Set up persistent connection to receive alarm/event information (supports alarm/event subscription).
LONG NET_DVR_SetupAlarmChan_V50( LONG lUserID, NET_DVR_SETUPALARM_PARAM_V50 lpSetupParam, char *pData, DWORD dwDataLen, );
[IN] Value returned by NET_DVR_Login_V40.
[IN] Arming parameters, refer to the structure NET_DVR_SETUPALARM_PARAM_V50 for details.
[IN] Alarm/event subscription conditions.
[IN] Length of alarm/event subscription conditions.
Return -1 for failure, and return other values as the handles of NET_DVR_CloseAlarmChan_V30.
If -1 is returned, you can call NET_DVR_GetLastError to get the error code.
This API supports alarm/event subscription, you can specify the types of alarm or event to be uploaded by device by setting pData and dwDataLen.