# Subscribing to State Changes of a Remote Object<a name="EN-US_TOPIC_0000001104030756"></a>
# Subscribing to State Changes of a Remote Object
IPC/RPC allows you to subscribe to the state changes of a remote stub object. When the remote stub object dies, a death notification will be sent to your local proxy object. You can also unsubscribe from the state changes if they are no longer needed. Such subscription and unsubscription are controlled by APIs. To be specific, you need to implement the **IRemoteObject.DeathRecipient** interface and the **onRemoteDied** method to clear resources. This callback is invoked when the process accommodating the remote stub object dies, or the device accommodating the remote stub object leaves the network. It is worth noting that these APIs should be called in the following order: The proxy object must first subscribe to death notifications of the stub object. If the stub object is in the normal state, the proxy object can cancel the subscription as required. If the process of the stub object exits or the device hosting the stub object goes offline, subsequent operations customized by the proxy object will be automatically triggered.
IPC/RPC allows you to subscribe to the state changes of a remote stub object. When the remote stub object dies, a death notification will be sent to your local proxy object. Such subscription and unsubscription are controlled by APIs. To be specific, you need to implement the **DeathRecipient** callback and the **onRemoteDied** method to clear resources. This callback is invoked when the process accommodating the remote stub object dies, or the device accommodating the remote stub object leaves the network.
**Development Using Native APIs**
Note that the proxy object must first subscribe to death notifications of the stub object. If the stub object is in the normal state, the proxy object can cancel the subscription as required. If the process of the stub object exits or the device hosting the stub object goes offline, subsequent operations customized by the proxy object will be automatically triggered.
The following APIs are used to add a recipient for death notifications of a remote stub object, remove such a recipient, and perform subsequent operations upon receiving a death notification of the remote stub object:
@@ -17,7 +17,7 @@ JS application event logging APIs are provided by the **hiAppEvent** module.
When an asynchronous callback is used, the return value can be processed directly in the callback. When a promise is used, the return value can also be processed in the promise in a similar way. For details about the result codes, see [Event Verification Result Codes](#event-verification-result-codes).
HiAppEvent provides event logging APIs for applications to log the fault, statistical, security, and user behavior events reported during running. Based on event information, you will be able to analyze the running status of your application.
The HiAppEvent module of OpenHarmony can be used to develop application event services and provide functions related to application events, including flushing application events to a disk and querying historical application event data.
## Basic Concepts
The HiAppEvent module of OpenHarmony can be used to develop application event services and provide functions related to application events, including flushing application events to a disk and querying historical application event data.
-**Logging**
**Logging**: Logs changes caused by user operations to provide service data for development, product, and O&M analysis.
Logs changes caused by user operations to provide service data for development, product, and O&M analysis.