to cloak the layered child window when animating a representation of the window's content via a DirectComposition visual that has been associated with the layered child window. For more details on this usage case, see How to animate the bitmap of a layered child window. Windows 7 and earlier: This value is not supported. Read more on docs.microsoft.com. Use with DwmSetWindowAttribute. Freeze the window's thumbnail image with its current visuals. Do no further live updates on the thumbnail image to match the window's contents. Windows 7 and earlier: This value is not supported. Read more on docs.microsoft.com. Use with [DwmSetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmsetwindowattribute). Enables a non-UWP window to use host backdrop brushes. If this flag is set, then a Win32 app that calls [Windows::UI::Composition](/uwp/api/windows.ui.composition) APIs can build transparency effects using the host backdrop brush (see [Compositor.CreateHostBackdropBrush](/uwp/api/windows.ui.composition.compositor.createhostbackdropbrush)). The pvAttribute parameter points to a value of type BOOL. TRUE to enable host backdrop brushes for the window, or FALSE to disable it. This value is supported starting with Windows 11 Build 22000. Read more on docs.microsoft.com. Use with [DwmSetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmsetwindowattribute). Allows the window frame for this window to be drawn in dark mode colors when the dark mode system setting is enabled. For compatibility reasons, all windows default to light mode regardless of the system setting. The pvAttribute parameter points to a value of type **BOOL**. TRUE to honor dark mode for the window, FALSE to always use light mode. This value is supported starting with Windows 11 Build 22000. Read more on docs.microsoft.com. Use with [DwmSetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmsetwindowattribute). Specifies the rounded corner preference for a window. The pvAttribute parameter points to a value of type [DWM_WINDOW_CORNER_PREFERENCE](ne-dwmapi-dwm_window_corner_preference.md). This value is supported starting with Windows 11 Build 22000. Read more on docs.microsoft.com. Use with [DwmSetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmsetwindowattribute). Specifies the color of the window border. The pvAttribute parameter points to a value of type [COLORREF](/windows/win32/gdi/colorref). The app is responsible for changing the border color according to state changes, such as a change in window activation. This value is supported starting with Windows 11 Build 22000. Read more on docs.microsoft.com. Use with [DwmSetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmsetwindowattribute). Specifies the color of the caption. The pvAttribute parameter points to a value of type [COLORREF](/windows/win32/gdi/colorref). This value is supported starting with Windows 11 Build 22000. Read more on docs.microsoft.com. Use with [DwmSetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmsetwindowattribute). Specifies the color of the caption text. The pvAttribute parameter points to a value of type [COLORREF](/windows/win32/gdi/colorref). This value is supported starting with Windows 11 Build 22000. Read more on docs.microsoft.com. Use with [DwmGetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmgetwindowattribute). Retrieves the width of the outer border that the DWM would draw around this window. The value can vary depending on the DPI of the window. The pvAttribute parameter points to a value of type **UINT**. This value is supported starting with Windows 11 Build 22000. Read more on docs.microsoft.com. Use with [DwmGetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmgetwindowattribute) or [DwmSetWindowAttribute](/windows/win32/api/dwmapi/nf-dwmapi-dwmsetwindowattribute). Retrieves or specifies the system-drawn backdrop material of a window, including behind the non-client area. The *pvAttribute* parameter points to a value of type [DWM_SYSTEMBACKDROP_TYPE](ne-dwmapi-dwm_systembackdrop_type.md). This value is supported starting with Windows 11 Build 22621. Read more on docs.microsoft.com. The maximum recognized DWMWINDOWATTRIBUTE value, used for validation purposes. The DWM_WINDOW_CORNER_PREFERENCE enumeration (dwmapi.h) specifies the rounded corner preference for a window. Let the system decide when to round window corners. Never round window corners. Round the corners, if appropriate. Round the corners if appropriate, with a small radius. Provides access to a rectangular area of the bitmap. Type: const WICRect* The rectangle to be accessed. Read more on docs.microsoft.com. Type: DWORD The access mode you wish to obtain for the lock. This is a bitwise combination of WICBitmapLockFlags for read, write, or read and write access. This doc was truncated. Read more on docs.microsoft.com. Type: IWICBitmapLock** A pointer that receives the locked memory location. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Locks are exclusive for writing but can be shared for reading. You cannot call CopyPixels while the IWICBitmap is locked for writing. Doing so will return an error, since locks are exclusive. Provides access for palette modifications. Type: IWICPalette* The palette to use for conversion. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Changes the physical resolution of the image. Type: double The horizontal resolution. Read more on docs.microsoft.com. Type: double The vertical resolution. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This method has no effect on the actual pixels or samples stored in the bitmap. Instead the interpretation of the sampling rate is modified. This means that a 96 DPI image which is 96 pixels wide is one inch. If the physical resolution is modified to 48 DPI, then the bitmap is considered to be 2 inches wide but has the same number of pixels. If the resolution is less than REAL_EPSILON (1.192092896e-07F) the error code WINCODEC_ERR_INVALIDPARAMETER is returned. Read more on docs.microsoft.com. The IID guid for this interface. {00000121-a8f2-4877-ba0a-fd2b6645fb94} Initializes the bitmap clipper with the provided parameters. Type: IWICBitmapSource* he input bitmap source. Read more on docs.microsoft.com. Type: const WICRect* The rectangle of the bitmap source to clip. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {e4fbcf03-223d-4e81-9333-d635556dd1b5} Retrieves the container GUID associated with the codec. Type: GUID* Receives the container GUID. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves a value indicating whether the codec supports animation. Type: BOOL* Receives TRUE if the codec supports images with timing information; otherwise, FALSE. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves a value indicating whether the codec supports chromakeys. Type: BOOL* Receives TRUE if the codec supports chromakeys; otherwise, FALSE. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves a value indicating whether the codec supports lossless formats. Type: BOOL* Receives TRUE if the codec supports lossless formats; otherwise, FALSE. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves a value indicating whether the codec supports multi frame images. Type: BOOL* Receives TRUE if the codec supports multi frame images; otherwise, FALSE. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves a value indicating whether the given mime type matches the mime type of the codec. Type: LPCWSTR The mime type to compare. Read more on docs.microsoft.com. Type: BOOL* Receives TRUE if the mime types match; otherwise, FALSE. Read more on docs.microsoft.com. Type: HRESULT This method can return one of these values. This doc was truncated.
Note  The Windows provided codecs do not implement this method and return E_NOTIMPL.
 
 Read more on docs.microsoft.com. The IID guid for this interface. {e87a44c4-b76e-4c47-8b09-298eb12a2714} Retrieves the capabilities of the decoder based on the specified stream. Type: IStream* The stream to retrieve the decoder capabilities from. Read more on docs.microsoft.com. Type: DWORD* The WICBitmapDecoderCapabilities of the decoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Custom decoder implementations should save the current position of the specified IStream, read whatever information is necessary in order to determine which capabilities it can provide for the supplied stream, and restore the stream position. Initializes the decoder with the provided stream. Type: IStream* The stream to use for initialization. The stream contains the encoded pixels which are decoded each time the CopyPixels method on the IWICBitmapFrameDecode interface (see GetFrame) is invoked. Read more on docs.microsoft.com. Type: WICDecodeOptions The WICDecodeOptions to use for initialization. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the image's container format. Type: GUID* A pointer that receives the image's container format GUID. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves an IWICBitmapDecoderInfo for the image. Type: IWICBitmapDecoderInfo** A pointer that receives a pointer to an IWICBitmapDecoderInfo. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Copies the decoder's IWICPalette . Type: IWICPalette* AnIWICPalette to which the decoder's global palette is to be copied. Use CreatePalette to create the destination palette before calling CopyPalette. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. CopyPalette returns a global palette (a palette that applies to all the frames in the image) if there is one; otherwise, it returns WINCODEC_ERR_PALETTEUNAVAILABLE. If an image doesn't have a global palette, it may still have a frame-level palette, which can be retrieved using IWICBitmapFrameDecode::CopyPalette. Retrieves the metadata query reader from the decoder. Type: IWICMetadataQueryReader** Receives a pointer to the decoder's IWICMetadataQueryReader. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If an image format does not support container-level metadata, this will return WINCODEC_ERR_UNSUPPORTEDOPERATION. The only Windows provided image format that supports container-level metadata is GIF. Instead, use IWICBitmapFrameDecode::GetMetadataQueryReader. Retrieves a preview image, if supported. Type: IWICBitmapSource** Receives a pointer to the preview bitmap if supported. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Not all formats support previews. Only the native Microsoft Windows Digital Photo (WDP) codec support previews. Retrieves the IWICColorContext objects of the image. Type: UINT The number of color contexts to retrieve. This value must be the size of, or smaller than, the size available to ppIColorContexts. Read more on docs.microsoft.com. Type: IWICColorContext** A pointer that receives a pointer to the IWICColorContext. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the number of color contexts contained in the image. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves a bitmap thumbnail of the image, if one exists Type: IWICBitmapSource** Receives a pointer to the IWICBitmapSource of the thumbnail. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The returned thumbnail can be of any size, so the caller should scale the thumbnail to the desired size. The only Windows provided image formats that support thumbnails are JPEG, TIFF, and JPEG-XR. If the thumbnail is not available, this will return WINCODEC_ERR_CODECNOTHUMBNAIL. Retrieves the total number of frames in the image. Type: UINT* A pointer that receives the total number of frames in the image. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the specified frame of the image. Type: UINT The particular frame to retrieve. Read more on docs.microsoft.com. Type: IWICBitmapFrameDecode** A pointer that receives a pointer to the IWICBitmapFrameDecode. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {9edde9e7-8dee-47ea-99df-e6faf2ed44bf} Retrieves the file pattern signatures supported by the decoder. Type: UINT The array size of the pPatterns array. Read more on docs.microsoft.com. Type: WICBitmapPattern* Receives a list of WICBitmapPattern objects supported by the decoder. Read more on docs.microsoft.com. Type: UINT* Receives the number of patterns the decoder supports. Read more on docs.microsoft.com. Type: UINT* Receives the actual buffer size needed to retrieve all pattern signatures supported by the decoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. To retrieve all pattern signatures, this method should first be called with pPatterns set to NULL to retrieve the actual buffer size needed through pcbPatternsActual. Once the needed buffer size is known, allocate a buffer of the needed size and call GetPatterns again with the allocated buffer. Read more on docs.microsoft.com. Retrieves a value that indicates whether the codec recognizes the pattern within a specified stream. Type: IStream* The stream to pattern match within. Read more on docs.microsoft.com. Type: BOOL* A pointer that receives TRUE if the patterns match; otherwise, FALSE. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new IWICBitmapDecoder instance. Type: IWICBitmapDecoder** A pointer that receives a pointer to a new instance of the IWICBitmapDecoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {d8cd007f-d08f-4191-9bfc-236ea7f0e4b5} Initializes the encoder with an IStream which tells the encoder where to encode the bits. Type: IStream* The output stream. Read more on docs.microsoft.com. Type: WICBitmapEncoderCacheOption The WICBitmapEncoderCacheOption used on initialization. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the encoder's container format. Type: GUID* A pointer that receives the encoder's container format GUID. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves an IWICBitmapEncoderInfo for the encoder. Type: IWICBitmapEncoderInfo** A pointer that receives a pointer to an IWICBitmapEncoderInfo. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Sets the IWICColorContext objects for the encoder. Type: UINT The number of IWICColorContext to set. Read more on docs.microsoft.com. Type: IWICColorContext** A pointer an IWICColorContext pointer containing the color contexts to set for the encoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Sets the global palette for the image. Type: IWICPalette* The IWICPalette to use as the global palette. Read more on docs.microsoft.com. Type: HRESULT Returns S_OK if successful, or an error value otherwise. Returns WINCODEC_ERR_UNSUPPORTEDOPERATION if the feature is not supported by the encoder. Only GIF images support an optional global palette, and you must set the global palette before adding any frames to the image. You only need to set the palette for indexed pixel formats. Sets the global thumbnail for the image. Type: IWICBitmapSource* The IWICBitmapSource to set as the global thumbnail. Read more on docs.microsoft.com. Type: HRESULT Returns S_OK if successful, or an error value otherwise. Returns WINCODEC_ERR_UNSUPPORTEDOPERATION if the feature is not supported by the encoder. Learn more about this API from docs.microsoft.com. Sets the global preview for the image. Type: IWICBitmapSource* The IWICBitmapSource to use as the global preview. Read more on docs.microsoft.com. Type: HRESULT Returns S_OK if successful, or an error value otherwise. Returns WINCODEC_ERR_UNSUPPORTEDOPERATION if the feature is not supported by the encoder. Learn more about this API from docs.microsoft.com. Creates a new IWICBitmapFrameEncode instance. Type: IWICBitmapFrameEncode** A pointer that receives a pointer to the new instance of an IWICBitmapFrameEncode. Read more on docs.microsoft.com. Type: IPropertyBag2** Optional. Receives the named properties to use for subsequent frame initialization. See Remarks. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The parameter ppIEncoderOptions can be used to receive an IPropertyBag2 that can then be used to specify encoder options. This is done by passing a pointer to a NULL IPropertyBag2 pointer in ppIEncoderOptions. The returned IPropertyBag2 is initialized with all encoder options that are available for the given format, at their default values. To specify non-default encoding behavior, set the needed encoder options on the IPropertyBag2 and pass it to IWICBitmapFrameEncode::Initialize.
Note  Do not pass in a pointer to an initialized IPropertyBag2. The pointer will be overwritten, and the original IPropertyBag2 will not be freed.
 
Otherwise, you can pass NULL in ppIEncoderOptions if you do not intend to specify encoder options. See Encoding Overview for an example of how to set encoder options. For formats that support encoding multiple frames (for example, TIFF, JPEG-XR), you can work on only one frame at a time. This means that you must call IWICBitmapFrameEncode::Commit before you call CreateNewFrame again. Read more on docs.microsoft.com. Commits all changes for the image and closes the stream. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. To finalize an image, both the frame Commit and the encoder Commit must be called. However, only call the encoder Commit method after all frames have been committed. After the encoder has been committed, it can't be re-initialized or reused with another stream. A new encoder interface must be created, for example, with IWICImagingFactory::CreateEncoder. For the encoder Commit to succeed, you must at a minimum call IWICBitmapEncoder::Initialize and either IWICBitmapFrameEncode::WriteSource or IWICBitmapFrameEncode::WritePixels. IWICBitmapFrameEncode::WriteSource specifies all parameters needed to encode the image data. IWICBitmapFrameEncode::WritePixels requires that you also call IWICBitmapFrameEncode::SetSize, IWICBitmapFrameEncode::SetPixelFormat, and IWICBitmapFrameEncode::SetPalette (if the pixel format is indexed). Read more on docs.microsoft.com. Retrieves a metadata query writer for the encoder. Type: IWICMetadataQueryWriter** When this method returns, contains a pointer to the encoder's metadata query writer. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {00000103-a8f2-4877-ba0a-fd2b6645fb94} Creates a new IWICBitmapEncoder instance. Type: IWICBitmapEncoder** A pointer that receives a pointer to a new IWICBitmapEncoder instance. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {94c9b4ee-a09f-4f92-8a1e-4a9bce7e76fb} Initializes the bitmap flip rotator with the provided parameters. Type: IWICBitmapSource* The input bitmap source. Read more on docs.microsoft.com. Type: WICBitmapTransformOptions The WICBitmapTransformOptions to flip or rotate the image. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {5009834f-2d6a-41ce-9e1b-17c5aff7a782} Retrieves a metadata query reader for the frame. Type: IWICMetadataQueryReader** When this method returns, contains a pointer to the frame's metadata query reader. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. For image formats with one frame (JPG, PNG, JPEG-XR), the frame-level query reader of the first frame is used to access all image metadata, and the decoder-level query reader isn’t used. For formats with more than one frame (GIF, TIFF), the frame-level query reader for a given frame is used to access metadata specific to that frame, and in the case of GIF a decoder-level metadata reader will be present. If the decoder doesn’t support metadata (BMP, ICO), this will return WINCODEC_ERR_UNSUPPORTEDOPERATION. Retrieves the IWICColorContext associated with the image frame. Type: UINT The number of color contexts to retrieve. This value must be the size of, or smaller than, the size available to ppIColorContexts. Read more on docs.microsoft.com. Type: IWICColorContext** A pointer that receives a pointer to the IWICColorContext objects. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the number of color contexts contained in the image frame. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If NULL is passed for ppIColorContexts, and 0 is passed for cCount, this method will return the total number of color contexts in the image in pcActualCount. The ppIColorContexts array must be filled with valid data: each IWICColorContext* in the array must have been created using IWICImagingFactory::CreateColorContext. Read more on docs.microsoft.com. Retrieves a small preview of the frame, if supported by the codec. Type: IWICBitmapSource** A pointer that receives a pointer to the IWICBitmapSource of the thumbnail. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Not all formats support thumbnails. Joint Photographic Experts Group (JPEG), Tagged Image File Format (TIFF), and Microsoft Windows Digital Photo (WDP) support thumbnails.

Note to Implementers

If the codec does not support thumbnails, return WINCODEC_ERROR_CODECNOTHUMBNAIL rather than E_NOTIMPL. Read more on docs.microsoft.com. The IID guid for this interface. {3b16811b-6a43-4ec9-a813-3d930c13b940} Initializes the frame encoder using the given properties. Type: IPropertyBag2* The set of properties to use for IWICBitmapFrameEncode initialization. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If you don't want any encoding options, pass NULL for pIEncoderOptions. Otherwise, pass the IPropertyBag2 that was provided by IWICBitmapEncoder::CreateNewFrame with updated values. For a complete list of encoding options supported by the Windows-provided codecs, see Native WIC Codecs. Read more on docs.microsoft.com. Sets the output image dimensions for the frame. Type: UINT The width of the output image. Read more on docs.microsoft.com. Type: UINT The height of the output image. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Sets the physical resolution of the output image. Type: double The horizontal resolution value. Read more on docs.microsoft.com. Type: double The vertical resolution value. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Windows Imaging Component (WIC) doesn't perform any special processing as a result of DPI resolution values. For example, data returned from IWICBitmapSource::CopyPixels isn't scaled by the DPI. The app must handle DPI resolution. Requests that the encoder use the specified pixel format. Type: WICPixelFormatGUID* On input, the requested pixel format GUID. On output, the closest pixel format GUID supported by the encoder; this may be different than the requested format. For a list of pixel format GUIDs, see Native Pixel Formats. Read more on docs.microsoft.com. Type: HRESULT Possible return values include the following. This doc was truncated. The encoder might not support the requested pixel format. If not, SetPixelFormat returns the closest match in the memory block that pPixelFormat points to. If the returned pixel format doesn't match the requested format, you must use an IWICFormatConverter object to convert the pixel data. Sets a given number IWICColorContext profiles to the frame. Type: UINT The number of IWICColorContext profiles to set. Read more on docs.microsoft.com. Type: IWICColorContext** A pointer to an IWICColorContext pointer containing the color contexts profiles to set to the frame. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This doc was truncated. Read more on docs.microsoft.com. Sets the IWICPalette for indexed pixel formats. Type: IWICPalette* The IWICPalette to use for indexed pixel formats. The encoder may change the palette to reflect the pixel formats the encoder supports. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This method doesn't fail if called on a frame whose pixel format is set to a non-indexed pixel format. If the target pixel format is a non-indexed format, the palette will be ignored. If you already called IWICBitmapEncoder::SetPalette to set a global palette, this method overrides that palette for the current frame. The palette must be specified before your first call to WritePixels/WriteSource. Doing so will cause WriteSource to use the specified palette when converting the source image to the encoder pixel format. If no palette is specified, a palette will be generated on the first call to WriteSource. Read more on docs.microsoft.com. Sets the frame thumbnail if supported by the codec. Type: IWICBitmapSource* The bitmap source to use as the thumbnail. Read more on docs.microsoft.com. Type: HRESULT Returns S_OK if successful, or an error value otherwise. Returns WINCODEC_ERR_UNSUPPORTEDOPERATION if the feature is not supported by the encoder. We recommend that you call SetThumbnail before calling WritePixels or WriteSource. The thumbnail won't be added to the encoded file if SetThumbnail is called after a call to WritePixels or WriteSource. This doc was truncated. Read more on docs.microsoft.com. Copies scan-line data from a caller-supplied buffer to the IWICBitmapFrameEncode object. Type: UINT The number of lines to encode. Read more on docs.microsoft.com. Type: UINT The stride of the image pixels. Read more on docs.microsoft.com. Type: UINT The size of the pixel buffer. Read more on docs.microsoft.com. Type: BYTE* A pointer to the pixel buffer. Read more on docs.microsoft.com. Type: HRESULT Possible return values include the following. This doc was truncated. Successive WritePixels calls are assumed to be sequential scan-line access in the output image. Encodes a bitmap source. Type: IWICBitmapSource* The bitmap source to encode. Read more on docs.microsoft.com. Type: WICRect* The size rectangle of the bitmap source. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If SetSize is not called prior to calling WriteSource, the size given in prc is used if not NULL. Otherwise, the size of the IWICBitmapSource given in pIBitmapSource is used. If SetPixelFormat is not called prior to calling WriteSource, the pixel format of the IWICBitmapSource given in pIBitmapSource is used. If SetResolution is not called prior to calling WriteSource, the pixel format of pIBitmapSource is used. If SetPalette is not called prior to calling WriteSource, the target pixel format is indexed, and the pixel format of pIBitmapSource matches the encoder frame's pixel format, then the pIBitmapSource pixel format is used. When encoding a GIF image, if the global palette is set and the frame level palette is not set directly by the user or by a custom independent software vendor (ISV) GIF codec, WriteSource will use the global palette to encode the frame even when pIBitmapSource has a frame level palette. Starting with Windows Vista, repeated WriteSource calls can be made as long as the total accumulated source rect height is the same as set through SetSize. Starting with Windows 8.1, the source rect must be at least the dimensions set through SetSize. If the source rect width exceeds the SetSize width, extra pixels on the right side are ignored. If the source rect height exceeds the remaining unfilled height, extra scan lines on the bottom are ignored. Read more on docs.microsoft.com. Commits the frame to the image. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. After the frame Commit has been called, you can't use or reinitialize the IWICBitmapFrameEncode object and any objects created from it. To finalize the image, both the frame Commit and the encoder Commit must be called. However, only call the encoder Commit method after all frames have been committed. Read more on docs.microsoft.com. Gets the metadata query writer for the encoder frame. Type: IWICMetadataQueryWriter** When this method returns, contains a pointer to metadata query writer for the encoder frame. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If you are setting metadata on the frame, you must do this before you use IWICBitmapFrameEncode::WritePixels or IWICBitmapFrameEncode::WriteSource to write any image pixels to the frame The IID guid for this interface. {00000105-a8f2-4877-ba0a-fd2b6645fb94} Retrieves the width and height, in pixels, of the locked rectangle. Type: UINT* A pointer that receives the width of the locked rectangle. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the height of the locked rectangle. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Provides access to the stride value for the memory. Type: UINT* Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Note the stride value is specific to the IWICBitmapLock, not the bitmap. For example, two consecutive locks on the same rectangle of a bitmap may return different pointers and stride values, depending on internal implementation. Read more on docs.microsoft.com. Gets the pointer to the top left pixel in the locked rectangle. Type: UINT* A pointer that receives the size of the buffer. Read more on docs.microsoft.com. Type: BYTE** A pointer that receives a pointer to the top left pixel in the locked rectangle. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The pointer provided by this method should not be used outside of the lifetime of the lock itself. GetDataPointer is not available in multi-threaded apartment applications. Read more on docs.microsoft.com. Gets the pixel format of for the locked area of pixels. This can be used to compute the number of bytes-per-pixel in the locked area. Type: WICPixelFormatGUID* A pointer that receives the pixel format GUID of the locked area. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {00000123-a8f2-4877-ba0a-fd2b6645fb94} Initializes the bitmap scaler with the provided parameters. Type: IWICBitmapSource* The input bitmap source. Read more on docs.microsoft.com. Type: UINT The destination width. Read more on docs.microsoft.com. Type: UINT The destination height. Read more on docs.microsoft.com. Type: WICBitmapInterpolationMode The WICBitmapInterpolationMode to use when scaling. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. IWICBitmapScaler can't be initialized multiple times. For example, when scaling every frame in a multi-frame image, a new IWICBitmapScaler must be created and initialized for each frame. The IID guid for this interface. {00000302-a8f2-4877-ba0a-fd2b6645fb94} Retrieves the pixel width and height of the bitmap. Type: UINT* A pointer that receives the pixel width of the bitmap. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the pixel height of the bitmap Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the pixel format of the bitmap source.. Type: WICPixelFormatGUID* Receives the pixel format GUID the bitmap is stored in. For a list of available pixel formats, see the Native Pixel Formats topic. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The pixel format returned by this method is not necessarily the pixel format the image is stored as. The codec may perform a format conversion from the storage pixel format to an output pixel format. Read more on docs.microsoft.com. Retrieves the sampling rate between pixels and physical world measurements. Type: double* A pointer that receives the x-axis dpi resolution. Read more on docs.microsoft.com. Type: double* A pointer that receives the y-axis dpi resolution. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Some formats, such as GIF and ICO, do not have full DPI support. For GIF, this method calculates the DPI values from the aspect ratio, using a base DPI of (96.0, 96.0). The ICO format does not support DPI at all, and the method always returns (96.0,96.0) for ICO images. Additionally, WIC itself does not transform images based on the DPI values in an image. It is up to the caller to transform an image based on the resolution returned. Read more on docs.microsoft.com. Retrieves the color table for indexed pixel formats. Type: IWICPalette* An IWICPalette. A palette can be created using the CreatePalette method. Read more on docs.microsoft.com. Type: HRESULT Returns one of the following values. This doc was truncated. If the IWICBitmapSource is an IWICBitmapFrameDecode, the function may return the image's global palette if a frame-level palette is not available. The global palette may also be retrieved using the CopyPalette method. Read more on docs.microsoft.com. Instructs the object to produce pixels. Type: const WICRect* The rectangle to copy. A NULL value specifies the entire bitmap. Read more on docs.microsoft.com. Type: UINT The stride of the bitmap Read more on docs.microsoft.com. Type: UINT The size of the buffer. Read more on docs.microsoft.com. Type: BYTE* A pointer to the buffer. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. CopyPixels is one of the two main image processing routines (the other being Lock) triggering the actual processing. It instructs the object to produce pixels according to its algorithm - this may involve decoding a portion of a JPEG stored on disk, copying a block of memory, or even analytically computing a complex gradient. The algorithm is completely dependent on the object implementing the interface. The caller can restrict the operation to a rectangle of interest (ROI) using the prc parameter. The ROI sub-rectangle must be fully contained in the bounds of the bitmap. Specifying a NULL ROI implies that the whole bitmap should be returned. The caller controls the memory management and must provide an output buffer (pbBuffer) for the results of the copy along with the buffer's bounds (cbBufferSize). The cbStride parameter defines the count of bytes between two vertically adjacent pixels in the output buffer. The caller must ensure that there is sufficient buffer to complete the call based on the width, height and pixel format of the bitmap and the sub-rectangle provided to the copy method. If the caller needs to perform numerous copies of an expensive IWICBitmapSource such as a JPEG, it is recommended to create an in-memory IWICBitmap first.

Codec Developer Remarks

The callee must only write to the first (prc->Width*bitsperpixel+7)/8 bytes of each line of the output buffer (in this case, a line is a consecutive string of cbStride bytes). Read more on docs.microsoft.com. The IID guid for this interface. {00000120-a8f2-4877-ba0a-fd2b6645fb94} Initializes the color context from the given file. Type: LPCWSTR The name of the file. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Once a color context has been initialized, it can't be re-initialized. Initializes the color context from a memory block. Type: const BYTE* The buffer used to initialize the IWICColorContext. Read more on docs.microsoft.com. Type: UINT The size of the pbBuffer buffer. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Once a color context has been initialized, it can't be re-initialized. Initializes the color context using an Exchangeable Image File (EXIF) color space. Type: UINT The value of the EXIF color space. This doc was truncated. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Once a color context has been initialized, it can't be re-initialized. Retrieves the color context type. (IWICColorContext.GetType) Type: WICColorContextType* A pointer that receives the WICColorContextType of the color context. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the color context profile. Type: UINT The size of the pbBuffer buffer. Read more on docs.microsoft.com. Type: BYTE* A pointer that receives the color context profile. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the actual buffer size needed to retrieve the entire color context profile. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Only use this method if the context type is WICColorContextProfile. Calling this method with pbBuffer set to NULL will cause it to return the required buffer size in pcbActual. Read more on docs.microsoft.com. Retrieves the Exchangeable Image File (EXIF) color space color context. Type: UINT* A pointer that receives the EXIF color space color context. This doc was truncated. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This method should only be used when IWICColorContext::GetType indicates WICColorContextExifColorSpace. The IID guid for this interface. {3c613a02-34b2-44ea-9a7c-45aea9c6fd6d} Initializes an IWICColorTransform with a IWICBitmapSource and transforms it from one IWICColorContext to another. Type: IWICBitmapSource* The bitmap source used to initialize the color transform. Read more on docs.microsoft.com. Type: IWICColorContext* The color context source. Read more on docs.microsoft.com. Type: IWICColorContext* The color context destination. Read more on docs.microsoft.com. Type: REFWICPixelFormatGUID The GUID of the desired pixel format. This parameter is limited to a subset of the native WIC pixel formats, see Remarks for a list. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The currently supported formats for the pIContextSource and pixelFmtDest parameters are: This doc was truncated. Read more on docs.microsoft.com. The IID guid for this interface. {b66f034f-d0e2-40ab-b436-6de39e321a94} Retrieves the component's WICComponentType. Type: WICComponentType* A pointer that receives the WICComponentType. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the component's class identifier (CLSID) Type: CLSID* A pointer that receives the component's CLSID. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the signing status of the component. Type: DWORD* A pointer that receives the WICComponentSigning status of the component. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Signing is unused by WIC. Therefore, all components WICComponentSigned. This function can be used to determine whether a component has no binary component or has been added to the disabled components list in the registry. Read more on docs.microsoft.com. Retrieves the name of component's author. Type: UINT The size of the wzAuthor buffer. Read more on docs.microsoft.com. Type: WCHAR* A pointer that receives the name of the component's author. The locale of the string depends on the value that the codec wrote to the registry at install time. For built-in components, these strings are always in English. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the actual length of the component's authors name. The author name is optional; if an author name is not specified by the component, the length returned is 0. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If cchAuthor is 0 and wzAuthor is NULL, the required buffer size is returned in pccchActual. Retrieves the vendor GUID. Type: GUID* A pointer that receives the component's vendor GUID. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the component's version. Type: UINT The size of the wzVersion buffer. Read more on docs.microsoft.com. Type: WCHAR* A pointer that receives a culture invariant string of the component's version. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the actual length of the component's version. The version is optional; if a value is not specified by the component, the length returned is 0. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. All built-in components return "1.0.0.0", except for pixel formats, which do not have a version. If cchAuthor is 0 and wzAuthor is NULL, the required buffer size is returned in pccchActual. Read more on docs.microsoft.com. Retrieves the component's specification version. Type: UINT The size of the wzSpecVersion buffer. Read more on docs.microsoft.com. Type: WCHAR* When this method returns, contain a culture invariant string of the component's specification version. The version form is NN.NN.NN.NN. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the actual length of the component's specification version. The specification version is optional; if a value is not specified by the component, the length returned is 0. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. All built-in components return "1.0.0.0", except for pixel formats, which do not have a spec version. If cchAuthor is 0 and wzAuthor is NULL, the required buffer size is returned in pccchActual. Read more on docs.microsoft.com. Retrieves the component's friendly name, which is a human-readable display name for the component. Type: UINT The size of the wzFriendlyName buffer. Read more on docs.microsoft.com. Type: WCHAR* A pointer that receives the friendly name of the component. The locale of the string depends on the value that the codec wrote to the registry at install time. For built-in components, these strings are always in English. Read more on docs.microsoft.com. Type: UINT* A pointer that receives the actual length of the component's friendly name. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If cchFriendlyName is 0 and wzFriendlyName is NULL, the required buffer size is returned in pccchActual. The IID guid for this interface. {23bc3f0a-698b-4357-886b-f24d50671334} Finalizes metadata changes to the image stream. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If the commit fails and returns WINCODEC_ERR_STREAMNOTAVAILABLE, ensure that the image decoder was loaded using the WICDecodeMetadataCacheOnDemand option. A fast metadata encoder is not supported when the decoder is created using the WICDecodeMetadataCacheOnLoad option. If the commit fails for any reason, you will need to re-encode the image to ensure the new metadata is added to the image. Read more on docs.microsoft.com. Retrieves a metadata query writer for fast metadata encoding. Type: IWICMetadataQueryWriter** When this method returns, contains a pointer to the fast metadata encoder's metadata query writer. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {b84e2c09-78c9-4ac4-8bd3-524ae1663a2f} Initializes the format converter. Type: IWICBitmapSource* The input bitmap to convert Read more on docs.microsoft.com. Type: REFWICPixelFormatGUID The destination pixel format GUID. Read more on docs.microsoft.com. Type: WICBitmapDitherType The WICBitmapDitherType used for conversion. Read more on docs.microsoft.com. Type: IWICPalette* The palette to use for conversion. Read more on docs.microsoft.com. Type: double The alpha threshold to use for conversion. Read more on docs.microsoft.com. Type: WICBitmapPaletteType The palette translation type to use for conversion. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If you do not have a predefined palette, you must first create one. Use InitializeFromBitmap to create the palette object, then pass it in along with your other parameters. dither, pIPalette, alphaThresholdPercent, and paletteTranslate are used to mitigate color loss when converting to a reduced bit-depth format. For conversions that do not need these settings, the following parameters values should be used: dither set to WICBitmapDitherTypeNone, pIPalette set to NULL, alphaThresholdPercent set to 0.0f, and paletteTranslate set to WICBitmapPaletteTypeCustom. The basic algorithm involved when using an ordered dither requires a fixed palette, found in the WICBitmapPaletteType enumeration, in a specific order. Often, the actual palette provided for the output may have a different ordering or some slight variation in the actual colors. This is the case when using the Microsoft Windows palette which has slight differences among versions of Windows.To provide for this, a palette and a palette translation are given to the format converter. The pIPalette is the actual destination palette to be used and the paletteTranslate is a fixed palette. Once the conversion is complete, the colors are mapped from the fixed palette to the actual colors in pIPalette using a nearest color matching algorithm. If colors in pIPalette do not closely match those in paletteTranslate, the mapping may produce undesirable results. WICBitmapDitherTypeOrdered4x4 can be useful in format conversions from 8-bit formats to 5- or 6-bit formats as there is no way to accurately convert color data. WICBitmapDitherTypeErrorDiffusion selects the error diffusion algorithm and may be used with any palette. If an arbitrary palette is provided, WICBitmapPaletteCustom should be passed in as the paletteTranslate. Error diffusion often provides superior results compared to the ordered dithering algorithms especially when combined with the optimized palette generation functionality on the IWICPalette. When converting a bitmap which has an alpha channel, such as a Portable Network Graphics (PNG), to 8bpp, the alpha channel is normally ignored. Any pixels which were transparent in the original bitmap show up as black in the final output because both transparent and black have pixel values of zero in the respective formats. Some 8bpp content can contains an alpha color; for instance, the Graphics Interchange Format (GIF) format allows for a single palette entry to be used as a transparent color. For this type of content, alphaThresholdPercent specifies what percentage of transparency should map to the transparent color. Because the alpha value is directly proportional to the opacity (not transparency) of a pixel, the alphaThresholdPercent indicates what level of opacity is mapped to the fully transparent color. For instance, 9.8% implies that any pixel with an alpha value of less than 25 will be mapped to the transparent color. A value of 100% maps all pixels which are not fully opaque to the transparent color. Note that the palette should provide a transparent color. If it does not, the 'transparent' color will be the one closest to zero - often black. Read more on docs.microsoft.com. Determines if the source pixel format can be converted to the destination pixel format. Type: REFWICPixelFormatGUID The source pixel format. Read more on docs.microsoft.com. Type: REFWICPixelFormatGUID The destination pixel format. Read more on docs.microsoft.com. Type: BOOL* A pointer that receives a value indicating whether the source pixel format can be converted to the destination pixel format. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {00000301-a8f2-4877-ba0a-fd2b6645fb94} Creates a new instance of the IWICBitmapDecoder class based on the given file. Type: LPCWSTR A pointer to a null-terminated string that specifies the name of an object to create or open. Read more on docs.microsoft.com. Type: const GUID* The GUID for the preferred decoder vendor. Use NULL if no preferred vendor. Read more on docs.microsoft.com. Type: DWORD The access to the object, which can be read, write, or both. This doc was truncated. Read more on docs.microsoft.com. Type: WICDecodeOptions The WICDecodeOptions to use when creating the decoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of the IWICBitmapDecoder class based on the given IStream. Type: IStream* The stream to create the decoder from. Read more on docs.microsoft.com. Type: const GUID* The GUID for the preferred decoder vendor. Use NULL if no preferred vendor. Read more on docs.microsoft.com. Type: WICDecodeOptions The WICDecodeOptions to use when creating the decoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of the IWICBitmapDecoder based on the given file handle. Type: ULONG_PTR The file handle to create the decoder from. Read more on docs.microsoft.com. Type: const GUID* The GUID for the preferred decoder vendor. Use NULL if no preferred vendor. Read more on docs.microsoft.com. Type: WICDecodeOptions The WICDecodeOptions to use when creating the decoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. When a decoder is created using this method, the file handle must remain alive during the lifetime of the decoder. Creates a new instance of the IWICComponentInfo class for the given component class identifier (CLSID). Type: REFCLSID The CLSID for the desired component. Read more on docs.microsoft.com. Type: IWICComponentInfo** A pointer that receives a pointer to a new IWICComponentInfo. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of IWICBitmapDecoder. Type: REFGUID The GUID for the desired container format. This doc was truncated. Read more on docs.microsoft.com. Type: const GUID* The GUID for the preferred encoder vendor. This doc was truncated. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Other values may be available for both guidContainerFormat and pguidVendor depending on the installed WIC-enabled encoders. The values listed are those that are natively supported by the operating system. Read more on docs.microsoft.com. Creates a new instance of the IWICBitmapEncoder class. Type: REFGUID The GUID for the desired container format. This doc was truncated. Read more on docs.microsoft.com. Type: const GUID* The GUID for the preferred encoder vendor. This doc was truncated. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Other values may be available for both guidContainerFormat and pguidVendor depending on the installed WIC-enabled encoders. The values listed are those that are natively supported by the operating system. Read more on docs.microsoft.com. Creates a new instance of the IWICPalette class. Type: IWICPalette** A pointer that receives a pointer to a new IWICPalette. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of the IWICFormatConverter class. Type: IWICFormatConverter** A pointer that receives a pointer to a new IWICFormatConverter. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of an IWICBitmapScaler. Type: IWICBitmapScaler** A pointer that receives a pointer to a new IWICBitmapScaler. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of an IWICBitmapClipper object. Type: IWICBitmapClipper** A pointer that receives a pointer to a new IWICBitmapClipper. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of an IWICBitmapFlipRotator object. Type: IWICBitmapFlipRotator** A pointer that receives a pointer to a new IWICBitmapFlipRotator. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of the IWICStream class. Type: IWICStream** A pointer that receives a pointer to a new IWICStream. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of the IWICColorContext class. Type: IWICColorContext** A pointer that receives a pointer to a new IWICColorContext. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of the IWICColorTransform class. Type: IWICColorTransform** A pointer that receives a pointer to a new IWICColorTransform. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates an IWICBitmap object. Type: UINT The width of the new bitmap . Read more on docs.microsoft.com. Type: UINT The height of the new bitmap. Read more on docs.microsoft.com. Type: REFWICPixelFormatGUID The pixel format of the new bitmap. Read more on docs.microsoft.com. Type: WICBitmapCreateCacheOption The cache creation options of the new bitmap. This can be one of the values in the WICBitmapCreateCacheOption enumeration. This doc was truncated. Read more on docs.microsoft.com. Type: IWICBitmap** A pointer that receives a pointer to the new bitmap. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a IWICBitmap from a IWICBitmapSource. Type: IWICBitmapSource* The IWICBitmapSource to create the bitmap from. Read more on docs.microsoft.com. Type: WICBitmapCreateCacheOption The cache options of the new bitmap. This can be one of the values in the WICBitmapCreateCacheOption enumeration. This doc was truncated. Read more on docs.microsoft.com. Type: IWICBitmap** A pointer that receives a pointer to the new bitmap. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates an IWICBitmap from a specified rectangle of an IWICBitmapSource. Type: IWICBitmapSource* The IWICBitmapSource to create the bitmap from. Read more on docs.microsoft.com. Type: UINT The horizontal coordinate of the upper-left corner of the rectangle. Read more on docs.microsoft.com. Type: UINT The vertical coordinate of the upper-left corner of the rectangle. Read more on docs.microsoft.com. Type: UINT The width of the rectangle and the new bitmap. Read more on docs.microsoft.com. Type: UINT The height of the rectangle and the new bitmap. Read more on docs.microsoft.com. Type: IWICBitmap** A pointer that receives a pointer to the new bitmap. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Providing a rectangle that is larger than the source will produce undefined results. This method always creates a separate copy of the source image, similar to the cache option WICBitmapCacheOnLoad. Read more on docs.microsoft.com. Creates an IWICBitmap from a memory block. Type: UINT The width of the new bitmap. Read more on docs.microsoft.com. Type: UINT The height of the new bitmap. Read more on docs.microsoft.com. Type: REFWICPixelFormatGUID The pixel format of the new bitmap. For valid pixel formats, see Native Pixel Formats. Read more on docs.microsoft.com. Type: UINT The number of bytes between successive scanlines in pbBuffer. Read more on docs.microsoft.com. Type: UINT The size of pbBuffer. Read more on docs.microsoft.com. Type: BYTE* The buffer used to create the bitmap. Read more on docs.microsoft.com. Type: IWICBitmap** A pointer that receives a pointer to the new bitmap. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The size of the IWICBitmap to be created must be smaller than or equal to the size of the image in pbBuffer. The stride of the destination bitmap will equal the stride of the source data, regardless of the width and height specified. The pixelFormat parameter defines the pixel format for both the input data and the output bitmap. Read more on docs.microsoft.com. Creates an IWICBitmap from a bitmap handle. Type: HBITMAP A bitmap handle to create the bitmap from. Read more on docs.microsoft.com. Type: HPALETTE A palette handle used to create the bitmap. Read more on docs.microsoft.com. Type: WICBitmapAlphaChannelOption The alpha channel options to create the bitmap. Read more on docs.microsoft.com. Type: IWICBitmap** A pointer that receives a pointer to the new bitmap. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. For a non-palletized bitmap, set NULL for the hPalette parameter. Creates an IWICBitmap from an icon handle. Type: HICON The icon handle to create the new bitmap from. Read more on docs.microsoft.com. Type: IWICBitmap** A pointer that receives a pointer to the new bitmap. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates an IEnumUnknown object of the specified component types. Type: DWORD The types of WICComponentType to enumerate. Read more on docs.microsoft.com. Type: DWORD The WICComponentEnumerateOptions used to enumerate the given component types. Read more on docs.microsoft.com. Type: IEnumUnknown** A pointer that receives a pointer to a new component enumerator. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Component types must be enumerated separately. Combinations of component types and WICAllComponents are unsupported. Creates a new instance of the fast metadata encoder based on the given IWICBitmapDecoder. Type: IWICBitmapDecoder* The decoder to create the fast metadata encoder from. Read more on docs.microsoft.com. Type: IWICFastMetadataEncoder** When this method returns, contains a pointer to the new IWICFastMetadataEncoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The Windows provided codecs do not support fast metadata encoding at the decoder level, and only support fast metadata encoding at the frame level. To create a fast metadata encoder from a frame, see CreateFastMetadataEncoderFromFrameDecode. Creates a new instance of the fast metadata encoder based on the given image frame. Type: IWICBitmapFrameDecode* The IWICBitmapFrameDecode to create the IWICFastMetadataEncoder from. Read more on docs.microsoft.com. Type: IWICFastMetadataEncoder** When this method returns, contains a pointer to a new fast metadata encoder. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. For a list of support metadata formats for fast metadata encoding, see WIC Metadata Overview. Creates a new instance of a query writer. Type: REFGUID The GUID for the desired metadata format. Read more on docs.microsoft.com. Type: const GUID* The GUID for the preferred metadata writer vendor. Use NULL if no preferred vendor. Read more on docs.microsoft.com. Type: IWICMetadataQueryWriter** When this method returns, contains a pointer to a new IWICMetadataQueryWriter. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Creates a new instance of a query writer based on the given query reader. The query writer will be pre-populated with metadata from the query reader. Type: IWICMetadataQueryReader* The IWICMetadataQueryReader to create the IWICMetadataQueryWriter from. Read more on docs.microsoft.com. Type: const GUID* The GUID for the preferred metadata writer vendor. Use NULL if no preferred vendor. Read more on docs.microsoft.com. Type: IWICMetadataQueryWriter** When this method returns, contains a pointer to a new metadata writer. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. The IID guid for this interface. {ec5ec8a9-c395-4314-9c77-54d7a935ff70} Gets the metadata query readers container format. Type: GUID* Pointer that receives the cointainer format GUID. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the current path relative to the root metadata block. Type: UINT The length of the wzNamespace buffer. Read more on docs.microsoft.com. Type: WCHAR* Pointer that receives the current namespace location. Read more on docs.microsoft.com. Type: UINT* The actual buffer length that was needed to retrieve the current namespace location. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If you pass NULL to wzNamespace, GetLocation ignores cchMaxLength and returns the required buffer length to store the path in the variable that pcchActualLength points to. If the query reader is relative to the top of the metadata hierarchy, it will return a single-char string. If the query reader is relative to a nested metadata block, this method will return the path to the current query reader. Read more on docs.microsoft.com. Retrieves the metadata block or item identified by a metadata query expression. Type: LPCWSTR The query expression to the requested metadata block or item. Read more on docs.microsoft.com. Type: PROPVARIANT* When this method returns, contains the metadata block or item requested. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. GetMetadataByName uses metadata query expressions to access embedded metadata. For more information on the metadata query language, see the Metadata Query Language Overview. If multiple blocks or items exist that are expressed by the same query expression, the first metadata block or item found will be returned. Read more on docs.microsoft.com. Gets an enumerator of all metadata items at the current relative location within the metadata hierarchy. Type: IEnumString** A pointer to a variable that receives a pointer to the IEnumString interface for the enumerator that contains query strings that can be used in the current IWICMetadataQueryReader. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The retrieved enumerator only contains query strings for the metadata blocks and items in the current level of the hierarchy. The IID guid for this interface. {30989668-e1c9-4597-b395-458eedb808df} Sets a metadata item to a specific location. Type: LPCWSTR The name of the metadata item. Read more on docs.microsoft.com. Type: const PROPVARIANT* The metadata to set. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. SetMetadataByName uses metadata query expressions to remove metadata. For more information on the metadata query language, see the Metadata Query Language Overview. If the value set is a nested metadata block then use variant type VT_UNKNOWN and pvarValue pointing to the IWICMetadataQueryWriter of the new metadata block. The ordering of metadata items is at the discretion of the query writer since relative locations are not specified. Read more on docs.microsoft.com. Removes a metadata item from a specific location using a metadata query expression. Type: LPCWSTR The name of the metadata item to remove. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. RemoveMetadataByName uses metadata query expressions to remove metadata. For more information on the metadata query language, see the Metadata Query Language Overview. If the metadata item is a metadata block, it is removed from the metadata hierarchy. Read more on docs.microsoft.com. The IID guid for this interface. {a721791a-0def-4d06-bd91-2118bf1db10b} Initializes the palette to one of the pre-defined palettes specified by WICBitmapPaletteType and optionally adds a transparent color. Type: WICBitmapPaletteType The desired pre-defined palette type. Read more on docs.microsoft.com. Type: BOOL The optional transparent color to add to the palette. If no transparent color is needed, use 0. When initializing to a grayscale or black and white palette, set this parameter to FALSE. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If a transparent color is added to a palette, the palette is no longer predefined and is returned as WICBitmapPaletteTypeCustom. For palettes with less than 256 entries, the transparent entry is added to the end of the palette (that is, a 16-color palette becomes a 17-color palette). For palettes with 256 colors, the transparent palette entry will replace the last entry in the pre-defined palette. Initializes a palette to the custom color entries provided. Type: WICColor* Pointer to the color array. Read more on docs.microsoft.com. Type: UINT The number of colors in pColors. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. If a transparent color is required, provide it as part of the custom entries. To add a transparent value to the palette, its alpha value must be 0 (0x00RRGGBB). The entry count is limited to 256. Read more on docs.microsoft.com. Initializes a palette using a computed optimized values based on the reference bitmap. Type: IWICBitmapSource* Pointer to the source bitmap. Read more on docs.microsoft.com. Type: UINT The number of colors to initialize the palette with. Read more on docs.microsoft.com. Type: BOOL A value to indicate whether to add a transparent color. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The resulting palette contains the specified number of colors which best represent the colors present in the bitmap. The algorithm operates on the opaque RGB color value of each pixel in the reference bitmap and hence ignores any alpha values. If a transparent color is required, set the fAddTransparentColor parameter to TRUE and one fewer optimized color will be computed, reducing the colorCount, and a fully transparent color entry will be added. Initialize the palette based on a given palette. Type: IWICPalette* Pointer to the source palette. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves the WICBitmapPaletteType that describes the palette. Type: WICBitmapPaletteType* Pointer that receives the palette type of the bimtap. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. WICBitmapPaletteCustom is used for palettes initialized from both InitializeCustom and InitializeFromBitmap. There is no distinction is made between optimized and custom palettes. Retrieves the number of colors in the color table. Type: UINT* Pointer that receives the number of colors in the color table. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Fills out the supplied color array with the colors from the internal color table. The color array should be sized according to the return results from GetColorCount. Type: UINT The size of the pColors array. Read more on docs.microsoft.com. Type: WICColor* Pointer that receives the colors of the palette. Read more on docs.microsoft.com. Type: UINT* The actual size needed to obtain the palette colors. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Retrieves a value that describes whether the palette is black and white. Type: BOOL* A pointer to a variable that receives a boolean value that indicates whether the palette is black and white. TRUE indicates that the palette is black and white; otherwise, FALSE. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. A palette is considered to be black and white only if it contains exactly two entries, one full black (0xFF000000) and one full white (0xFFFFFFF). Retrieves a value that describes whether a palette is grayscale. Type: BOOL* A pointer to a variable that receives a boolean value that indicates whether the palette is grayscale. TRUE indicates that the palette is grayscale; otherwise FALSE. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. A palette is considered grayscale only if, for every entry, the alpha value is 0xFF and the red, green and blue values match. The IID guid for this interface. {00000040-a8f2-4877-ba0a-fd2b6645fb94} Initializes a stream from another stream. Access rights are inherited from the underlying stream. Type: IStream* The initialize stream. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. Learn more about this API from docs.microsoft.com. Initializes a stream from a particular file. Type: LPCWSTR The file used to initialize the stream. Read more on docs.microsoft.com. Type: DWORD The desired file access mode. This doc was truncated. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The IWICStream interface methods do not enable you to provide a file sharing option. To create a shared file stream for an image, use the SHCreateStreamOnFileEx function. This stream can then be used to create an IWICBitmapDecoder using the CreateDecoderFromStream method. Read more on docs.microsoft.com. Initializes a stream to treat a block of memory as a stream. The stream cannot grow beyond the buffer size. Type: BYTE* Pointer to the buffer used to initialize the stream. Read more on docs.microsoft.com. Type: DWORD The size of buffer. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. This method should be avoided whenever possible. The caller is responsible for ensuring the memory block is valid for the lifetime of the stream when using InitializeFromMemory. A workaround for this behavior is to create an IStream and use InitializeFromIStream to create the IWICStream. If you require a growable memory stream, use CreateStreamOnHGlobal. Read more on docs.microsoft.com. Initializes the stream as a substream of another stream. Type: IStream* Pointer to the input stream. Read more on docs.microsoft.com. Type: ULARGE_INTEGER The stream offset used to create the new stream. Read more on docs.microsoft.com. Type: ULARGE_INTEGER The maximum size of the stream. Read more on docs.microsoft.com. Type: HRESULT If this method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. The stream functions with its own stream position, independent of the underlying stream but restricted to a region. All seek positions are relative to the sub region. It is allowed, though not recommended, to have multiple writable sub streams overlapping the same range. The IID guid for this interface. {135ff860-22b7-4ddf-b0f6-218f4f299a43} Specifies the desired alpha channel usage. Learn more about this API from docs.microsoft.com. Use alpha channel. Use a pre-multiplied alpha channel. Ignore alpha channel. Specifies the desired cache usage. The CreateBitmap of the IWICImagingFactory interface does not support WICBitmapNoCache when the pixelFormat is a native pixel format provided by Windows Imaging Component (WIC). Do not cache the bitmap. Cache the bitmap when needed. Cache the bitmap at initialization. Specifies the type of dither algorithm to apply when converting between image formats. Learn more about this API from docs.microsoft.com. A solid color algorithm without dither. A solid color algorithm without dither. A 4x4 ordered dither algorithm. An 8x8 ordered dither algorithm. A 16x16 ordered dither algorithm. A 4x4 spiral dither algorithm. An 8x8 spiral dither algorithm. A 4x4 dual spiral dither algorithm. An 8x8 dual spiral dither algorithm. An error diffusion algorithm. Specifies the cache options available for an encoder. Learn more about this API from docs.microsoft.com. The encoder is cached in memory. This option is not supported. The encoder is cached to a temporary file. This option is not supported. The encoder is not cached. Specifies the sampling or filtering mode to use when scaling an image. Learn more about this API from docs.microsoft.com. A nearest neighbor interpolation algorithm. Also known as nearest pixel or point interpolation. The output pixel is assigned the value of the pixel that the point falls within. No other pixels are considered. Read more on docs.microsoft.com. A bilinear interpolation algorithm. The output pixel values are computed as a weighted average of the nearest four pixels in a 2x2 grid. Read more on docs.microsoft.com. A bicubic interpolation algorithm. Destination pixel values are computed as a weighted average of the nearest sixteen pixels in a 4x4 grid. Read more on docs.microsoft.com. A Fant resampling algorithm. Destination pixel values are computed as a weighted average of the all the pixels that map to the new pixel. Read more on docs.microsoft.com. A high quality bicubic interpolation algorithm. Destination pixel values are computed using a much denser sampling kernel than regular cubic. The kernel is resized in response to the scale factor, making it suitable for downscaling by factors greater than 2.
Note  This value is supported beginning with Windows 10.
 
 Read more on docs.microsoft.com. Specifies the type of palette used for an indexed image format. Learn more about this API from docs.microsoft.com. An arbitrary custom palette provided by caller. An optimal palette generated using a median-cut algorithm. Derived from the colors in an image. A black and white palette. A palette that has its 8-color on-off primaries and the 16 system colors added. With duplicates removed, 16 colors are available. A palette that has 3 intensity levels of each primary: 27-color on-off primaries and the 16 system colors added. With duplicates removed, 35 colors are available. A palette that has 4 intensity levels of each primary: 64-color on-off primaries and the 16 system colors added. With duplicates removed, 72 colors are available. A palette that has 5 intensity levels of each primary: 125-color on-off primaries and the 16 system colors added. With duplicates removed, 133 colors are available. A palette that has 6 intensity levels of each primary: 216-color on-off primaries and the 16 system colors added. With duplicates removed, 224 colors are available. This is the same as WICBitmapPaletteFixedHalftoneWeb. A palette that has 6 intensity levels of each primary: 216-color on-off primaries and the 16 system colors added. With duplicates removed, 224 colors are available. This is the same as WICBitmapPaletteTypeFixedHalftone216. A palette that has its 252-color on-off primaries and the 16 system colors added. With duplicates removed, 256 colors are available. A palette that has its 256-color on-off primaries and the 16 system colors added. With duplicates removed, 256 colors are available. A palette that has 4 shades of gray. A palette that has 16 shades of gray. A palette that has 256 shades of gray. Contains members that identify a pattern within an image file which can be used to identify a particular format. Learn more about this API from docs.microsoft.com. Type: ULARGE_INTEGER The offset the pattern is located in the file. Read more on docs.microsoft.com. Type: ULONG The pattern length. Read more on docs.microsoft.com. Type: BYTE* The actual pattern. Read more on docs.microsoft.com. Type: BYTE* The pattern mask. Read more on docs.microsoft.com. Type: BOOL The end of the stream. Read more on docs.microsoft.com. Specifies the flip and rotation transforms. Learn more about this API from docs.microsoft.com. A rotation of 0 degrees. A clockwise rotation of 90 degrees. A clockwise rotation of 180 degrees. A clockwise rotation of 270 degrees. A horizontal flip. Pixels are flipped around the vertical y-axis. A vertical flip. Pixels are flipped around the horizontal x-axis. Specifies the color context types. Learn more about this API from docs.microsoft.com. An uninitialized color context. A color context that is a full ICC color profile. A color context that is one of a number of set color spaces (sRGB, AdobeRGB) that are defined in the EXIF specification. Specifies the type of Windows Imaging Component (WIC) component. Learn more about this API from docs.microsoft.com. A WIC decoder. A WIC encoder. A WIC pixel converter. A WIC metadata reader. A WIC metadata writer. A WIC pixel format. All WIC components. Specifies decode options. Learn more about this API from docs.microsoft.com. Cache metadata when needed. Cache metadata when decoder is loaded. Represents a rectangle for Windows Imaging Component (WIC) API. Learn more about this API from docs.microsoft.com. Type: INT The horizontal coordinate of the rectangle. Read more on docs.microsoft.com. Type: INT The vertical coordinate of the rectangle. Read more on docs.microsoft.com. Type: INT The width of the rectangle. Read more on docs.microsoft.com. Type: INT The height of the rectangle. Read more on docs.microsoft.com. Gets the length of the BSTR in characters. The COLORREF value is used to specify an RGB color. When specifying an explicit [RGB](/windows/desktop/api/Wingdi/nf-wingdi-rgb) color, the **COLORREF** value has the following hexadecimal form: `0x00bbggrr` The low-order byte contains a value for the relative intensity of red; the second byte contains a value for green; and the third byte contains a value for blue. The high-order byte must be zero. The maximum value for a single byte is 0xFF. To create a **COLORREF** color value, use the [RGB](/windows/desktop/api/Wingdi/nf-wingdi-rgb) macro. To extract the individual values for the red, green, and blue components of a color value, use the [**GetRValue**](/windows/desktop/api/Wingdi/nf-wingdi-getrvalue), [GetGValue](/windows/desktop/api/Wingdi/nf-wingdi-getgvalue), and [GetBValue](/windows/desktop/api/Wingdi/nf-wingdi-getbvalue) macros, respectively. Read more on docs.microsoft.com. The DECIMAL structure represents a decimal data type that provides a sign and scale for a number. Reserved. The high 32 bits of the number. 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. Places the window at the top of the Z order. Learn more about this API from docs.microsoft.com. Places the window at the bottom of the Z order. If the hWnd parameter identifies a topmost window, the window loses its topmost status and is placed at the bottom of all other windows. Learn more about this API from docs.microsoft.com. A pointer to a null-terminated, constant, ANSI 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, decoding as UTF-8. A , or if is . Returns a span of the characters in this string, up to the first null character (exclusive). 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). 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. The length of the inline array. Gets this inline array as a span. ⚠ Important ⚠: When this struct is on the stack, do not let the returned span outlive the stack frame that defines it. Gets this inline array as a span. ⚠ Important ⚠: When this struct is on the stack, do not let the returned span outlive the stack frame that defines it. The length of the inline array. Gets a ref to an individual element of the inline array. ⚠ Important ⚠: When this struct is on the stack, do not let the returned reference outlive the stack frame that defines it. Gets this inline array as a span. ⚠ Important ⚠: When this struct is on the stack, do not let the returned span outlive the stack frame that defines it. Gets this inline array as a span. ⚠ Important ⚠: When this struct is on the stack, do not let the returned span outlive the stack frame that defines it. The length of the inline array. Gets a ref to an individual element of the inline array. ⚠ Important ⚠: When this struct is on the stack, do not let the returned reference outlive the stack frame that defines it. Gets this inline array as a span. ⚠ Important ⚠: When this struct is on the stack, do not let the returned span outlive the stack frame that defines it. Gets this inline array as a span. ⚠ Important ⚠: When this struct is on the stack, do not let the returned span outlive the stack frame that defines it. Copies the fixed array to a new string up to the specified length regardless of whether there are null terminating characters. Thrown when is less than 0 or greater than . Copies the fixed array to a new string, stopping before the first null terminator character or at the end of the fixed array (whichever is shorter). Represents a Win32 handle that can be closed with . Represents a Win32 handle that can be closed with . Represents a Win32 handle that can be closed with . The IID guid for this interface. The reference that is returned comes from a permanent memory address, and is therefore safe to convert to a pointer and pass around or hold long-term. Non generic interface that allows constraining against a COM wrapper type directly. COM structs should implement . Represents a Win32 handle that can be closed with . Specifies the geographical location class. Learn more about this API from docs.microsoft.com. Class for nation geographical location identifiers. Class for region geographical location identifiers. Starting with Windows 8: Class for all geographical location identifiers.