# Subsessions Subsessions allow you to create separate sessions that users can choose to join. This is similar to the breakout room feature in Zoom Meetings. A Video SDK for Windows session can have up to 50 subsessions. ## Call the subsession helper After joining a session, call `getSubSessionHelper` to get the subsession helper. This method can be called only by the session's host and manager. ```cpp IZoomVideoSDK* videoSDK = CreateZoomVideoSDKObj(); if (videoSDK) { IZoomVideoSDKSubSessionHelper* subsessionHelper = videoSDK->getSubSessionHelper(); if (subsessionHelper) { // Continue with subsession methods here } } ``` ## Configure subsessions Sessions can be configured only by the host. To prepare the subsession list, call the following methods as needed: - `addSubSessionToPreList(const zchar_t* sSubSessionName);` - Add a subsession to the prepared list. - `getSubSessionPreList` - Get the subsession prepared list. - `removeSubSessionFromPreList(const zchar_t* sSubSessionName)` - Remove any subsession from the added prepared list. - `clearSubSessionPreList` - Remove all subsessions from the prepared list. ```cpp ZoomVideoSDKErrors err = subsessionHelper->addSubSessionToPreList(L"Subsession to add"); IVideoSDKVector* list = subsessionHelper->getSubSessionPreList(); err = subsessionHelper->removeSubSessionFromPreList(L"Subsession to remove"); err = subsessionHelper->clearSubSessionPreList(); ``` Once you have created the prepared list, call the following methods as needed to create the committed list of subsessions: - `commitSubSessionList` - Withdraw all committed subsession lists and commit the prepared list. - `getCommittedSubSessionList` - Get the committed subsession list. Calling this right after `commitSubSessionList` will not work, as you will have to wait for the `onSubSessionStatusChanged` callback to know the committed list was created. - `withdrawSubSessionList` - Withdraw the committed subsession list. The SDK calls `onSubSessionStatusChanged` whenever the committed subsession lists change. The callback returns a `ZoomVideoSDKSubSessionStatus` value and a list of `ISubSessionKit` objects. Each kit contains the subsession's name, ID, user list, and the `joinSubSession` method. ```cpp ZoomVideoSDKErrors err = subsessionHelper->commitSubSessionList(); IVideoSDKVector* list = subsessionHelper->getCommittedSubSessionList(); err = subsessionHelper->withdrawSubSessionList(); virtual void onSubSessionStatusChanged(ZoomVideoSDKSubSessionStatus status, IVideoSDKVector* pSubSessionKitList) { } // ZoomVideoSDKSubSessionStatus enum ZoomVideoSDKSubSessionStatus { ZoomVideoSDKSubSessionStatus_None, ZoomVideoSDKSubSessionStatus_Committed, ZoomVideoSDKSubSessionStatus_Withdrawn, ZoomVideoSDKSubSessionStatus_Started, ZoomVideoSDKSubSessionStatus_Stopping, ZoomVideoSDKSubSessionStatus_Stopped, ZoomVideoSDKSubSessionStatus_CommitFailed, ZoomVideoSDKSubSessionStatus_WithdrawFailed, ZoomVideoSDKSubSessionStatus_StartFailed, ZoomVideoSDKSubSessionStatus_StopFailed, } ``` ## Manage subsessions The host and managers can manage subsessions from the main session. The SDK calls these callbacks based on the following scenarios: - `onSubSessionManagerHandle` - The local user has the subsession manager role. - `onSubSessionParticipantHandle` - The local user has the subsession user role. We recommended that you save an instance of the `IZoomVideoSDKSubSessionManager` or `IZoomVideoSDKSubSessionParticipant` object upon receiving the respective callback, as the local user will be using its dedicated methods later on. ```cpp IZoomVideoSDKSubSessionParticipant* subsessionUser; IZoomVideoSDKSubSessionManager* subsessionManager; // Subsession manager role virtual void onSubSessionManagerHandle(IZoomVideoSDKSubSessionManager* pManager) { if (!pManager) { return; } subsessionManager = pManager; } // Subsession user role virtual void onSubSessionParticipantHandle(IZoomVideoSDKSubSessionParticipant* pUser) { if (!pUser) { return; } subsessionUser = pUser; } ``` ### Subsession manager Both the main session's host and managers hold the subsession manager role. The subsession manager role can call the following methods: - `startSubSession` - Start subsessions. - `stopSubSession` - Stop subsessions. - `isSubSessionStarted` - Determine if subsessions have started. - `broadcastMessage(const zchar_t* sMessage)` - Broadcast a message from the main session to all subsessions. Upon a successful broadcast, the SDK calls the `onBroadcastMessage` callback. ```cpp // Subsession manager role if (!subsessionManager) { return; } ZoomVideoSDKErrors startRes = subsessionManager->startSubSession(); ZoomVideoSDKErrors stopReserr = subsessionManager->stopSubSession(); bool isStarted = subsessionManager->isSubSessionStarted(); ZoomVideoSDKErrors err = subsessionManager->broadcastMessage(L"Hello World"); ``` ### Subsession user The user role can call the following methods: - `returnToMainSession` - Leave subsession and return to the main session. - `requestForHelp` - Request the manager's help. This can be used to notify and request that a manager come into the subsession. The manager will receive the `onSubSessionUserHelpRequestHandler` callback. After a manager responds to this request, the subsession user who requested help will receive the `onSubSessionUserHelpRequestResult` callback. ```cpp // Subsession user role if (!subsessionUser) { return; } ZoomVideoSDKErrors err = subsessionUser->returnToMainSession(); err = subsessionUser->requestForHelp(); ``` ### List users in a subsession To list users in a specific subsession, call `getSubSessionUserList`. Each `ISubSessionUser` object contains the local subsession user's username and GUID. When subsession users are changed, the SDK calls `onSubSessionUsersUpdate` and returns an updated `ISubSessionKit` object. ```cpp virtual void onSubSessionUsersUpdate(ISubSessionKit* pSubSessionKit) { IVideoSDKVector* users = pSubSessionKit->getSubSessionUserList(); } ``` ## Navigate subsessions Users can navigate across different subsessions. ### Join subsession Hosts and managers can't assign users to subsessions, but users can join a subsession once it has started. You can offer them a choice of which subsession to join. Upon receiving the `onSubSessionStatusChanged` callback with the `ZoomVideoSDKSubSessionStatus_Started` status, you can identify which `ISubSessionKit` they can join by calling `joinSubSession`. ```cpp ZoomVideoSDKErrors err = subsession->joinSubSession(); ``` ### Leave subsession To leave a subsession and return to the main session, call the `returnToMainSession` method from the previously saved `subsessionUser` object. ```cpp ZoomVideoSDKErrors err = subsessionUser->returnToMainSession(); ``` ## Request help All users in subsessions can request that the manager come into their subsession. The manager will be notified of these help requests and can take a follow-up action, which will also be sent back to the requester. ### Subsession user request for help To request help, the user in a subsession can send a `requestForHelp` call to notify and request that the manager come into the subsession. After the manager responds to the request, the user who requested help will receive the `onSubSessionUserHelpRequestResult` callback. ```cpp // User requested for help ZoomVideoSDKErrors err = subsessionUser->requestForHelp(); // User received back the result virtual onSubSessionUserHelpRequestResult(ZoomVideoSDKUserHelpRequestResult result) { } enum ZoomVideoSDKUserHelpRequestResult { ZoomVideoSDKUserHelpRequestResult_Idle = 0, ZoomVideoSDKUserHelpRequestResult_Busy, ZoomVideoSDKUserHelpRequestResult_Ignore, ZoomVideoSDKUserHelpRequestResult_HostAlreadyInSubSession } ``` ### Manager responds to request for help Whenever a user in a subsession requests help, the manager receives the `onSubSessionUserHelpRequest` callback. The manager can decide what to do with the received `ISubSessionUserHelpRequestHandler`, which contains the user information and the subsession name. ```cpp virtual void onSubSessionUserHelpRequest(ISubSessionUserHelpRequestHandler* pHandler) { if (!pHandler) return; const zchar_t* name = pHandler->getRequestUserName(); const zchar_t* subsessionName = pHandler->getRequestSubSessionName(); ZoomVideoSDKErrors err = pHandler->ignore(); err = pHandler->joinSubSessionByUserRequest(); } ``` ## Chat in subsession Users can [chat](/docs/video-sdk/windows/chat/) in a subsession. The SDK scopes the chat to the user's subsession. ## More details For more information, see the [IZoomVideoSDKSubSessionHelper Class Reference](https://marketplacefront.zoom.us/sdk/custom/windows/class_i_zoom_video_s_d_k_sub_session_helper.html).