harmony 鸿蒙Unsubscribing from Common Events in C

2025-06-06
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Unsubscribing from Common Events in C

When to Use

After completing service requirements, subscribers need to unsubscribe from common events.

Available APIs

For details about the APIs, see CommonEvent.

API	Description
CommonEvent_ErrCode OH_CommonEvent_UnSubscribe(const CommonEvent_Subscriber* subscriber)	Creates the subscriber information.

How to Develop

Reference header files.

   #include <cstdint>
   #include "hilog/log.h"
   #include "BasicServicesKit/oh_commonevent.h"

Add dynamic link libraries to the CMake script.

   target_link_libraries(entry PUBLIC
       libace_napi.z.so
       libhilog_ndk.z.so
       libohcommonevent.so
   )

Unsubscribe from a common event.

After a subscriber subscribes to a common event and meets service requirements, the subscriber can use OH_CommonEvent_UnSubscribe to unsubscribe from the event.

   void Unsubscribe(CommonEvent_Subscriber* subscriber) {
       // Unsubscribe from a common event by passing a subscriber.
       int32_t ret = OH_CommonEvent_UnSubscribe(subscriber);
       OH_LOG_Print(LOG_APP, LOG_INFO, 1, "CES_TEST", "OH_CommonEvent_UnSubscribe ret <%{public}d>.", ret);
   }